TCLEE 2009: Lifeline Earthquake Engineering in a Multihazard Environment

This paper provides an overview of the Philosophy, Policies, and Criteria (PPC) along with how The Seattle Department of Transportation (SDOT) developed its seismic retrofit philosophy and established its policies upon which the criteria are based. The application of the PPC to one of the seven bridges, the Fauntleroy Expressway, will be demonstrated in this paper. The precast prestressed concrete "I" girder Fauntleroy Expressway was built in 1963 and consists of 25 spans ranging from 26 meters to 39 meters.

This paper investigates the efficiency of using elastic-gap devices (EGDs) to improve the performance of seismic-isolated bridges (SIBs) in near-fault (NF) zones. The EDG is intended to function at two performance levels under service and maximum considered design level (SDL and MCDL) NF earthquakes to reduce isolator displacements (IDs) while keeping the substructure forces (SFs) at reasonable levels. Analyses of structural models of bridges with EGDs revealed that providing EGD is beneficial for decreasing the IDs to manageable ranges while improving the performance of the isolators by reducing the heat generated.

Concrete filled steel tubes (CFT) can result in rapid and economical construction. The steel tube serves as formwork and reinforcement to the concrete fill. The fill increases compressive strength and stiffness, delays and restrains local buckling of the tube, and enhances ductility and resistance if composite action is achieved. CFT bridge piers can achieve greater strength and stiffness for a given quantity of material than normal reinforced concrete pier construction. Research is in progress to develop a practical and economical connection of circular CFT bridge piers to their footing or pile cap that provides good seismic performance. The connection is quite simple and does not require any reinforcement in the tube or dowels connecting the tube to the footing. Two variations of this connection have been developed and are discussed. Twelve large-scale experiments and limited inelastic analyses have documented the connection performance. This work shows that the CFT pier and the connection can develop the full capacity of the composite element, and provide greater ductility under inelastic seismic deformation than achieved by reinforced concrete piers.

This paper presents an overview of the site seismicity and conceptual seismic retrofit design for the Ballard Bridge. It covers the pre- and post-retrofit analysis methods which included a displacement-based methodology for the approach spans and force-based methodology for the bascule span. The development and selection of the recommended retrofit concepts for the final design is also described. Retrofit concepts are presented to address seismic deficiencies of foundation overturning, inadequate shear and flexural strengths of superstructure and substructure members, weak axis bending of floor beams, inadequacy in bearing anchorage and roadway slab joints, and lateral spreading. Retrofit alternatives include additional piling, strengthening pier diaphragms and longitudinal girders, enlarging footings, adding partial column jackets, encasing bearings, adding girder stops and shear blocks, reinforcing roadway deck joints, foundation post-tensioning, trunnion strengthening, and soil improvement.

Fragility analysis for highway bridges is essential for risk assessment of highway transportation networks exposed to seismic hazards. This study uses detailed nonlinear analytical models of a typical California box girder bridge to develop fragility curves which can be used in regional seismic risk assessment of transportation networks. The review of the bridge inventory in the state of California is first conducted using data from the 2008 National Bridge Inventory. Then a three-dimensional nonlinear finite element bridge model for the reference bridge is established and used in probabilistic seismic demand analysis. The analytical bridge model is calibrated using responses recorded during the 1979 Imperial Valley earthquake. Further component fragility analysis for the bridge model is also carried out. The component fragility curves indicate that the transverse abutment is the most vulnerable component of this bridge type at the slight damage state and the column is the most vulnerable component at the remaining damage states.

Generally deterministic design procedures are to achieve target of different structural performance under earthquake excitation are used. However, for the current levels of seismic performance, it may not be the most appropriate. In this paper, a framework of seismic risk analysis procedure which includes seismic hazard analysis, seismic vulnerability analysis and seismic risk assessment is proposed. Some suitable suite of ground motions are adopted by applying seismic hazard analysis, and the seismic vulnerability curves of bridges are depicted by using incremental dynamic analysis method (IDA). When getting the results with respect to hazard intensity-recurrence relations, a risk related matrix in which the importance of different elements of bridges and vulnerability of different elements are considered is used to get the probability of structural damage states. The evaluation using a risk assessment matrix can be referenced for seismic design or seismic mitigation. An illustrative example of this procedure is given for a long-span cable-stayed bridge and the main tower which is the most important element. It is shown that the main tower remains well under the earthquake excitation with PGA=0.3g. When PGA is about 0.6g, different countermeasures should be taken to reduce the risk of damage of the tower.

Under earthquake impacts, the failure of transportation infrastructure not only hinders normal everyday activities, but also impairs the post-disaster response and recovery, resulting substantial socio-economic losses. This paper describes recent developments of the network loss analysis (NLA) module for transportation system functionality assessment at the Mid-America Earthquake (MAE) Center. Traffic assignment models are used to evaluate the travel delays on the transportation network. The network loss analysis module is demonstrated through a case study of the real-world road network in the seismically vulnerable St. Louis metropolitan area. The MAEViz NLA module is useful to evaluate system performance of transportation systems for emergency management. The results of traffic flow and travel delays provide useful information for emergency managers and relevant government agencies to make emergency response plans for ingress and egress of impacted area (e.g. disaster relief dispatch and evacuation), and to indentify emergency routes and evaluate their performance under extreme events.

The paper aims to assess the uncertainty involved in the estimated seismic risk of highway transportation systems. For this purpose, the highway transportation network in the area of Los Angeles and Orange County in California is considered. A set of USGS hazard-consistent future earthquakes are used that approximately represent the regional seismic hazard. Post-earthquake network damage is assessed through the predictive simulation of damage states of all highway bridges under these future earthquakes. An integrated traffic assignment model is utilized to evaluate the post-event performance of the network in terms of social cost arising from driver delay and opportunity loss. Seismic risk curves are developed that show the annual exceedance probabilities of various levels of total social cost in the network due to future seismic events. Uncertainty associated with these seismic risk curves is then investigated by quantifying uncertainties involved in various components of the risk assessment framework. Such investigation is extremely important for a reliable evaluation of system risk under extreme natural hazards.

Robust analytical techniques that quantify the uncertainty in response and damage due to earthquake excitation are of great value for design, emergency response, and infrastructure management purposes. Researchers have proposed different methods for generating analytical bridge fragility curves based on nonlinear dynamic analysis. This paper examines the analytical damage fragility methodology previously implemented for typical bridges in the Central and Southeastern US and California. A unified analytical fragility method, based on the bridge component approach, is investigated that combines aspects of probabilistic seismic demand analysis and Latin hypercube bridge population sampling. The procedure separates uncertainty arising from aleatory randomness in the ground motion, epistemic uncertainty pertaining to bridge component damage, and uncertainty pertaining to the bridge parameters. The unified methodology is demonstrated for a multiple-span box girder bridge common in California.

Slope failures were observed in the Japan Mid-Niigata earthquake of 2004 and the Noto Hanto earthquake of 2007, and it is an urgent task to evaluate the seismic stability of existing slopes along expressways. However, the earthquake motions to check the seismic performance of expressway embankments should be different site by site along the expressway. In this study, we measured microtremors at the sites along the actual expressway. Based on the measurement results, the variations of the input earthquake motions considering the seismic site effects are introduced.

In this study, closed form equations as functions of the isolator, bridge and ground motion properties are formulated to calculate the optimum characteristic strength, Q_d and post-elastic stiffness, k_d, of the isolator to minimize the maximum isolator displacement (MID) and force (MIF) for seismic isolated bridges (SIBs). This formulation required more than 13000 nonlinear time history analyses of simplified SIB models. The analyses results revealed that the optimum Q_d and k_d are highly dependent on the site soil conditions and peak ground acceleration of the ground motion.

This paper discusses the ductility requirement for a typical bridge pier or bent subjected to extreme loads such as those from pulse-like near-fault ground motions. The ductility requirement as stated by prevailing design codes may not be valid for such structures in near-fault (less than 10 miles) zones. Due to dominance of the pulses, medium to long period structures are highly affected; often resulting in high residual or permanent deformations after the cessation of seismic ground motions. As per most design codes, the magnitude of displacements associated with P-Delta effects is required to be captured using non-linear time history analysis. The higher the value of the target displacement ductility demand or the P-Delta ratio, the larger is the magnitude of the residual displacements. Because permanent deformations in a bridge bent would lead to a higher eccentric loading from the superstructure, the bent would be subjected to higher secondary moments from it own design load. A suitable balance should therefore be made between ductility and residual displacements in the design of such structures using Performance-Based Seismic Design procedures.

The directional effects plays an important role in the seismic design of bridge structure. Most of the past studies on the bridges have been conducted by ignoring the directional effects. However, such effects can play crucial role in the seismic response of the bridge. In the present paper, the seismic response of a continuous bridge under bi-directional excitation has been studied, considering the interaction effects in Bearings and piers. The effect of orientation of the major component of ground motion with respect to the axis of the bridge has also been studied. A comparison of the responses obtained from the Nonlinear (Static) Pushover analysis and Nonlinear Dynamic Time History analysis have also been done. It has been observed that the bi-directional excitation has resulted in significantly higher response with the maximum effect in case of PF system, where the uni-directional analysis yield significantly underestimated results, which might be crucial in seismic design.

Seismic resiliency of new bridges has improved over the years due to improved seismic codes and design practices. However, the vulnerability of seismically deficient bridges, coupled with aging and deterioration, poses a significant threat to life safety and integrity of lifeline systems. It is economically not feasible to retrofit the entire seismically deficient bridges. Therefore, there is need for a comprehensive plan to identify critical bridges and prioritize their retrofit and upgrade requirements. A risk-based seismic evaluation technique is proposed in this paper to develop a ranking scheme for bridges. The complex interaction between seismic hazard, bridge vulnerability and consequence of failure is handled in a hierarchical manner. Some of the input risk parameters, expressed as qualitative and quantitative quantifiers, are transformed into commensurable values. A fuzzy-logic based modelling technique is used to aggregate through the hierarchy and obtain final risk index for prioritization. The efficacy of the proposed method is illustrated with bridges in the British Columbia, Canada.

The seismic performance analysis and design optimization of a self-anchored suspension bridge is studied in this paper. Based on the preliminary design of the bridge, a finite element model has been built for performing structural dynamic analysis. For time history analysis of the bridge subjected to seismic excitation, generated artificial site-specific earthquake waves were adopted as the ground motion input. The seismic performance objectives have been set for the bridge when earthquake events of expected intensities occur. The structural dynamic characteristics of the bridge have been obtained by performing modal analysis. In order to improve the seismic performance of the bridge, the tower design has been optimized and nonlinear fluid viscous dampers have been applied at the points of intersection between the two towers and the deck of the bridge. The parametric sensitivity analysis has been conducted on the design parameters of the dampers to determine a proper combination. Nonlinear time history analysis has been performed for the bridge. The analysis results show that the expected performance objectives of the bridge can be reached after the optimization of the towers design and the installation of dampers.

Historical seismic hazard characterizations did not include earthquake ground motion waveforms at frequencies below approximately 0.2 Hz (5 seconds period). This resulted from limitations in early strong motion instrumentation and signal processing techniques, a lack of measurements in the near-field of major earthquakes and therefore no observational awareness, and a delayed understanding in the engineering community of the potential significance of these types of motions. In recent years, there is a growing recognition of the relevance of near-fault, low frequency motions, particularly for long-period structures such as large bridges. This paper describes a computationally based study of the effects of low frequency (long-period) near-fault motions on long-span bridge response. The importance of inclusion of these types of motions for long span cable supported bridges is demonstrated using actual measured broad-band, near-fault motions from large earthquakes.

This paper presents a structural reliability estimation method which incorporates vibration-based structural parameter identification results. Parameter identification studies were carried out on a large scale shaking table test of a three-bent concrete bridge model. First, a set of bridge models with varying structural parameters were generated based on the Monte Carlo simulation. Then, each of them was analyzed using nonlinear time history analyses to obtain damage levels at the specific locations. Another set of structural parameters was obtained by updating the first set of structural parameters in Bayesian sense using parameter identification results. Lastly, reliability estimation was performed for these two sets of bridge models. In the scope of this paper, it was shown that residual reliability of the bridge models estimated using the updated structural parameters is lower than the one estimated using the non-updated structural parameters. The results clearly reveal the importance of integration of structural parameter identification into the reliability estimation. The feasibility of this approach is currently being studied for the instrumented toll bridges located in California. The seven bridges in the bay area are the Antioch, Benicia-Martinez, Carquinez, Dumbarton, Richmond-San Rafael, San Francisco-Oakland Bay and San Mateo-Hayward bridges. The last one is the Coronado Bridge which is located in San Diego.

A research program conducted at the University of California, Berkeley, studied breaking strength of porcelain insulators subjected to cyclic loading. One of main goals of the experimental program was to expand insulator manufacturers' data that usually specifies the breaking strength obtained in unidirectional loading up to failure with a series of cyclic loading tests at increase loads to failure. The project also explored feasibility to assess the condition of porcelain insulator sections with a simple technique that could be performed in a shake table test program, in the field right after an earthquake or during maintenance shutdown. A total of six sections of 230-kV insulator posts were subjected to incrementally increasing quasi-static cyclic loading, with intermediate experiments to study possible damage detection techniques. Process of loading was continued up to failure. Impact hammer and snap-back tests were employed to determine if damage could be detected. The insulators sections were extensively instrumented by strain gages and accelerometers. It was shown that a simple unidirectional impact or snap-back test causes a complex three-dimensional vibration of the insulator section. Effect of hammer impacts on overall breaking strengths of the insulator sections was studied also.

This paper describes a seismic damage estimation system for electric power distribution equipment called RAMP-Er. Since a huge number of electric power distribution equipment is spatially installed in local areas, a lot of equipment is simultaneously damaged due to a seismic event. Thus, a highly accurate damage estimation system for equipment is needed to realize its effective seismic countermeasures and restoration. RAMP-Er applied a Bayesian Network modeling process to improve the accuracy of the damage estimation based on sequential updated multiple disaster information such as power failure information which can be collected just after an earthquake event. In numerical examples, it is illustrated that compared with the existing damage estimation models, which only use the earthquake intensity as the seismic damage estimation parameter, the proposed model enables us to more accurately estimate the damage just after the earthquake.

This paper presents preliminary results and analysis of a cantilever load test on two types hollow-core composite insulators and summarizes the response of the insulators to different types of loading. The tube of the insulator is a cylindrical shell of fibers-glass in a resin-based matrix with aluminum flange end fittings. The integrity of the tube-flange connection is checked for leaks, slip, damage, and bond degradation. Tests indicate that he actual cantilever load causing failure was much higher than the rated SML provided by the manufacturers. While there were occasionally sounds indicating that something was going on in the insulator prior to catastrophic failure, there was no change in the force deflection curve of the test. While there were slight changes in the damping and frequency of the insulators as the loading increased, the changes were small and did not indicate degradation of the insulator. Two failure modes were observed: failure of the lower flange and shear failure at the tube-flange connection. In one case the shear failure was in the bond to the flange and in the other it was in the tube adjacent to the bonding material. In the unbonded tube, there was clear friction damping. In bonded tubes, the presence of friction damping needs further investigation.

