International Collaboration in Lifeline Earthquake Engineering 2016

Spatially extended long-span bridges, which crossing an active fault or located near fault area are subjected to both static step-like deformation and dynamic ground motions. Due to there are lack of near-fault recordings, numerical simulations of near fault time-histories are required. This paper proposes a hybrid synthesis method combining the modified statistical Green’s function and theoretical Green’s function. It considers both the dynamic vibration and static terms (namely permanent displacement) of the near-fault strong ground motion, also the simulation simply considered the complete seismic waveforms including the near-, intermediate-, and far-field terms. Then by this synthesis method, near-fault ground motions are calculated as the input time-histories to analyze seismic response of a simple bridge. The results well showed the applicable of this method provides a useful reference for seismic design guidelines for near-fault bridge engineering.

Large-scale composite bumper system (LCBS) for bridge piers can be used as protection facilities against ship collision. The segment of LCBS is made of glass fiber-reinforced polymer (GFRP) skins, GFRP lattice webs, polyurethane (PU) foam cores, and ceramsite filling materials. In present paper, an in-depth analysis of performance evaluation of LCBS is conducted for a cable stayed bridge using a nonlinear explicit dynamic finite-element analysis program (ANSYS/LS-DYNA). Typical collision cases for both protected and unprotected bridge piers are investigated. The maximum impact force and impact duration are discussed in detail. The simulation results indicate that LCBS can effectively increase the impact time of ship-bridge collision and significantly reduce the peak collision forces. Overall, the LCBS provides a new idea to the design of anti-collision system for waterway bridges.

The purpose of the research is to develop the index model of bending performance of RC members under impact loadings. Based on the numerical simulation method, the flexure resistance of a RC column under different velocities and impact mass is studied. The rotation is used as the damage index and the damage classification is defined. According to the results of numerical simulations, the dynamic moment-rotation relationship is obtained by modifying the static results. Through the statistical analysis, an empirical bending performance index model is developed for RC members under impact loadings. A good agreement is shown in the comparison of the results of numerical simulations of statistic models.

There are many kinds of bridge anti-vessel collision devices, and each device has different ability in buffering and reducing vessel-collision force. The study employs dynamic analysis methods to investigate the influence of stiffness of anti-collision devices on its buffering effect of vessel-collision force. Through the analysis of the pier stiffness, the vessel stiffness and the stiffness of the anti-vessel collision devices, the methods for choosing reasonable stiffness of anti-vessel collision devices is proposed based on the stiffness matching principle. By comparing stiffness of steel box, composite material box, and rubber fender, the scope of application of different anti-collision devices is declared. In terms of the anti-vessel collision design of the bridge, the conclusions of the study may have a certain guiding significance.

Most current bridge design codes and specifications employ the equivalent static force in the design for vessel bridge collisions, which ignores the structural dynamic effects. To develop the simplified impact force time history model, 6 finite element models of barges ranging from 90DWT to 2000DWT are developed. With the use of barge-rigid-column oblique collision model, concerning different geometries and impact velocities, 180 samples of the barge impact force time history are obtained. Based on the 180 samples and a modified half-sine function, the simplified impact force time history model is developed through the statistical analysis. Finally, the dynamic structural analysis of a cable-stayed bridge is conducted to discuss the precision of the simplified impact force time history model.

The study of ultra-large scale ship bridge collision is still in the initial stage. In present paper, a 300k DWT crude carrier is chosen as the impact vessel, whose finite element model is correctly established. Considering the influence of the surrounding flow and regarding the bridge pier as a rigid body, the strongly nonlinear process of ship-bridge collision is accurately simulated. Firstly, the time history curve of the impact force is obtained and both the energy absorption and damage condition are analyzed. Then, the comparison between the results based on the given standard and empirical formula formulas and the FEM simulation is carried out. It is found that the collision is a complicated nonlinear dynamic process with huge energy exchange in a very short time. And, the modified Woisin formula is much closer to the FEM result compared with the other formulas and more reasonable for predicting the impact force of VLCC. That is to say, the results can be used in the design of bridge preventing ultra-large scale ship collision.

This paper deals with the behavior of hot-rolled square tubular T-joints subjected to impact loadings by means of experimental investigation. A drop hammer setup is used for testing four tubular T-joints, including three stiffened details (with transversely-stiffened chord, doubler plate-stiffened top flange of chord, ribbed tubular brace) and one unstiffened tubular configuration for comparison. The dynamic responses of these four tubular T-joints are discussed with emphasis on the effect of different stiffeners. Based on the experimental results, the key patterns of behavior including the development of impact force, deformation and failure modes are presented, and the impact mechanism as well as the energy-dissipation mechanism under impact loadings are also studied. It is shown that the strengthening effect of the stiffeners in the chord on T-joint dynamic performance, involving the transversely stiffened chord and stiffened top flange, are more obvious than that of the stiffeners in the brace. For the former, the joint stiffness is effectively improved, and the energy dissipation is mainly attributed to the overall bending deformation of the specimen, but little from the local buckling of the chord. The results also provide reliable testing data for design-oriented studies on the dynamic behavior of the tubular T-joint.

Vehicle-impact force to the bridge piers depends on many factors, however, only a constant static force is specified as design value in the anti-impact design of the bridge, which are far from enough to correctly describe the dynamic effects of the impact nor to meet the growing demands of the rapid development of modern transportation and infrastructure construction. In order to clarify the influence of all the structural parameters to the heavy vehicle-bridge impact, a refined FE vehicle-bridge model is built and a systematic parametrical study is conducted. Attentions are focused on several factors of major importance to the impact which are the pier high, velocity, and weight of the impacting vehicle. The combined effects as well as their relative importance to the time variation characteristics of impact forces are discussed in details.

Steel and rubber have good energy absorption performance. In present paper, a steel plate-rubber energy absorption ring is designed for vessel-bridge collision protection structures, and a practical design method is established. Based on numerical simulation, 216 steel plate-rubber ring finite element models, including different plate thickness, ring wall thickness, diameter are established, and the performance parameters (radial pressure, energy absorption) of the energy dissipation ring are obtained. Through statistical analysis, the empirical function for the performance parameters and the material parameters of the energy absorption ring is developed, and based on the former, the design method of the energy absorption ring is proposed. Compared with the numerical simulation, it is shown that the empirical function has a good precision, the model is easy to use and has a good engineering application potential.

The dynamic behavior of reinforced concrete (RC) structures under impact loadings has received great attention from civil engineers and researchers. However, few studies have been conducted to evaluate the flexural behavior of the impact-damaged RC beams. In order to further understand the effect of impact loading on the residual flexural behavior of RC beams, simply-supported RC beams with stirrups were impacted by a drop-weight hammer. Subsequently, the static tests were conducted on the impact-damaged beams to obtain the residual behavior. Another RC beam for comparison was loaded to failure without impacted damage. The crack patterns of the specimens were observed in order to investigate the mechanical behavior in detail. The effects of impact energy on the residual flexural resistance and mid-span deformation of the impact-damaged beams are discussed. The results of tests illustrate that the significant strain hardening effect should be considered in order to evaluate the residual flexural capacity of the impact-damaged beams reasonably.

