Summary
Damage identification forms a key objective in structural health monitoring. Several state‐of‐the‐art review papers regarding progress in this field up to 2011 have been published. This paper ...summarizes the recent progress between 2011 and 2017 in the area of damage identification methods for bridge structures. This paper is organized based on the classification of bridge infrastructure in terms of fundamental structural systems, namely, beam bridges, truss bridges, arch bridges, cable‐stayed bridges, and suspension bridges. The overview includes theoretical developments, enhanced simulation attempts, laboratory‐scale implementations, full‐scale validation, and the summary for each type of bridges. Based on the offered review, some challenges, suggestions, and future trends in damage identification are proposed. The work can be served as a basis for both academics and practitioners, who seek to implement damage identification methods in next‐generation structural health monitoring systems.
•Flexural behavior of UHPC wet joint in prefabricated multi-girder bridge.•Eleven full-scale specimens were tested under bending moment.•Cracking resistance and flexural capacity of the specimens ...were discussed.•Key factors influencing flexural behavior of UHPC wet joint were revealed.•Configuration and flexural capacity were provided for UHPC wet joint.
A new type of prefabricated multi-girder bridge with UHPC wet joint was used in an expressway bridge under construction in China, taking advantage of the excellent mechanical property of UHPC. As a kind of accelerated bridge construction (ABC) technology, the bridge decks are prefabricated in the factory with normal concrete and connected by cast in-situ UHPC wet joint. Straight overlapping of the longitudinal reinforcement was designed in this paper to simplify the complex configuration of the wet joint with annularly overlapped reinforcements in engineering practice. Eleven full-scale specimens divided into five groups were manufactured and tested to investigate the flexural behavior of the multi-girder bridge deck with UHPC wet joint. The influence of overlapping form, overlapping length and reinforcement ratio of the longitudinal reinforcement as well as the section form of the wet joint on the flexural behavior of the UHPC wet joint was revealed and discussed systematically, and compared with the integral concrete bridge deck. The crack load, location of the initial crack, nominal cracking stress, and ultimate load bearing capacity of the specimen were observed and discussed in detail. The test results indicate that the straight overlapped reinforcement is capable of providing sufficient anchorage effect between the rebar and UHPC with a minimum overlapping length of 10 times of the diameter of the reinforcement (10 db). It is demonstrated that the adoption of UHPC is beneficial to simplify the complex overlapping of the reinforcement and minish the width of the wet joint. Increasing overlapping length of the reinforcement has marginal influence on the flexural behavior of the bridge deck in case that the minimum overlapping length is satisfied. However, increasing reinforcement ratio and using the diamond-shaped wet joint are helpful to improve the flexural behavior of the bridge deck including crack load, location of the initial crack and ultimate load bearing capacity. The ultimate bending capacity of the bridge deck with UHPC wet joint was analyzed theoretically and the theoretical analysis results agreed well with the test results and failure mode of the specimens. The present research findings are useful to provide comprehensive understanding on flexural performance and design guidance of UHPC wet joint in prefabricated multi-girder bridge.
•Multi-Euler Domain method is updated from 1D to 3D on personal computers.•Most damaging cases for three modern types of bridges are identified.•Different CRFP strengthening schemes on slab-on-girder ...bridge are evaluated.•Safe distance for cable-stayed bridge pylon under vessel explosions is defined.
Since the collapse of the WTC towers in September 2001, concern about the protection of buildings and infrastructures against blast loads has increased significantly. Comprehensive experimental and numerical studies of blast loading effects on buildings have been carried out in recent years, whereas for bridge engineers, blast-resistant design is still a new area which requires separate and systematic investigation. The objective of this paper is to simulate the performance of three modern types of reinforced concrete bridges under various blast loads, including a slab-on-girder bridge, a box-girder bridge and a long-span cable-stayed bridge. To solve the computational constraints in performing numerical analysis on a personal computer, a Multi-Euler domain method based on the fully-coupled Lagrange and Euler models is adopted and further developed for long–span bridge application. This study investigates various detonation scenarios in terms of the explosive weight and location, and their interactions with bridge structures. Both the localized damage mechanism and the global structural response of three bridges are examined. By studying the blast-resistance of each bridge under different explosion threats, the most critical scenarios are identified respectively. Studies of bridge protection against potential attacks by using Carbon Fibre Reinforced Polymer (CFRP) strengthening are also discussed. Numerical results in this study provide bridge owners and engineers with thorough and important information on the structural performance of highway bridges under blast loads, helping them in choosing effective protection strategies for possible potential explosion events.
•We emphasize the significance of two bridge guidelines in Germany.•We present a detailed review of almost all German high speed railway bridges.•We present the specific innovation highlights of ...railway bridge design in Germany.•The preference of bridge types has changed to the new innovations.
Bridges are vital components of high-speed rail (HSR) lines for crossing obstacles such as valleys, rivers, and existing highways or railway lines. The main goal of this paper is to provide a review of the development of HSR bridges in Germany. A short summary of the history of high-speed rail lines is given first. Subsequently, the development of HSR bridges, along with emerging design issues and the two relevant German design guidelines, is reviewed. Further, bridge structure types on German HSR lines, such as simply supported bridges, continuous bridges, arch bridges, integral and semi-integral bridges, composite truss bridges and rigid-frame bridges are discussed. The article concludes with a short discussion about the current situation and future trend of HSR bridges.