A disconnect switch used in sub-stations of large electrical grids is an important part that supports the functionality of the electrical network. Its failure may have consequences to the local network and to the entire grid. Such a switch is a combination of a support structure and the switching mechanism, which in turn is made of fixed and moving metal parts and of ceramic, or composite, electrical insulators. The construction includes therefore a combination of highly nonlinear components some with low and some with high stiffness, some extremely brittle and some ductile. In order to find the static and dynamic characteristics of these high voltage three-phases disconnect switches and their capacity to withstand earthquakes, testing was performed on different types of switching systems. The testing was performed using the standard IEEE693 procedures (with some modifications) for (i) a single post insulator; (ii) a sub-assembly of single insulator connected to the switch system; (iii) a sub-assembly of a single phase of the whole switch and (iv) a full assembly of the disconnect switch system including the support structure. It was found that the switch base, i.e. the structure which supports the mechanism and post insulators for each phase, has a large influence on the fundamental frequencies of post insulators assemblies. Changing the stiffness of the "switch base" could be a constructive way to alter the fundamental frequency of the system to avoid the frequency range in the input motion which has damage potential. Moreover, the switch base connection was found to be much more flexible than the post insulators and their connections, such that it caused smaller forces at base and larger displacements at the top of these insulators. In order to check the possibility to protect the post insulators mounted in the switch assembly, the entire systems was isolated with self-centering sliding isolators of the type of (i) Friction Pendulum System and (ii) wire rope isolators. Base isolation reduced the induced stresses in the post insulators by 50% to 90%. Therefore, such isolation could be a good retrofit solution for existing overstresses disconnect-switches. However, this recommendation must be further checked for connector compatibility due to increased lateral movements of the entire switch structure.

In the post-earthquake environment, operation of high-voltage substation equipment and control facilities are essential for maintaining the integrity of the electrical power transmission and distribution network. Poor seismic performance of these system components can result in extended power outages that may propagate far beyond the local epicentral region. Due to the significant importance of the power network, reliable seismic performance is required. However, historically substation equipment has shown marginal seismic performance primarily due to equipment anchorage and brittle insulator material (for electrical purposes) issues. Operability of the power system is dependent on not only the performance of substation equipment, but also the performance of substation control buildings and the support facilities associated with the power network. This paper provides a brief overview of documented historical seismic performance of high-voltage substations. In addition, seismic vulnerabilities of highvoltage substations components, including yard equipment, control houses and support facilities, will be discussed. Finally, a discussion of seismic retrofit strategies will be presented for substation equipment and facilities. Examples of seismic retrofitting of high-voltage electrical substation facilities will also be presented.

Substations are among the most important parts in the electric power networks, and play a vital role in the stability, controllability and serviceability of the electric energy, yet the experiences gained from the earthquakes have shown that these elements are very vulnerable and the direct and indirect losses resulting from their damages are sometimes really considerable. This high degree of vulnerability is due to different reasons. Based on the recent earthquakes in Iran, the substations' equipments and buildings have experienced various damages.In this paper the seismic performance of the electric substation equipments and their causes in Iran's great Bam earthquake (2003) is discussed and the lessons learned from those are expressed. Finally, some recommendations to reduce this vulnerability and upgrade the seismic performance of the existing equipments are given.

Past earthquakes have shown that the low-voltage or distribution substations are among the most vulnerable components of electric distribution networks, and regarding that there are many of these substations in the distribution network of each city, their seismic risk study is a very important part of the risk evaluation and management of these networks. This paper presents a risk evaluation and reduction method for distribution networks by concentration on low-voltage substations. The proposed method has been applied to Tehran Metropolis to show its efficiency. For this purpose, at first, various earthquake scenarios have been considered based on the seismic sources around the city and next the vulnerability of 20 kV voltage transformers, as the main component of distribution substations, has been assessed for each scenario by using the fragility curves and the micro-zonation maps corresponding to each scenario. By using these maps and having the number and type of electric power users in various parts of the city, the number of consumers in each neighborhood who will suffer from the power outage in each earthquake scenario have been obtained, based on which the risk reduction measures can be developed.

The electric utility industry has been without uniform guidelines for the design of substation structures. An American Society of Civil Engineers (ASCE) Substation Structure Subcommittee, of the Electrical Transmission Structures (CETS) Committee, has completed a document to address this issue. The primary purpose of this design guide is to document electrical substation structural engineering practice and to give guidance and recommendations for the design of outdoor electrical substation structures. The design guide, Manual 113 (2009), provides guidance for analysis methods, loading and deflection criteria, member and connection design, structure testing, quality control and quality assurance, structural members used in foundations, detailing and fabrication, construction and maintenance issues. A summary of some of the content presented in the substation design guide is presented in this paper.

Recent earthquakes have again demonstrated the seismic vulnerability of the high voltage electrical components. These components are a critical link in the power generation, transmission, and distribution system. The damage to such components in the 2007 and 2008 earthquakes in Asia delayed the response of emergency units and resulted in business interruptions. Fortunately, experimental and analytical methods are available to assess the performance of these components and cost effective retrofits can be used to mitigate damage. In recent years, the data from experimental investigations have led to major improvements in the standards used for seismic qualification. In particular, new generation of seismic inputs are developed for use in testing. This paper presents a brief overview of the observed earthquake damage, and the basis for the revisions to the standard based on the experimental data.

A new method is proposed to seismically qualify power transformers and their bushings to meet the requirements of IEEE Standard 693. The new method utilizes a dynamic finite element model of the transformer and bushings to assess the affect of interaction of the bushings with the transformer system. A research effort to evaluate the ability of economical models to meet the needs of the standard is under way. This effort will also be used to develop guidelines to be used by modelers to help assure acceptable models are developed.

IEEE 693 has become a leading seismic design standard for electrical substation equipment primarily among utilities in high seismic hazard areas in North America. For the seismic qualification of switchgear and controlgear, IEC 62271 Part 300 presents an alternative that has been adopted primarily in Europe. The Institute of Electrical and Electronic Engineers (IEEE) and the International Electrotechnical Commission (IEC) have been engaged for many years in efforts to unify their standards for electrical equipment. These efforts are motivated by globalization and a desire to streamline the standards for equipment for the benefit of equipment manufacturers and users alike. This paper compares the key aspects, features, and rationale for the seismic qualification requirements of IEEE 693 and IEC 62271-300. While the overarching objectives of these two standards are the same, i.e., to provide the means for qualifying and procuring seismically rugged substation equipment, the philosophy and methods employed differ somewhat. Preliminary discussions to unify these two standards have begun, but much work remains to be done.

Life-Cycle cost functions for typical electrical substations and power transmission towers located on eolic zones of Mexico have been calculated and the effect of updating the maximum wind velocities over the unconditional annual failure probability is examined and discussed here. The impact that epistemic uncertainty of the maximum wind velocity has over the structures annual failure probability is explored and quantitatively assessed. The economical advantage of preventing failure consequences throughout extensive and further wind velocities recording is appraised and emphasized as a mitigation measure. Information from new recording campaigns is incorporated throughout Bayesian updating. The expected life-cycle cost of substations with and without additional wind velocity recording are estimated and the economic benefit of additional recording is measured for several levels of failure consequences. Information inferred from recent hurricanes is used to update the wind occurrence probability for a site.

One of the important challenges facing the US today is the need for resilient networked infrastructure. The electric power delivery system is one of the critical lifelines that comprise the networked infrastructure. Power delivery systems have received a great deal of attention in recent years because most of the other lifelines such as telecommunications, transportation and water supply require power to function properly. In this paper, the resilience of power delivery systems is assessed for wind and seismic loadings using definitions derived by Bruneau (2003) and applied to in-situ post event data for extreme events.

Reinforced concrete beams are widely used for transmitting electric power in urban environment in some countries like IRAN. In this paper, one kind of these RC beams are investigated and optimized. The available section can sustain lateral forces much more than necessary that's why the need for optimizing the section seems essential. To achieve the optimized section, nonlinear programming is carried out by the use of analytical formulas from ACI. After that, the adequacy of the beam is checked by the use of pushover analysis. Finally, to obtain the actual behavior of the proposed sections, three specimens are constructed and tested. According to the provision for accepting these beams, a concentrated load should be exerted at the top of the beam and monotonically increases to obtain the pushover curve of the beam. Displacements at the top of the beam should not exceed certain values at different levels of load. Here, first of all, a new reinforcement arrangement is proposed for the beam based on nonlinear programming. After that, the adequacy of proposed reinforcement will be checked by the means of pushover analysis. Finally, three beams with proposed reinforcement arrangement are built and tested. The final results of all of the constructed beams satisfied the provisions, hence can be used in practice.

British Columbia Transmission Corporation [BCTC] plans, manages and operates 18,000 km of transmission lines, 286 substations and 124 telecommunication sites on behalf of BC Hydro. Much of the existing transmission system was constructed in the 1960s and 1970s, although some portions date back almost a century. The original system was designed and built with minimal or no specific consideration of seismic events. The British Columbia Transmission System is expected to withstand and readily recover from high probability but low impact events and perform in a safe and acceptable manner in low probability but high impact events such as earthquakes, ice storms etc. Transmission assets have typically performed well historically during earthquakes around the world. In the case of steel lattice towers in particular, the importance of these assets and the rigor of their design for climatic loadings provides added robustness against induced dynamic loading from earthquakes. Tower failures from ground motions during seismic events have largely been due to liquefaction, slope instability, lateral movements, and differential movements leading to localized tower footing failure. This paper demonstrates a utility's approach for analysing seismic risks in order to prioritize, plan, fund and execute risk mitigation. Discussions on the analysis, design and evaluation carried out in order to make consistent decisions on the most cost effective engineering upgrade options are also included.

In practice, mostly for simplicity of evaluation and design processes, the seismic analyses of piping and the supporting pipe-ways are performed independently, without consideration of their interactions. This study focuses on how this interaction can affect the seismic behavior of the whole system. For this purpose the considered pipe-way structures have been assumed to support multiple pipes so that the weight of the piping can be in some cases more, and some cases less than 25% of the pipe-way structure to evaluate how the ASCE code recommendation for analyzing the piping and pipe-way separately or as a whole system is valid. The effects of piping end conditions on the system responses have been also discussed. Numerical results show that not only the weight percentage of piping but also the type of connection between pipes and the pipe-way structure and pipes dimensions supported on pipe-way are important factors affecting the whole system behavior and may cause the system conditions to be different form the code assumptions.

Practicing engineers usually use the design codes or standards, such as ASME 08, for seismic evaluation purposes as well. Therefore, there are some common missing factors in such evaluation processes which may lead to inadequate estimation of seismic vulnerability of equipments, and this in turn results in either unsafe or uneconomical retrofit design of the facilities. This paper discusses that some of these shortcomings may cause serious mistakes in dynamic response values of the equipment, which is a key factor in vulnerability evaluation. For this purpose at first, various major equipments of petrochemical plants have been considered and their seismic vulnerability has been evaluated by using the common practice in engineering offices, which is based on seismic design codes or standards. Then, the seismic vulnerability of the same equipments has been evaluated once more by considering their detailed dynamic models and using linear and nonlinear Pseudo Dynamic or spectral as well as Time History Analyses methods. The obtained numerical results have been compared to show the effects of missing factors in engineering practice. Results show that neglecting some details can lead to significant differences in the dynamic response of many types of equipments.

For almost forty years the engineering community has realized the risk severe earthquakes pose to lifelines, including natural gas infrastructure. During this time numerous guidelines have been written detailing methodologies to mitigate risk to natural gas facilities. However, only since December of 2004 have owners and operators of high pressure "transmission" pipelines been required to address seismic hazards as part of on-going system integrity management programs.

Past earthquakes have shown that metal cylindrical tanks containing liquid products at chemical processing plants undergo significant damage when subjected to strong ground motions. The most commonly used design code for cylindrical tanks is the American Petroleum Institute's API 650 Standard. The basis of the design calculations relies on modeling the sloshing phenomenon by two single degree of freedom oscillators that represent the impulsive and convective response of the liquid product inside. The use of more advanced analysis techniques is possible by taking into account the fluid-structure interaction directly. This study investigates the use of the Arbitrary Lagrangian Eulerian (ALE) method to simulate the sloshing effects by fluid-structure coupling. The seismic response of a typical cylindrical tank is analyzed. Comparisons are made with the API 650 approach. The overhead of using more advanced analysis techniques is discussed.

Wave propagation hazards result from traveling waves that induce out-of-phase motion along a pipe axis. These in turn result in the generation of axial and flexural strains in buried pipe. For straight sections of buried pipe, axial strains are typically an order of magnitude larger than the wave propagation induced flexural strains. However at an elbow, the reverse occurs. By the nature of an elbow, the axial strains are comparatively small while the flexural strains are comparatively large. This paper presents calculated axial and flexural strains at an elbow in a buried continuous pipe subject to wave propagation. For most cases the flexural strains at the elbow are less than the corresponding wave propagation induced ground strains. Only for piping systems containing relatively thick walled pipe exposed to moderate wavelengths does the elbow flexural strain exceed the ground strain. That is, for most piping systems containing an elbow, the ground strain serves as an upper bound for the generated strain at an elbow due to wave propagation hazards.

Accurately evaluating the seismic response and performance of lifeline structures requires a solid understanding of the characteristics of the ground motions that the lifeline structure will be subjected to in the future. Recent research by the Pacific Earthquake Engineering Research (PEER) Center's Ground Motion Selection and Modification (GMSM) Program has investigated the seismic response of building structures, and shown that commonly used ground motion selection and scaling methods can lead to an overestimation of the seismic response (e.g. building displacements) by up to 40%. This same research has compared a large number of methods for selecting ground motions, and identified the specific methods that should be utilized to obtain accurate predictions of seismic response. This paper presents an overview of the GMSM Program, and the recent findings related to building structures. The paper then discusses the implication that these findings have on proper selection and scaling of ground motions for lifeline structures, and discusses how the GMSM Program research could be extended to provide specific guidance on this topic.

This paper presents a promising earthquake protection method by placing rubber-soil mixtures (RSM) around underground tunnels for absorbing vibration energy and exerting a function similar to that of a cushion. The validity of the method will be demonstrated by numerical simulations using various recorded earthquake ground motions. The use of scrap tires as the rubber material can provide an alternative way of consuming huge stockpiles of scrap tires from all over the world. Moreover, the low cost of this proposed method can greatly benefit developing countries where resources and technology are not adequate for earthquake mitigation using welldeveloped, yet expensive, techniques.