A fiber beam-column element is adopted to simulate the damage development process of circular reinforced concrete (RC) bridge columns under quasi-static loading considering global buckling and low-cycle fatigue of longitudinal bars. The tensile strain and low-cycle fatigue are used to represent the damage of longitudinal bars while compression strain is adopted to calculate the damage of the cover concrete. A section damage index is proposed based on the material damage definition and bridge performance assessment. A set of circular RC bridge columns tested under different cases of quasi-static loading are adopted to verify the reliability of the fiber beam-column element and the proposed damage index. The results show that the fiber beam-column element can simulate the RC columns under different loading cases with good accuracy. The damage index proposed in present paper is compared against experimental results and other damage indices and it is found that the proposed index can reflect the damage state at any stage and the gradual accumulation of damage in RC columns more convincingly than most of other indices.

In order to study the seismic response of the high-speed operating train-bridge coupling system, simply-supported girder bridge and high-speed train are taken as the objects of the research, the train is simulated as spring-mass-damping system, the bridge is simulated by using the beam element model, and the contact relationship between the train and the bridge is simulated by spring and damper, then the finite element model of the train-bridge coupling system is set up. The train operation is simulated by using the element birth and death technology, and the seismic responses of the train-bridge coupling system under typical ground motions are calculated. The results are analyzed and compared with the seismic responses of the model which does not consider the operation of the train. The dynamic responses of the train-bridge coupling model under different velocities and different ground motions are analyzed.

The serious consequences from the March 11th in 2011 earthquake in Japan emphasized the necessity of research into multiple hazard bridge design. However, current bridge design criteria do not consider multiple hazards. In preset paper, multiple hazard theory is introduced and the application to bridge design is investigated. Studies based on two extreme loads are performed, incorporating optimization theory, experimental verification for component multiple hazard design, vulnerability analysis, and partial failure probability. Several issues are identified. A methodology to address these issues is proposed based on load combination, optimization, and probability, with the aim to promote the concept of multiple hazard design for bridges. Finally, a numerical case is employed to illustrate the methodology.

During 2011 Great East Japan earthquake, the pounding between the wind-tongue and wind-shoe was observed on the Yokohama-Bay Bridge. If the wind-tongue is damaged by pounding, other members may be damaged serially. However, this pounding phenomena was not considered during design time; safety evaluation of the wind-tongue considering pounding is required. In this study, three-dimensional frame model is constructed. The model is validated by comparing the measurement data with analysis result. Three-dimensional dynamic analysis is then conducted to reproduce the dynamic response considering pounding. Furthermore, nonlinear dynamic analysis using level 2 earthquake ground motions is conducted to clarify the pounding force and to evaluate the safety of wind-tongue. As a result of the dynamic analysis, the seismic response during the Great East Japan earthquake has a good agreement with the observed response by considering the pounding and applying the damping based on the measurement result. In addition, pounding force is shown to exceed the capacity of the wind-tongue during level 2 earthquakes, resulting in shear damage at the wind-tongue base.

A series of nonlinear dynamic analysis is conducted for a bridge system consisting of two eight-span curved bridges with total length of 378.92 m supported by isolation bearings subjected to strong earthquake ground motions. Acceleration and relative displacement response of two decks, the initial gap, and the rubber cushion hardness are analyzed. This study describes a numerical analysis to clarify the effectiveness of rubber cushion to mitigate pounding effect between girders and blocks. The pounding effect is idealized by the impact spring. The study indicate that the application of rubber cushion makes the rotation center of curved bridge transfer and the offset direction change. The reasonable selection of parameters of initial gap and hardness have great influence on the pounding of girders and blocks. In present study, the hardness of Shore A 55 is appropriate.

On August 3rd, 2014, the Ludian earthquake in China with the magnitude of 6.5 caused tremendous loss in infrastructure systems. The Niulanjiang Bridge is a high pier bridge, which situates close to the epicenter. In the present paper, the damage features of lifeline system based on field investigations are firstly discussed. Then the earthquake response analysis of the Niulanjiang Bridge is implemented by adopting the real strong ground motions, and the parts which may be dangerous during this earthquake excitation are studied. Finally, some seismic countermeasures for this bridge are proposed.

The seismic vulnerability of skewed bridges has been realized in many major earthquakes. Damage to skewed bridges has been found to be aggravated by the occurrence of collisions between the bridge segments and adjacent abutments. Some bridges have even suffered catastrophic failures or unseating of girders due to the pounding. To study this phenomenon, a 1:20 scale straight and 30° skewed bridge-abutment model were constructed and subjected to uniform ground excitations through shake table testing. This paper focuses on the girder unseating potential of skewed bridges based on the girder seating length requirements specified in the New Zealand Transport Agency (NZTA) bridge manual. It was found that pounding restricts the girder movement in the longitudinal direction, causing significant reduction of the relative displacements. However, pounding of the skewed bridge induces out-of-plane movements, generating large transverse relative displacements. It was further deduced that the seating length requirements specified in the NZTA bridge manual for skewed bridges could potentially severely underestimate its girder unseating potential.

Bridges have covered more than 50 percent of high-speed railroad lines by far in China, it is of great probability that high-speed trains running on bridges when an earthquake occurs which constitutes a direct threat to the running safety of the trains. In order to evaluate the seismic safety of high-speed train on bridge, obtain the seimic alarm threshold of trains with different speed considering train-bridge coupling effect, a train-track coupling model with 31 degrees is established to simulate the track irregularity of the high speed rail, and the rail irregularity condition is studied considering China power spectral density (PSD) of ballastless track irregularities of high-speed railway. A reasonable analysis model of train-bridge coupling system is set up to obtain the dynamic response characteristics of the model under the excitation of typical earthquakes. Considering PSD of ballastless track irregularities of high-speed railway and different train speed, variation laws of the derailment coefficient, wheel unloading rate, and lateral wheel-rail force have been calculated under typical earthquakes. Compared with the limit values in the code, earthquake alarm threshold value of high-speed trains has been preliminarily confirmed. The research findings will be of great significance to improve the reliability of earthquake emergency disposal system in our country.

Bridge structure, as an important component of the lifeline engineering, supports the economic development of a country. The seismic performance of a bridge structure depends on the operation and service conditions. Misemployment and the earthquake destruction strongly influence the safety of the bridge. To reduce the hidden dangers and to better understand the changes of vibration characteristics, dynamic load tests are carried out. The ambient test provides the natural characteristics and barrier-free traffic test gives the parameters of impact coefficient and peak acceleration response. Based on load tests, it can be concluded that the rigidity of the bridge remains to be good, but the bridge is still damaged. Analysis indicates dynamic load tests are a helpful nondestructive method to investigate the safety of the bridge. Periodic detection using load tests plays a crucial role for later service.