This book begins with a clear and concise exposition of theory and practice of bridge engineering, design and planning, materials and construction, loads and load distribution, and deck systems. This ...is followed by chapters concerning applications for bridges, such as: Reinforced and Prestressed Concrete Bridges, Steel Bridges, Truss Bridges, Arch Bridges, Cable Stayed Bridges, Suspension Bridges, Bridge Piers, and Bridge Substructures. In addition, the book addresses issues commonly found in inspection, monitoring, repair, strengthening, and replacement of bridge structures.
•Statistical analysis of existing Italian prestressed concrete girder bridge decks.•Computational procedure based on uncertainty modelling, ultimate capacity models and deck analysis.•Tornado ...diagrams to quantify the sensitivity of structural performance to multiple variables.•Probabilistic structural analysis of bridge decks using Monte Carlo simulation.•Traffic-load fragility models for large-scale risk assessment of existing highway bridges.
Even if previous studies investigated seismic fragility of existing bridges, some recent collapse cases set the need to investigate their vulnerability under gravity loads. In this study, the class of simply supported, beam-type, prestressed concrete bridges built between 1970 and 1980 was considered to carry out a fragility analysis of the most recurrent type of Italian bridges to traffic loads. Based on the literature and new data collected by the authors from real bridges, geometric, material and load variables were defined through probability distributions and regression models. Then, a code-based capacity modelling of bridge decks was carried out, followed by the implementation of a simplified deck analysis method that allows extensive simulations. In a first step, a sensitivity analysis was performed to identify the random variables that mostly affect the structural response, to be taken into account in the fragility analysis for the ultimate limit state. Then, a fragility analysis was carried through a fully automatic procedure implemented in MATLAB. The main output consists of fragility models that might be used by engineers, roadway management companies and decision-makers in large-scale risk assessments of existing highway bridges under code-based traffic loads, as a basis for prioritization of more refined performance evaluations and structural retrofitting programmes.
Train-track-bridge dynamic interaction is a fundamental concern in the field of railway engineering, which plays an extremely important role in the optimal design of railway bridges, especially in ...high-speed railways and heavy-haul railways. This paper systematically presents a state-of-the-art review of train-track-bridge dynamic interaction. The evolution process of train-bridge dynamic interaction model is described briefly, from the simplest moving constant force model to the sophisticated train-track-bridge dynamic interaction model (TTBDIM). The modelling methodology of the key elements in the TTBDIM is systematically reviewed, including the train, the track, the bridge, the wheel-rail contact, the track-bridge interaction, the system excitation and the solution algorithm. The significance of detailed track modelling in the whole system is highlighted. The experimental research and filed test focusing on modelling validation, safety assessment and long-term performance investigation of the train-track-bridge system are briefly presented. The practical applications of train-track-bridge dynamic interaction theory are comprehensively discussed in terms of the system dynamic performance evaluation, the system safety assessment and train-induced environmental vibration and noise prediction. The guidance is provided on further improvement of the train-track-bridge dynamic interaction model and the challenging research topics in the future.
•Seismic fragility was conducted for a highway bridge with deteriorated LRBs.•Parameter uncertainty of the mechanical behavior of LRBs and cable restrainers was modeled.•Response uncertainty of the ...bridge caused by the LRBs and cable restrainers was investigated.•Performance of cable restrainer retrofit in mitigating the vulnerability and response uncertainty of the bridge was analyzed.
Overcoming the deterioration of aging infrastructure has aroused increasing concern in recent years, particularly, problem of deteriorated elastomeric bearings has emerged as one of the greatest challenges in maintenance and reliability strategies for isolated highway bridges. Though the abundant applications of cable restrainers to provide alternative measure against bearing deterioration and reduce the risk of bridge collapse due to deck unseating, the performance of cable restrainer retrofit is not well understood because of the complicated and nonuniform deterioration process of elastomeric bearings. This paper presents an in-depth seismic fragility and variation analysis to evaluate cable restrainer retrofit for isolated highway bridges, with a special emphasis on the introduction and mitigation of structural response uncertainty caused by the deteriorated lead rubber bearings (LRBs) and cable restrainer retrofit. Firstly, the mechanical properties of deteriorated LRBs and cable restrainers including the associated parameter uncertainty were modeled based on the consideration of past relevant researches. Subsequently, seismic response of a simplified model of a typical continuous girder isolated highway bridge subjected to various scaled earthquake ground motions was computed to statistically evaluate the effect of typical uncertainties of the mechanical behavior of deteriorated LRBs and cable restrainers upon the risk of global seismic failure of the bridge. Finally, the contribution of cable restrainer retrofit in mitigating the vulnerability and response uncertainty of structural components is quantitatively assessed by comparing the cases with and without the application of cable restrainers. The statistical assessments not only reveal the effect of restrainer cable retrofit at the earthquake levels for design standards, but also consider the levels of seismic events greater than consideration in the design, incorporating the seismic performance uncertainty introduced and enlarged by the aging deterioration of LRBs.
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