Challenges and Advances in Sustainable Transportation Systems

Two in-line Bus Rapid Transit (BRT)stations along State Route (SR-) 15 at El Cajon Boulevard and University Avenue in the Mid-City area are under design. The in-line stations are within the median of the freeway at the freeway level. The project will construct northbound and southbound BRT lanes within the existing median with offset side platforms at University Avenue and El Cajon Boulevard, and they are part of Interstate (I-) 15 BRT system. This paper will discuss the planning and design challenges during the project implementation.

This paper summarizes the comprehensive system development and intermodal traffic management center deployment currently underway in China that can serve as an excellent development model for other cities in China and Asia. ShenZhen, China, has been actively expanding its port infrastructure and urban development with a unique sustainable, environmentally-friendly enhancement.The ShenZhen Transport Commission in ShenZhen City is currently integrating planning, system design, prototype demonstration, logistics, and eco-friendly green port operations and water transport to improve the environment, resources, community, and investment to successfully attract new energy-efficient industry through integrated high-tech development and improved intermodal logistics. As one of China's major gateways with a unique economic development zone, ShenZhen is applying various ITS technologies to reduce emissions, improve energy efficiency, and provide green logistics to link Hong Kong and the Chinese Mainland for a sustainable inland waterway environment, integrated logistics, and system planning development.

One of the challenges facing airport development is the ongoing encroachment of incompatible land uses around airports such as high intensity residential areas, schools, and environmentally sensitive land uses. In California, airport land use compatibility issues are particularly challenging since airport operators generally do not have direct authority over local land use decisions. In addition, local governments often consider economic incentives from land use development around airports to outweigh airport land use compatibility considerations.China is building 50 to 60 airports in the next five years, including the world's largest airport, the Beijing Daxing International Airport by 2018. Using various U.S. examples, this paper focuses the airport land use compatibility planning issues China may be facing.A right balance through the use of airport land use compatibility planning must be sought between promoting the economic benefits and preserving the vitality of new airport development versus protecting the safety and the environment of nearby communities.

The Next Generation Air Transportation System (NextGEN) is the future of the US National Airspace System. Because of its revolutionary innovation of new technologies, NextGEN is still in its infancy on how it would change the aviation industry. This paper presents an overview of NextGEN and its effects on the aviation industry as a whole. The paper compares the current technology of the air transportation system with NextGEN and examines how the latter would affect airports of all sizes, aircraft operation, and the aviation industry. Several key elements are addressed. The "NextGEN for Airports" highlights the awareness and the role of future airports on how it may change the airport infrastructure, industry characteristics and aviation economics. The latest innovation of aircraft technologies is discussed focusing on how these innovations would interact with future NextGEN airports. Finally, the costs and implementation timeline of NextGEN are also addressed.

With the development of high-speed railway construction, existing service costs are generally high, delivery time long, poor service quality, affecting the lifting Materials Distribution service level of China Railway. In this paper, in order to improve the scientific decision-making in China Railway Materials Distribution System, making reference to relevant research field of the latest achievements, research on the Materials Distribution related decision problems. In this paper, the comparative analysis of the railway logistics operation mode is to be done, put forward index system of "mode selection better", and then with the traditional AHP and TOPSIS method, operation mode optimization model is improved and constructed based on GAHP and GTOPSIS. Research shows that the system of railway Materials Distribution, the selection of service operation mode is practical, effective, can help enterprises to choose the best operation mode that match their needs.

This paper is based on resident travel survey data in Jinan City using adisaggregate model and conducts exploratory research related to the travel mode choice behavior of the elderly. The results show that age, gender, having a driver's license and a monthly pass, number of bikes and electric cars in the family, travel purpose, travel distance, travel time, and other variables have an important impact on the travel mode choice of the elderly. After determining the characteristics of the variables, the parameters of the model were calibrated. According to the model calibration results, combined with the sample data used in the parameter calibration, the future travel choice probability of the elderly was predicted. The result of personal choice was calculated using aggregate analysis after predicting the average probability of all types of travel modes and comparing them with the actual survey sample selection ratio. The final model errors were below 2 percent, which is within the allowable range, so the model parameter calibration is effective.

Latent class model (LCM) is an analytical technique which is applied to establish model with latent variables. This paper first analyzed the principles of the latent class model, the calibration method of parameters and the evaluation indices after introducing the concepts of latent variables and categorical variables. Then, combined with the number of explicit variables and the number of latent classes which were achieved from the relative fit index, a latent class model of travel mode choice was formulated. Moreover, based on the personal trip survey data of Beijing in 2005, this model was calibrated using Mplus software. At the same time, the proportion of explicit variables in the latent variables was obtained. The calibrated parameters were thoroughly discussed, as well as the characteristics of latent classes. The results show that the latent class model provides a more powerful tool to analyze categorical data for the research of travel mode choice problem.

As an advanced cargo organizational structure and mode, road freight network operation can greatly improve the efficiency of road transport and reduce transport costs. With the promotion of the external environment and internal market factors in road freight, developing a road freight network is the direction in China and is an effective way to change the current development situation of China's road freight. Therefore, it is significant to study and learn the evolution of foreign road network transport and development of the law. This study analyzed the evolution process of the development of foreign road freight transport from two angles in the transportation business—outsourcing and the carriage of goods—and summed up the basic laws of foreign road freight transport network development, which is that competition and cooperation are the two main themes. Mergers and restructuring also are important, and contracts and standards are important elements of foreign road freight transport network development. Combined with the characteristics of the transport of a domestic freight transportation network, the focus is on network transport development in China. This will guide enterprises toward market network operation, promote synergies among the main bodies of the freight market, strengthen technical innovation, and guide enterprises to achieve specialization, so that the road freight market can be more efficient.

New urban districts are the inevitable outcome of urban development at a certain stage and, good or bad, planning directly affects the development of the whole city. The choice of a public transportation development mode is an urgent problem in the process of the implementation of public transport priority development in urban districts including the functional orientation, traffic characteristics, and current situation and problems related to land use, combined with existing technical and economic characteristics of the city's main public transit mode. This paper probes the influence factors of public transit mode choice and establishes a new urban district public transit mode decision matrix. Finally, taking the Nanjing Hexi new district as an example, the paper verifies the applicability of the matrix.

Functional vehicle detection and signal system communication are essential for a traffic signal system to execute its intended coordinated signal timing plans. The degradations of vehicle detection and signal system communication could impose barriers to successful operations of a traffic signal system. To achieve and maintain an acceptable operational level set by a traffic agency, an agency has to prioritize its resource allocation. This paper first introduces the concept of traffic signal system performance. It defines a traffic signal system degradation index which measures the proportion of increased travel time attributable to failures in detection and communication components with respect to the total observed travel time of a traffic signal control section. The paper uses the degradation index and traffic simulation to evaluate the effectiveness of major strategies to improve vehicle detection and signal system communication. These strategies include upgrading detection technologies, improving the responsiveness to detection and communication repair work, providing adequate training, increasing the frequency of inspection, and installing a GPS clock to maintain synchronization of the time clock in the controller. Finally, recommendations for optimal allocation of operation and maintenance resource allocation strategies for traffic signal systems are provided.

Urbanization and motorization have increased rapidly in China during the last decades, along with China's economic boom. The increasing amount of motor vehicles brings frequent congestion, crashes, pollution and other negative impacts on the metropolis. Meanwhile, aberrant driving behaviors often happen among Chinese drivers and even enhances those negative impacts. Scrambling behavioris a common aberrant driving behavior and always occurs at a two-phase signalized intersection without a left-turn signal. Some left-turn drivers will "scramble" to pass through the intersection and not yield the way to the straight flow coming from the opposite direction, which has a higher priority. Thus, they may increase the risk of crash and delay at the intersection. This paper focuses on the effect of this scrambling driving behavior on traffic efficiency. By analyzing the character of left-turn drivers' behavior and calculating the delay on the conflict point, some findings are presented: (1) The stopping time of the straight flow caused by average scrambling vehicle on the conflict point, or the average time a scrambling vehicle uses to pass through the conflict point, is linear proportional to the number of scrambling vehicles; (2) The scrambling behaviors significantly increase the delay of traffic flow and decrease the efficiency of the whole intersection. A theoretical model to estimate the delay of the straight-going vehicle on the conflict point is proposed in this study. This paper can help to understand scrambling behavior and provides some basis for the practical operating process on signalized intersections in China.