It is known that long-span suspension bridges play an important role in the lifeline engineering construction, and real time monitoring of the health condition of bridges are needed to ensure the safety of bridge structures. To this end, a strong motion monitoring system has been set up on a suspension bridge with a main span of 1108 m in 2012, and this system has recorded plenty of real time ambient vibration data since then. In present paper, the strong motion monitoring system of this long-span suspension bridge is introduced at first. Then the history signals from 2013 to 2014 are extracted to conduct the modal analysis. In addition, a structural damage index deduced from the covariance of the covariance matrix of acceleration is used to evaluate the health condition of the bridge. Results of the analyses indicate that the strong motion monitoring system on the bridge has being effective and stable since 2012, and the real-time ambient vibration records are helpful to estimate the operating state of the bridge.

Accurate stiffness estimation is of great significance for a maglev guideway prestressed concrete (PC) girder due to the complex construction technique and the high demand of deformation control. Field testing is firstly conducted on a typical PC girder of the Jiading Maglev Test Line in Shanghai. Two kinds of sensors including fiber Bragg gratings (FBGs) and accelerometers are installed to acquire the strain and acceleration responses under the passing maglev train, based on which the flexural stiffness of the girder is identified. A non-linear analysis method based on section fiber model (SFM) is then proposed to evaluate the flexural performance of the girder with unbounded post-tensioning curvilinear tendons. Good agreement between the identified and calculated results verifies that the test methods and the SFM can evaluate the stiffness of the PC girder with high accuracy.

In order to reveal the damage mechanism of concrete bridges suffered from the near-fault pulse motions, firstly velocity pulse ground motions within the rupture distance of 100 km in Wenchuan earthquake are identified by a fully automated classification scheme proposed in present paper. Then, the velocity pulse characteristics of near-fault ground motions are analyzed. Finally, a multi-scale finite element model of a concrete girder bridge is established by using ABAQUS and the earthquake responses of the structure subjected to the near-fault pulse and near-fault non-pulse motions are simulated, respectively. The results show that the predominant periods are apparently different between the pulse and non-pulse motions in terms of the velocity response spectrum. Compared with the non-pulse motions in the near-fault region, the pulse motions greatly affect the seismic damages of the bridge.

Bridges in a regional transportation network are generally designed following similar design guidelines, usually those developed by the local Department of Transportation. This, in turn, makes the seismic performance of these bridges similar. The Pacific Earthquake Engineering Research (PEER) Center framework for probabilistic performance-based seismic evaluation involves the sub-models of hazard intensity measure (IM), engineering demand parameter (EDP), damage measure (DM), and decision variable (DV) for individual structures. Further, in 2013, a model consistent with the PEER framework is proposed. The aim of the present paper is to present the numerical approach for the investigation of bridge seismic performance correlation following the PEER framework. And further, some case study would be illustrated to verify the correlation model.

The seismic performance of underground reservoir structures depends on the flexibility of the structure, soil properties, soil geometry, ground motion characteristics as well as the kinematic constraints imposed on the structure. This paper seeks to evaluate the influence of site response and excitation frequency on the performance of buried structures. A series of centrifuge experiments were conducted at the University of Colorado Boulder to evaluate seismic soil-structure-interaction, lateral earth pressures, bending strains, moments, and racking displacements of scaled model structures representing water reservoirs buried in medium dense, dry sand. The preliminary results indicate that the effective and fundamental frequency of the buried structure-soil system was primarily controlled by the response of the far-field soil rather than the fixed-base fundamental frequency of the isolated structure. It was found that the controlling frequency that determines the maximum seismic soil pressure, bending strain, and racking is that corresponding to the strain-dependent, effective natural frequency of the far-field soil.

Communication facility is one of important utility part of lifeline systems. Many communication facilities and exchange office buildings suffered from extensive damage in Wenchuan Ms 8.0 earthquake. The communication interruption seriously impeded the post-earthquake emergency response and rescue actions. Based on the site survey, the communication towers on the top of reinforced concrete (RC) buildings were seriously damaged because of the seismic whiplash effects. A series of finite element analysis models are established to analysis the seismic response of communication towers fixed on the top of RC buildings. The axial forces of the bottom components of the tower which are fixed on the top of RC buildings was compared with that of the tower fixed on the ground. The results show that the whiplash effect is very serious when the natural period of communication tower is close to the basic natural period of building, and can also be found that when the natural period of the communication tower is near to one of the high order natural periods of the main building.

Base isolation technology has been widely used in areas of buildings and bridges, while no application is found in cooling towers. In present paper, base isolation design using LRB is applied to an ultra large cooling tower structure with the height of 220 m. Seven earthquake acceleration time history records inputted in three orthogonal directions are used in the analysis of the seismic response of the cooling tower structures with and without base isolation. Considering the travelling wave effect, three earthquake acceleration time history records inputted in single direction are used in the analysis of the seismic response of cooling tower structures with and without base isolation under inconsistent seismic displacement excitations. It is found that the base isolation technic diminishes the seismic action on the ultra large cooling tower structure significantly and reduces the base shear force by 74% in rare earthquakes and protect the cooling tower from the adverse travelling wave effect.

In present paper, take a steel frame structure with single degree of freedom as the research object, a series of experiments were carried out under harmonic excitation, influences of additional mass ratio of particles, particle size, the roughness of the bottom of the container, the intensity, and frequency of the excitation were studied. The experimental results show that, accumulation state is a key factor that affects the performance of particle damper, with the increasing of added mass of particles, the performance of the damper becomes better and then gets worse. Particle size has little effect on the optimal performance of particle damper, while the roughness of the bottom of the container has unremarkable influence on the performance of the damper. With the increase of the excitation intensity, the response of the structure with particle damper decreases and tends to be stable. When the frequency of the excitation is smaller, the response of the structure with particles is likely to be amplified, while when the frequency of the excitation is larger than or equal to the natural frequency of the structure, the response of the structure decreases greatly.

In present paper, the main components and characteristics of the electric power system in Nepal are introduced. The loss of the service function and the damage of equipments are investigated in the two counties under the Nepal Ms 8.1 earthquake. The typical damage mode of each research object in electric power system is derived based on the investigation data, and the main factors are discussed to find out the dominant reason which leaded to the damage. At last, a state comment on the seismic damage of electric power system under Nepal Ms 8.1 earthquake is present based on the investigation data. The conclusion can be used to deeply understand the damage mechanism and help to develop the rehabilitation and reconstruction project of electric power system for Nepal.

This paper examines the seismic performance and fragility of 11 kV to 21 kV low voltage overhead and underground electric distribution systems from the 2014 Napa, California, earthquake. There were 127 repairs required for the low voltage power system in this earthquake. It took 38 hours to complete all the repairs. Peak power outages during this time were to 70,000 customers. Fragility models were developed that correlate the observed damage with the level of shaking and ground deformations. Underground performed better than overhead distribution. Design strategies are outlined that should reduce the level of damage in distribution systems in future earthquakes.

Porcelain cylindrical electrical equipment (PCEE) is important to power supply system while its seismic performance is poor. This paper proposed a damping method for PCEE based on multiple tuned mass dampers (MTMD) with large mass ratio. Two types of PCEE, used in practical applications, are chosen as objects to study their seismic performance and the effectiveness of MTMD. Finite element analysis and shaking table test are carried out. Dynamic responses of tested facilities without control and with damping device are compared. Results show that PCEE are fragile during earthquake, one of the tested equipment cracked under the earthquake with 0.5 g PGA. MTMD is effective for reducing the seismic vibration of the PCEE. MTMD with large mass ratio has not only better effectiveness as already known in theory but also superiority in robustness. A non-conventional MTMD with a large mass ratio is found to be more robust against off-optimum deviations resulting from uncertainties such as conductor connections and icing loads.