An important consideration in slope studies is the installation of instrumentation for monitoring movements and stresses as well as groundwater conditions. In this paper, a monitoring technique for the evaluation of slope stability was developed to real-time remote monitor the perturbed forces on the cable through sliding body and sliding bed. The link between slope sliding force and remote monitoring perturbed forces was described by a simple relation based on the limit equilibrium principle of instantaneous rigid body, responded for slope sliding mechanism with the synthesized mechanical effects due to rain, groundwater change, and self weight of rock masses. Two typical applications show that the real-time remote intelligent monitoring of perturbed stresses in cables can be used to forecast and evaluate the stability of various reinforced slopes such as those formed on open-pits and expressway. This technique can be useful underground lifeline facilities such as pipelines, telecommunication and power cables.

Although seismic performance of large underground structures has been extensively studied recently, the focus of these researches is on the behavior of soil during earthquake motion, considering simple assumptions for the structure. The present study tries to have a more precise view towards the performance of large underground structures subjected to earthquake excitations. To achieve that aim, a typical subway tunnel is analyzed using dynamic Finite Element method coupled with soil and pore water. Both linear and nonlinear elements are used to model the underground structure. The computational results prove that nonlinearity of the structure should be considered to realize the accurate deformation and internal force response. Furthermore, the simulation is carried out in both drained and perfectly undrained conditions to clarify the effect of liquefaction on seismic response of the structures. It shows that ground liquefaction greatly deteriorates the soil skeleton stiffness and results in the reduced damage to RC structures even though large displacement of the ground is produced. It implies that the required ductility of RC ducts can be moderated provided that the liquefaction risk is high.

The City of Hayward, a city of 148,000 residents, is situated along the Hayward Fault. Along with its residential population, Hayward is also home to numerous commercial, industrial and institutional entities, including two hospitals, a state university, community college, large beverage bottling plant, and several moderately sized manufacturing and research facilities. The City owns and operates a water distribution system consisting of over 300 miles of transmission mains, 14 reservoirs, 7 pump stations, and numerous pressure reducing valves, serving about 32,000 connections. Hayward relies on a sole wholesale supplier, the San Francisco Public Utilities Commission (SFPUC), for all of its water supply, and purchased about 19 million gallon per day (mgd) of water in 2008. The Hayward Fault runs through Hayward's downtown corridor, with about 46 water lines crossing the fault. It is estimated that a magnitude 7 earthquake could cause four- to six-foot displacements. Prior to the Loma Prieta earthquake in October 1989, Hayward had implemented some basic strengthening strategies, such as reinforcing some concrete tanks with pre-tensioned bars.

For more than 20 years, the Pacific Gas and Electric Company (PG&E) has been actively involved in managing earthquake risks for natural gas transmission and distribution systems throughout California and within the San Francisco Bay area. The PG&E service territory spans 70,000 square miles providing natural gas service to 4.2 million customers in both northern and central California. The natural gas service system consists of more than 6,000 miles of gas transmission pipelines and more than 40,000 miles of gas distribution pipelines. Various PG&E programs have been developed to minimize the impact of future earthquakes to our customers and the community. The Risk Management and Integrity Management Programs within the California Gas Transmission group assess and manage the risk of each distribution pipeline section installed before 1940 as well as transmission pipeline segments. The Gas Pipeline Replacement Program (GPRP) was implemented in 1985 to improve overall system safety and reliability through a long-term program of replacing aging and leak-prone sections of distribution pipelines and transmission lines within the San Francisco Bay area considered susceptible to earthquake damage.

Pacific Gas and Electric Company (PG&E) is a major energy provider in the San Francisco Bay Area, and Northern and Central California. The East Bay region of the San Francisco Bay Area is home to numerous residences, businesses, and industrial customers stretching from San Pablo Bay in the north to the cities of Silicon Valley in the south. Historically, electric substation equipment has not performed as well as desired during large earthquakes, as evidenced by damage sustained in the San Fernando, Northridge and Loma Prieta Earthquakes, and even in some smaller earthquakes. A large earthquake on the Hayward Fault would present unprecedented challenges, and would severely test PG&E's electric transmission system. While more remains to be done, PG&E has made significant improvements to the seismic capability of its electric transmission system. These efforts have included substation and control building seismic strengthening, equipment anchorage strengthening, development and implementation of new seismic design standards leading to procurement of more rugged equipment, development of an emergency response organization, and partnerships with other utilities and research organizations. PG&E has taken the first steps toward a network performance assessment of the electric transmission system in the San Francisco Bay Area which should provide valuable information on damage estimates, system vulnerabilities, and emergency response demands.

The East Bay Municipal Utility District (EBMUD) has successfully completed a ten year, award winning Seismic Improvement Program to bring the performance of its system to modern standards while meeting both its budget and schedule commitments. As additional earthquakes occur and seismic research advances, our understanding of the seismic impacts on water lifelines and facilities continually improves. Establishing and meeting post-earthquake service goals plus wise, efficient use of customer-provided funding make the Seismic Improvement Program (SIP) an outstanding example of successful seismic mitigation for water systems. But the work of maintaining seismic readiness is never complete. This paper examines EBMUD's completed and ongoing efforts to enhance system reliability for its customers by continually improving its design and construction standards for water systems. These standards use the best available tools for risk management, the latest developments in seismic research, numerous innovative design techniques and careful management controls to provide reliable, post-earthquake system performance for the benefit of the 1.3 million people in our service area. Case studies of completed and planned projects to improve system seismic performance are presented illustrating how standards are the key to seismic preparedness.

The hurricane winds had only a minor direct impact on hospital facilities. However, the subsequent flood severely impacted most of the hospital facilities investigated. Many facilities completely evacuated patients and staff, and the family members of patients and staff that had taken shelter in the facilities before the hurricane arrived. The evacuations were necessary because the flood caused the loss of emergency power, safe domestic water, and the ability to remove waste water from the facilities. Many facilities had electrical power equipment, pumps, compressors and critical medical equipment that were located in flooded areas, such as basements or street level floors. Other non-flooded facilities had to evacuate people and terminate their functions because of loss of the water supply. Some evacuations were necessitated by concerns regarding the security of personnel in the facilities.

Hurricane Katrina caused significant damage to the bridges in the Gulf Coast region of the United States, including Louisiana, Mississippi, and Alabama. Damage to these key components of the transportation system can cause significant economic losses and impede post-event recovery and restoration. The overall cost to repair or replace the 44 bridges damaged during Katrina, including emergency repairs, was estimated at well over $1 billion. The paper summarized the findings of reconnaissance along the Gulf Coast by analyzing the observed damage patterns to bridges, including storm surge, wind, and impact damage. These bridges suffered span shifting and unseating, yielded piers, spalling of bent beam, shearing of bearings, and damage to electrical and mechanical equipment, among others. Common features of the severely damaged bridges include low elevation, limited connectivity between superstructure and substructure, and simply supported spans. Potential improved design details and retrofit measures will be presented, drawing upon lessons from Katrina. Nationwide risk assessment packages for lifeline systems lack any reliable input models of bridge fragility to assess the risk to the transportation infrastructure posed by hurricane induced storm surge. As a first step toward the development and validation of quantitative models of bridge reliability under hurricane induced storm surge and wave loading, evidence from the 2005 Hurricane Katrina is used to evaluate hazard intensity measures and bridge characteristics indicative of increasing level of bridge damage. This information can be used for binning of bridges and identification of viable intensity measures for fragility analysis.

This paper will summarize the performance of water and gas piping systems during the past 6 earthquakes and in 4 countries: US (1906 San Francisco earthquake; 1989 Loma Prieta earthquake; 1994 Northridge earthquake), Japan (1995 Great Hanshin-Awaji earthquake (Kobe), Thailand (2005 Tsunami) and Columbia. Also, the paper will report about the performance of pipes during the hurricane Andrew hurricane Katrina. Last, the paper will provide multiple references to assist design engineers and owners in selecting pipe materials based on past performance of these systems during earthquakes and hurricanes.

The authors conducted a weeklong field assessment of damage to selected South Louisiana river and coastal port facilities resulting from the Hurricane Katrina event of August 29, 2005. Based on review of available data and internal team discussions, the assessment focused on four river ports and three coastal ports believed to have received damage from the event. The field assessment, consisting of site observations and discussions with port or terminal facility personnel, was conducted from October 17–21, 2005 — seven weeks after the event. The assessment focused on preparation, response, and recovery activities of the affected ports, with an eye toward identifying "lessons learned" that could be beneficially applied or implemented to mitigate impacts from future such events. The key lessons learned include: (1) communications were inhibited by lack of reliable back-up systems to maintain reliable, open channels; (2) stockpiling of emergency materials, such as fuel for standby power generation, is a necessary measure; (3) locating critical equipment, such as communications, controls, and power supply, above flooding levels to maximize survival; and (4) providing organized evacuation policies and procedures for port staff, including post-event communications and logistics to enable quicker recovery of operations.

Wind-related damage is a threat to most dockside container cranes. Typically, damage is localized and easily repaired, but occasionally cranes collapse. Recent crane collapses have been caused by hurricane winds, usually when tie-downs fail, and by lesser winds under operating conditions. This paper presents recent trends in hurricane wind loads, a novel design "ductile link" tie-down system, and an acceptable risk method for guiding the selection of an appropriate level of retrofit for an existing crane structure. This paper also discusses winds during crane operations, and provides recommendations for braking and stowage systems.

This paper presents an overview of the migration of a traditionally based GIS application to a more modern, spatially enabled database application to evaluate water system performance after an earthquake. The new application was based on a previously developed GIS application called Graphical Iterative Response Analysis for Flow Following Earthquakes (GIRAFFE), developed for the hydraulic network simulations of heavily damaged water supply systems. The migration to a more modern platform utilized object oriented programming techniques, storage of spatial data within a database management system, the adaptation of spatial constructs in a traditional database language (SQL), and performance of analytical processing in computer memory. The results showed the advantages of utilizing more modern approaches for GIS processing in the form of ease-of-use, speed, and system modification and maintenance.

This paper presents estimated durations of post-earthquake water supply outages in Los Angeles for five realistic possible earthquake scenarios. The analysis was conducted using a new discrete event simulation model of the post-earthquake restoration process for the Los Angeles Department of Water and Power (LADWP) water supply system. Based on extensive collaboration with LADWP personnel, the model mimics the real-life restoration process in detail, simulating the movement of different types of crews as they inspect, reroute around, isolate, and repair system damage. A previous comparison of model results with observations for the 1994 Northridge earthquake suggested that the model can estimate the time and spatial sequence of the restoration accurately enough for planning purposes. The analysis in this paper suggests that there is substantial variability in how the post-earthquake restoration may unfold, and examining model results can be useful in better understanding what might happen and what might be done to effectively plan for restorations across the full range of possible scenarios.

This paper describes the potential impacts of a magnitude 7.8 San Andreas Fault earthquake scenario to three major aqueducts providing domestic and industrial water supply to Southern California and the Los Angeles Department of Water and Power (LADWP) water transmission and distribution system. The aqueducts will sustain significant damage, and restoration of water flow to different lines are estimated to take between 4 and 18 months. Local emergency water supplies may not be sufficient to match the duration of aqueduct repairs, requiring severe water rationing. Large ground motions cause nearly 2,700 damage locations in the LADWP transmission and distribution pipe networks. Due to the large number of leaking pipes, system serviceability declines rapidly, resulting in 66% of unmet water demand after 24 hrs. Restoration of water flows to all customers may take up to several months and restoration of pre-earthquake water demand may take a year. The earthquake scenario estimates a super conflagration in a densely populated area of Los Angeles, where water serviceability is no more than 31%, causing difficulties for firefighting. Business interruptions due to long term water rationing may affect the regional economy greater than previously anticipated. Results of this study show how critical it is for all water agencies to prepare for a great San Andreas Fault earthquake.

This paper discusses new approaches for modeling the social impacts of lifeline losses in disasters. It focuses on two types of impacts: displaced persons (and associated demand for public shelter), and reduction in functionality of health care facilities such as hospitals. The models are applied to Los Angeles. The shelter model simulates households' decision-making and considers socio-economic and locational factors in addition to housing damage and lifeline loss. It performs well in simulating the Northridge earthquake. In a M6.8 Verdugo Fault scenario, with much higher building damage and lifeline outage durations, as many as 212,000 households are estimated to seek public shelter. Accounting for lifelines substantially raises estimates compared to considering building damage alone. The health care model draws on empirical data to model the operational performance of a hospital's interacting systems (structural, nonstructural, lifeline, and personnel) in an earthquake. Results for Verdugo indicate that nearly half of L.A. county hospitals have at least a 50% chance of experiencing significant loss of functionality. The contribution of regional lifeline disruption to this loss is fairly small.

We have developed a liquefaction hazard screening tool for the California Department of Transportation (Caltrans) that is being used to evaluate the liquefaction hazard to approximately 13,000 bridge sites in California. Because of the large number of bridge sites to be evaluated, we developed a tool that makes use of parameters not typically considered in site-specific liquefaction investigations. We assessed geologic, topographic, seismic hazard, and subsurface conditions at about 100 sites of past liquefaction in California. Among the parameters we found common to many of these sites are: (a) low elevations, (b) proximity to a water body, and (c) presence of geologically youthful deposits or artificial fill materials. The nature of the study necessitated the use of readily available data, preferably datasets that are consistent across the state. The screening tool we provided to Caltrans makes use of the following parameters: (1) proximity to a water body, (2) whether the bridge crosses a water body, (3) the age of site geologic materials and the environment in which the materials were deposited, as discerned from available digital geologic maps, (4) probabilistic shaking estimates, (5) the site elevation, (6) information from available liquefaction hazard maps [covering the 9-county San Francisco Bay Area and Ventura County] and California Geological Survey (CGS) Zones of Required Investigation. For bridge sites at which subsurface boring data were available (from CGS' existing database), we calculated Displacement Potential Index values using a methodology developed by Allison Faris and Jiaer Wu. Caltrans' staff will use this hazard-screening tool, along with other tools focused on bridges and foundations, to prioritize site-specific investigations.

This paper presents an overview of a report presenting recommended analysis practice for pile foundations for bridges in laterally spreading ground under development for Caltrans by the authors. The past decade of research has produced numerous insights into the behavior and performance of pile foundations and bridges impacted by liquefaction and lateral spreading. The purpose of the report is to develop a set of recommended procedures and practices for analysis and design that are based on a synthesis of research findings when supporting research is available and on the professional opinions of the authors when supporting research is lacking. The scope of the report is to summarize those recommendations in a concise document that provides references to supporting materials and/or identifies areas where supporting materials are lacking. While the report is currently under development, this paper presents an overview of the guidelines, essentially introducing topics that will be covered in each chapter.

