scholarly journals Feasibility simulation of aseismic structure design for long-span bridges

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 1107-1117
Author(s):  
Li Lai

Abstract In the traditional finite element analysis method, when simulating the feasibility of aseismic structure design of long-span bridges, only finite element analysis is carried out on the bridge structure without considering the aseismic situation of the aseismic structure of the bridge under different schemes, which leads to one-sidedness of the simulation results. Therefore, a new simulation method for the feasibility study of seismic design of long-span bridges is proposed in this paper. 5 seismic isolation schemes for long-span bridge structures are designed. The lock-up devices and liquid viscous dampers are deployed in bridge structure. Numerical simulation of bridge structure is carried out by establishing calculation model and improved hierarchical Kerr spring model. The responses of long-span bridges under seismic loading for 5 seismic isolation schemes are analyzed. On this basis, the seismic performance of long-span bridges is tested by using the multi-point excitation motion equation, the response power spectrum and the structural dynamic reliability analysis based on the first transcendental failure criterion. Experimental results show that all the five seismic isolation schemes are feasible, and the seismic effect of the schemes 4 and 5 is the strongest. The maximum horizontal thrust of pier top is 6.27E+062, 0.50E+07 and 6.00E+06, 2.78E+07, respectively. The proposed method can be used to simulate the seismic response of long-span bridges.

2021 ◽  
Author(s):  
Xiaolin Zhang ◽  
Tianyi Guan ◽  
Lei Fan ◽  
Na Wang ◽  
Li Shang ◽  
...  

2019 ◽  
Vol 22 (11) ◽  
pp. 2530-2542
Author(s):  
Qianhui Pu ◽  
Jingwen Liu ◽  
Hongye Gou ◽  
Yi Bao ◽  
Hongwei Xie

Ship collision is rare, yet it leads to serious consequences once it occurs, in particular for long-span bridges. This study investigates dynamic responses of a long-span, rail-cum-road cable-stayed bridge under ship collision through finite element analysis. Three ship tonnages were investigated, which are 3000, 5000, and 8000 t, respectively. The displacement, velocity, and acceleration of the bridge under ship collision are analyzed. The collision process is simulated in two explicit steps to improve the computational efficiency. First, the collision force is determined through a collision simulation of the ship to a rigid body that simulates the massive bridge pier. The collision force is then applied to the bridge to analyze the dynamic responses of the bridge. The simulation results of the collision force are compared with four different design codes. Analysis results from different codes show significant discrepancies, demonstrating lack of reliability of the formula recommended by the codes. The results indicate that the maximum displacement and acceleration occur at the top of the bridge pylon. The bridge’s responses under ship collision decrease as the collision angle increases from 0° to 20°.


2021 ◽  
Vol 5 (7) ◽  
pp. 170
Author(s):  
Pablo Castillo Ruano ◽  
Alfred Strauss

In recent years, interest in low-cost seismic isolation systems has increased. The replacement of the steel reinforcement in conventional elastomeric bearings for a carbon fiber reinforcement is a possible solution and has garnered increasing attention. To investigate the response of fiber-reinforced elastomeric bearings (FREBs) under seismic loads, it is fundamental to understand its mechanical behavior under combined vertical and horizontal loads. An experimental investigation of the components presents complexities due to the high loads and displacements tested. The use of a finite element analysis can save time and resources by avoiding partially expensive experimental campaigns and by extending the number of geometries and topologies to be analyzed. In this work, a numerical model for carbon fiber-reinforced bearings is implemented, calibrated, and validated and a set of virtual experiments is designed to investigate the behavior of the bearings under combined compressive and lateral loading. Special focus is paid to detailed modeling of the constituent materials. The elastomeric matrix is modeled using a phenomenological rheological model based on the hyperelastic formulation developed by Yeoh and nonlinear viscoelasticity. The model aims to account for the hysteretic nonlinear hyper-viscoelastic behavior using a rheological formulation that takes into consideration hyperelasticity and nonlinear viscoelasticity and is calibrated using a series of experiments, including uniaxial tension tests, planar tests, and relaxation tests. Special interest is paid to capturing the energy dissipated in the unbonded fiber-reinforced elastomeric bearing in an accurate manner. The agreement between the numerical results and the experimental data is assessed, and the influence of parameters such as shape factor, aspect ratio, vertical pressure, and fiber reinforcement orientation on stress distribution in the bearings as well as in the mechanical properties is discussed.


2015 ◽  
Vol 8 (2) ◽  
pp. 382-389 ◽  
Author(s):  
Naijia Xiao ◽  
Rafi L. Muhanna ◽  
Francesco Fedele ◽  
Robert L. Mullen

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Tao Fu ◽  
Yang Liu ◽  
Zhixin Zhu

Damage to bridge structures caused by vessel collision is a risk for bridges crossing water traffic routes. Therefore, safety around vessel collision of existing and planned bridges is one of the key technical problems that must be solved by engineering technicians and bridge managers. In the evaluation of the reliability of the bridge structure, the two aspects of vessel-bridge collision force and structural resistance need to be considered. As there are many influencing parameters, the performance function is difficult to express by explicit function. This paper combines the moment method theory of structural reliability with finite element analysis and proposes a statistical moment method based on finite element analysis for the calculation of vessel-bridge collision reliability, which solves the structural reliability problem with a nonlinear implicit performance function. According to the probability model based on current velocity, vessel velocity, and vessel collision tonnage, the estimate points in the standard normal space are converted into estimate points in the original state space through the Rosenblatt reverse transform. According to the estimate points in the original state space and the simplified dynamic load model of vessel-bridge collision, the sample time-history curve of random vessel-bridge collision force is generated, the dynamic response of the bridge structure and the structural resistance of the bridge are calculated by establishing a finite element model, and the failure probability and reliability index of the bridge structure is calculated according to the fourth-moment method. The statistical moment based on the finite element analysis is based on the finite element analysis and the moment method theory of structural reliability. The statistical moment of the limited performance function is calculated through a quite small amount of confirmatory finite element analysis, and the structural reliability index and failure probability are obtained. The method can be widely used in existing finite element analysis programs, greatly reducing the number of finite element analyses needed and improving the efficiency of structural reliability analysis.


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