Exposure assessment was done for energy-related base facilities exposed to tsunami inundation caused by the anticipated megathrust earthquakes along the Nankai trough subduction zones. The distribution maps of tsunami inundation depth used in this study were predicted by the Cabinet Office, Government of Japan. By overlaying those maps on the distribution maps of thermal power generation plants and LNG storage tanks, exposure levels were evaluated in terms of power generation capacities or storage capacities.

Buckling of a wind turbine tower with different imperfections is studied through linear and nonlinear numerical analysis, and the effect of the initial imperfections of the wind turbine tower on the buckling capability under lateral loads is also investigated. The maximum initial imperfections which are derived from EN 1993-1-6 and DNV-OS-C 401 are added into the nonlinear analysis through the first buckling mode. It is shown that these initial deformations significantly reduce the load carrying capability of the structure while linear buckling analysis gives no significant difference in the buckling resistance under the different types of imperfections. The design checks are also performed for four different classes of imperfections based on nonlinear analysis results. It can be concluded that the incorporation of the initial imperfections and the lateral loads into the tower models which form the basis for design criteria should be emphasized.

In order to discuss the structural characteristics and seismic performance of high temperature gas-cooled reactor nuclear power plant (HTGR-NPP) under near-fault ground motions with velocity pulse, we established three-dimensional nonlinear model and carried out the numerical calculation of modal frequency and dynamic time history analyses. We simulated the seismic responses of the model, in which four strong motion records with velocity pulse and the corresponding synthetic time histories with same response spectra and without velocity pulse were used as ground motion inputs. The acceleration, displacement time history, and floor response spectrum of nuclear power plant model were analyzed. Our test results show that ground motions with velocity pulse can make strong disadvantageous influence on seismic displacement responses of HTGR-NPP. This research can provide scientific reference and technology support for building HTGR-NPP in near-fault areas.

Though there are several studies in lifeline interrelation, research on quantitative evaluation of post-earthquake lifeline interrelations has been limited. In this study, terms related to other lifelines in a disaster report are set under assumption that terms means the post-earthquake lifeline is somewhat influenced by other lifelines. Then, the number of related terms is counted to show the relationship among the lifelines. This study is applied to the 2011 Tohoku earthquake. I found that many lifelines are dependent on the electric power system though the accident at the nuclear power plant is not considered.

The inter-story isolation system is modeled by a simple two degree of freedom finite element model in present paper. By establishing the dynamic differential equation of the inter-story isolation system, some key structural parameters including the frequency ratio, mass ratio, and damping ratio of inter-story isolation system are optimized systematically based on the random model for earthquake ground motion, in which the base shear of the structure is chosen as the objective function in the optimization. Furthermore, the accumulated and instantaneous energy response equations of inter-story isolation system based on energy balance principle are derived. Control mechanism of inter-story isolation system is investigated from the perspective of energy. Numerical simulation results indicate that for a small mass ratio of substructure, inter-story isolation system performs similarly to structure-TMD system, and the transfer energy of superstructure as well as the elastic energy of substructure is large in general. When the mass ratio of substructure is increased, the performance of inter-story isolation system is gradually close to base isolation system with small input energy. In the case of 1 < u < 4, the quantities of input energy and transfer energy of inter-story isolation system are between those of structure-TMD system and base isolation system.

Seismic soil liquefaction problem in the soil site of lifeline engineering is a key issue. It should be avoided to misjudge the liquefaction as much as possible for lifeline engineering projects. In present studies, deterministic assessment of seismic soil liquefaction triggering potential is programmed on the Matlab GUI platform, which is based on the SPT and PGA-based method, V_S and PGA-based method, respectively. The accuracy of these methods is verified by real seismic soil liquefaction cases. The software calculates CSR (cycle stress ratio) and CRR (cyclic resistance ratio) and estimates the seismic resistance of soil to liquefaction automatically. The software has an important engineering application value for engineers and researchers.

The oil and gas pipeline is one of the important lifeline systems. Based on the ground motion intensities obtained by Shakemap, a method for rapid evaluation of the seismic damage distribution of oil and gas pipelines is proposed in the present paper. The spatial distribution of PGA and PGV along the oil and gas pipeline could be obtained by Shakemap_XJEQ in about 30 minutes after the earthquake. The seismic disaster state of pipeline is determined by whether or not the strain in pipeline caused by ground motion is larger than the allowable strain value of the pipe. According to the density of population and the important level of pipeline function, the possible consequences of the damage of oil and gas pipeline are evaluated. Considering the important level of pipeline and the population density near the pipeline, the possible seismic disaster distribution of oil and gas pipeline is evaluated. The rapid disaster assessment of oil and gas pipeline was realized through this method in the Pishan Ms 6.5 earthquake on July 3, 2015, and it provided the help for the oil and gas pipeline maintenance department to decide the emergency response after the earthquake.

In present paper, the numerical simulation is conducted to investigate the dynamic response of the composited pavement system under multiple drop weight impact loads. This composited pavement system consists of asphalt concrete (AC) layer reinforced with geogrid (GST), followed by high strength concrete (HSC) layer, and then engineered cementitious composites (ECC) layer, taking into account their relative advantages in terms of strength and relative ductility. Actual measurements from the laboratory test are used as a validation for the results of the numerical simulation. It is shown that the numerical results and laboratory measurements from two times of impact tests are in great accordance in terms of damage pattern, crater diameter, and potentiometer readings. This calibrated model from numerical simulation could then be further used to investigate the factors that might enhance the impact resistance of the composited pavement system subject to various levels of impact loads.

Concentration parameter method is a major solution in seismic design of bridges. From the finite element perspective, concentration parameter method considers the stratum semi-infinite space as a mechanical model without geometric dimensions, which is called the macro-element in present paper. And, the determination methods of the model, such as the interaction spring stiffness, the damping and the equivalent mass for the soil around the piles are crucial to the calculation precision. Having considered the common types of soil in engineering, a comparative study of the Boulanger model is carried out. The ‘m’ method and the Mindlin method (which is equivalent to linear spring) based on a large number of parameter analysis is aim to explain the key point of parameter selection for horizontal soil-pile spring which has a strong influence on seismic response of bridge.

Advancements in high-speed computing and developments in material modeling techniques are increasingly allowing for large-scale three-dimensional (3D) geotechnical finite-element (FE) simulations. With the aid of the open-source computational platform OpenSees and the graphical user interface OpenSeesPL, 3D computations for seismic ground-foundation analyses are greatly facilitated. In present paper, an effort is made to capture key features associated with seismic response of soil-pile system in time domain. To this end, a parametric study is performed to evaluate the effects of pile configurations on the dynamic performance of foundation system. Response under linear soil behavior representations is mainly discussed.