Traffic congestion, energy shortcoming and environment pollution are nowadays the common problems faced by many metropolises and which have severely restricted the further development of these cities. Therefore, the sustainable development of an urban transportation system has aroused more and more attention. Based on this background, this paper attempts to investigate the transportation network design problem from the perspective of sustainable development, and focuses on the impacts of road broadening on total travel time, total fuel consumption, and total vehicular emission at the network level. We integrate these three indicators into a sustainable development index, and then establish the corresponding bi-level optimization model. The upper level problem is to maximize the sustainable development index from the viewpoint of traffic managers, and the lower level problem is to depict travelers' route choice behavior based on user equilibrium (UE) theory. Finally, the genetic algorithm is used to solve the bi-level model. The numerical example shows that the model and algorithm are feasible and can be taken as a basis for the related research.

Traffic conflicts exist among mixed traffic conditions. Considering influences of pedestrians, bicycles and mixed traffic flows, this paper first summarized the right-turn capacity calculation methods based on conflict analysis by applying the gap theory. Furthermore, the key of this paper is the right-turn capacity calculation formula based on statistical analysis (i.e., the vehicle capacity is presented as a curve with the capacity as the vertical axis and the pedestrian or bicycle flow as the horizontal axis) which is fitted using traffic survey data of six typical intersections in Beijing. Comparing the above two methods upon influences from pedestrians, bicycles and mixed traffic flows, the characteristics of right-turn capacity in different situations could be acquired. By comparing the queue length obtained from inputting right-turn capacity calculation data from this paper with that from existing methods, the results of this paper were closer to the practical situation and more accurate because the calculation formula of this paper not only applied the gap theory, but also adequately took the influence of pedestrians, bicycles and mixed traffic flows into account.

Drop-and-pull transport, according to a predetermined operation plan, refers to a tractor dropping a trailer in a cargo loading area and unloading. This paper introduces the significance of the development of drop-and-pull transport and the achievements of the drop-and-pull transport pilot project of Shandong Province. There are problems with lag in dedicated infrastructure construction, regulations, policies, and standardized construction of models, as well as a lack of leading enterprises and cooperation among enterprises. By adjusting laws and regulations, strengthening the standardization of vehicle types, and constructing a freight market network, leading enterprises can solve the problems in the pilot project and promote the development of Shandong's drop-and-pull transport.

Traffic congestion has become a vital issue for improvement in the quality of living in thelargest cities. Transit station distribution has a great impact on traffic flows in a city. This paper takes Beijing as a case to analyze the causes of traffic congestion in terms of station distribution, transportation network and traffic flow. As a conclusion, it proposes a new mode of metropolitan transport network planning by integrating multiple transportation modes and optimizing regional distribution of stations. It plans to create three integrated transport hubs which integrate urban railways stations, long-distance bus stations with inner city bus stations. The hubs are evenly distributed on the east, north and south Sixth Ring of Beijing. One of advantages of the new mode is that suburb-to-center traffic flow could be reduced, and thus traffic congestion would be relieved. This paper also introduces a universal pattern of station distribution in big cities.

Traffic congestion relief has become a key issue in relation to building green transport in large cities in developing countries. In particular, in high-density cities in East Asia, traffic congestion is still getting worse even though huge investments have been made in transit and roads. One important reason for this is the disintegration of planning between road, transit and pedestrian systems. This paper introduces an innovation in green transport for high-density cities named as a rail transit-road system (RTRS). It is based on a standard urban road system with the introduction of a rail transit system on the roads. It gives the priority to green transport modes — such as pedestrians, cycling and public transport — while at the same time taking cars and other vehicles into account. That makes it possible for cars, pedestrians, cycling and public transport to run efficiently without disturbing each other. Compared with existing roads, the RTRS system would enhance the efficiency of use of road spaces, save the investments, reduce traffic congestion on roads, and improve the walking and bicycling environment. It would be an innovative way of achieving green transport in high-density cities in East Asia — China, for example.

The German philosopher Emmanuel Kant once said that there were only two bodies of knowledge in the world, viz. history and geography.Both studies reflect on time and space, and one cannot be separated from the other. History has to be studied in the context of geography. The purpose of this paper is to use the names of streets on Hong Kong Island to provide a glimpse of the history of Hong Kong.Hong Kong represents the first time in modern history where a western power has officially ruled over a predominantly Han Chinese population.Prior to the colonization of Hong Kong, the Dutch occupied Taiwan (but only for 38 years and the rule was over the local aborigines). While Macao was occupied by the Portuguese much earlier, the occupation was not official. Macao was not declared a colony until after the first opium war, when the Portuguese took advantage of the weak Qing government to press their demands.

The installation site of loop detectors directly influences the quantity and quality of information detected and processed. Searching appropriate installation sites not only contributes to realizing more accurate traffic estimation, but also is able to accomplish a better cost-effectiveness. In this paper, three positions were chosen as the loop location alternative sites: (1) site beside upstream intersection; (2) site beside downstream intersection; and (3) sites in the middle of the link. By comparing their average relative errors (AREs) and relative AREs distribution of link travel time, a better loop location site could be determined on the basis of definition of link travel time in HCM 2000. Moreover, different volumes in road network were also considered to test the outcomes. VISSIM simulation was used to build the road network in order to detect all the traffic data. The purpose of this paper is to seek superior locations of loop detectors for dynamic link travel time estimation on urban roads.

Walking is the main way to travel short distances, and is also one of the terminals connected to a variety of transport modes. Today, pedestrian traffic is a way to encourage, and walking quality has become an important indicator of quality of life. To many mountain cities, walking has a special meaning. People have become accustomed to walking down the street, shopping, playing, and socializing. Walking has become a way of life. With the trip character in Chongqing City, this study analyzed the problems of a walking system and trip behavior and proposed the requirements to the pedestrian facilities. Combined with urban waterfront space and spatial characteristics of the mountain, walking facilities are divided into three types:transportation, recreation and fitness business. This study also proposed a different walking function system plan concept and planned a ‘Mountain River City' feature walking system.

Nantong City will become an important transport node when the railway network is perfected in 2020. Then, coaches from Nantong City will serve new railway transfer passengers and increase regional and local passengers. Both types and the destination proportion will change, obviously. In the research, we allocate the passengers into current and pre-planned coach stations with the principles of accessibility, least transportation interference, and convenience. Four schemes are compared to determine the best scale and distribution of coach stations for better service and operating efficiency.

This paper describes the role of ITS in implementing California's Global Warming Solutions Act of 2006, which requires reduction of GHG emissions to 1990 levels by 2020. The paper considers the "Common Methodology" being developed for use at the international level to enable independent third party verification of GHG emission reductions due to ITS. Evaluation is made of the $7.6 billion in ITS planned in the Regional Transportation Plan and Sustainable Community Strategies (RTP/SCS) adopted by the Southern California Association of Governments (SCAG). These ITS projects are to help achieve a nine (9) percent reduction by 2020 compared to the 2005 level on a per capita basis. Analysis is made of the SCAG 2012-2035 RTP/SCS planned ITS for enhanced incident management, advanced ramp metering, traffic signal synchronization, advanced traveler information, improved data collection, universal transit fare cards (Smart Cards), and Transit Automatic Vehicle Location (AVL) to increase traffic flow and reduce congestion to consider whether these are the most beneficial ITS investments. Transportation policy-makers in Europe, Japan and the US are cooperatively developing a Common Methodology that can be accepted and widely used at the international level. Qualitative analysis has been drafted to rate ITS categories for potential GHG emission reductions, and case studies are planned to enable the first version of the Common Methodology to be available for use by the end of 2016.

