Seismic performance of steel structures with seesaw energy dissipation system using fluid viscous dampers

2013 ◽  
Vol 56 ◽  
pp. 431-442 ◽  
Author(s):  
Jae-Do Kang ◽  
Hiroshi Tagawa
2017 ◽  
Vol 3 (2) ◽  
pp. 124-136 ◽  
Author(s):  
Mohammad Ganji ◽  
Hossein Kazem

In the present research, seismic behaviours of a steel frame equipped with either viscous damper or lead-core rubber bearings (LRB) isolator were evaluated and compared under the effect of near-fault earthquake records. For this purpose, three buildings of 5, 10, and 15 stories equipped with lateral bearing systems composed of steel moment-resisting frames were subjected to 7 near-fault earthquake accelerogram pairs at earthquake hazard levels 1 and 2, so as to evaluate their responses under three scenarios, namely without any energy dissipation system, with viscous damper, and with LRB isolator, using dynamic analysis of time history utilizing PERFORM 3D v5 software. The results were indicative of enhancement in seismic performance of the viscous damper-equipped structures at earthquake hazard level 1, as the corresponding performance level was enhanced from life safety to uninterrupted usability, while no significant seismic performance level enhancement was determined at seismic level 2. Seismic isolator-equipped structures were also associated with seismic performance level enhancement from life safety to uninterrupted usability at both earthquake hazard levels. Relative lateral displacement at floor levels in damper-equipped structures and seismic isolator-installed buildings were found to be about 29% and 68% improved over that of the structure with no energy dissipation system. Results of distribution of shear forces within structures equipped with viscous damper and seismic isolator, as compared against that of the structures with no energy dissipation system, indicted increased and decreased shear forces, respectively..


2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Xiong Liang ◽  
Baomu Li ◽  
Xiaolu Liu ◽  
Linong Liang

To investigate the optimal longitudinal seismic energy dissipation system of straddle-type monorail-cum-road long-span cable-stayed bridges, the Niutianyang Bridge was selected as the engineering background, and the explicit time-domain dimension-reduced iteration method was adopted to carry out nonlinear time-history analysis. To consider the dynamic characteristics of longitudinal movable supports, the static and dynamic responses of four kinds of energy dissipation systems were studied, including longitudinal unconstrained, elastic cable, viscous damper, and speed lock-up devices. The damping effect of four types of schemes in which viscous dampers were installed at piers or towers was analysed, and the parameters of the viscous dampers were optimised. The influences of the straddle-type monorail train braking force and the running vibration of the straddle-type monorail traffic on the parameters of the viscous dampers were analysed. This study shows that the viscous damper system had the lowest bending moment at the bottom of the tower and a smaller displacement response, and the energy dissipation was the best. Each viscous damper had the highest energy dissipation efficiency when they are installed only at the main tower. The damping effect was better when the damping coefficient c ranged from 3500 to 5000 kN⋅m/s−α and the velocity exponent α ranged from 0.35 to 0.5. The static friction of the straddle-type monorail-cum-road long-span cable-stayed bridge support can resist the trains’ braking force, and the parameters of the viscous damper can be selected regardless of train braking. A suitably large value of velocity exponent α may be required to increase the working velocity of the viscous damper to reduce the damper’s participation in the process of the train crossing the bridge.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Qingguang He ◽  
Yanxia Bai ◽  
Weike Wu ◽  
Yongfeng Du

A novel assembled self-centering variable friction (SCVF) brace is proposed which is composed of an energy dissipation system, a self-centering system, and a set of force transmission devices. The hysteretic characteristics and energy dissipation of the SCVF brace with various parameters from low-cyclic loading tests are presented. A finite element model was constructed and tested under simulated examination for comparative analysis. The results indicate that the brace shows an atypical flag-type hysteresis curve. The SCVF brace showed its stable self-centering ability and dissipation energy capacity within the permitted axial deformation under different spring and friction plates. A larger deflection of the friction plate will make the variable friction of this SCVF brace more obvious. A higher friction coefficient will make the energy dissipation capacity of the SCVF brace stronger, but the actual friction coefficient will be lower than the design value after repeated cycles. The results of the fatigue tests showed that the energy dissipation system formed by the ceramic fiber friction blocks and the friction steel plates in the SCVF brace has a certain stability. The finite element simulation results are essentially consistent with the obtained test results, which is conducive to the use of finite element software for calculation and structural analysis in actual engineering design.


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