Within the scope of urban service area, the seismic failure of buried pipelines is interdependent to each other in a pipeline network system, which is caused by similar structural parameters of pipelines and the spatial correlation of ground motion intensities. In present paper, a Monte Carlo simulation (MCS) strategy for seismic reliability evaluation of the pipeline networks under correlated ground motions is proposed. The correlated coefficients of pipeline failure events, affected by spatial correlated ground motions, are determined according to the measures presented by Lim and Song. To calculate pipeline network reliability, in the MCS method proposed in present paper, the seismic failure events of pipelines are firstly taken as correlated random variables and transformed into uncorrelated random variables by orthogonal transformation. The validity of the proposed MCS method is verified by results comparison between the analytical method and the MCS method.

In the current seismic design of a buried pipe, the axial ground restraint force between a pipe and the ground is modeled as a bi-linear system with respect to the relative displacement. In other words, the soil friction determining the ground restraint force is assumed as constant regardless of the pipe velocity. However, it is thought that the soil friction depends on pipe velocity because of the relocation of the soil particles. This study attempted to examine the velocity dependency of the dynamic soil friction using a pipe-pulling test on a shaking table. The conclusions were as follows: (1) the maximum friction in the low velocity case was larger than that in the high velocity case, (2) the soil dilatancy affected the friction, and (3) the friction in the cases with a pipe fitting was 1.5 times larger than that without the fitting regardless of the pipe velocity.

The recent earthquake damage has highlighted the importance of performance-based design and functional resilience of nonstructural components. Directing at seismic bracings used in piping systems, the construction and design procedure of seismic bracings is introduced in present paper at first. The seismic code requirements and relevant seismic research of bracings are also reviewed. The shaking table test of seismic bracings in a 6-meter full-size piping system is conducted. In addition to theoretical analysis, the seismic performance and failure mode of seismic bracings are studied. The results indicate that failure of bracings in piping systems is mostly due to the bolt looseness in connection components, and the longitudinal response of pipes is basically identical to the floor response. Based on the results, both technical improvement measures to enhance weak connections and design optimization suggestions considering cost are put forward. The use of real-time monitoring in bracings may be an effective way in condition-based maintenance.

This paper describes the results of the field survey of water pipelines damages in the village of Hakuba caused by the 2014 northern Nagano Prefecture earthquake (M6.7, maximum seismic intensity lower 6 in JMA scale). The fault runs from north to south through Hakuba. Near the fault, compressed damages were observed for ductile iron pipes (standard joint), polyethylene pipes, steel pipes, and PVC pipes body. These damages were caused by ground compression. At a certain site, no damage was observed for polyethylene (HDPE) pipes and PVC pipes crossing the fault where the fault emerged at the ground surface. The polyethylene pipe was deformed in S-shaped across the fault. It was not corresponding with Z-shaped deformation of the stratum. Based on the ground displacement measured in this site, FEM analysis was conducted considering the geometric nonlinearity of the ground and pipe. The results indicated that the inner and the outer side of S-shaped polyethylene pipe cause strain concentration and the strain exceeds the maximum allowance value in case of 50 cm compressed deformation.

The key to obtain equivalent soil spring coefficient is to calculate the ultimate soil bearing capacity of soil-pipe interaction. The domestic and international criterions adopt the bearing capacity coefficient to characterize the ultimate bearing capacity, which is considered to be only related to the internal friction angle of soil and the ratio of embedded depth to diameter, but the ratio of embedded depth to diameter in the criterion is relatively small (about 10 or less). At the same time, the literature about ultimate soil bearing capacity of buried pipeline-silt clay lateral interaction is very few. So in order to study the lateral interaction between the buried pipeline and the silt clay, a series of model tests were carried out. In present paper, the experiment is introduced firstly, including the equipment and the test cases. Then the test results are shown, and the damage mechanism and damage mode are studied. Finally, the influence factors are studied and some conclusions are obtained.

In the past fifteen years, the urban underground pipelines in China have been developed rapidly due to the rapid urbanization of China. Urban underground pipelines mainly consist of the water supply system, water drainage system, heating supply system, and gas supply system those are made of pipeline networks. The total length of the above four types is about 1840000 km. Urban pipeline failures or accidents are reported frequently for their technical and managerial problems exposed distinctly which lead to serious fatalities and tremendous economic losses. It is a pity that there is few statistical analysis of pipeline accidents in China. The public data about accidents of urban underground pipelines in China from 2000 to 2014 is collected here and analyzed in order to study the features of municipal pipelines on operation and maintenance. The occurrence mechanism is discussed based on some typical accidents. The statistical result reveals the accident factors such as type, cause, and casualty. It eventually gives a reference to control and reduce the hazard occurrence for security operation in the urban area.

Oil and gas transmission pipelines engineering is the important lifeline engineering, and pipeline crossing engineering is the most important one of lifeline engineering. Considering the complexity of pipeline aerial crossing structure and the dependence of structural seismic response on apparent wave velocity, it is very necessary to analyze the traveling wave effect of aerial crossing structure. Taking a long-span ultra-narrow suspension cable pipeline aerial crossing structure as the engineering example, three-dimensional finite element calculation model is established. Seismic traveling wave effect of aerial crossing structure is studied by the capacity to demand ratio (C/D ratio) method. And the influence of different apparent wave velocity and seismic wave propagation direction on seismic response of the structure is analyzed, and the vulnerable parts of the structure are identified. The results show that the C/D ratio of the aerial crossing structure is significantly reduced when traveling wave effect is considered, especially in low apparent wave velocity. Vulnerability weak parts are mainly located in the anti-slipping between main cable and saddle, pile foundation, and key sections of pylon. Meanwhile, the vulnerability of the storm ropes cannot be ignored. Through the analysis of the traveling wave effect of the long-span suspension cable pipeline aerial crossing structure, it can provide reference for the seismic analysis of the similar structures.

As known to all, buried pipe networks are the important parts of urban lifeline engineering, which have significant influence on people’s daily life and industrial activities. Once the networks are destroyed by earthquakes, they cannot provide necessary energy for us or even cause some severe secondary disasters resulting in serious loss of life and properties. Therefore, in order to study the seismic behaviors of buried pipe network, a 24 m × 24 m buried pipe network is constructed and an artificial earthquake test is conducted with buried TNT explosive. The pipe network consists of ductile cast iron pipes to simulate water distribution network and welded steel pipes to simulate gas supply network, which is paved at 0.5 m depth underground. Meanwhile, in order to produce long-lasting earthquake, eighty-five kilograms TNT explosive which is divided into three parts are detonated by millisecond blasting technology. In present paper, two groups of test contents are introduced in detail. The first is the movement of the test site, including the acceleration and velocity at different site points. The second is the response of pipes, including the deformation of joints of ductile cast iron pipes and the axial strain of welded steel pipes.