International trends show that the vehicle industry is moving towards energy-saving, safe, comfortable and entertainment-oriented vehicles. The operating patterns and energy-saving features of new-energy buses match these trends and will move them to the center of energy development policies. Although the central government and local governments have subsidy policies for the purchase of new-energy buses, the subsidies are apparently not enough for operators to effectively support the new-energy bus industry. This research attempts to discover the influencing factors in introducing new-energy buses to Taiwan through data analysis and interviews with industry operators and owners. The results showed that even if purchase costs are reduced with the help of subsidies, operators still would not purchase new-energy buses. This is mainly due to a lack of technology, an immature industrial environment, and insufficient government policies, as well as other factors.

There is not much literature on fuel economy performance of motorcycles from laboratory approval tests in the real world. The mainstream official statistics from laboratory approval tests report fuel efficiencies for each motorcycle model. However, our tests reveal that fuel efficiencies of urban arterials are 55-60% to the lab-test harmonic means regardless of age deterioration. Alternatively, with the on-board measurement system OBS-584 developed by ARTC suitable for motorcycles, it enables on-road data available for motorcycles. We found that average fuel consumption by speed showed positive correlations to speeds, regardless of laboratory approval tests, urban or rural on-road tests. Moreover, similar correlation patterns of younger and older motorcycles suggest that the statistic regressions are probably a shared form among models or across ages. Further investigations into data directly collected from motorcycles in the real world might shed light on new approaches to better quantifying fuel consumptions of motorcycles driving on the road.

The increasing popularity of the use of electric bicycles in China in recent years has transformed the urban traffic travel structure, changing the impacts on the natural environment from the traffic system. By analyzing the energy consumption and emissions from various traffic modes during life cycle, this paper discussed the impacts (energy consumption, carbon emissions, SO₂, PM and pb consumption) ontheenvironment from the transformation of urban travel behaviors caused by the development of electric bicycles. Taking advantage of the electric bicycle travel survey data in Xi'an, 2012, results have been found that the use of electric bicycles has increased the emissions of SO₂, PM and the consumption of pb. However, energy consumption and CO₂ emissions were reduced.

This study analyzes urban development and green transportation design for Taipei and Kaohsiung, Taiwan. Traffic usage characteristics are analyzed, the public bike development experience of the two cities is compared, and, finally, a reference for other cities to develop green transportation is proposed.

For various reasons, it may be necessary to design a section of highway with substandard values for some elements. Such design exceptions require appropriate assessment and justification of the potential impacts to highway safety and operations. It is necessary to conduct economic analyses for proposed design exception projects to compare with the standard designed projects. An economic analysis method was developed to conduct benefit-cost evaluations for design exception highway projects. The method considers life-cycle-costs as well as life-cycle-benefits resulting from a proposed built project in terms of monetary values. Agency costs are estimated by engineers or designers based on past experience, bid prices, design specifications, materials costs, and other information. Travel time and delay costs are usually valued as a percentage of average personal wages. Accident or crash costs are the monetary values for fatalities and injuries associated with crashes. The vehicle operating costs are attributed to the changes in highway speeds, traffic congestion, pavement surface, and other conditions that affect vehicle fuel consumption and wear and tear. With this analysis method, engineers will be able to conduct benefit-cost analysis efficiently and accurately for design exception projects.

Based on the hypothesis of chloride ion concentration in concrete surfaces changing linearly, a convective depth model was established in this study. The rationality of the model was verified by experiment. In addition, a novel method for calculating the equivalent chloride ion content in the natural environment is proposed. The results showed that the diffusion of the chloride ion in concrete can be described by Fick's second law, and there was an exact convective depth value in a concrete surface. In general, the value of the convective depth is relative to the wetting-drying ratio of the environment and the permeability coefficient of the concrete. Compared with the water influence depth in concrete, the convective depth was shallow. Moreover, the equivalent chloride ion content in the environment was determined by the characteristics of the environment.

The time-varying of the diffusion coefficient and distribution of the chloride ion content in concrete was investigated in this paper. Based on the testing time and methods, the difference and the application range of the diffusion coefficient are discussed. In addition, the difference of the chloride ion ingress in concrete with various strength levels was also researched. Results showed that chloride diffusion in concrete can be described by Fick's diffusion law, and the fitting curve based on the annual diffusion coefficient was more suitable for describing the change. Generally speaking, the diffusion coefficient tends to stabilize the value when the testing time is more than a certain constant value.

Based on Fick's Law of Diffusion, this research created a correlation model between the chlorine ion content in concrete surfaces and the elevation and distance away from the ocean in a natural environment. The real-time monitoring data of concrete chloride erosion in a natural environment were used to validate the rationality of the proposed correlation model. In addition, the variations of the chloride diffusion coefficient in concrete and the maximum chlorine ion content in a concrete surface along an elevation were investigated. The results showed that the chlorine ion content in concrete in a natural environment significantly changed and correlated with the elevation and distance from the ocean. The variation of chloride ion content in concrete surfaces along an elevation can be characterized by an S curve, and the variation of chloride diffusion coefficient of concrete along an elevation had a Gaussian distribution.

The emerging strengthening technology of high strength steel wire mesh and high performance mortar is widely used in the field of seismic strengthening, bending and shear strengthening, and reinforcement of beam-column connections in China. In this paper, through the experimental research on impact and flexural behavior of RC beams strengthened with high strength steel wire mesh and high performance mortar, two different stress responses under different stress modes were evaluated. Drop hammer impact test was conducted on the B1 beam and static loading test was conducted on the B2 beam. Through the analysis of the failure mode, the strain of the steel and the mortar, and the change of deflection under different loading conditions, the difference was obtained under the two loading modes. The results showed that the beam, under the impact, resisted the instantaneous impact load, which reached the maximum quickly and then rapidly decreased to the minimum. The transfer of the impact energy was slightly slower than the change of the load. Additionally, the structure deformation of the beam under the static loading increased with the increasing load.

Existing deep reinforced concrete (RC) coupling beams with low shear span ratios and conventionally reinforced shear stirrups tend to fail in a brittle manner with limited ductility and deformability under reversed cyclic loading. Retrofitted coupling beams with laterally restrained steel plates (LRSP) have been demonstrated experimentally and numerically in the previous studies to be a viable method for improving the structural performance of existing deep coupling beams. In this paper, an original seismic design procedure of LRSP coupling beams is proposed and it consists of five main parts, which are:(1) estimation of the ultimate rotation of the original coupling beams; (2) estimation of axial force; (3) rotation capacity of bolt group; (4) rotation capacity of steel plate; and (5) rotation compatibility of retrofitted coupling beam.

High-early-strength precast concrete technology can improve production efficiency and save energy. The use of early-strength type polycarboxylate water reducers can shorten the setting time of concrete and steam curing time of precast concrete and can significantly improve the early strength of concrete. Early-strength superplasticizer BTC300 bearing with sulfonic acid groups and amide groups is synthesized at room temperature and has some significant functions, such as slow release, early strength improvement, and high water reduction. The tests of preparing C30 ~ C80 precast concrete show that compared with concrete with the normal superplasticizer BTC100, concrete with early-strength type superplasticizer BTC300 have higher 1- to 3-day average strength, whether under steam curing conditions or at room temperature. The feature becomes more prominent as the strength grade increases.Also, the 28-day strength of concrete with BTC300 is slightly higher. GPC analysis shows that the active ingredients of BTC300 superplasticizer molecules are much higher and the content of small monomer polymers is low, so it has little influence on delay of cement hydration reaction. Hydration heat tests show that the second hydration exothermic peak with BTC300 is nearly 10 hours earlier than that of BTC100. These tests proved that the function of BTC300 is relatively early strengthening.

Under seismic action, local buckling in plastic hinge regions of CFT columns could be attributde to induced force and unrecoverable deformation. To study local buckling behaviors of CFT columns, a theoretical analysis formula of buckling stress through energy principle was proposed which included elastic buckling stress and inelastic stress. It was found that local buckling of CFT columns is greatly affected by the yielded elasticity modulus of steel tube. An extensive set of tests on forty-two CFT columns under axial force for local buckling behaviors is presented by taking into account the parameters of slenderness ratio, diameter-to-thickness ratio, and compressive strength of unconfined concrete. Comparing experimental and theoretical results, the characteristic of yielded elasticity modulus of steel tube was obtained.