We have computed maps of probabilistic tsunami inundation hazard for California using a hybrid approach of numerical tsunami simulations and probabilistic integration of the hazard. The earthquake sources mainly include large subduction zone sources around the Pacific Rim. Our method uses a two-step process: the first step consists of the computation of probabilistic offshore waveheights, based on several thousands of scenario calculations, that include both epistemic uncertainty through the use of logic trees as well as aleatory variability, by applying a standard deviation (sigma) to the probabilistic waveheights. We then use these offshore waveheights, and the source disaggregation, to develop sets of fully non-linear tsunami simulations, including inundation, that span the range of probabilistic offshore waveheights. We present inundation maps for several return periods of engineering interest and discuss their implications and use for infrastructure applications.

Post-earthquake repair costs and repair times are important for evaluating the performance of new bridge design options and existing bridges in preparation for the next major earthquake. Hazard and structural demand models describe the probabilistic structural response during earthquakes. Damage and decision models link the structural response to decisions on repair actions and costs. This paper proposes a step-by-step probabilistic methodology to evaluate repair metrics for different bridge components and the bridge as a system, corresponding to varying degrees of damage. Repair actions, quantities, times, and costs are input into spreadsheet templates, and a numerical tool evaluates the expected value and variance of both repair costs and repair times for a range of earthquake intensities. This methodology uses the concept of performance groups—groups defined to account for bridge components that are repaired together. Data can be customized for repair methods and bridge types particular to different regions.

This paper introduces an efficient method for quantifying the impact of bridge retrofit on subsystem reliability and risk to transportation networks. This study also demonstrates the significant influence of ground motion and damage correlations in quantifying the benefits of mitigation. These concepts are illustrated through a case study for an existing transportation subsystem in Contra Costa County, CA. After retrofit of critical components, a mean direct loss reduction of 50% and an increase in network reliability of 40% is achieved for the 475 year return period. Incorporating statistical dependence in ground motions and bridge damage resulted in a wide band of uncertainty. Bounds on subsystem failure associated with a 1% annual rate of exceedence decreased from 2.5% – 8% to 1.2% – 5.5% after retrofit of critical bridges. While the relative importance of critical bridges to subsystem reliability was sensitive to seismological parameters and statistical dependence, the subset of bridges identified as critical were consistent in all cases.

Reliability-based design guidelines are necessary to achieve uniform levels of lifeline network performance. For this purpose, inverse reliability methods are explored in the context of geographically distributed networks. However, this inverse approach requires explicit limit state functions which are not readily available for networked systems. In addition, most of the lifeline network reliability research and design to date has focused on element strengthening and capacity increase without considering the topology of the overall networked system and without explicitly considering the interdependencies among different lifeline networks. To address these limitations, the proposed inverse FORM reliability design method uses an artificial neural network (ANN) that uniquely balances accuracy and efficiency. The procedure explicitly accounts for both system interdependencies and network-level topological features through an explicit limit state approximation of the implicit functional relationship of network performance. The merits of the proposed inverse reliability strategy for networks are demonstrated with real interdependent lifeline systems under seismic hazard.

In this paper, interdependence measures are assessed using post-event in-situ data for power delivery and other lifelines through an input-output approach based upon the work of Haimes (2004), McDaniels et al. (2008) and Reed et al. (2009). The methodology is presented and an application to two events is provided.

Anticipated scenarios of restoration process associated with critical infrastructures such as electric power supply systems, gas supply systems, water treatments, and communication networks due to a seismic disaster are clarified and modeled. To clarify their scenarios, current operational plans for disaster prevention offered by stakeholders associated with subject critical infrastructures distributed in the Tokyo metropolitan area, are qualitatively analyzed based on the graph theory. And the related interdependency is modeled by selecting the dominant events in the restoration process and by idealizing them as a directed graph. From sensitivity analysis to the derived graphs it was found that strong and weak connectivity associated with the communication of human, material, and information resources regarding the seismic-disaster restoration process between various stakeholders involved in the management of critical infrastructures is quantitatively shown.

This study is an effort to more reliably and accurately assess the seismic response of utility network systems during a major seismic event. Major events such as the 1989 Loma Prieta Earthquake and 1994 Northridge Earthquake showed the vulnerability of these systems by causing major damage to water and electricity networks. In order to assess the system performance more accurately, lifelines are topologically modeled as a system of interacting networks. The assessment tools are implemented in MAEviz—a GIS based loss assessment software developed by the Mid-America Earthquake Center (MAE Center) and the National Center for Supercomputing Applications (NCSA). A demonstration of the assessment tool was made by analyzing power and water networks in Zeytinburnu, Istanbul.

Climate affects the design, construction, safety, operations, and maintenance of transportation infrastructure and systems. The prospect of a changing climate raises critical questions regarding how alterations in temperature, precipitation, storm events, and other aspects of the climate could affect the nation's transportation system. This regional assessment of climate change and its potential impacts on transportation systems addresses these questions for the central Gulf Coast between Houston and Mobile. Warming temperatures are likely to increase the costs of transportation construction, maintenance, and operations. More frequent extreme precipitation events will likely disrupt transportation networks with flooding and visibility problems. Relative sea level rise will make much of the existing infrastructure more prone to frequent or permanent inundation. Increased storm intensity may lead to increased service disruption and damage. Consideration of these factors in today's transportation decisions should lead to a more robust, resilient, and cost-effective transportation network in the coming decades.

Computing the overall reliability of lifeline systems requires studying the changes in target operational objectives, such as connectivity loss and flow reduction, for all possible failure scenarios. Even for simple cases with sparse network topologies where the state of every node and link is binary, this approach involves a combinatorial analysis that leads to an NP-hard computational problem. This paper presents a topology-based method that provides a lower and upper bound to the reliability estimation of networked systems. The size of network failure sets is investigated for several ideal infrastructures, which range from minimally connected radial topologies, to enhanced mesh-like topologies. Sensibility analyses are conducted across different topological layouts and multiple system-level operational criteria. Results show that clustered reliability relationships emerge as signatures for distinct lifeline topological configurations. This observation allows for customized reliability assessment of infrastructure systems that minimize the computational complexity and provides insights into the effects of topology on network performance.

This paper discusses recent efforts to gather and synthesize empirical data on the societal impacts of infrastructure failure interdependencies (IFIs). A systematic database has been developed on IFIs and their social, economic, health, safety, and environmental consequences. Data pertain to several events, including the August 14, 2003 blackout (affecting the northeastern U.S. and eastern Canada), the 1998 Quebec ice storm, and three 2004 Florida hurricanes. The database emphasizes IFIs deriving from electric power disruptions. Data are drawn primarily from print/text media reports. Verification exercises are conducted against various other primary and secondary information sources. The database is used to comparatively assess patterns in the severity of societal consequences from IFIs, including characterizing hazard, infrastructure sectors, and impact types according to their "intensive" or "extensive" nature. Hurricanes and ice storms are found to be more similar to each other than to blackouts. Infrastructure sectors of greatest concern include transportation and utilities. Specific IFIs are identified that frequently occur and cause significant societal impacts. These results provide a basis for considering priorities for risk mitigation.

Critical infrastructure systems provide a foundation for socio-economic stability, national security, and quality of life. Their performance is continuously threatened by an array of hazards, while insufficient physical performance can have cascading social, environmental, and economic consequences. This paper frames the various threats to sustainable infrastructure and summarizes the state of the art for measuring sustainable performance with indicators. A risk based paradigm of "engineering sustainable infrastructure against threats" is presented. Threats considered include aging and deterioration, population growth and urbanization, natural hazards and climate change. Performance measures of sustainable systems challenged by these threats span the three core areas of sustainable engineering including social, environmental, and economic impacts, such as safety, energy usage, and life-cycle cost. A simple application is provided for bridge infrastructure systems located in seismic zones. This paper illustrates the critical link that the natural hazards and risk assessment community can play in developing strategies to select and promote sustainable lifeline systems.

One of the most common types of deck structure in steel cable-stayed and suspension bridges is the steel orthotropic box girder deck. This paper summarizes results from a study that investigated the response of such bridges to blast loads and developed new blast protection technologies for these bridges. In this study, we subjected inelastic, non-linear finite element models of typical orthotropic deck structures that are used in major cable-supported bridges to simulated blast effects using the MSC.Dytran finite element analysis software. The three most important findings were: (1) decks with mild steel perform better under blast load than the decks with high strength steel, (2) traditional suspension bridges, where the main cables are anchored to the anchor blocks in the ground, perform extremely well when subjected to blast loads on the deck; and (3) the self-anchored suspension bridges, where the main cables are anchored to the bridge deck rather than the anchor blocks performed poorly and underwent global P-Δ instability and progressive collapse. These large P-Δ effects were created by the presence of large axial forces in the deck. An innovative protection system called "Son-Astaneh Fuse System (SAFS)" was developed and proposed that can effectively and economically prevent progressive collapse of the cable-supported bridge spans, especially those, such as the self-anchored suspension bridges, with high blast-induced axial loads in the deck.

Both steel and reinforced concrete bridges are vulnerable to fire caused by a multitude of events such as tanker truck accidents, wildfires, arson or terrorism. This paper addresses bridges with steel super-structure and steel reinforced concrete or composite piers. After a brief summary of fire effects on bridges, the paper discusses the fire-induced collapse of two spans of the MacArthur Maze, a steel elevated freeway in Oakland, California. The two spans collapsed on April 29th, 2007 due to a fire caused by a tanker truck that overturned on the bridge. This paper discusses solutions and technologies that can mitigate the fire hazard in steel bridges. Based on the field investigation and analysis of collected data as well as fire analysis results, the following conclusions were reached: (1) the collapse could be prevented if the bridge was studies for the fire risk which would have led to recognition of high fire hazard at this intersection and vulnerability of the exposed steel girders,(2) the steel bridges and overpasses can be fire-protected using a variety of technologies and products successfully used in buildings; and (3) the current analytical tools could predict the time of the collapse accurately.

Exercise Ruaumoko was a national disaster preparedness exercise based on the scenario of a volcanic eruption within the Auckland Volcanic Field in New Zealand. More than 1,500 participants from approximately 125 organisations were directly involved, including local and central government agencies and private companies, making it the largest exercise of this type held in New Zealand. All lifeline utilities were affected to various degrees by this scenario, which highlighted again how vulnerable the Auckland region is to disruptions of lifeline utilities, and the national implications of the loss of some of those services. This paper provides an overview of the exercise and summarises the physical impacts and management issues arising for each of the key lifeline sectors in response to the volcanic scenario, along with the post-exercise action points. The response and technical issues faced by bulk water and wastewater service provider Watercare Services (both seismic and volcanic in nature) in their simulated operational response are discussed.

In recent decades, the frequency and severity of natural hazards have substantially escalated as a result of accelerating deterioration of natural environmental conditions, increasing concentration of population in high-risk zones, and greater susceptibility of modern industrial societies to catastrophes. The main goal of this paper is to address the theory and practice for developing simulation models for mitigation of the negative financial effects associated with extreme natural events. Though current catastrophe simulation models have been lately dynamic in predicting the effect of natural hazards; they cannot account for the socioeconomic and stakeholder dimension of natural catastrophic risk. Most previous research to study and mitigate the financial impact of such risks has only analyzed the problem from unilateral aggregated simulation perspective. Moreover, the employment of micro-level representation in simulation models for disaster planning is very rare and is only limited to work that: (1) did not cover the societal aspect of the problem represented by associated stakeholders; (2) did not provide a mechanism to measure the costs associated with these stakeholders as a result of interdependencies, constraints, and uncertainties; and (3) did not attempt to study financial mitigation of natural hazards from an integrated societal perspective that optimize position of interrelated stakeholders. Accordingly, it is advised to study and model the extremely complex and dynamic environments governing natural catastrophic risk using a micro level multi agent stochastic simulation approach. This would provide an express shift from previous simulation models as well as efficient and effective decentralized communication of information, and consequently; a detailed and more accurate simulation environment.

This paper discusses the approach used to develop a design for the shoreline protection of the new 150 kilometer long highway (through Parsons as the lead contractor and sponsored by USAID) designed as a response to the December 2004 tsunami; the trade-offs between locating the route where locals prefer to live or being protected from shoreline dynamics and possible future tsunami events; the challenges to developing the design with scarce pre-tsunami data and a dramatic post-tsunami coastal environment; and highlights the subsequent risks and risk mitigation. This paper also discusses one case to illustrate these observations.

An analytical fragility relation for seismic damage to segmented pipe is presented. The relation is based upon a simplified mechanistic model with rigid pipe segments and flexible joints, subject to ground strain parallel to the pipeline longitudinal axis. As such it is applicable to both wave propagation and PGD hazards. In the model, ground strain is accommodated by opening of the pipeline joints. That is, the current model considers tensile ground strain only. The results for small diameter cast iron pipe subject to tensile ground strain match the empirical observation (repairs per kilometer) quite well for roughly an order of magnitude of ground strain. It is felt that the current model provides a good starting point for analytical models applicable to other diameters and pipe material as well as all levels of both tensile and compressive seismic ground strains.

Over the past three decades, seismic fragility formulations for buried pipeline systems have been developed following two tendencies: 1) the use of earthquake damage scenarios from several pipeline systems to create general pipeline fragility functions; and, 2) the use of damage scenarios from one pipeline system to create specific-system fragility functions. In this paper, the advantages and disadvantages of both tendencies are analyzed and discussed; in addition, a summary of what can be considered the new challenges for developing better pipeline seismic fragility formulations is presented. The most important conclusion of this paper states that more efforts are needed to improve the estimation of transient ground strain —the main cause of pipeline damage due to seismic wave propagation; with relevant advances in that research field, new and better fragility formulations could be developed.

After the 2004 Niigata-ken Chuetsu, Japan, earthquake, an open-cut survey of damaged wastewater systems was conducted by the Nagaoka city government. The survey compiled valuable datasets for sewer pipeline damage due to strong shaking. The main feature of the collected data includes locations of damaged sections and inclination of pipes before and after the earthquake. In the present study, by using the datasets and the SPT borehole logs in the affected area, both provided by the Nagaoka city government, the cause of damage to wastewater systems is investigated. Correlation analysis between the pipeline damage and the geological settings in the affected area reveals that ground water depth and native soils are the key parameters for manhole uplift behavior. The simple method for estimation of the maximum uplift of a manhole, is compared with the observed data recorded in Nagaoka.

Some mistakenly believe that wave propagation damage to continuous buried pipe does not occur. Although not common, there have been situations in the past where it has occurred. Two such case histories are presented in the paper with the intension of clarifying the issue. The first case history is local buckling damage to 42 inch diameter welded steel water pipe occasioned by R-wave propagation in Mexico City during the 1985 Michoacan earthquake. In this case, the special circumstances which lead to the damage was the very low propagation velocity of the R-waves in the Lake Zone of Mexico City. The second case history is girth weld failures to a 12 inch diameter gas pipeline occasioned by S-wave propagation in Potrero Canyon during the 1994 Northridge earthquake. In this case, the special circumstances which lead to the damage was very strong ground shaking combined with what turned out to be very poor welds.