This paper summarizes the earthquake performance of the welded steel Thames water transmission pipeline which was crossing the Kullar fault in the 1999 Kocaeli earthquake. The pipe suffered wrinkling damage at three locations (two major and one minor) due to net compression which was caused by the right lateral movement of the fault. However, it still managed to stay in service in the aftermath of the earthquake. It is known to be one of the best documented pipe failure cases due to fault displacement hazard. A 3D nonlinear analysis of the pipe-soil interaction system is utilized to investigate the effects of both native and artificial backfill soils. The failure mode and limit state of pipe for compressive and tensile strains are mentioned. The rotation and displacement demands at the wrinkles due to incrementally applied fault displacements are calculated. Results are compared with the field observations. Recommendations are provided to mitigate earthquake risk and for safe operation of similar critical infrastructures against fault displacement hazards.

The tsunami generated by the undersea fault rupture from the March 11, 2011 M_w 9.0 Great East Japan earthquake inundated an estimated 561 km² of land. After the tsunami receded, residual flooding remained over approximately 170 km² of land. Investigations identified the primary mechanisms for this flooding to be: (a) tectonic subsidence, (b) tsunami scour, (c) post-tsunami residual water, (d) coastal protection system damage, (e) breach of river and levee systems, and (f) clogging of and damage to storm water drainage systems. The greatest amount of flooding was from post-tsunami residual water.

Based on the finite element numerical simulation of sandy slope, the influence of rainfall intensity and duration on slope pore water pressure, stress and strain, displacement, and safety factor is studied. Research shows that the longer of the rainfall duration is, the bigger of the slope deformation accumulation will be. The vertical displacement of slope top, surface, and bottom was greater than horizontal displacement. The maximum of horizontal displacement and vertical displacement appeared at the slope toe position. With the increase of rainfall intensity, the horizontal and vertical effective stress of slope decreased. When the 3~10 days rainfall reached the slope weak surface, the safe factor became the minimum. With the increase of rainfall intensity, the vertical displacement increased gradually, and the bigger horizontal displacement happened in slope foot, which we should pay more attention to.

Small scale shaking table tests in a 1-g gravity field were carried out to evaluate the effectiveness of deformation mitigation method for road embankment during liquefaction by using gyosynthetics sandwiched between gravel. The gravel layer could dissipate the excess pore water pressure during liquefaction immediately, and restrained the shear deformation under the embankment because of its high permeability. Furthermore, the composite layer which consisted of the gravel with geosynthetics could perform as a rigid plate with high permeability. As a result, the improved layer could restrain the deformation of embankment, and this effect could keep shape of embankment.

In this paper, a new approach is proposed to disclose primary causes that will lead to earthquake’s uncertainty. The proposed model is to establish a physical relation between random earthquake motion with key random parameters including the basal spectrum parameter, the natural angular frequency, and the damping ratio of engineering sites. Using the random Fourier spectrum as model function, the probability configuration of seismic motion can be obtained simultaneously. Associating with seismic risk analysis, conditional random earthquake function is defined, which is assumed as a possible access to reduce random degrees of the suggested model.

In the present paper, the effects of controlling geological discontinuity on seismic stability of underground caverns subjected to near-fault ground motions are studied. Based on a nonlinear continuously yielding joint model, the mechanism of the impact of the near-fault ground motions on unfavorable geological structure is analyzed with ground motion records collected from NGA-West2 database. Then, the PGV is proposed as the damage potential index (DPI) of unfavorable geological structure. Finally, the 1# surge chamber of Baihetan hydropower project is studied. The results demonstrate the cavern is apparently fragile under the near-fault ground motion; thus, some special seismic reinforcement measures should be carried out.

The non-stationarity of frequency in earthquake ground motion has an important effect on structural responses. By introducing a frequency-dependent amplitude envelope function, a method which takes the response spectrum as the target in the practical simulation of non-stationary earthquake ground motion is proposed. An example of analyzing the effects of the amplitude envelope function is presented and the results demonstrate that the new simulation method can consider the non-stationarity of frequency effectively and emphasize the effect of low-frequency components in later seismic actions. Furthermore, a fitting result of the artificial earthquake to the target response spectrum can be satisfied following iterative adjustments. Because the parameters of the frequency-dependent amplitude envelope function can be constrained statistically, the proposed simulation method in present paper is feasible for engineering practice.

Many studies show that the earthquake duration has a large influence on the engineering failure due to the low cycle fatigue and accumulative effect. We investigate the distribution of the duration of earthquakes. In order to highlight the relationship between the characteristic of ground motions and the fault, we decompose the horizontal ground motion into the one along the fault parallel direction and the one along the fault normal direction. We simulate the characteristic of significant durations of near-field earthquakes in Kyushu, Japan, M_JMA 6.5 through the empirical Green function method. This method adopts an appropriate aftershock as the Green function. The Green function composes the main earthquake time histories according to a rupture pattern. Incorporating the sites conditions and terrains, we compare the characteristics of distributions of significant durations between the measured data and the simulated data. Comparison shows that the simulated results are able to reflect the characteristic of distribution of significant durations of earthquakes of which epicenter distance is less than 25 km. There is a very large difference between the simulated significant durations and measured significant durations at the regions of stations MYZ009 and KGS012 where the terrains are very complicated. Significant duration will be extended in complicated basin and mountain areas. Simulated significant duration is shorter than the measured significant duration at the east of Kyushu, Japan.

We have built an accurate 3-dimensional underground velocity structure model including topography of Yuxi basin and simulated the ground motion spreading in the basin under four scenario earthquakes by using finite-difference numerical simulation method. Based on the results of simulation, we have studied the basin amplification effect on ground motion during the period of 2~10 second, and acquired three main conclusions: (1) Intensity and duration of ground motion in the basin are usually larger than those in its vicinities; (2) basin amplification factor is mainly affected by sedimentary thickness and period. It increases with equivalent thickness of sediment, but decreases with period; (3) basin amplification factors on different ground motion components show some difference. The value on fault-parallel component is usually larger than those on fault-perpendicular component and vertical component. Moreover, by adopting the regression analysis method, we have proposed a set of functional relation for quantificational computing basin amplification factor. These efforts will give some scientific advice for city future planning and seismic fortification of long-period building structures in Yuxi basin.

The coherency function is often used to describe the variability of strong earthquake ground motion at nearby sites and to account for it in seismic response analyses of spatially extended structures and structures on multiple supports and on extended foundations. For this purpose, coherency functions are used that have been derived empirically from earthquake observations by dense array. Such arrays, however, are only few worldwide, and the derived coherency is specific for the geology of the particular array. Comparison of coherency obtained from arrays with different geology has suggested that it depends on the site conditions. However, systematic study of the effect of site conditions has not been possible due to the small number of dense arrays. For that reason, we study systematically these effects using synthetic earthquake data. We use the SYNACC method to generate a database of earthquake acceleration at closely spaced points on the ground surface for nine sites, each characterized by a combination of the local soil condition parameter, s_L, and the geologic site parameter, s, and by a corresponding representative set of parallel layers. We considered three variations of s_L (rock soil, stiff soil, and deep soil) and three variations of s (sediments, rock, and intermediate geology). The results show that, for small separation distances (100 m in this study), the coherency decreases with decreasing stiffness of the geology near the ground surface, and with progressively deeper soil deposits. Additional loss of coherency caused by irregularities of the layer geometry, by surface topography, and by three-dimensional inhomogeneities beneath the site is not considered in this study.