The dynamic modulus is one of the fundamental properties defining the response of asphalt mixtures in a flexible pavement system. It is an essential input of the Mechanistic-Empirical Pavement Design Guide (MEPDG) software for asphalt pavement design. The dynamic modulus can be evaluated by several existing direct testing procedures, but the tests are difficult and costly, proving complicated for engineers to carry out during the pavement design process. Many studies have been done concerning the predictive model of dynamic modulus. This presentation presents a comprehensive study about developing a predictive model of dynamic modulus for characterizing the asphalt concrete mixtures used in Florida. A laboratory experimental program was developed to evaluate the dynamic modulus of selected Florida Superpave asphalt concrete mixtures. Based on the test results and analyses, a dynamic modulus prediction model was constructed. The results showed that the variables related to aggregate gradation, mix volumetric, percent weight of asphalt content, loading frequency and temperature had influence on the dynamic modulus of the hot mix asphalt mixtures. The predicted results of the developed model were very comparable with the test data.The predictive model could be more suitable for predicting dynamic modulus of the hot mix asphalt mixtures used in Florida.

Artificial neural networks (ANN) have been used in many pavement prediction modeling analyses. However, the convergence characteristics and model selection guidelines are rarely studied due to the requirement of extensive network training time. Thus, the techniques and applications of back propagation neural networks were briefly reviewed. Three ANN models were developed using deflection databases generated by factorial BISAR runs. A study of the convergence characteristics indicated that the resulting ANN model using all dominating dimensionless parameters was proved to have higher accuracy and require less network training time and data than the other counterpart using purely input parameters. Increasing the complexity of ANN models does not necessarily improve the modeling statistics. With the incorporation of subject-related engineering and statistical knowledge into the modeling process, reasonably good predictions may be achieved with more convincing generalization and explanation yet requiring minimal amount of time and effort.

From the testing of cold in-place recycling asphalt pavement in cold regions of China, combined with pavement design data, some pavement performance indicators and information were obtained, such as design deflection of recycling pavement, actual rebound deflection of pavement before and after regeneration, structure strength coefficient index (SSI), and pavement condition index (PCI). Through the analysis of the test data, condition of the cold in-place recycling asphalt pavement in cold regions and structural strength improvement of recycling asphalt pavement through regeneration were evaluated. The prediction model of the recycling pavement performance was established. Two approaches to predict the service life of the cold in-place recycling asphalt pavement were developed.

This paper presents a research study to evaluate performance of recycled asphalt pavement (RAP) mixtures with ordinary and high-viscosity rejuvenating agent.Asphalt content in RAP, properties of recycled asphalt, and aggregate gradation curve were determined through centrifugal extraction test. Rutting test, freeze-thaw splitting and bending test were utilized to compare the impact on the percentage of RAP and rejuvenating content. The results indicated that with the increase of the RAP content, high temperature stability will increase, whereas the low-temperature deformation capacity and water stability of recycled mixture will decrease at a certain degree. Compared to RA-1 with higher viscosity, RA-75 can also help improving the recycled mixture in high temperature performance. But the improvement is not significant in recycled mixture with low percentage of RAP content.

Design procedure of hot in-plant recycled asphalt mixture assumes that the residue aged binder in reclaimed asphalt pavement (RAP) is fully blended with virgin binder. However, recent research shows that the interaction between aged binder and virgin binder may not achieve a total blending status. The difference between design assumption and actual blending status means that insufficient asphalt binder used in mixtures may cause dry hot mix asphalt (HMA) and premature pavement distress. Therefore, it is significant to evaluate the reasonableness of design assumption and mixing quality of recycled asphalt mixtures to measure the blending status between aged binder and virgin binder. In this paper, four typical measurement method of blending status — binder-marked method, difference-identified methods, staged extraction method, and indirect performance measured method — are summarized. The future development in measurement method is also discussed.

The properties of two different asphalt mixtures blended with direct coal liquefaction residue (DCLR) and binder using two processing methods were studied in this paper. One processing method is to blend powdered DCLR and binder, and the other processing method is to blend molten DCLR and binder. The optimum content of DCLR was determined using the PG system and furfural extract oil was used to improve the low-temperature properties of the blends. The performance of DCLR modified asphalt mixture with the two different blends was also studied in this paper. At first, the DCLR-13 was designed using the Marshall method. Then, the rutting test, the freeze-thaw splitting test, and the low-temperature bending test were conducted on the DCLR-13. Finally, the performances of DCLR-13 with the two different blends were evaluated and compared. The test results indicated that the performance of DCLR modified asphalt mixtures satisfied the specification. The processing method has an influence on the performance of DCLR modified asphalt mixtures.

OGFC (open graded friction course) asphalt mixture is one of the bituminous materials of wearing course for flexible pavement. The permeable mixture allows water to flow through the material and drain out to the sides. The material significantly reduces splash/spray from vehicles and reduces vehicle noise. The air void and particle size of OGFC asphalt mixture are important factors which influence the material performance properties and permeability. In this research, the large particle size OGFC-20 asphalt mixtures with three air voids (18%, 21% and 24%) were prepared. The temperature stability, water stability, and permeability of OGFC asphalt mixtures were evaluated and compared to OGFC-13 (popularly used in China) to ensure better drainage, noise reduction quality, and durability. The results showed that the Marshall and dynamic stability reduced with the increase of air voids. Under the same air voids, the stability of OGFC-20 asphalt mixture is significantly more than that of OGFC-13. Furthermore, the permeability coefficient of OGFC asphalt mixture increased as the increasing of air voids. It showed a good linear correlation between them. To balance the performance and the permeability of OGFC asphalt mixture, OGFC-20 with 21% air voids is recommended for wearing course of flexible pavement.

Open graded friction course (OGFC) asphalt mixture is a permeable mixture allowing water to flow through the pavement and drain out to the sides. The friction course significantly reduces splash/spray from vehicles and reduces vehicle noise. However, the accumulated pollutants in the surface of pavement, caused by vehicle fuel leak, tire wear, and vehicle exhaust adhesion can drain into natural water. It can cause environmental water pollution. In this study, the decontamination ability of OGFC with different air voids was investigated. The high temperature resistance of OGFC asphalt mixture was evaluated by wheel tracking testing. A new rain simulation device was designed to control the rainfall intensity and duration in laboratory. The densities of chemical oxygen demand (COD) and suspended solid (SS) were measured. The results showed that the decontamination ability increased with the increasing of air voids for OGFC asphalt mixture and the decontamination effect for COD was less than that for SS. Furthermore, to balance the performance and decontamination effect, the OGFC asphalt mixture with 21% air voids was recommended for wearing course of pavement.

Warm recycled asphalt mixture (WRAM) is a new typeofbituminous material for green, environmentally friendly pavement construction. The WRAM technology combines the benefits of hot recycled and warm mix. It significantly reduces energy consumption and gas effusion due to lower mixing and compact temperature. However, related research indicated that low temperature and water stability of WRAM with high RAP content (more than 30% by weight) cannot meet the requirements of the specification. In this research, the fiber was applied to improve the performance of AC-20 WRAM with 40% and 50% RAP content. The composition design was carried out using the Marshall test. The optimum bitumen content is 4.9% and 5.1%, respectively. A series of laboratory tests — such as wheel tracking before and after conditioning and beam bending at low temperature — were carried out to evaluate the performance properties of AC-20 WRAM with reinforcing fiber. It was shown that this method can effectively improve the low temperature and water stability of asphalt concrete pavement. The properties of WRAM meet the requirements of the specification.

This draft version of “Study on the Performances of Direct Coal Liquefaction Residue Modified Mixture Asphalt” (DOI 10.1061/9780784413364.039) was erroneously included in the published proceedings.