Steel pipelines with welded slip joints (WSJs) are susceptible to buckling and fracture as a result of compressive ground deformation during earthquakes. This paper summarizes the full-scale test results for WSJs with nominal diameters of 300, 810, and 910 mm and diameter-to-thickness ratios (D/t) of 50 to 255. Finite element simulations and experimental results show substantial reductions in the axial compressive capacity of pipelines with WSJs that exceed 50% for D/t = 250. A suite of finite element simulations were used to develop families of curves relating normalized slip joint capacity with D/t for pipes with different wall thicknesses. The curves can be used to evaluate the compressive load capacity of steel pipelines with WSJs for design or pipeline risk assessment. In all instances the values shown by the normalized curves compare favorably with the normalized data from the full scale tests, thus providing validation for the curves.

Clustering techniques are used commonly in a variety of engineering and scientific fields although it is rarely used in lifeline earthquake engineering. Cluster analysis deals primarily with the discovery of structures or groupings within data. This paper presents the application of cluster analysis in pipeline damage assessment and identification of high damage areas. Identification of sites where pipeline damage concentrates has special importance because these sites are generally problematic areas and/or pipelines in these sites have some weaknesses. Understanding why damage is high there may contribute and improve future works related to pipeline damage prevention and mitigation. The 1994 Northridge earthquake water distribution pipeline damage in the city of Los Angeles was used herein to illustrate the application of subtractive and fuzzy c-means cluster analysis.

Although welded slip joints (WSJs) are used extensively in critical water supply pipelines, data are lacking on full-scale response to direct tension loads that cause deformation beyond yield. Such loads can be experienced during earthquakes, floods, landslides, and subsidence associated with underground construction, mining, and dewatering. This paper describes two large-scale direct tension tests on nominal 300 mm diameter steel pipelines with WSJs that were fabricated by the Los Angeles Department of Water and Power (LADWP). The test specimens were loaded to complete circumferential tensile failure. Load vs. displacement plots are presented for each specimen. Both radial deformation and longitudinal and circumferential strains are plotted as a function of longitudinal distance along the pipe. Failure of both specimens occurred in the main body of the pipe several diameters from the WSJs. Maximum longitudinal strains were on the order of 28–38%, with a corresponding decrease in circumference by necking of 10 and 18%, respectively. The results of numerical simulations with a 3-D axi-symmetric solid finite element model using the program ABAQUS compare favorably with the experimental measurements. Conclusions are drawn with respect to WSJ ductility, pipeline performance, and the ability of the numerical simulations to replicate the experimental behavior.

The increasing size of container cranes has resulted in vulnerability to seismic loads which has not previously been recognized. This paper presents the results of scale testing and analysis of a typical jumbo container crane subjected to earthquake loading. A series of 1/20^th scale shake table tests of the model structure is performed under increasing levels of acceleration to assess the response and identify potential failure modes. Numerous responses, including lateral displacement and uplift are monitored during the testing. Complimentary detailed nonlinear finite element time history analyses are also performed. It is found that the portal frame response dominates elastic behavior, which is captured well by analytical models. Stronger excitation produces uplift, which couples closely with elastic behavior. The resulting rocking, including its isolating nature, can be captured by analytical models.

A NEESR Grand Challenge Project is being carried out to develop and implement improved procedures for seismic risk management of container port systems. Central to these procedures is a risk analysis framework for deterministic or probabilistic assessment of economic risks due to earthquake-induced interruption of shipping operations for an entire system of berths that comprises an overall port system. Probabilistic assessment requires the use of fragility models for wharf structures that define the probability of occurrence of various damage states as a function of the seismic hazards at the structure site. In these models, damage states are represented not only in terms of the extents, types, and locations of damage throughout the structure, but also in terms of the costs and times to repair this damage, and the ability of the wharf to accommodate shipping demands as the repairs proceed over time after the earthquake. This paper describes the methodology that has been developed under this project to provide wharf structure fragility models that meet this objective.

Pile-supported marginal wharves are a critical infrastructure component of ports. Experience from previous earthquakes indicates that the connection between the pile and the wharf deck is a major source of damage during and earthquake. Previous studies indicate that although connections designed using current guidelines can maintain cyclic drift demands, they sustain damage and initiate strength deterioration, even at low levels of drift. Therefore, there is an interest in improving the performance of precast pile connections. A study to improve the performance of pile-wharf connections, part of the NEES-GC Seismic Risk Mitigation of Ports, was undertaken to develop damage-resistant connection. The results of the study and associated performance tools are summarized. To mitigate the pile and deck damage, several structural concepts were evaluated including (1) intentional debonding of the headed reinforcing bars, (2) supplemental rotation capacity through the addition of a cotton duck bearing pad and (3) supplemental material to sustain the lateral deformations while minimizing deck damage. The test results show minimal damage and strength loss relative to current practice and achieving performance-based design objectives. These results have been combined with prior test results on connections. By separating the connection responses by categories, individual connection-rotation based fragility curves have been developed for three repair-specific damage states. These curves would be appropriate for performance-based evaluation of older, current, or innovative connections in port construction.

Recent earthquakes have highlighted the vulnerability of piled-supported container wharves to moderate-to-strong ground motion. In this paper, a detailed seismic analysis is performed for a typical pile-supported container wharf. A three-dimensional nonlinear analytical model is constructed using the OPENSEES platform. Nonlinear beam-column elements with fiber sections are adopted to adequately capture the nonlinear deformations in the pile-deck connection. The wharf deck is modeled using rigid beam elements, and P-Y spring elements are used to represent the subsurface condition below the wharf. A series of pushover, modal, and time-history analyses are performed to evaluate the seismic response of the model.

Current practice for seismic design, retrofit, and analysis of container port structures (e.g., wharves and cranes) typically considers only the seismic performance of the structures themselves. They do not consider how damage and downtime of these structures might disrupt the overall port system's ship handling operations and the regional, national, and even international economic impacts that could result from extended earthquake-induced disruption of a major container port. To address this issue, research on managing risks from such system-wide disruptions due to earthquake damage is being conducted as a central element of a Grand Challenge project under the auspices of the Network for Earthquake Engineering Simulation (NEES) program. This paper summarizes the basic concepts and methods that are being developed to address one key element of this overall project — the analysis of seismic risks to a port-wide system of berths (with their particular wharf and crane structures). It also discusses how results from such analyses can guide port decision makers in making a more informed selection of design, retrofit, operational, and other seismic risk managment options that may be under consideration.

This paper reviews the history of seismic design codes and practices in the United States and the relation with model building codes. Until the 1980's, design was done using a single level earthquake, and equivalent lateral force design. Since the mid-1980's, common practice in high seismic areas has been to use performance-based design with multiple level earthquakes, and different performance objectives for each level. The current state-of-practice is to use displacement-based design methods, with strain criteria based on several large scale experimental tests performed over the last 10 years. This practice has become prevalent throughout the United States. The history of building code development is also reviewed, and the impact on the marine industry. In particular, the introduction of the Maximum Credible Earthquake with a 2,475 year return period, has created inconsistent design premises for buildings and marine structures. The paper further describes what is currently happening in codes and standards developments in the marine industry. An ASCE Standards committee is preparing a consensus document that will address seismic design of piers and wharves. Because of varying jurisdictional authorities throughout the United States, it is still expected to take many years before the design approach becomes unified in this country.

The Port of Long Beach (POLB) acknowledged in the late 1990's that the continuous increase in container throughput volume would require establishing a consistent system of standards and guidelines for the design of container wharves to successfully execute the necessary capital improvement. The understanding of seismic requirements for design of pile-supported wharves has considerably increased during recent years. New and larger ships provided new challenges; new details and practices for the design and construction of wharves were developed and followed by new codes and guidelines for port structures. This work, however, was driven by different authorities, often not closely coordinated: Code Writing Authorities, Owners (Ports), and Consultants. As a result of the rapid development in this field, the resulting documents for the seismic design of wharves made their interpretation sometimes difficult. POLB recognized the need for uniform and port-specific guidelines and developed port specific Wharf Design Criteria. This paper specifically addresses the Seismic Design Criteria. They include Ground Motions and Performance Criteria, Geotechnical Considerations with particular attention to soil-structure interaction, Structural Design and Analysis Methods, and Seismic Detailing. These subjects are specifically adjusted for site-specific conditions in POLB, such as seismicity, foundation soils, construction practices and the requirements of the Port's Engineering Bureau, which had an important function in the development of the criteria. All seismic design and analysis procedures are based on displacement-based procedures. The development of the criteria was reviewed at various stages by experts in structural, geotechnical, and earthquake engineering disciplines. An experimental program verified the analytical assumptions. POLB's recent wharf construction experience confirmed the practicality of the construction details. It is anticipated that these Criteria will provide more uniformity, focus on design, quality assurance, and minimize construction costs, while providing better coordination between POLB's engineering staff and consultants.

Historically, seismic forces have not been a concern for early container cranes, which were lighter and less stable than today's larger jumbo cranes. During an earthquake, the earlier cranes would lift from the rails before significant inertia forces could develop in the crane structure. Current large cranes, with 100-foot or greater rail gages, are much heavier, which results in significantly larger seismic forces in the crane structure. Liftech has performed time-history analyses of A-frame and low profile jumbo cranes. Our studies indicate that many jumbo cranes will be extensively damaged in moderate earthquakes, and that many jumbo cranes will be severely damaged, or will collapse, in a major earthquake. Container crane seismic design criteria are changing to address the seismic risk to jumbo cranes. Several upcoming design standards, one from the American Society of Civil Engineers, and others from ports, will specify seismic performance requirements for new cranes. This paper presents the following: 1. Expected seismic performance of cranes built to early design criteria 2. Recent design standards and their crane seismic performance requirements 3. New crane seismic design criteria, their effect on the crane design and costs 4. Options for retrofitting existing cranes

ASCE 7-05 (ASCE, 2005) was developed as the national standard to provide minimum life-safety standards for designing buildings and other structures. However, it does not address in detail the requirements for seismic design of pile-supported piers and wharves. Piers and wharves are typically built on sloping ground and the evaluation of and designing for kinematic loading on pile foundations and structures due to permanent ground deformation during an earthquake has been a challenge. Performance-based seismic design codes and criteria have been adopted by some local and state jurisdictions on the West Coast for the seismic design and evaluation of piers and wharves to achieve a specific level of performance using a displacement approach based on a minimum of two levels of earthquake motions. ASCE is in the process of developing a national standard for the seismic design of piers and wharves by incorporating salient features from available performance-based seismic design codes and criteria. As a part of this effort, seismic soil-structure interaction associated with piers and wharves are being addressed by a group of structural and geotechnical engineers and owners with interest in seismic design of piers and wharves. This paper discusses lateral soil-structure interaction issues and provides guidelines and suggestions to simplify the evaluation process while maintaining a robust design.

This panel discussion will involve an entire conference session. The paper for this session, presented herein, is a compilation of responses to questions regarding seismic risks to ports prepared by invited panel members consisting of eight port engineers from key U.S. port facilities subject to seismic shaking. Invited ports are: Oakland, Long Beach, Los Angeles, Portland, Tacoma, Seattle, Anchorage and Charleston. A short biography of each port representative is included in the paper. The format for this conference session will be a panel discussion of seismic issues related to port facilities by these panel members, based initially on topics presented in this paper and from questions from the audience. Seismic risk related questions include key seismic issues that affect the cost of new and existing wharves in liquefiable ground, definitions of what seismic risk means to the port, how does the port determine what level of risk they are willing to accept, and what engineering design issues the port is most interesting in having their consultants address. The responses by the port engineers to these pre-selected questions have been compiled and included in the paper for this session.

This paper presents some of the analytical issues encountered and lessons learned during the seismic assessment and rehabilitation design of marine oil terminal structures in compliance with Chapter 31F of the California Building Code, otherwise known as the Marine Oil Terminal Engineering and Maintenance Standards (MOTEMS). Specific topics discussed include best-practice analytical approaches for demonstrating MOTEMS compliance, the use of moment-hinges in pile supported systems, evaluation of battered pile supported systems, as well as incorporation of orthogonal effects in analysis for irregular structural systems.

There is an infrastructure of marine oil terminals in California, with an average age of over 50 years. Historically, there has been no consideration for the increased seismic risk and the possibility of massive amounts of oil to be spilled in California's ports or in San Francisco Bay. Most of these structures were built with little or no consideration for seismic loading and the current state of repair is generally poor. Additionally, the petroleum pipelines have never been analyzed for the displacement motion associated with the seismic demand. As these structures were inspected above the water line for many years by the California State Lands Commission (CSLC), operators/owners were in no rush to make any improvements. As a result of the 1994 Northridge Earthquake, a federal hazard mitigation grant was given to the CSLC to develop standards to mitigate future damage to port/harbor pile-supported structures. The code was completed in 2006, and is primarily for marine oil terminals, but is generally applicable to port/harbor pile supported wharves or piers. This new set of standards is Section 31F of the California Building Code and is now enforceable. An initial group of 10 "high risk" terminals have submitted their initial audits, documenting the structural condition, above and below the water line, along with plans for seismic rehabilitation. A fitness-for-purpose criterion not only provides inspection results, but also provides a structural assessment, as to whether or not the facility will meet the performance standard of two levels of seismic demand. These initial 10 terminals are in high seismic zones, and the seismic demand for a Level 1 earthquake is 50% probability of excedance in 50 years, and for a Level 2, the standard is a 10% probability of excedance in 50 years. This paper will provide summary results of some of these terminals, providing a general description of how they were modified to meet the seismic criteria, with minimum down-time.

This paper discusses the seismic assessment and rehabilitation of timber structures. The author and his colleagues have inspected and strengthened timber trestles and dolphins for marine oil terminals and bulk handling piers and wharves. We have inspected and assessed several timber structures and developed alternative repair designs that allow the structures to meet the required operational and seismic demands. The design process is discussed and includes: seismic analyses, seismic strengthening, and geotechnical constraints. The paper also includes some lessons learned and pitfalls to avoid for future rehabilitation projects.

Advanced fiberwrap composites (i.e. fiber reinforced polymers, FRP) have been used to structurally rehabilitate concrete, timber and steel structures in North America for more than two decades. Using these advanced composite systems, engineers routinely strengthen bridges, buildings, industrial facilities, large diameter water pipes, and many other several works structures that have been in service for many years. There are multiple reasons for using the FRP systems as a construction alternative in waterfront structures as well. Seismic retrofitting, structural strengthening (due to change of use or for code compliance), environmental protection and corrosion mitigation of coastal structures are the primary reasons. FRP composite systems have been used in municipal port facilities as well as industrial private facilities for more than a decade. To illustrate the capacities of FRP's more specific to waterfront structures, a case study recently completed by Fibrwrap Construction Inc. will be discussed in depth. The structural problems requiring attention on the case study include: structural strength deficiencies, high volumes of spalled concrete and steel corrosion. The following items regarding the case study will be explored in the paper: 1). Methods of concrete repair 2). Addressing the corrosion issue 3). Selection of proper Advanced Fiberwrap Composite System to perform structural strengthening The project that will be discussed is on the San Diego Harbor, in National City. Part of the scope of work was to work from floating platforms to execute concrete repair, apply corrosion inhibiting materials and install FRP strengthening systems. The FRP applicator successfully completed the project within schedule.

