Time-variant fragility analysis of the bridge system considering time-varying dependence among typical component seismic demands

2019 ◽  
Vol 18 (2) ◽  
pp. 363-377
Author(s):  
Shuai Song ◽  
Yongjiu Qian ◽  
Jing Liu ◽  
Xiaorui Xie ◽  
Gang Wu
Keyword(s):  
Fragility Analysis ◽  
Time Varying ◽  
Seismic Demands ◽  
Typical Component ◽  
Bridge System

Dependence analysis on the seismic demands of typical components of a concrete continuous girder bridge with the copula technique

2018 ◽  
Vol 21 (12) ◽  
pp. 1826-1839 ◽  
Author(s):  
Shuai Song ◽  
Jing Liu ◽  
Yongjiu Qian ◽  
Fang Zhang ◽  
Gang Wu
Keyword(s):  
Ground Motion ◽  
Transverse Direction ◽  
Tail Dependence ◽  
Longitudinal Direction ◽  
Nonlinear Dependence ◽  
Lower Tail ◽  
Distance Method ◽  
Seismic Demands ◽  
Seismic Reliability ◽  
Bridge System

The seismic reliability of a bridge system is significantly affected by the dependence among typical bridge components. This study demonstrates the process of using a copula technique to describe the nonlinear dependence among component seismic demands isolated from their marginal probability distributions. A suite of 100 bridge-ground motion samples were developed with the Latin hypercube sampling approach and bin approach. Based on the incremental dynamic analysis, the tail dependence among component seismic demands at different intensity levels was analyzed with the best-fitting copula function selected by the minimum distance method. In the longitudinal direction, the dependence increased first and then decreased with the ground motion intensity, while the dependence slightly decreased in the transverse direction. At low-intensity levels, the upper tail dependence among components was strong in both directions. At high-intensity levels, the upper and lower tail dependences were weak in the longitudinal direction, while the upper and lower tail dependences were strong in the transverse direction. Compared to the linear correlation coefficient, the copula technique provides an efficient way to describe the tail dependence among component seismic demands and can be used extensively in the seismic reliability analysis of the bridge system.

Time-Varying LQG Control for Vibration of Coupled Vehicle-Bridge System

2013 ◽  
Vol 347-350 ◽  
pp. 541-547 ◽  
Author(s):  
Gang Song
Keyword(s):  
Ride Comfort ◽  
Time History ◽  
Vehicle Body ◽  
Time Varying ◽  
Mass Model ◽  
Riccati Differential Equation ◽  
Active Suspensions ◽  
Precise Integration ◽  
Lqg Control ◽  
Bridge System

Time-varying linear quadratic Gaussian (LQG) control for vibration of coupled vehicle-bridge system is studied. The vehicle is modeled as a moving mass model with three degrees of freedom, which consists of vehicle body, bogie and wheel. Active suspensions are adopted for the primary and secondary ones, and the control forces are produced by two actuators placed between the bogie and wheel, and between the vehicle body and the bogie, respectively. Vehicle-bridge coupling systems are time-dependent, which lead to the time-varying Riccati differential equation and the time-varying Kalman-Bucy filter equation in the LQG controller design. However, both of them are solved precisely via precise integration method and symplectic conservative perturbation method. In the example, the time history responses of the bridge and the vehicle were calculated respectively for the vehicle with passive suspensions or with active suspensions. Numerical results show that with active suspensions adopted, ride comfort can be improved when the vehicles passing through the bridge.

scholarly journals Seismic Fragility Analysis of Long-Span Bridge System with Durability Degradation

2019 ◽  
Vol 121 (1) ◽  
pp. 177-214 ◽  
Author(s):  
Yan Liang ◽  
Jialei Yana ◽  
Zhanqi Cheng ◽  
Huai Chen ◽  
Ruimin Mao
Keyword(s):  
Fragility Analysis ◽  
Seismic Fragility ◽  
Long Span ◽  
Long Span Bridge ◽  
Bridge System

scholarly journals Seismic Fragility Analysis of Bridge System Based on Fuzzy Failure Criteria