In recent years, a number of injuries and fatal collisions have occurred at certain highway-rail grade crossings located adjacent to highway intersections, driveways, or freeway on-ramps. Some guide signage, pavement markings, and other traffic control devices currently present at the crossings may have confused drivers and caused them to turn onto the railroad tracks rather than at the nearby intersections, driveways, or freeway on-ramps. Due to limited research in this new area of prevention of incorrect turns at highway-rail grade crossings, a research project was sponsored by the National Center for Transit Research and Florida Department of Transportation to seek cost-effective solutions. This paper first provides an intensive literature review to identify available sources of information and best practices throughout the world for innovative and cost-effective infrastructure treatments. It then presents analysis of the contributing causes of crashes that occurred in the past and offers a set of countermeasures for planning and design aimed at improving incorrect turns at highway-rail grade crossings.

This presentation analyzes the impact of transit technologies on the urban environment and evaluates land use, station design, and transit costs as a means of projecting the best options for intermodal stations and transit-oriented developments. Several commuter rail, AMTRAK, and freight rail corridors may be used in the future to accommodate heavy, light and/or high-speed rail systems in the United States. Diesel/electric locomotives, which populate urban rail corridors, have heavy load requirements and are industrial and/or utilitarian in appearance. However, diesel multiple units (DMUs) with lighter weight, increased fuel efficiency, ease of accessibility, additional capacity, enhanced performance and lower costs are competing for their market share. Currently, monorails, people movers, and streetcars - along with the traditional light and heavy rail systems - have public acceptance to enrich the urban environments surrounding the existing corridors, and enhance commuter experience. Many cities, however, are at a crossroads regarding transitioning from an automobile culture to a rail culture. Therefore, local cities willingly embrace opportunities for better environments.

Track components —such as rail, fastening, and ballastless slab — in urban rail transit are damaged frequently by train dynamic load or temperature and humidity of the environment around the track. Traditional inspection methods, like human inspection and identification, were low in efficiency and high in missing rate. In this paper, based on the theory of Image Recognition (IR), the identification algorithm for track components' condition and damages was researched. The image processing method, the identification operators and data transform method were analyzed. The image recognition method for track component damages was presented. The broken rail and crack in rail food from the photo graphics by inspection were recognized and identified. It shows this method has high accuracy and identification capability. It will be the key technology for the software of high-speed photograph technology and image recognition technology in the inspection of the track components in urban rail transit.

With the complex conditions in urban rail transit, the rail in continual welded rail (CWR) may be broken in some sections. Track circuits in a traditional signal system can find the broken rail when this damage happens. However, after a state-of-the-art signal system — such as the Communication-Based Train Control System (CBTC) — was applied, the role of the track circuits disappeared. In this paper, the existing broken rail detection methods and technology were summarized. A monitoring system of broken rail for urban rail transit based on ultrasonic guided waves was proposed combined with automatic data collection and transmission technology. Considering the overall system, the level and frame structure of the system was analyzed. Moreover, the signal frequency of ultrasonic guided wave, the type and location of broken rail, and the data transmission methods were discussed. A large number of laboratory tests was carried on to determine different calibration conditions.

To research the evaluation and optimization of an urban subway plan, this paper selects Changsha as the case study and designs the models of a subway network and an urban spatial network based on the subway plan and urban spatial plan of Changsha. We represent 14 districts as nodes and regard 91 connections between the districts as edges from the perspective of complex network analysis. By analyzing the node power, edge weight, and coordination degree between the two models, we determine if the subway network can match the urban space and then determine the subway plan defects and optimized strategies.

Line planning is the primary task of high-speed railway construction. Station layout design along the previously-planned line is the second phase. Optimized distribution of high-speed railway stations could improve passing capacity and operational performance of the line. First, the paper details a general layout theory of high-speed railway stations. To estimate the quantity of high-speed railway stations a concept of "reasonable distance between stations" — which is a focused point in the planning of railway stations — was introduced. The paper then establishes a hierarchical index system, measures the weights of the indexes by the Analytic Hierarchy Process, and establishes a layout evaluation model of high-speed railway stations in which the marks of quantitative indexes are determined by membership function, and the marks of qualitative indexes are determined by fuzzy comprehensive evaluation. Finally, based on the model, the best layout scheme of Xi'an-Chengdu high-speed railway stations was determined, which was consistent with the actual situation.

Pedestrian speed is a key factor in pedestrian evacuation analysis. The speed is closely related to the guidance efficiency of a pedestrian sign system. The guidance efficiency of a pedestrian sign system is defined in this paper. A test method for the extraction of the guidance efficiency index was also confirmed through the pedestrian test in integrated rail transit hub. The level of the guidance efficiency of pedestrian sign system was also evaluated preliminarily in the paper. The guidance efficiency not only can be used to evaluate the guidance performance of the pedestrian traffic oriented sign in the transport hub, but also can correct the pedestrian speed which is the key factor in pedestrian evacuation analysis. The difference of the evacuation time in each period between the original evacuation model and real evacuation situation can be clearly demonstrated. Therefore, the results of the pedestrian evacuation analysis will be more reliable based on this study.

Based on the engineering background of Beijing urban groundwater levels rebounded, the stress behavior of a subway station structure under cases of the groundwater in different water levels from the view of numerical mechanical models is researched in this paper. The working condition of this paper is the actual engineering of the Beijing subway line 10. The results demonstrate that different underground water levels could lead to obvious vertical displacements and vertical stress changes of structures. The groundwater level upturn (obviously, within a certain range) could make the underground structures deform and float overall. Indeed, it could cause craze, water seepage, harmful ion erosion, and a series of problems resulting in influence on the durability of structures. Some conclusions are important references for further improvement of the design and construction of underground structures and reinforcement of existing substructures.

On the basis of accident data of some railway administration from October 2011 to January 2013 and another railway administration from January 2011 to December 2012, the main influencing factors of both ordinary and high-speed railway operation safety are summarized. Then characteristics of high speed railway operation safety were analyzed. High speed railway operation safety is a high demand at the management level. andhas more traffic safety accidents owing to the management but few accidents owing to the outside factor out of the high-speed railway system, many accidents involve in vehicle system, communication signal system and emergency rescue system. Then it constructed a high-speed railway operation safety evaluation model by uncertain multi-attribute method. It took railway administration bureau A as example and concluded its operation safety situation is general in the end.

The TRANSMIT system is a regional traffic monitoring system that uses RFID tag readers to read E-ZPass tags at strategic locations throughout New York, New Jersey and Connecticut. The readers installed along or over a roadway section are used to identify vehicles equipped with E-ZPass tags provided by multi-agencies through E-ZPass Regional Customer Service Center. These vehicle tags are detected by an upstream reader and re-detected by a downstream reader. The sequential identifications of a vehicle tag allow the measurement of the travel time between the two reader locations. Through multi-agencies' initial efforts, TransCom (operators of TRANSMIT) started the TRANSMIT system installation in metropolitan areas in 1998 with 58 pilot TRANSMIT reader locations on major state highway corridors. Two out of nine MTAB&T facilities (Verrazano Narrows Bridge and Robert F. Kennedy Bridge) were part of this pilot system with a total of three reader sites installed at each bridge. The TRANSMIT system provided regional the valuable real time travel time information and was expanded through each agency thereafter. The current system has more than 250 readers throughout the Metropolitan area and is still expanding.

This paper describes how Taipei City's ITS/ATIS development experience provides an excellent ITS example on how user-oriented, advanced ITS services can be designed, developed, implemented, and deployed with available information communication technology (ICT) by keeping the end-user in mind in world-class cities.There is an immediate need in many megacities in Asia and throughout the world to elevate traffic management, system control, and operational practice to the next level by maximizing the system, equipment, and personnel already in place.Since most cities and counties are now well-equipped with new control centers, signal systems, and capable operational staff, the results can be significant. Implementation guidelines, real-time data platforms, and information exchange standards are readily available in Taipei for potential implementation elsewhere to improve and deliver sustainable transport in the 21st century.