This paper the use of a multi-tiered approach for analyzing the effectiveness of stone column ground improvement to limit deformations of slopes containing liquefiable soil layers. The application addressed in the paper relates to ground improvement below a new pile-supported wharf at the Port of Tacoma. The purpose of stone columns is to reduce slope movements in the slope caused by liquefaction and lateral spreading such that the wharf and its supporting piles are not damaged during a design level earthquake. The authors performed numerous stability and deformation analyses at the wharf slope, with and without ground improvement. In order of complexity and cost, the analyses included slope stability (Slope/W), simple slope movement (Newmark), more advanced slope deformation but with a simplified soil model (PLAXIS) and more advanced slope deformation but with an effective stress soil model that includes pore pressure considerations (FLAC). The results indicate that while the simpler analyses provide a reasonable estimate of slope movement and the impact on the wharf piles, they tend to be somewhat conservative. The most advanced analyses (FLAC) that include pore pressure impacts and a better method to model pile-soil interaction provide the least conservative results. Thus, FLAC was used in the final analyses to verify that 5 rows of stone columns is adequate to reduce slope movements and piles deformations to an acceptable level.

The Port of Oakland (Port) was established in 1927 at which time it became a separate autonomous department of the City of Oakland. The Port inherited old timber pile-supported wharf infrastructure that was then primarily used for break-bulk operations with on-dock transit sheds. These maritime facilities have since been converted from break-bulk to container terminal operations. Although many of the original wharf structures were demolished and rebuilt, many of these rebuilt structures no longer meet today's latest design criteria. Accordingly, the Port of Oakland underwent a system-wide evaluation of its maritime wharf structures to categorize them from the most seismically vulnerable to least seismically vulnerable. Using this information, coupled with the impacts of both operational and retrofitting costs and the Port's financial capacity to perform the improvements, the Port began a series of retrofit projects. This paper will explain the numerous factors the Port of Oakland considered in determining which retrofit projects should be considered and the schedule of those proposed improvements.

Existing Berths 145–147 at the Port of Los Angeles (POLA) were built in 1980's and were designed for smaller, older generation ships and 50-ft gauge cranes. The terminal needed operational upgrades to be able to accommodate the new ships with deeper draft and 100-ft gauge cranes. The upgrade of Berths 145–147 also constituted a seismic upgrade, which made them the first berths at POLA to be seismically upgraded. The upgraded structure was designed using the seismic hazard criteria for two earthquake levels the operating level earthquake (OLE), and the contingency level earthquake (CLE), defined in the POLA seismic code (Ref. 5). The wharf upgrade requires the removal and replacement of Berth 147 and a partial removal of the existing structure at Berths 145–146. The wharf upgrade design of Berths 145–146 requires additional piles to be driven on the landside to increase the lateral seismic capacity of the wharf. Also, a new concrete deck will be constructed to transfer load to these additional piles. The existing deck was used as falsework to reduced construction cost. Due to cost implications, the wharf upgrade design considered not removing the existing seismic piles as long it could be shown they have sufficient capacity to resist expected seismic demands. Therefore, a representative connection was built similar to the actual field condition and tested at the University of California at San Diego (UCSD) to assess the seismic capacity when subjected to reversed cyclic loading conditions. A full scale pile-to-deck connection test specimen was built and tested in upright position and supported by a hinged steel collar simulating at the point of contraflexure. The existing pile-to-deck connection reached displacement ductility greater than eight in both directions. This performance indicates that the existing pile elements and connections are able to can resist the expected demands and can be incorporated in the new wharf seismic upgrade. It is not necessary to cut the existing pile connection to the deck nor is it necessary to provide special reinforcement to the existing pile-deck connections. In addition, a dynamic soil-structure interaction analysis was performed using the finite difference computer program FLAC to evaluate and support the use of a king pile an underwater bulkhead system at the toe of the slope to accommodate the channel deepening to -53 ft.

An intake pipeline was to be constructed on a channel bank which partially retained by anchored concrete sheet pile walls. To evaluate seismic stability and deformation of the channel bank and the anchored sheet pile walls subject to the design earthquake we utilized three engineering approaches which consisted of the limit equilibrium method, the p-y method and the time history soil-structure-interaction (SSI) analysis method. The subsurface soils consisted of medium stiff to stiff clays and silts underlain by medium dense to dense sands to silty sands with liquefiable layers in the upper 50 feet. Groundwater table was about 10 feet below ground surface. The earth pressure method assumed the passive side (embedded portion) of the sheet pile walls were resisted by an allowable passive earth pressure while the active side was subject to surcharge, active static and seismic earth pressures including hydrodynamic pressures. The p-y method considered nonlinear response of soils in the passive side through p-y curves while the active side was subject to the same pressures. Seismic earth pressures were evaluated using the modified Mononobe-Okabe procedure presented by Ebeling and Morrison (1992) which accounts for the effects of a submerged backfill. Post-liquefaction residual strength was used for liquefiable layers in the p-y method. A nonlinear effective-stress SSI analysis using the commercial software FLAC coupled with a pore-pressure generation model was performed and the forces, moments and deflections from the above three methods were compared. Differences of the results and deficiencies of the methods described above were discussed and the recommendations for the final design of the project were made.

Past earthquakes have demonstrated that port facilities suffer extensive seismically induced damage due to poor foundation and backfill soil that are common in waterfront environments. Focusing on pile-supported wharves, this study evaluates seismic behavior of port structures recognizing that most of the parameters controlling the properties of soil are of a random nature. The response of such structures inherently presents a complex soil-structure interaction (SSI) problem involving ground shaking, pile-failure mechanism, and liquefaction and lateral spreading in backfill and sand layers. In this study, using a representative model of a typical pile-supported wharf in the west coast of United States and considering an ensemble of ground motions with different hazard levels, effect of soil parameter uncertainty on seismic response is evaluated. For numerical simulations, an effective stress analysis method has been utilized. In order to investigate the effect of soil parameter uncertainty on seismic response, random samples are generated using Latin Hypercube Sampling and nonlinear time history analysis is carried out repeatedly for each realized sample. Finally, the effect of parameter uncertainty is demonstrated in terms of seismic fragility curves. The results of this study can be utilized to evaluate the seismic vulnerability of similar pile supported wharves.

The California Strong Motion Instrumentation Program (CSMIP) has instrumented five port structures. Instrumentation of two more port structures is underway and another one is in planning. Two of the port structures have been seismically strengthened. The primary goals of the strong motion instrumentation are to obtain strong earthquake shaking data for verifying seismic analysis procedures and strengthening schemes, and for post-earthquake evaluations of port structures. The wharves instrumented by CSMIP were recommended by the Strong Motion Instrumentation Advisory Committee, a committee of the California Seismic Safety Commission. Extensive instrumentation of a wharf is difficult and would be impossible without the cooperation of the owners and the involvement of the design engineers. The instrumentation plan for a wharf is developed through study of the retrofit plans of the wharf, and the strong-motion sensors are installed at locations where specific instrumentation objectives can be achieved and access is possible. Some sensor locations have to be planned during design; otherwise they are not possible to install after construction. This paper summarizes the two seismically-strengthened wharves and discusses the instrumentation schemes and objectives.

Probabilistic seismic risk assessment for lifelines is less straightforward than for individual structures. Analytical risk assessment techniques such as the "PEER framework" are insufficient for a probabilistic study of lifeline performance, due in large part to difficulties in describing ground-motion hazard over a region. As a result, Monte Carlo simulation and its variants appear to be the best approach for characterizing ground motions for lifelines. A challenge with Monte Carlo simulation is its large computational expense, and in situations where computing lifeline losses is extremely computationally demanding, assessments may consider only a single "interesting" ground-motion scenario and a single associated map of resulting ground motion intensities. In this paper, a probabilistic simulation-based risk assessment procedure is coupled with a deaggregation calculation to identify the ground-motion scenarios most likely to produce exceedance of a given loss threshold. The deaggregation calculations show that this "most-likely scenario" depends on the loss level of interest, and is influenced by factors such as the seismicity of the region, the location of the lifeline with respect to the faults and the current performance state of the various components of the lifeline. It is seen that large losses are typically caused by moderately large magnitude events with large average values of inter-event and intra-event residuals, implying that the scenario ground motions should be obtained in a manner that accounts for ground-motion uncertainties. Explicit loss analysis calculations that exclude residuals will demonstrate that the resulting loss estimates are highly biased.

The Alfred E. Alquist California Seismic Safety Commission (SSC) recently conducted policy-level reviews of changes to the San Francisco Public Utilities Commission's (SFPUC) Water System Improvement Program and a study by the California Energy Commission regarding the seismic vulnerability of nuclear power plants at Diablo Canyon and San Onofre. In both cases, the SSC identified system management policies that warrant changes to ensure that seismic safety is more comprehensively addressed. The SSC recommended that the SFPUC change its review protocols to ensure their independence consistent with SSC's long-standing Policy on Independent Reviews of Critical Facilities. The SSC also found that delays in implementing the SFPUC Program will have adversely impacted the Program with respect to public health and safety if a major earthquake occurs during the approximately year-long period after the previously scheduled completion date and before the currently scheduled completion date. The SSC also recommended that a regulatory gap be filled because neither the State of California nor the United States Nuclear Regulatory Commission currently regulates non-nuclear portions of nuclear power plants; the NRC allows utilities to self-regulate these portions of the plants.

Methodology is developed for simulating spatially correlative time-frequency non-stationary earthquake ground motions compatible with the code spectra in this paper. The traditional methods for simulating earthquake ground motions are mainly base on the power spectra. However, the earthquake load sometimes is represented as the code response spectra, so the proposed methodology is more available for engineering application. Currently used method simulated ground motions are non-converge in local fields, which contradicts the propagating mechanism of the real earthquake wave, by modifying random phase angle, the local non-convergent is eliminated. The amplitude and frequency non-stationarity are expressed by using envelope function and phase difference spectrum respectively. Numerical example is presented to illustrate the features of the proposed methodology and the response spectra of the simulated motions are compatible well with the target spectra. The simulated motions by the proposed methodology can be used for more realistic seismic response analysis of extended structures such as bridges, power plants, dams, etc. for considering the spatial variation of ground motion.

The U. S. Geological Survey (USGS) ShakeCast system is a freely-available, post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users' facilities, sends notifications of potential damage to responsible parties, and generates facility damage assessment maps and other Web-based products for emergency managers and responders. The ShakeMap/ShakeCast combined system allows a consistent approach for the evaluation of facility performance using the ShakeMap methodology by combining observations with ground motion predictions and covers major geographic regions and earthquakes, real-time, historical, and scenario, worldwide. We present common approaches to assessing facility impact estimates by combining measured or estimated ground-motion parameters with vulnerability functions. Vulnerability functions can be pre-computed, use one of these ground-motion parameters as input, and produce a multi-state discrete output of damage likelihood (or, inspection priorities). Two custom modules for evaluating Arias Intensity and Newmark landslide displacements are presented as examples of using the ShakeCast application with more advanced, customized damage functions.

We are currently working toward the development of a probabilistic decision-support system (DSS) for near-real time emergency response and recovery following a seismic event. We utilize a Bayesian Network (BN) framework for assessing the performance of spatially distributed infrastructure systems subjected to seismic hazards. BNs have many valuable characteristics (e.g. they are graphical, adaptable, efficient, and enable Bayesian updating) that make them well-suited for such an application. We model seismic demands on an infrastructure system by constructing a BN model of ground motion intensity as a spatially distributed random field. In this paper we present this seismic demand model with recent enhancements including the addition of a finite source model. The performance of infrastructure system components and the overall system is modeled using fragility functions and BN system connectivity formulations. An example application to a hypothetical transportation system is presented to illustrate the power and value of the proposed BN framework.

A heuristic minimal path sets method for analyzing seismic reliability of lifeline networks is proposed. For large-scale lifeline networks reliability computation can become prohibitive or inaccurate using the current enumeration methods. Although a few studies have considered both node and link failures, none of these methods has utilized the minimal paths method. This paper proposes a minimal path algorithm to evaluate reliability of relatively large lifeline networks with unreliable nodes and links. As the primary task, the method can deduce all minimal paths of a directed/undirected network. In the algorithm, minimal paths for both nodes and links are traced performing several procedures. The terminal-pair reliability of the network is then evaluated by performing an efficient Monte Carlo simulation as an alternative to exact reliability calculation methods. In terms of computational speed, the results obtained compare well with existing algorithms. The algorithm requires minimum memory storage and minimum user-defined data to represent the topology of a network. A series of case studies illustrate that the method can be used to evaluate reliability of the large-scale lifeline systems subject to node and link failures, efficiently.

Multi-hazard risk assessment of lifeline systems is becoming more popular as utilities try to balance the risk across multiple hazards. In past decades, tremendous research efforts have been expended in assessing reliability and performance of lifeline networks under single catastrophic event, but there are minor researches presenting a multi-hazard model. In this paper, simulating multi-hazard effect as common cause failure group, an efficient minimal path sets method is applied to multi-hazard reliability analysis of lifeline networks. Recently, a few researchers have incorporate common cause failures (CCF) in the reliability analysis of the networks. However, the existing CCF models have various limitations, such as having inability to handle the networks subject to both link and node failures, and being applicable only to small networks. In this paper, we seek to address the limitations in developing a more general CCF model for the network reliability of networks. The method has a low computational complexity and is easy to implement. A sample network from literature is analyzed to test the efficiency of the model. A case study on a theoretical lifeline network is performed to illustrate the advantage of the model to multi-hazard reliability evaluation of a real-life network.

This study proposes a certain measure for decision making associated with the seismic retrofitting investment strategy reducing the risk of a large-scale malfunction such as water supply loss under seismic risks. Newly developed stochastic value index is adopted for the overall evaluation of social benefit, income, life cycle costs and failure compensation associated with the existing lifeline systems damaged by an earthquake during the remaining service period. Discussions are given for the optimal seismic disaster prevention investment of the existing deteriorated lifeline system. Finally, the present study can provide a performance-based design method for seismic retrofit strategies of existing lifelines which can be carried out through the target probabilities of value loss and structural failure.