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Leping Ren ◽  
Shuanhai He ◽  
Haoyun Yuan ◽  
Zhao Zhu
Keyword(s):  
Structural Damage ◽  
Fragility Curves ◽  
Failure Criteria ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Actual Condition ◽  
Seismic Load ◽  
Analysis Method ◽  
Damage State ◽  
Bridge System

In the traditional bridge seismic fragility analysis, the criterion for judging the structural damage state is clear. That is to say, when the damage index exceeds a specific value, the structure is judged to enter the new damage state. However, the actual condition is that the boundary of structural damage is not clear but fuzzy. Taking a three-span V-shaped continuous girder bridge as an example, the damage process of the structure is described by fuzzy mathematics. Considering the uncertainties of ground motion and structure itself, a seismic fragility analysis method is established, which can consider the randomness of bridge itself, seismic load, and structural failure fuzziness simultaneously. Finally, the improved product of conditional marginal (I-PCM) method for fragility analysis of bridge system is further optimized and improved. The new improved method is used to form the seismic fragility curves of bridge structure system. The results show that it is possible to underestimate the potential seismic fragility of bridge components and system without considering the structural fuzzy failure criteria; the fragility curves formed by different membership functions are obviously different; the new system fragility analysis method can significantly improve the analysis accuracy.

Research on Dynamic Behavior of Vehicle-Bridge System

2012 ◽  
Vol 256-259 ◽  
pp. 1462-1465
Author(s):  
Yan Hong Wu ◽  
Guang Cai Han ◽  
Zhi Qiang Liu ◽  
Fu Guo Bian
Keyword(s):  
Numerical Simulation ◽  
Modal Analysis ◽  
Dynamic Behavior ◽  
Vertical Displacement ◽  
System Model ◽  
Time Varying ◽  
Moving Vehicle ◽  
Roughness Surface ◽  
Bridge System

Dynamic behavior of a vehicle-bridge system model is presented. A set of time-varying equations of the system considering roughness surface of bridge are given. The equations are rewritten in the form of matrix for numerical simulation. Modal analysis of the equations is carried out. Simulation and visualization of the equations are given. Effects of different speeds and accelerations of moving vehicle and roughness surface of bridge on the vertical displacement of mid-span of bridge are studied.

scholarly journals Time-Variant Seismic Fragility of Offshore Continuous Beam Bridges Based on Collapse Analysis

2020 ◽  
Vol 10 (23) ◽  
pp. 8595
Author(s):  
Zhaodong Shi ◽  
Yan Liang ◽  
Yang Cao ◽  
Jialei Yan
Keyword(s):  
Working Conditions ◽  
Damage Model ◽  
Seismic Fragility ◽  
Time Varying ◽  
Bridge Structure ◽  
Damage State ◽  
Concrete Carbonation ◽  
Service Period ◽  
Whole Life Cycle ◽  
Bridge System

In this paper, the concrete carbonation and chloride-induced corrosion of bridge structure in the service period under the offshore environment were comprehensively considered. Based on the time-varying degradation effect of mechanical properties of materials and continuous damage model, the time-varying seismic fragility of bridge components was analyzed with using incremental dynamic analysis. The time-varying brittleness curves of the bridge system and components were established according to the results of the analysis. According to the analysis of the time-varying fragility of the structure in the complete damage state, the collapse working conditions of the bridge structure and a method of quantifying the fragility coefficient were proposed. The results show that the fragility coefficient of the bridge system is higher than that of the components in the whole life cycle, and all of them increase with the increase of the bridge service cycle. When the peak acceleration of ground is small, the removing of 1# pier is more fragile. When reaching the design service life, the fragility coefficient of the bridge system is about 30% higher than that of the original state. The fragility coefficient of the bridge system in removing of 1# is the maximum value between three working conditions.

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