Graphic-aided, portable, changeable message sign(PCMS) is an innovative, temporary traffic control device that has been proven in recent studies to improve drivers' response more effectively than the traditional text-based PCMSs. This study investigated the impact of drivers' gender and age on their acceptance of using graphic-aided PCMSs in highway work zones. A total of 429 driver surveys were conducted in a real-world highway work zone traffic condition under three graphic-aided PCMSs with different settings. Chi-square tests of independence were used to determine the relationship between drivers' gender and age and their preferences to message format. The results revealed that drivers' gender and age did not have a significant impact on their preferences to message format. The results also suggested that the majority of drivers preferred to see the warning messages displayed on PCMSs in the graphic-aided format instead of the traditional text format in highway work zones. This study provided valuable knowledge to government agencies and the transportation industry on the use graphic-aided PCMSs in highway work zones.

Real-time traffic counts between entry and exit of intersections are important input data for traffic signal control systems, and also difficult to obtain. In on-line systems, it is impossible to detect such data directly through a traffic surveillance system and also unrealistic to gather them from conducting surveys. This paper first reviewed the evolution process of the traffic signal control system and analyzed characteristics of real-time traffic counts at intersections. Then a back-propagation neural network (BPN) model was proposed to estimate and forecast the dynamic turning movements, and an algorithm was designed to solve the model. Furthermore, based on the estimated turning movements, a multi-objective model was put forward to achieve the real-time signal control parameters and the evaluation indices. Simulation experiments and case study were implemented and the results were compared with classical Webster method. The reported examples have clearly indicated that the models and algorithms are rather efficient and accurate, and can realize the real-time signal control for intersections.

The Tom Lantos Tunnels at Devil's Slide are located along the California coast between Pacifica and Monterey, west of the San Francisco Bay Area in a region with steep and unstable geological formation. The project replaces the stretch of coastline for much of the distance between the two towns that had a long history of closure due to recurring rockslides. After years of studies, it was decided to bypass it with two inland tunnels, providing a safe, dependable highway between the two towns. The twin tunnels are 9 m wide by 6.8 m high, 1.3 km long, and sit in very complex geological settings in a high seismic zone and an environmentally-sensitive area. The tunnels were constructed beneath San Pedro Mountain using the New Austrian Tunneling Method — a method determined to be the most viable because of its flexibility, adaptability, and ability for adjustment locally to the site's changing ground conditions.At 1,310 m long, it is the longest highway tunnel in California. (The Wawona Tunnel was completed during 1933 in Yosemite National Park. At 1,290 m in length, it was previously the longest highway tunnel in California.)

Nonlinear time history analysis is known for simulating a structure behavior under severe earthquake more proper than other methods. However for simplicity, most of the bridges in the category of Ordinary Standard Bridge (OSB) are being analyzed by a combined procedure which consists of a linear ARS analysis for earthquake response (demand) and a static nonlinear pushover for ultimate displacement (capacity) per the guidelines of many transportation agencies worldwide. The demand and capacity are then compared to determine the safety of the bridge. For the single degree of freedom (SDF) system, this procedure has been proven to be an effective method with satisfactory accuracy. For bridges in the category of OSB but with noticeable characteristics of multi-degree of freedom (MDF) system, large discrepancies between deformation patterns from linear analysis and nonlinear pushover are often observed by engineers. So, the accuracy of conclusion from this procedure is questioned. To explore nonlinear dynamic behavior of these bridgesand investigate the adequacy of the popular combined linear with nonlinear analysis procedure, a series of bridges within the category of OSB ranging from slight to severe mass and stiffness unbalance was analyzed. The analysis methods used for each bridge include linear and nonlinear time history analysis, linear ARS analysis and nonlinear static pushover. To ensure valid results comparison, a ground acceleration time history is used for both linear and nonlinear time history analysis. Its frequency domain ARS curve is used for ARS analysis. Selected bridges model, ground acceleration and analysis methods, procedures, results, comparison, discussion, conclusions and suggestions are all presented in the paper.

To meet the demands of static analysis, fixed bearings that could restrict horizontal displacement were installed in a continuous beam bridge. However, the seismic design of a continuous beam bridge would be rather difficult in high earthquake intensity regions because of fixed bearings. Some measures were taken to improve the seismic performance of continuous beam bridges to some extent, such as replacing all bearings to seismic-isolation bearings. But the seismic safety of continuous beam bridges would not be ensured by these measures when subjected to earthquakes exceeding the preset parameters. Hence, the principle of sliding-restricting was proposed, which was achieved by a Cable-sliding Friction Aseismic Bearing (CFAB). Based on the example of a continuous beam bridge, seismic performance under different types of earthquakes was investigated using a conventional method and a sliding-restricting method. It was found that the initial gap and stiffness of strand cables were two key parameters of CFAB and that the seismic force of a fixed pier could be effectively reduced by CFAB, but seismic displacement at the girder end would be increased.

A novel, multi-spherical, sliding friction isolation bearing for seismic design of bridges is developed in this paper. The configuration characteristics, operation and sliding mechanism are explained. The nonlinear restoring model is presented and the simplified calculation formula of force-displacement relationship of the bearing with identical friction coefficient of frictional interface is established. Experiment of mechanics performance is carried out and the sliding order and the force-displacement relationship are verified. The results show sliding order in theoretical analysis and experimental observation is identical and force-displacement relationship curve derived from theoretical analysis is well agreed with experimental results. The multi-spherical sliding friction isolation bearing has good energy dissipation capacity, horizontal displacement capacity, designated re-centering function, smart stiffness and smart damping behavior under different intensity amplitudes external excitation as it can optimize the parameters of an isolation system for a given bridge based on multiple performance objectives or multiple earthquake levels. These characteristics make the proposed bearing suits for performance-based seismic design of bridges for multiple levels of ground shaking.

Seismic isolation technology has been developed for several decades from the 1970s. Massive research works on seismic isolation devices, isolation theory and engineering practice were performed by scholars and engineers, and abundant achievements were acquired in this field. First, development of bridge isolation technology is briefly summarized in this paper. Several isolation devices for bridge engineering are introduced, including some novel isolators developed in recent years. Isolation fundamental theory researches in bridge engineering on near-fault effect, collision effect, experimental technology, and new design methods are reviewed in this paper to provide references for next generation research on isolation technology in bridge engineering. At the end, recommendations and discussion are proposed for future research and practice.

This paper first introduces the basic principles and stimulation methods of the grillage method, using such method to conduct stimulation analysis of a certain curved beam bridge—a ramp bridge of Jingkai Road in Beijing—as its engineering background. By using MIDAS/CIVIL, a software finite element method to analyze structures, a single beam model and grillage method model were built, and the comparisons and the analysis about deflection and stress among these models was conducted. The conclusion indicates that the calculation results obtained from the grillage method are closer to the values required in actual construction. The analysis revealed that the models based on the grillage method can reflect the mechanical properties and stress state more efficiently and accurately. Therefore, the grillage method is a very convenient and practical method for analyzing urban curved beam bridges, and it is verified that it can be used in the analysis of urban curved bridges.

For a wide range of reinforcement and high rates of water plugging, full-face curtain grouting technology is one of the major measures to improve soft surroundings and seal high-pressure water, especially to excavate underwater tunnels that lack a complex stratum owing to a large amount of groundwater. Because of high pressure, large quantities, and long cycles of injection, full-face curtain grouting technology has a great effect on tunnel excavation. This paper discusses the control action of full-face curtain grouting technology on deformation of a tunnel and recommends sensible preventive action.

Subway running tunnel construction is rather difficult when using an earth pressure balance shield in alternating hard and soft rock strata for problems of dealing with full-face hard rock, upper-soft lower-hard ground, full-face soft rock, and the interface of hard and soft rock. In response to these technical problems, taking measures of theoretical analysis, indoor tests, and combined with engineering practice, we studied the three following matters:construction parameters for shield tunnels in different strata, the building settlement law, and countermeasures and construction technology for shield tunnels in complex strata. The main conclusions are as follows: (1) shield tunnel construction is demanding of a shield machine in alternating hard and soft rock strata such that the shield machine should have the ability to drive in hard rock and soft soil, preventing spewing, overbreak, etc.; (2) technical countermeasures and construction parameters of different strata are presented by cutting tools, driving mode, driving parameters, etc., and (3) all measuring points are affected by secondary disturbance when the rear shield passes buildings and the sedimentation value increases, which accounts for 45-66% of the final settlement.