Using the earthquake catalogues from China and Mongolia and supplemented by the global earthquake catalogue, the uniform catalogue of North China, Mongolia, and adjacent areas has been established for the seismic hazard analysis as well as the seismic zoning of Mongolia according to the determined principles. Based on the uniform catalogue, the seismicity of the North China, Mongolia, and adjacent areas have been analyzed, and the following conclusions are made. 1) The epicenter map can be roughly divided into two parts by the longitude line 105°E, which is in accordance with the “North-South Seismic Belt” of China. The seismicity is in a high level with many strong earthquakes in the west and is in a low level with little strong events in the east. 2) Most earthquakes are shallow-focus events in the study area. 3) Earthquakes with magnitude greater than 5 are basically complete since 1450 A.D. 4) Two seismic belts, Altay seismic belt and Bolnay-Baikal seismic belt, are determined according to the epicenters and tectonics. 5) The b-values of magnitude–frequency relationship for the whole areas are between 0.6 and 0.7, 0.677 for the Altay seismic belt and 0.699 for the Bolnay-Baikal seismic belt.

Ocean engineering structures are frequently suffered from wave excitations. FLAC^3d is employed to analyze the free-field seismic effect of seabed under wave excitations. The dynamic response of seabed under earthquake and wave simultaneous excitation is analyzed, and the development of excess pore-pressure is also discussed. The results indicate that the dynamic interaction of wave-seabed model is able to reflect the regular pattern of excess pore-pressure development; the excess pore-pressure development rules in seabed induced by earthquake and wave simultaneous excitation is quite different from those induced only by earthquake excitations. The excess pore-pressure grows due to accumulating effect and obvious oscillation characteristic, which results in large pore-pressure difference along the horizontal direction; besides, the amplitude of excess pore-pressure is magnified in the shallow depth of the seabed, yet rapidly attenuating along the depth. This special development pattern of excess pore-pressure may have significant influence on the ocean engineering structures such as submarine pipeline and immersed tunnel segment. Thus, the effect of wave excitations should be considered in the seismic response analysis and the safety evaluation of ocean engineering structures.

Under irregular cyclic loadings, adoption of the extended Masing criterion in the modification of the stress-strain hysteresis curves will bring about the user material subroutine with a large number of state variables. In this paper, the initial stress-strain skeleton curve is simulated by Davidenkov model, simplified loading-reloading rules are adopted instead of the upper boundary rule of the extended Masing criterion. In order to achieve the balance between computational accuracy and efficiency of large-scale nonlinear seismic site effect analyses, a three-dimensional explicit subroutine of the Davidenkov model with simplified loading-reloading rules is adopted in ABAQUS/Explicit module. After that, a two-dimensional numerical simulation is carried out, so, the peak acceleration and surface spectral acceleration can be compared with those using one-dimensional nonlinear seismic site response analysis program Deepsoil. The results demonstrate that the simplified loading-reloading rules based on Davidenkov skeleton curve are rational and valid.

The Los Angeles Metro Red Line subway tunnels in Los Angeles, California, are important transportation lifelines and are currently operating adjacent to the Wilshire Grand redevelopment project. The construction of the basement and foundation of the new 73-story tower required excavation between 57 to 93 feet (17 to 28 m) deep. Adjacent to the subway tunnels, shoring is needed within about 6 to 10 feet (1.8 to 3.0 m) horizontally from the tunnels. Monitoring was performed during construction of the Wilshire Grand project, such as monitoring of the shoring and the subway tunnel, including vibration monitoring on the interior of the closest Red Line tunnel. The moment magnitude 5.1 La Habra earthquake of March 28, 2014 was recorded by the tunnel vibration monitoring sensors as well as California Strong Motion Instrumentation Program (CSMIP) strong-motion accelerometers in the basements of nearby buildings. The accelerations within the tunnel and those in the basements of the nearby buildings are compared. Earthquake acceleration records along a length of a buried lifeline facility such as a subway tunnel are not common and provide an opportunity to evaluate relative earthquake response between different tunnel locations and adjacent structures.

To investigate the damage mechanisms of a variable cross-section subway station structure in complex geological ground, a three-dimensional numerical model is constructed in the nonlinear dynamic modeling software ABAQUS. The phenomena of high frequency filtering and low frequency amplification effect of the soft soil can be observed. The seismic response of sub-layer of the variable cross-section subway station structure with a narrow base is stronger than that of the up-layer. The peak of relative lateral displacement at the different sections exhibited spatial effects. In addition, the peak acceleration and the spectrum characteristic of ground motion input have great influence on the seismic response of the underground structure. The results can provide valuable insight into the seismic investigation of variable cross-section subway station structure.

This paper attempts to identify the elements that lead to defining the resilience goal. The intent is not to provide solutions but identify elements to be considered in developing resilience. There are multiple means of solving an issue. It all depends on the boundary conditions of the issue. The intent is to influence decision and policy makers to consider supporting engineers to deal with building resilience to reduce community hardship in a post disaster situation. In addition to lifeline system robustness to withstand stress and quickness returning to normal operating mode, welfare of lifeline systems users have to be integrated into the approaches and processes to resilience. The users include other lifeline system operators–lifeline interdependency. Lifeline interdependence is an essential part of an integrated approach to reach the resilience goal. It is a reasonable starting point to create a balanced approach to achieve resilience. With climate change taking a firm hold, the lifeline systems are experiencing more interruptions more often by severe weather disasters such as flood. Lifeline systems engineers and operators are being challenged, which actually created opportunities for them to deal with both improving mitigation and speed of recovery. This is added to their normal tasks of maintenance, equipment upgrades, and components repairs and changes due to aging.

This study developed a numerical model to estimate the restoration time of expressways after an earthquake. A series of logistic regression analyses was performed based on a dataset obtained after recent earthquakes in Japan: the 2004 Niigata Chuetsu earthquake, the 2007 Niigata Chuetsu-oki earthquake, the 2008 Iwate-Miyagi Nairiku earthquake, and the 2011 Great East Japan earthquake. The distribution of the Japan Meteorological Agency’s (JMA) seismic intensity, the length of expressway, and the moment magnitude of the earthquake were selected as significant variables to predict the restoration time. The model constructed in this study had an excellent discriminating ability based on the assessment of the receiver operating characteristic (ROC) curve. The model was applied to estimate the restoration time of expressways after a scenario earthquake that may occur in the Nankai trough. A restoration time of greater than two weeks was predicted in areas where severe ground shaking might be observed.

This paper describes a framework for the post-earthquake performance assessment of the highway network, including the network connectivity reliability model and the travel time model of traffic flows, based on Monte Carlo simulation (MCS). The two-terminal reliability, k-terminal reliability, and all-terminal reliability measures of the highway network are implemented; the traffic flow assignments of the intact and earthquake damaged highway network are carried out. Comparisons between these measures are conducted in a numerical example. Application results show that network post-earthquake travel time delay is mainly caused by traffic capacity decreases of roads and bridges, the enhancement of the highway network post-earthquake performance can be achieved through the increases of network origins (sources). There are notable differences between assessment results obtained by network connectivity reliability and traffic travel time analysis.