The operational capacity of most lifelines during natural disasters requires substantial improvement in today's world. Engineers need to apply our expertise towards improving lifeline resiliency, including working with politicians and stakeholders to develop the means to obtain suitable levels of lifeline resiliency during disasters. Major questions involving uncertainties with the performance of lifelines arose from a planning exercise hypothesizing a Cascadia magnitude 9 earthquake. Portland, Oregon's risk in terms of earthquake hazards and lifeline vulnerabilities are discussed, including a focus on North-Northwest Portland. High hazard areas, such as riverbanks and hydraulic fills, that have critical lifelines require 1) seismic vulnerability assessments that address the potential consequences, and 2) risk management programs that mitigate unacceptable damage and losses including ripple effects. ASCE TCLEE's influence in the Portland region involves activities by the eight TCLEE committees: Investigation; Electrical Power and Telecommunications; Water and Wastewater; Gas and Liquid Fuels; Transportation; Ports and Harbors; Seismic Risk, and Programs and Publications. A three step policy approach towards improving lifeline resiliency is proposed. Policies could involve new state or federal initiatives, or improvements to the National Earthquake Hazard Reduction Program (NEHRP), which includes NIST, FEMA, NSF, USGS, OMB, OSTP and ACEHR (see list of abbreviations).

Due to recent advancements in performance-based earthquake engineering methods, in modeling of complex nonlinear structural behavior, and in characterization of earthquake ground motions, it is becoming possible to directly simulate earthquake-induced structural collapse. These simulations can be used to develop probabilistic descriptions of structures' seismic collapse risk. This paper first summarizes recent developments in assessment of seismic collapse risks for building structures, which apply nonlinear time-history analyses to predict when structural collapse occurs. In the second part, the discussion focuses on how the lessons learned from these building collapse risk assessments can be applied to predicting the seismic collapse risk of bridge structures. The paper proposes extending current assessments of bridge seismic performance (which typically focus on prediction of structural damage prior to collapse) to include robust assessments seismic collapse safety. Key issues for structural collapse assessment relate to ground motion scaling and spectral shape, creation of nonlinear structural simulation models (differing in certain critical characteristics from models used to predict pre-collapse response), and incorporating uncertainties in ground motions and structural modeling.

Due to its complex nature, risk assessment of a lifeline network is often performed by repeating computational simulations on network connectivity or flow that are determined by random samples of hazard intensities and corresponding component status. Despite its wide applicability, this sampling approach may prevent rapid risk assessment and risk-informed decision making for hazard mitigation and responses. As an attempt to identify opportunities and challenges in rapid stochastic risk assessment of urban infrastructure networks, non-sampling-based network reliability analysis methods have been recently developed based on a matrix-based system reliability method. This paper presents these methods along with numerical examples of a gas network and a bridge transportation network. The method developed for post-hazard connectivity can assess the risk of disconnections in a lifeline network and identify important network components or parameters at multiple scales while spatial correlation of seismic intensity is considered. The method developed for post-hazard flow capacity analysis can account for the time-varying effect of the structural deterioration on the network flow capacities in an efficient manner.

A permitting-level design was conducted for a liquefied natural gas (LNG) facility, proposed on the northwest Oregon coast. The permitting-level design required the structure to operate safely during the design level ground shaking from an earthquake on the underlying Cascadia Subduction Zone interface fault. The site is underlain by 350 feet (107 meters) of predominantly soft non-plastic silt and medium-dense to dense sand layers. The design of the LNG facility, as well as the foundation system, required an estimation of the liquefaction potential and cyclic performance of the silt and sand soil layers, however, there is limited published information for evaluating the cyclic behavior of deep soil deposits. This paper summarizes the results of (a) an extensive site investigation and cyclic soil laboratory testing conducted to develop cyclic parameters and (b) nonlinear effective-stress site-response analyses using the computer program D-MOD2000. The analyses were conducted to evaluate the cyclic performance of the soil layers for use in designing the foundation system. The results of the cyclic testing and lessons learned during the numerical modeling are presented.

This paper summarizes proposed seismic design methods for culverts and drainage structures used by transportation agencies for highway systems. The design methods were developed as part of National Cooperative Highway Research Program (NCHRP) Project 12–70 Seismic Analysis and Design of Retaining Walls, Buried Structures, Slopes and Embankments. This project was sponsored by the Highway Subcommittee on Bridges and Structures (HSCOBS T-3) of the American Association of State Highway and Transportation Officials (AASHTO). The intent of NCHRP Project 12–70 was to address shortcomings in the current AASHTO LRFD Bridge Design Specifications. The culvert and drainage structure portion of the NCHRP 12–70 Project focused on the development of simple equations and charts that could be used by transportation agencies. Both transient ground displacement and permanent ground displacement were considered. This paper summarizes the development work and the proposed draft specifications written as part of the NCHRP 12–70 Project.

It took more than 10 years for the San Francisco Bay Area to fully recover from the 1989 Loma Prieta earthquake, and many retrofit programs have been underway since then to seismically upgrade or replace critical infrastructure. The Bay Area Rapid Transit (BART) District is currently undertaking a major seismic retrofit program of its system and has several projects already under construction. In 2002, BART began seismic re-evaluations of its infrastructure. Using updated seismic criteria since the original design of the late 1960s / early 1970s, BART found that parts of its system were not as reliable as desired and developed a range of possible seismic upgrade options. Using a benefit-cost model, BART adopted a $1.3 billion seismic upgrade program. The cost of this program was approved by a two-thirds majority of voters in 2005 in a bond issue.

Anchorage International Airport is a critical component of Alaska's transportation system and its economy. Annually, over 4.5 million people use the Anchorage International Airport for air travel to other parts of Alaska, North America, and international destinations. Because of the distance between Alaska and the rest of the United States, and the sheer size of the state, air travel is one of the most popular and important means of transportation—a lifeline for Alaskans not living in close proximity to the Anchorage area. The importance of this facility, coupled with the region's high seismicity, makes seismic vulnerability an important factor of this lifeline's dependability. In 2002, Alaska's Department of Transportation (ADOT) commissioned a multi-disciplinary design team to evaluate the airport's 384,000 square-foot South Terminal, which supports domestic flights, for seismic vulnerability. The purpose of the seismic evaluation was to gain an overall understanding of the seismic deficiencies and to assess the risks associated with the facility, thereby allowing ADOT and the design team to collaboratively formulate a seismic risk reduction strategy. A major component of this risk reduction strategy was the implementation of a seismic upgrades project utilizing Performance-Based Earthquake Engineering (PBEE). This paper presents a PBEE case study of the Anchorage International Airport Seismic and Security Improvements Project, including evaluation findings, and rehabilitation design parameters and strategies for the South Terminal buildings that make up this important lifeline facility.

The perimeter dike is located in seismically active region, the San Francisco Bay Area. The Hayward Fault is the closest active fault to the site, located 5.5 miles east of the site. Based on the findings from recent seismicity studies conducted by the Working Group on Bay Area earthquakes, it is likely that the perimeter dike will be subjected to large ground motions generated by future large seismic events on the active faults in the area. This paper summarizes the results of the vulnerability assessment of the perimeter dike for both the static and seismic loading conditions. The vulnerability assessment is based on seepage, slope stability, overtopping, and seismic analyses. The seismic deformation analysis was performed using a nonlinear finite difference computer program. The seismic analyses indicated that the dike model accurately predicts the deformations observed from the 1989 Loma Prieta earthquake. The same model was then used to predict the seismic deformations of the perimeter dikes for design ground motions.

The City of Milpitas has a strategic plan to prepare, respond, and recover from the impact of a major earthquake on its water utility. Located in the seismically active San Francisco Bay Area, this Silicon Valley community of 65,000 is vulnerable to seismic events on the nearby Calaveras, Hayward, and San Andreas Faults. There is a 62 percent chance of an M 6.7 or greater earthquake on these faults by 2032 and, in such an event, the City will experience strong ground shaking, liquefaction in the valley floor, and landslides in the hills. The City expects pipeline displacements of up to 8 inches and 150 water main breaks during a major earthquake. The City depends on an intact water service to protect public health and safety, as water is needed for fire protection as well as basic sanitation. Broken pressure mains may also damage transportation routes, hindering emergency response after a major earthquake. Because it is infeasibly expensive to seismically upgrade all components of the water infrastructure within a reasonable timeframe, the City developed a multi-component plan to optimize expenditure of its scarce utility funds while building its ability to protect and restore its water services. Planning included an infrastructure risk assessment to define water system vulnerabilities and consequences of failure. The City assessed its emergency response ability by evaluating personnel, equipment, contract supplies, and service needs. The City's wholesale suppliers are also implementing seismic response plans, so the assessment takes into account expected out-of-service times for supply. The City developed hazard maps for potential rupture zones, landslides, and liquefaction and mapped its water and transportation infrastructure into GIS so that emergency transportation routes and water pipeline networks and nodes are defined. Response preparation includes training to address gaps in personnel skills and preparation of emergency kits for staff and mutual aid personnel. GIS maps are loaded into laptop computers for field personnel and the City's Emergency Operations Center. The City is stockpiling an inventory of temporary and replacement equipment and expects to eventually acquire over 5,000 feet of flexible hose, deployable from trailer-mounted reels, to allow temporary bypass from hydrants around main breaks.

Water supply is vital for our life especially after an earthquake. In the water supply departments in large cities in Japan, more than 1,000 employees commute for 1 hour on average using several means of transportation. If an earthquake or other event occurs in the middle of the night or early in the morning, staff mobilization would be delayed due to the malfunction of public transportation systems and staff personal issues. This study purposes a model to evaluate staff mobilization for water supply departments based on the results of the questionnaire survey in Osaka City during 1995 Kobe earthquake. It also discusses one phenomenon about inter- dependence of water supply and transportation systems. Simulation of staff mobilization can estimate staff availability for emergency waterworks in terms of number and response time.

This paper describes a decision support system for water supply response to earthquakes, which is used to simulate the Los Angeles Department of Water and Power (LADWP) water distribution network after a 7.8 M_w earthquake on the southern San Andreas Fault. The simulation was performed as part of the 2008 ShakeOut earthquake preparedness drill, which was the largest exercise of its kind in US history. The simulation covered all 11,691 km of water trunk and distribution pipelines and related facilities (e.g., tanks, reservoirs, pressure regulation stations, etc.) in the LADWP system, plus the performance of the Los Angeles Aqueducts. The main findings of the simulation are summarized, with serviceability quantified as the ratio of water flow after to water flow before the earthquake on both a system-wide level and for 15 different water service areas. The simulation accounts for the effects of seismic ground waves and of permanent ground deformation associated with fault rupture, liquefaction, and landslides. Severe deterioration in water delivery is shown over 24 hrs due to damaged and leaking pipelines. The simulation shows nearly 2700 locations of pipeline repair of which approximately 5% are breaks and 95% are leaks. The system serviceability is approximately 34% after 24 hrs, which means that 66% of the normal water demand cannot be met.

In this paper an analytical procedure is described for modeling probabilistic seismic damage to water supply networks in urban areas. The methodology proposed here intends to model uncertainties associated with different factors controlling damage to water supply networks following big earthquakes. In this paper, synthetic earthquake catalogues representing long term seismicity and attenuation functions are used to model strong ground motions on water structures and pipeline networks. Probabilistic seismic damages to water supply network and potential water loss are estimated using Monte Carlo simulation and logic tree analyses on various sources of uncertainties. The process involves simulation of damages to pipelines and water tanks, using thousands of earthquake scenarios. Each earthquake scenario results in probabilistic and spatial distributions of damages to pipeline networks and water tanks. Hydraulic network analysis is then performed on each scenario of damaged pipelines in order to estimate probabilistic water loss and potential restoration time period. A GIS-based computer tool has been also developed in this study which consists of modules for analytical and probabilistic analyses as well as GIS functionality for spatial analyses and data visualization. To test the model, the water supply network for a small commune in Tehran is used and preliminary results are presented at the end of this paper.

The 75 MGD Joint Water Commission (JWC) water treatment plant (WTP) serves potable water to 500,000 people southwest of Portland, Oregon. The project included a seven step process leading to a decision to seismically upgrade the WTP. The WTP is located in a seismically active area dominated by the Cascadia Earthquake Subduction Zone that can produce a magnitude 9 earthquake every 475 years. The probability of this large magnitude event coupled with liquefiable site soils that will amplify the ground motion pose a significant seismic risk to the WTP. The seven step evaluation process included: 1.) Defining the desired WTP level of service goals following the 72, 475, and 2,475-year return earthquakes in terms of WTP capacity and outage time. 2.) Quantifying the ground motion for the three levels of earthquakes, the probability of liquefaction and/or lateral spreading occurring, and the consequences is liquefaction and/or lateral spreading should occur. 3.) Evaluating the seismic performance of the WTP components and overall system when subjected to the three levels of earthquakes, in terms of structural capability. 4.) Evaluating the impact of the expected structural capability on unit processes and WTP flow capacity and outage/reduced capacity restoration time. 5.) Designing four seismic mitigation packages and developing their associated costs for later use in risk-based decision making. 6.) Evaluating the expected performance of the WTP for the three levels of earthquakes for each of the four upgrade packages in terms of flow capacity and outage/restoration time. 7.) Assessing the risk-based economic consequences of implementing the four improvement packages considering direct damage, the owner's cost resulting from outage and business interruption to the community. The analysis concluded that the lowest net cost and highest benefit-cost ratio was attained when the 72-year improvement package was implemented.

Concrete arch dams, specially the large ones, are important structures which could be considered as critical points in each region. They have extremely large damage potentials and they must also be able to endure the effects of natural hazards. On the other hand, the earthquake is the main natural hazard which impacts the dam body. During the earthquake, huge amounts of forces imposed on the dam create large stresses in the various zones of the dam body. This may cause significant impacts or even dangerous damages. The above mentioned forces include the inertial forces of the dam body as a vibrating structure and additional forces which are due to the dam-reservoir-foundation rock interactions. These complicated effects influence the seismic responses of concrete arch dams significantly. Therefore, they should be considered in the dynamic analysis procedures of the dams. In this article, a new effective procedure is implemented for evaluating the seismic response of concrete arch dams including dam-reservoir interaction effects in the frequency domain. It is worthwhile to mention that the modeling concept is based on the FE-(FE-HE) approach. This means, the dam is discretized by solid finite elements, while, the reservoir is divided into two parts, a near field region (usually an irregular shape) in the vicinity of the dam and a far field part (assuming uniform channel), which extends to infinity. The former region is discretized by fluid finite elements and the latter part is modeled by a three-dimensional fluid hyper-element. To achieve a suitable efficiency, the analysis is carried out by the general modal analysis. For this reason, a new technique is proposed for calculating an approximation for the coupled mode shapes of fluid-structure systems. This can be visualized as a modification for the original Sandberg method (Sandberg, 1995). Moreover, a simple relation is derived which enables one to readily calculate the left eigen-vector from the corresponding right eigen-vector. Overall, this new approximate approach is believed to be very promising and it is shown that it could lead to almost exact eigen-values and coupled modes of the dam-reservoir systems. Also, the analysis of the Morrow Point arch dam is presented as a numerical example and the frequency response functions are provided for different cases.