During strong earthquakes, the surrounding shield tunnel soil may enter the non-linear regime. When the springs and the dampers are utilized to simulate the soil-structure interaction, nonlinear properties of equivalent springs must be considered in dynamic analysis. This paper derived the nonlinear motion equations of tunnel segments under longitudinal seismic action. The characteristics of the nonlinear response of the shield tunnel segments under longitudinal seismic actions were analyzed. The influences of seismic P-wave velocity in soil and the parameter of tunnel segment bolting stiffness on internal force and deformation under non-linear soil-structure interaction were investigated. The numerical results showed that, if soil-structure interface enters nonlinear stress regime, the relative displacement between tunnel structure and soil will increase. This may lead to the increase in internal forces of structures which will produce stress concentration in structures.

According to a real engineer of health detection of the Zhu Yong highway tunnels, this paper first introduces the proper defining parameters which should compare with other engineering and combine with the aims of detection. Then, on the basis of post-treatment on the inspire results to the thickness and compactness of the left-right spandrel and the arch crown of the tunnel, referring to the construction design specification, it gives an evaluation about the lining thickness and the compactness, that is most parts of the lining thickness and compactness on the spandrel and the arch crown of the tunnel content with the requirements of the construction and design, parts of that cannot satisfy it. Lastly, the paper also discusses problems associated with the use of geological radar detection in tunnels and the process of radar signal denoising and line of determining.

Combining highway tunnel testing and assessment with the application of geological radar technology in tunnel detection, key technologies of survey line layout, setting of acquisition parameters, and on-site testing are reviewed. Relying on field test data, lining thickness and density degrees of the left and right spandrels and the arch crown being safely used are more deeply researched. According to test results, whether the actual lining thickness of the spandrels and arch crown of the tunnel meet the requirements of design and specification is analyzed. Studies show that geological radar detection technology for tunnel nondestructive testing and evaluation is an effective method, and the correlation detection technique and analysis method have some reference value for similar tunnel structures.

Precast, post-tensioned segmental bridge construction has been widely used in non-seismic regions in the U.S. for the objectives of accelerated bridge construction (ABC), higher quality control, less traffic disruption, and better workman safety. However, use of segmental bridges in moderate and high seismic regions is limited due to insufficient understanding of its behavior. This paper presents the results of a series of shake table tests on large-scale bridges with pre-cast, post-tensioned, concrete segmental columns. The seismic behavior of segmental columns was observed, segmental joint opening and closing were studied, and the self-center capability of segmental bridge was analyzed. This research is a U.S.-PRC international cooperative project established by the Multidisciplinary Center for Earthquake Engineering Research, University at Buffalo, the State University of New York, under contract with the Federal Highway Administration (Contract No. DTFH61-07-C-00020), and the Chongqing Communication Research and Design Institute, State Key Laboratory of Bridge Structural Dynamics, Chongqing, China, with the International Science & Technology Cooperation Program of China (Project No.: 2011DFA83300).

The Strength I Limit State of American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) specification deals with the failure probabilities of the combination of non-extreme loads. This design limit state equation (DLSE) has been fully calibrated for dead load and live load by using the reliability-based approach in previous research. However, most of other DLSEs, including the extreme event I and II, with certain probability-based concepts considered, have not yet been fully calibrated by using the reliability-based approach. This paper presents an evaluation of the bridge reliabilities under the limit state of Extreme Event I combination of dead load, live load and earthquake load, by using a force-based and a displacement-based approach on a set of nine simplified bridge models. Results show that the displacement-based approach came up with more convergent and accurate reliabilities for selected models.

Taking an example of a continuous steel-concrete composite beam bridge with single column piers under a ramp, a space finite element model was built. According to the structure characteristics and relevant design manual, an anti-overturning stability analysis of the bridge under the design limit load was conducted, and a practical vehicle load and possible arrangement of different forms of the load were analyzed. A further study on the influence of related parameters of anti-overturning stability was developed to determine the probability of overturning under extreme load arrangement. Finally, a field-loading test with the designed vehicle arrangement was conducted to investigate the experimental anti-overturning stability properties of the designed bridge. The test results were used to further verify the consistency of the related standards about the anti-overturning stability of this kind of bridge. Some suggestions to avoid the corresponding accidents are provided.

To improve the calculation efficiency and accuracy of numerical simulation of structure seismic damage, multi-scale finite element modeling is introduced in this paper. Two different treatment schemes of interface coupling between different-scale models by using a force equilibrium condition and a deformation compatibility condition were researched. Finally, a bridge that collapsed in the Wenchuan earthquake is used as an example to illustrate the suggested approach in this paper. A multi-scale finite element model of a bridge was established based on ABAQUS software. The seismic damage and the collapse process were simulated and compared with the actual seismic damage investigation to verify the validity of multi-scale finite element modeling. The research indicates that multi-scale finite element model can be applied to reasonably and effectively simulate the local damage and whole collapse of a complex bridge due to an earthquake, and the treatment scheme by using a force equilibrium condition can meet the stress and deformation compatibility well at the interface between different-scale models.

To study the seismic performance of reinforced concrete hollow piers, models with different axial compression ratios, reinforcement ratios, and height were established and their seismic performance was observed by nonlinear analysis based on the finite element analysis software OpenSees. The results indicate that hollow piers have good seismic performance, and the change of the relative property parameters will affect the performance. The research result of this paper can be used in bridge engineering.

With the rapid development of highway projects, more and more long-span, curved, continuous, rigid frame bridges are built. However, there is very little research about the dynamic characteristics of curved, continuous, rigid frame bridges (especially the seismic response characteristics) to date. To analyze the seismic response, a long-span, continuous, rigid frame, curved bridge - WaYaoBao Bridge- with a double-thin, wall-high pier was taken as an example. Using midasFEA software, a structural, spatial, finite element bridge model was introduced. The Midas software was used to analyze the influence of radius of curvature on a bridge's seismic behavior. The seismic response of the curved, continuous, rigid frame in the incentives under the different direction was investigated. Finally, some beneficial conclusions were obtained which can provide reference for the research and design of similar bridges.

Many structure forms can be chosen when designing an urban expressway viaduct. To get an optimal structure, a comparison study on the seismic performance of different structural forms for urban expressway viaducts should be done carefully. Taking multi-span, simply-supported, small box girders as a basic structure type, a double column pier and double pile cap structure (DCPDPC), adouble column pier and single pile cap structure(DCPSPC), and a single column pier and single pile cap structure (SCPSPC) were chosen as substructures of the same bridge. Seismic performances — such as deformation capacity of bearings, bending capacity and shearing capacity of piers and piles in common earthquakes, and ductile capacity of piers under rare earthquakes of different structural forms — were compared by the demand capacity ratio method. The optimal structures are discussed herein. It can be concluded that the structural form of DCPDPC and DCPSPC have better advantages than others, and the SCPSPC has poor seismic performance and should be carefully used when designing an urban expressway viaduct. This research provides good technical support for the conceptual design for urban expressway viaducts.

The monitoring strategy for bridges considering signal-to-noise ratio and vehicle-bridge interaction is proposed in order to discard a large amount of low signal-to-noise ratio data or normal data. The composition of the vibration signal is discussed, and the reasonable and accurate monitoring threshold should be determined according to vehicles-bridge interaction dynamics. A time-varying dynamic vehicle group model, which includes main uniform parameters and coupling mass, is established. The dynamic coupling equations for bridge and car groups are established, and the analytical expression is given. The health monitoring for a simply-supported beam is discussed. The dynamic response under different uniform mass, speed, and vibration frequency of the car group is analyzed based on the vehicle-bridge interaction theory. The monitoring threshold is determined according to simulated results and measured signals.