Earthquake damage to urban highway system can cause major traffic disruption which can adversely impact post-earthquake emergency response, repair, and reconstruction operations, and the economy of region will be also greatly affected. In present paper, the seismic risk analysis of urban transportation networks is presented, which focuses on the development of seismic risk analysis simulation system for urban transportation networks. By applying several numerical analysis methods, seismic response simulation of components in a highway system (e.g., bridges, roadways, etc.) is carried out. With the aid of the latest WebGIS technology, the results of all simulations are published to the network so that residences and government officials can share a common recognition of earthquake hazard and disaster. Moreover, combined with the city’s real-time traffic status, the system can be used as a command platform for the post-earthquake emergency rescue.

This paper presents a post-disaster transportation network capacity and mobility analysis through different bridge failure scenarios. The goal of this paper is to investigate the transportation performance under the loss of capacity, and specifically, the bridge failure caused by natural disasters. A specific scenario from ODOT to PDX in City of Portland is developed to examine the travel time variation, and further, the results are validated through a Monte Carlo simulation. In addition, travel time sensitivity and zone to zone travel times are investigated for different failure scenarios to rank the bridges of the network based on their importance. The results show that Portland transportation network is resilient to minor damage until the number of damaged bridges reaches a critical threshold. The results are expected to be used to devise an optimal retrofitting and resource allocation plan to facilitate recovery and business continuity.

Taking Zhoutouzui Immersed Tunnel as an example, finite-infinite element model of immersed tunnel-joint-soil is developed. Through numerical calculation, dynamic response of the tunnel and its joints is studied in detail under different joint stiffness. The objectives of these researches are to provide strong technical support for immersed tunnel projects in China, provide theoretical and experimental basis for revision of the seismic code, accumulate information to establish the analysis theory and design method, and understand the possible damage mechanism of underwater tunnel structures.

According to laws and regulations, the double-line cross-river shield tunnels should be set up with evacuation exits which are generally chosen as the transverse evacuating passages, for the need of disaster prevention, rescue, and ventilation. However, due to the stiffness difference between tunnel and transverse passage, it will generate differential settlements and additional local stress under various factors, causing cracks easily and bringing about great hidden danger to waterproof and normal operating condition. This paper takes a certain crossing tunnel as an example to estimate the long-term settlement under vehicle loads, using the method combined with empirical formula and finite element analysis, and the calculation model of accumulative plastic strain and accumulated pore pressure, which is based on the theory of self-organized criticality. Finally, by comparing the long-term settlements in different positions, the risk for main tunnel and transverse passage during the operation caused by long-term differential settlement is analyzed.

The 2011 Great East Japan earthquake caused severe damage to on-ground and elevated water tanks in broad areas. First, the authors conducted a detailed questionnaire survey on the damage of water tanks in the areas mainly affected by the earthquake. Through the survey, 163 damage data concerning rectangular water tanks were obtained, and the characteristics of the damage are discussed. Next, the authors compare the damage locations with the contour maps of the response spectra obtained from the strong ground motion records at 1,249 stations. The results show that the characteristics of the damage can be well explained from the viewpoint of the short- and longer-period responses to the earthquake.

In order to realize the earthquake damage emergency assessment of the large regional water supply pipe network, based on the statistical yearbook of water supply industry, the basic data of urban water supply network are extracted, the seismic damage rates of current underground pipeline made of different materials under different earthquake intensities are obtained by using the scientific investigation, and statistical analysis of Wenchuan earthquake, etc. The seismic damage calculation formula for water supply pipe network is put forward. Taking the urban underground water supply pipeline network of cities in East China as examples, the earthquake damage emergency assessments are conducted. This method is not only applicable to the post-earthquake emergency evaluation of water supply networks, but also provides an effective way of seismic performance evaluation of large regional water supply network before the earthquake.

Early detection of leakage is of great importance for life-cycle maintenance and management of municipal pipeline system. Due to economical and technical efficiency, ductile iron pipe segments and socket joints are widely used in practice to construct water distribution systems. The ductile configuration of the socket joint allowing for large deformation constitutes the most common cause for water leakage. Aiming to the leakage due to failure of socket joint, this paper presents an experimental study on acoustic emission (AE) based leakage detection in a water supply system. The acoustic characteristics of leak signals propagating along pipe segments are investigated. Based on a logistic regression method, leakage occurrence is recognized after inputting several training sets while obtaining a series of parameter identifying the leakage event. Results show that the leakage identification using logistic regression method is capable of detecting leakage with a good accuracy of 97.76%.

The water supply system of Yangon, Myanmar, is aging so that almost 50% of the supplied water is lost due to leakage. To upgrade the water system, a retrofitting plan appropriate to a developing country is expected. In this regard, a simplified seismic design guideline for underground structures is proposed. Seismic design formula is prepared not only for continuous pipes, but also for mechanical joint pipes. As current seismic design method for above ground structures is often formulated for three different performance modes (IO, LS, and CP) so the similar design formula should be prepared for underground structures. Failure modes for those three different limit states are defined and their corresponding pipe joint criterion for their performances is formulated in this study. The seismic performance of the pipes can be assessed by the pipe damage mode such the leakage, pull-out, and buckling failures at the joint. The numerical calculation is given to show the seismic assessment of the pipes with current seismically vulnerable joints as well as that of seismically resilient continuous pipes.

This paper examines the characteristics of damage to water supply system in heavy rain disasters in order to take effective measures against heavy rain. Firstly, a database of damage to water supply system in heavy rain disaster was made. The data include the damage to water supply facilities induced by heavy rain in Japan from 1999 to 2015. Thirty-six heavy rain disasters are picked up here because sufficient information of water stoppage and amount of rainfall are available from the database. The relation between water stoppage and amount of rainfall was clarified by using the database.

Earthquakes cause rapid increase of water flow and rapid decrease of water pressure at water distribution stations. There is the possibility of the stop of water supply due to the behavior, and we might not be able to send water to the areas that need water. According to the questionnaire survey on Great East Japan earthquake, the behavior might cause the breakages of air valves as well. However, we have never found out a cause of this abnormal behavior, therefore, we cannot take specific countermeasures against them on the present situation. The purpose of this study is to find out the cause of the abnormal behavior. We investigated the water flow and water pressure when the earthquakes occurred and seismic characteristics of earthquakes that occurred in Saitama city in 2011. We found out that the seismic motion of horizontal direction and the specific period gives a strong influence to water supplies.

The study of earthquake strong ground motion using wave motion analyzing method is of great value in lifeline earthquake engineering. The application of multi-transmitting boundary in spectral element method has been investigated, which is aiming at combining their high accuracy and superior convergence rate. Detailed examine of the classical multi-transmitting formula (MTF) scheme in finite element analysis manifests the feasibility of the combination. Several polynomial-based interpolation schemes of MTF are investigated, but they do not always work well. An applicable spectral interpolation scheme of MTF, which involves the consideration of both the interpolation order and spectral element displacement mode, is then proposed and some improvement immediately are obtained. Numerical tests indicate that the polynomial-based interpolation schemes give rise to stable solutions in most cases, but the good accuracy and convergence of the spectral interpolation scheme may be kept all the time.