Collapse prognosis of a long‐span cable‐stayed bridge based on shake table test and nonlinear model updating

2020 ◽  
Author(s):  
Kaiqi Lin ◽  
You‐Lin Xu ◽  
Xinzheng Lu ◽  
Zhongguo Guan ◽  
Jianzhong Li
Keyword(s):  
Nonlinear Model ◽  
Model Updating ◽  
Shake Table Test ◽  
Shake Table ◽  
Cable Stayed Bridge ◽  
Long Span

scholarly journals Train-Bridge Dynamic Behaviour of Long-Span Asymmetrical-Stiffness Cable-Stayed Bridge

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yuexing Wu ◽  
Jianting Zhou ◽  
Jinquan Zhang ◽  
Qiang Wen ◽  
Xuan Li
Keyword(s):  
Dynamic Behaviour ◽  
Model Updating ◽  
Ride Comfort ◽  
Observation Point ◽  
Main Beam ◽  
Train Track ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Significant Difference ◽  
Track Bridge

Long-span cable-stayed bridge (LCB) with unequal-height towers is being designed and constructed in metro lines due to its better adaptability to environment and terrain conditions compared to traditional cable-stayed bridge with equal-height towers. However, the asymmetrical arrangement of towers leads to obvious nonuniformity of the structural stiffness along the longitudinal direction, which intensifies the wheel-rail coupled vibration behaviour, and affects the running safety of operating trains and ride comfort. Therefore, train-bridge dynamic behaviour of long-span asymmetrical-stiffness cable-stayed bridge is deeply investigated in this work. Primarily, considering the comprehensive index of frequency difference and modal assurance criterion (MAC), a nonlinear model updating technique (NMUT) based on penalty function theory is proposed, which can be used to optimize the bridge numerical model. Secondly, on the basis of the train-track-bridge dynamic interaction theory (TDIT), a train-track-bridge coupled dynamic model (TCDM) is established. Finally, a LCB with unequal-height towers is applied as a case to illustrate the influence of asymmetrical stiffness on the train-track-bridge dynamic characteristics. Results show that the proposed NMUT is efficacious and practical. For the LCB with unequal-height towers, a significant difference between the bridge vibration at low tower location and that at high tower location appears. The vertical displacement difference of the main beam on both sides of the bridge increases with the distance from the observation point to the bridge tower increasing. The variation of acceleration difference on both sides of the bridge is influenced by the speed of the train and the position of the observation point simultaneously. In general, vibrations of the main beam at low tower location are larger than those at high tower location.

scholarly journals Shake Table Test of Long Span Cable-Stayed Bridge Subjected to Near-Fault Ground Motions Considering Velocity Pulse Effect and Non-Uniform Excitation

2020 ◽  
Vol 10 (19) ◽  
pp. 6969
Author(s):  
Chao Zhang ◽  
Guanghui Fu ◽  
Zhichao Lai ◽  
Xiuli Du ◽  
Piguang Wang ◽  
...  
Keyword(s):  
Ground Motions ◽  
Near Field ◽  
Shake Table ◽  
Velocity Pulse ◽  
Maximum Displacement ◽  
Maximum Acceleration ◽  
Shake Table Tests ◽  
Near Fault ◽  
Cable Stayed Bridge ◽  
Long Span

This paper presents the results of shake table tests of a scaled long span cable-stayed bridge (CSB). The design principles of the scaled CSB are first introduced. The first six in-plane modes are then identified by the stochastic subspace identification (SSI) method. Furthermore, shake table tests of the CSB subjected to the non-pulse near-field (NNF) and velocity-pulse near-fault (PNF) ground motions are carried out. The tests indicated that: (1) the responses under longitudinal uniform excitation are mainly contributed by antisymmetric modes; (2) the maximum displacement of the tower occurs on the tower top node, the maximum acceleration response of the tower occurs on the middle cross beam, and the maximum bending moment of the tower occurs on the bottom section; (3) the deformation of the tower and girder subjected to uniform excitation is not always larger than that subjected to non-uniform excitation, and therefore the non-uniform case should be considered in the seismic design of CSBs.

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