Water is essential to life itself and, therefore, water supply is a critical post-disaster lifeline. Robust infrastructure is, of course, the key to post-disaster water system reliability. One key element of a water system's infrastructure is its water supply and storage. The East Bay Municipal Utility District (EBMUD), which serves 1.3 million customers in parts of Alameda and Contra Costa Counties on the eastern side of San Francisco Bay in Northern California, relies primarily on surface water for its supply and has several large storage reservoirs impounded by dams. These dams provide vast storage, but also carry with them risks for life safety. To mitigate this risk, EBMUD has developed a comprehensive dam safety program. This paper presents an overview of EBMUD's Dam Safety Program and highlights recent dam studies and improvement projects to ensure post-disaster lifeline services. EBMUD's Dam Safety Program strives to prevent property damage, personal injury, and loss of life from the failure of dams through instrumentation monitoring, visual inspection, and periodic dam safety reviews. The safety of each dam is re-evaluated as advances are made in the field of geotechnical, structural and earthquake engineering. For example, several dams were recently re-evaluated in light of advances in knowledge of earthquake ground motions. Dams are also re-evaluated based on observations due to changes in seepage or ongoing ground movement. EBMUD has a total of 31 dams that impound reservoirs: 2 major remotely located raw water reservoirs in the Mokelumne River watershed (Pardee and Camanche), 5 local water supply reservoirs, and 24 open-cut reservoir dams in the service area of the water distribution system. Most of these dams are under the jurisdiction of the California Division of Safety of Dams (DSOD). Periodic seismic evaluations have pro-actively revealed the need for various improvements, including a recent $76 million seismic upgrade to San Pablo Dam, a local water supply reservoir. Also, to better improve ongoing and post-disaster evaluation of dams, recent improvements have included the installation of automated dam surveillance instrumentation. In addition, EBMUD developed a plan for self-deployment of inspection personnel after a disaster to speed up response and save critical time in the critical first few hours. All of these efforts are undertaken with the goal of providing a reliable and robust water supply system for its customers.

The 10 million gallon, Rancho Bernardo Reservoir is owned and operated by the City of San Diego and serves a portion of the Rancho Bernardo community. It was constructed in approximately 1963 and consisted of an earth embankment with open graded asphalt and rubber butyl liner. The concrete roof system contained a post tensioned slab, prestressed columns, beams and girders. Roof deterioration in the late 1980's led to discussions for rehabilitation. To meet current building codes and seismic requirements, numerous options for design were presented and the best alternative was selected with final design completed in 2006.

As part of its Seismic Improvement Program, the East Bay Municipal Utility District (EBMUD) performed seismic retrofits on the roof structures on the Sobrante Water Treatment Plant Clearwell (8.2 MG) and the Upper San Leandro Water Treatment Plant Clearwell (6.6 MG). Both clearwells are open-cut reservoirs with timber roofs built in the early 1960's. The objective of each retrofit is to prevent the reservoir roof structure from collapsing into the water and thus degrading water quality and blocking the inlet-outlet piping. The designs were prepared using the 1997 Uniform Building Code and the EBMUD's Engineering Standard Practice.

Concrete gravity dams may break into several blocks by penetrated cracks under action of strong ground earthquake motion. The places of penetrated cracks are determined first by adopting a concrete damaged plasticity model and considering geometric nonlinearity of the crack based on nonlinear FEM. Then, a "hard" contact algorithm is adopted to simulate normal interaction of the crack and a Coloumb friction model is employed to simulate tangent interaction of the crack. With three different seismic peak accelerations, the seismic stability of Koyna Dam is discussed in detail. The results show that the dam will be stable when the horizontal peak acceleration is less than 0.061g. It also shows the friction coefficient have a great effect on stability of the dam. The maximum sliding displacement of the top block will lesson and the maximum opening displacement of the upstream end will increase with an increasing friction coefficient of the crack.

This paper covers the various hindrances to emergency response efforts after the May 12, 2008 Wenchuan China Earthquake. Hundreds of landslides blocked roads, destroyed bridges and flooding restricted travel in and out of the affected areas. This isolated numerous towns and cities hindering emergency response efforts. This paper examines how the Chinese government overcame these difficulties to rescue injured citizens, provide relief supplies, provide temporary housing, and general restoration of normal services.

The Wenchuan Earthquake occurred in a mountainous region where landslides caused damage to many highway and railway lines. Heavy rains and aftershocks made matters worse. Bridges in the area hadn't been adequately designed for earthquakes, resulting in the loss of many river crossings. Surface faulting also damaged roads and bridges. Damage to the transportation system had a negative impact on rescue and recovery operations. Approximately 30,000 miles of roads and railways, 1,000 bridges, 100 tunnels, and many miles of retaining structures were damaged. Losses to the transportation sector exceeded $10 billion.

The Wenchuan M 7.9 earthquake of May 12, 2008 had its epicenter in Yingxiu, about 100 km northwest of Chengdu. The epicenter was 31.0 degrees latitude, 103.4 degrees longitude. The earthquake occurred at 2:28 pm local time. The earthquake caused widespread and extensive damage to the high voltage power transmission network as well as local distribution systems. If China adopts modern seismic design guidelines for its power system, likely more than 90% to 95% of all such damage will be avoided in future earthquakes in China.

The May 12, 2008 M7.9 Wenchuan earthquake was one of the most costly and damaging earthquakes in recent memory. The impact of this horrific event will be felt in the Sichuan region for generations and will require hundreds of billions of dollars for recovery, rebuilding, and restoration. Vital to any community is a reliable and safe water supply and the Wenchuan earthquake damaged over 2,600 dams and reservoirs of all sizes and types in 8 provinces in China. Sichuan province experienced the majority of the damage to their dams and reservoirs with 1,996 dams experiencing some form of damage, which represents 30% of the dams in Sichuan. Of the 1,996 dams in Sichuan province that were damaged 69 were classified as Dangerous Situations of Dam-Break, 310 were classified as High Dangerous Situations, and 1,617 were classified as Secondary High Dangerous Situations. Damage to dams included cracks in 1,425 dams, collapse and settlement in 687 dams, slides in 354 dams, leaks and seepage in 428 dams, mechanical hoisting equipment damage in 161 dams, and outlet works, spillway, and office building damage to 422 dams. In the modern area of dam design and construction this extent of damage to a countries water supply and hydroelectric system has never before been realized or documented. This affords engineers a unique opportunity to evaluate the performance of these dams after they were subjected to significant earthquake loading and learn from our findings. This paper looks at damages to dams in Sichuan region, including Zipingpu Dam near Duijanyan, Shapai Dam, and other dams damaged by the Wenchuan earthquake and offers lessons learned for the design, construction and operation and maintenance of these structures. This paper will also compare Chinese dam design and safety practices with US dam design and safety practices for earthen, concrete, and rockfill dams.

This paper briefly summarizes the tectonic setting, seismic source mechanism and strong motion characteristics of the May 12, 2008 Wenchuan earthquake. Geotechnical factors that contributed to the earthquake damage are then described. The paper also outlines the general damage as well as specific damage to the lifelines. Finally, the immediate emergency response and longer-term post-earthquake recovery and reconstruction efforts are discussed, highlighting some lessons that could be applied to future occurrence of seismic or other natural and man-made hazard event.

Extensive water system damages have been reported and witnessed by the two separate ASCE TCLEE reconnaissance teams dispatched to the disaster area in July and October, 2008. This paper will present observations and lessons learned for damage prevention and system recovery of potable water systems. It will also describe the emergency response by the Chinese government and military and contrast it with U.S. practices.

The May 12, 2008 devastating earthquake in Sichuan Province, China impacted all lifelines. This paper provides a record of observed damage to the telecommunications systems in the earthquake disaster area in Sichuan as a result of the earthquake. A brief over view of the network, the components, and the standards used will be presented. Conclusions of importance of a secured network, and lessons learned will be discussed.

This paper describes the development of a numerical finite element algorithm used for the analysis of reinforced concrete structure equipped with shakes energy absorbing device subjected to earthquake excitation. For this purpose a finite element program code for analysis of reinforced concrete frame buildings is developed. The performance of developed program code is evaluated by analyzing of two reinforced concrete frame buildings model. The results are show that using damper device as seismic energy dissipation system effectively can reduce the structural response of framed structure during earthquake occurrence.

This paper compares the main characteristics of blast and seismic loading effects. Although the ductile and redundant requirements in seismic and blast design are similar, there are important differences in the structural design process. On the one hand, mitigation measures against weapon effects, e.g. blast, can significantly reduce the seismic performance. On the other hand, mitigation of weapon effects can also benefit from seismic design. These interaction effects and their implications are demonstrated. An integrated and balanced design approach is presented which is the basis for efficient design in a multi-hazard context. The presented design approach can lead to a better, more economic, and safer design. Concluding case studies show the performance of a three storey frame system and of a one storey building when subjected to seismic and air blast loading.

Nonlinear Static Pushover, NSP, is approximately reliable solution for time consuming problem of estimating the capacity and deformations of structures subjected to earthquakes. Conceptually, NSP methods rely on pushing the structure with incremental static lateral loads by considering material inelasticity and geometric nonlinearity. Despite of some distinct demerits of conventional pushover analysis these methods are credited with new trend of performance-oriented seismic codes. Subsequently, several methods with varying degree of rigor and success have been developed to overcome their deficiencies. In this study a comparative study in two aspects including estimating the capacity of structure and interstorey drifts of an R/C regular framed structure were implemented. The results of applying 5 types of NSP methods including conventional FEMA-356 "Triangular" and "Uniform" methods, "Force-based", "Displacement-based" and "Interstorey drift-based" adaptive methods were evaluated referenced to the "Incremental Dynamic Analysis" outcomes as the most precise approach. The numerical outcomes, demonstrated the reliability of interstorey drift-based method in evaluating the capacity of structure as well as superiority of this method in estimating the interstorey drifts by increasing the value of control-node displacement.

In dynamic analysis of many lifeline structures, the soil-structure interaction plays a very important role. It is well known that, the soil must be dealt as an infinite domain to include properly the effect of this interaction into analysis. Apart from modal analysis, one can reduce the number of final equations by assuming the deformed shape of the structure as a linear combination of independent Ritz vectors. The efficiency of this method relies heavily on the vectors selected, especially when an infinite domain is included in the analysis. In this paper, a new set of Ritz vectors is proposed. It is primarily proved that these vectors are linearly independent. Subsequently, various two and three-dimensional concrete dam-foundation systems are analyzed based on the proposed method. In each case, the results are compared with the ones obtained based on usual Ritz and modal analysis methods. It is finally concluded that the proposed method is very effective and efficient method for dynamic analysis of structures including soil-structure interaction.

Connection between an I-shaped beam and a CFT column has a prominent role in transferring gravity and seismic loads of the beam to the column; consequently, details of the connection shall mobilize the capacity of the concrete core and the steel tube simultaneously. In the proposed connection, beams on the forth sides of the column, are connected to the through plate assemblage which passes through the CFT column. Load transfer from the through plate to the column will take place through the weld between the connection plate and the steel tube, and also the bearing action and the friction force between the through plate and the concrete core. The proposed connection may promote confinement of concrete core in the region of connection in CFT columns as well, so the concrete section can mobilize to bear the load properly. This specification improves the seismic behavior of the connection, and it can be effective in seismic areas. The through plate connection has some advantages than other usual connections such as the mobilization of concrete by the friction force, load bearing and the lateral confinement in comparison to the steel beam which is only connected to the steel tube, and continuous place for casting concrete in the through plate connection which is more effective than the continuous through beam connection, because it can inhibit constructional problems, thus the quality of concrete mix might be improved in the connection zone. The behavior of this case under gravity and seismic loads is studied by the Finite element method.

Earthquake forces cause distress and damage to structures. The structures suffer different levels of distress. The present design philosophy of life safety and collapse prevention generally results which are safe under normal earthquakes, suffer repairable damage in moderate earthquakes and continue to stay without collapse under major earthquakes .It has been observed in the recent earthquakes that the structures designed following the above philosophy have withstood the earthquake forces but needed variety of retrofitting and rehabilitation measures resulting in economic losses of different proportions .Thus there is definite need to quantify the performance of the structures and the damage potential so that the levels of the safety can be assessed. A step-by-step procedure is presented in this study for this purpose. The seismic performance of an existing low-rise reinforced concrete building is evaluated in terms of its potential drift and damage levels as well as the performance curve obtained from a nonlinear pushover analysis. A probabilistic analysis is carried out to compare the performance of an existing frame to that of the retrofitted frames. The ground motions as well as the structure capacity are considered as random variables. The results of the analysis show that increasing the strength or strength with stiffness of reinforced concrete columns is the most appropriate technique to retrofit the structure under consideration due to the reduced values of drift and damage levels and the improved performance in the static pushover analysis. An evaluation procedure was proposed to estimate the maximum seismic demands and capacities using an enhanced capacity spectrum based approach. The shear forces vs. drift response at each storey level was determined and used to capture potential soft-storey mechanisms. The adaptive pushover analysis provided a more rational basis for applying the lateral forces, which in turn yielded a response that was more consistent with the expected system behavior under seismic loading.

Steel-framed houses are usually built of light thin-walled load bearing structures having different solutions for interior and exterior cladding.The main component to provide earthquake performance of a light-guage steel house are the shear panels.The shear panels are discontinued in story levels which are caused complicating their connections of story levels.One of the requirement of shear panels seismic design is TI809-07 2006 of U.S Army Corps.Except for story levels, in TI809-07, it is presented requirements for designing all elements and connections of shear panels. This paper investigates connection between shear panels in story levels and two methods which are developed for seismic enhancement of shear panel details in TI809-07 2006 and earthquake performance and also the modified steel stud wall system is developed and presented.

The ever-increasing need for housing generated the search for new and innovative building methods to increase speed, efficiency and enhance quality, one direction being the use of light thin steel profiles as load bearing elements and different materials for cladding. Nowadays, these systems are constructed as platform system. Lateral bracing is often provided by cross-bracing using tension-only straps in selected bays which make the shear panels. Because of the shear panels of platform system in story levels are discontinued, constructing this system in height are limited and in high seismic regions are not suitable. In this study a new system is introduced to overcome the current practice. Hybrid System are included load bearing wall made of cold-formed steel members for gravity loads and braced frame made of hot-rolled steel members for resisting wind loads and seismic forces. This paper presents a case study for a five story building included hybrid system as a primary seismic and gravity load carrying system in a zone of high seismicity and related special details are presented.

In recent years the height of buildings increased dramatically. Today high-rises with heights of more than 500m are built, even in areas with high earthquake risks and strong tropical storms, as for example in the Middle East or in Asia. This makes it necessary to think about new ideas for damping vibrations of these buildings. One possibility is the installation of tuned liquid dampers. Hereby water tanks are installed in the building. The damping characteristics can easily be adjusted to the natural frequencies of the building by changing the height of the water filling in these tanks. In the current contribution a small-scale experiment will be presented and the results of the experiment will be compared to an analytical solution. It can be shown that a damper mass of only 1% of the mass of the building is sufficient to reduce the amplitude of vibrations by 50%.