A frequency method was proposed to analyze cable tension from measured natural frequencies according to cable tension monitoring of acable stayed bridge during construction. Xinzao Pearl River Grand Bridge was chosen as an example. A geometrical calculation simulation model was established to compare measured cable tension to theoretical cable tension during construction. This paper introduces several cable tension test methods. The principle and theoretical derivations under certain conditions, the method of which fundamental vibration frequency is deduced by dominating vibration frequency, the influence of boundary conditions, bending stiffness, and cable sag on the frequency method testing, and the practical application of frequency method were discussed. A spatial finite element model was established based on finite element software MIDAS. The application of the forward-analysis iterative method was considered to analyze the cable tension during construction. Then the cable tension test method and analysis principle were explored. Finally, it was shown that measured cable tension based on the frequency method was accurate. The measured value is approximately equal to the theoretical value. The experimental error was within the permitted range. The accuracy and reliability of the frequency method was effectively confirmed. The cable tension test for the similar bridges during construction was compatibly applied.

As a new type of bridge, extradosed cable-stayed curved bridge is widely used in mountainous areas. The box girder bears not only axial pressure, but also a considerable part of moment and shear force. The existence of curvature makes the force state more complex and the spatial stress state uneven. Moreover, the broadening of box girder leads to serious shear lag effect. Based on the engineering background of Longjing River Bridge, the positive stress distribution and shear lag effect in top and bottom slabs of the curved box girder under different curvature radius during the completion phase were studied using FEA method. The research indicated that the difference of shear lag effect between the inside and the outside of the curved box girder would be more serious if the curvature radius decreases under dead load action. The positive and negative shear lag effect would simultaneously appear in the inner and outer sides of the flange plate in one section under the influence of curvature radius. Curvature radius has a greater influence on the top plate than the bottom plate. The shear lag effect coefficient would be calculated as straight bridge when the curvature radius is greater than 800m.

Creeping diseases can reduce driving comfort and endanger structural safety, so it is necessary to analyze the causes of creeping. Based on existing research, the factors of the creeping phenomenon using TianNingSi overpass as an example related to the features of radial displacement under dead load, live load, concrete shrinkage and creep, temperature, prestress, etc., were analyzed. The study shows that centrifugal force is the main cause of creeping in curved bridges, which have heavy traffic and large curvature radii. The deficiencies in infrastructure and bearing form should be the main cause of creeping disease. Bearing form optimization can prevent creeping diseases.

In this paper, finite element models based on Wayaobao Bridge in Chongqing with a span combination of 71m+3×125m+71m are established using the finite element analysis software Midas/Civil 2010 to simulate the right-hand-side bridge. In the modeling, the action of self-weight, secondary dead load, prestressed load, and shrinkage and creep of the concrete -which may affect the natural vibration properties - are taken into account. With the concept of the consolidation damage degree being defined at the beginning, the natural vibration properties of the structure under different conditions with a series of damage degree of 0, 10%, 20%, 30%, and 100% at the side pier top were studied. What is shown from the comparative analysis of the results data is that the natural vibration properties of the whole structure are sensitive to the damage degree, and with the accumulation of the consolidation damage, stiffness of the structure continues to reduce. The process and the conclusion of the study may provide some reference for damage identification of bridge structures as well as similar studies on the connection damage.

Movement of high-speed trains is modeled by moving load technology. Radiation damping and elastic recovery of infinite foundations are simulated by a three-dimensional, viscoelastic, static-dynamic, unified, artificial boundary. By considering the influence of the static stress state after embankment and rail system construction on subsequent dynamic analysis, material nonlinearity and dynamic interaction between reinforced concrete roadbeds and the upper layer of formation, large-scale, three-dimensional, dynamic, parallel computation of a rail embankment foundation system on a high-speed railway was performed. Results - including vibration displacement, vibration velocity, vibration acceleration, and dynamic stresses - were obtained. On these bases, an attenuation law of vertical dynamic stress with depth was analyzed and the influence depth of dynamic load was determined. It was found that the principal stress axes in the three planes rotated continuously during the period of load moving, and the rotation in YZ plane was dominant. The rotation of the principal stress axes was compared with that of a soil element induced by the moving load applied directly to the foundation surface.

The distribution of coarse aggregate in concrete at different depths from the surface layer was investigated. Based on the fractal theory, the fractal dimension model of the coarse aggregate in concrete was induced. Meantime, the cross-sectional area percentage of the coarse aggregate in concrete was calculated by sectioning method. The fractal dimension value was also indirectly estimated. The results indicate that there was certain change regularity of the coarse aggregate content in concrete, which presents a low percentage value in the surface region and a high percentage value at the depth. That may be caused by the effect of the size effect and boundary effect during the process of the production. In addition, the fractal dimension value of the coarse aggregate in concrete is about 1.35, which differs from the traditional Euclidean geometry. That may be due largely to the coarse aggregate in concrete with fractal character.

Asaoka method is one of the main methods in settlement prediction of pile foundation. Asaoka method estimates final settlement data according to an unknown data calculated from the actual settlement observation. It is simple and has high accuracy and reliability features in the prediction. For this reason, Asaoka method has been widely used because of the good prospects forecast in the pile settlement. However, there are also two shortcomings of Asaoka method:(1) the choices of starting time influence the correlation coefficient and completion rates; and (2) the time interval also has a direct impact on the final settlement prediction result. Based on the large field testing settlement data of pile foundation of high speed railway bridge, we can make the predictions get closer to the actual results through the suitable choice of starting time and time interval.

Subway stations or shield pit (or shaft) are often constructed by reinforced concrete supporting structure materials. These concrete retaining structure materials must be manually destroyed before launching and receiving of shield. Therefore, some security risks may arise during manual destroying, and the structure strength may be weakened. In the supporting structure, concrete supporting structure materials have been partially substituted by glass fiber-reinforced plastic bars (GFRP) in shield engineering worldwide. However, physical and mechanical properties of GFRP bars differ significantly from those of reinforcing steel. So the deformation and stability of construction pit should be considered when GFRP bar is installed in the soft-eyes instead of steel reinforcement. The stability analysis of construction pit is presented here. Through 3-dimensional numerical simulation and field test in Beijing subway, the deformation of GFRP concrete pit was larger than that of steel concrete pit; but, the deformation of GFRP concrete pit was about 15 mm. Therefore, the GFRP concrete pit was in stability. The results are useful for further application of GFRP bars in shield engineering.

In the last years, much attention has been paid to the dynamic responses and failure of roof slab of underground box-type structures; but, less attention has been paid to the dynamic responses and failure of bottom slab of underground structures. The seismic damage to bottom slabs should not be neglected because, under seismic actions, bottom slabs may fracture and bulge and produce adverse effects on the other parts of the structure. Therefore, the seismic response of bottom slabs should be considered in aseismic design of underground structures. In this paper, dynamic response of rectangular bottom slab of box-type underground structure under vertical seismic action was studied. In view of the complexity of dynamic soil-underground structure interaction analysis, and in order to simplify the analysis, we consider the roof slab and side wall as rigid ones. Only the deformation of the bottom slab was considered. Hinged and clamped connections between thebottom slab and side walls were considered. The eigenfunctions of motion equation of the bottom slab were obtained with consideration of the restraints of the side walls on the bottom slab, and the analytical solution of forced dynamic response of the bottom slab under vertical seismic action was obtained.

In this paper, a simplified soil-underground structure interaction analysis is presented. The soil was modeled as Winkler elastic ground, with which the box-type structure interacts. A matrix method was used for the soil-underground structure interaction analysis. The primary unknowns of the problem were structure joint rotations and translations. The axial deformation of the members of the structure was neglected. The rotation of structure as a whole was considered to reduce the number of the primary unknowns. The stiffness coefficients of the structure were obtained based on the theory of beam-on-elastic ground. Davis's (2003) dynamic soil pressure distribution over sidewall height was used to determine the equivalent joint loads, and a stiffness assembly method was used to obtain the governing equation of the problem. One numerical example is given to improve the effectiveness of the proposed model.