Development of Optimal Viscous Dampers for RC Structures in Near Field Ground Motions

2008 ◽  
Author(s):  
Arun M. Puthanpurayil ◽  
Paul Reynolds ◽  
Adolfo Santini ◽  
Nicola Moraci
2018 ◽  
Vol 12 (05) ◽  
pp. 1850011 ◽  
Author(s):  
Jiang Yi ◽  
Jianzhong Li ◽  
Zhongguo Guan

To investigate the effectiveness of viscous damper on seismic control of single-tower cable-stayed bridges subjected to near-field ground motions, a 1/20-scale full cable-stayed bridge model was designed, constructed and tested on shake tables. A typical far-field ground motion and a near-field one were used to excite the bridge model from low to high intensity. The seismic responses of the bridge model with and without viscous dampers were analyzed and compared. Both numerical and test results revealed that viscous dampers are quite effective in controlling deck displacement of cable-stayed bridges subjected to near-field ground motions. However, due to near-field effects, viscous damper dissipated most energy through one large hysteresis loop, extensively increasing the deformation and damping force demand of the damper. Further study based on numerical analysis reveals that to optimize deck displacement of cable-stayed bridges during an earthquake, a viscous damper with relatively larger damping coefficient should be introduced under near-field ground motions than far-field ones.


2022 ◽  
Vol 2022 ◽  
pp. 1-14
Author(s):  
Qihui Peng ◽  
Wen-ming Cheng ◽  
Peng Guo ◽  
Hongyu Jia

Assessing the seismic performance of the gantry crane is significant since the structure is more vulnerable to earthquakes with the increase in size and lifting weight capacity. This paper aims to investigate the seismic response of the gantry crane incorporating near-field ground motions using incremental dynamic and endurance time analysis (IDA and ETA) methods. To model the structure accurately, a nonlinear finite element model of the gantry crane considering the viscoelastic effect is developed in the OpenSees platform. Then, the IDA method is also carried out for a comparison with the ETA method. The results of the two methods are consistent with a correlation of 93.9% while the computational demand of the ETA method is much less than those of the IDA method. To study further, both the seismic incident angle and the application of viscous dampers using the Maxwell model are analyzed and discussed in detail. The results show that seismic incident angle has a distinct influence on the maximum seismic displacement and viscous dampers can significantly reduce the seismic demand of the gantry crane. These findings support the seismic design of gantry cranes and evaluate the structural seismic performance efficiently.


Abstract. Seismic fragility analysis is essential for seismic risk assessment of structures. This study focuses on the damage probability assessment of the mid-story isolation buildings with different locations of the isolation system. To this end, the performance-based fragility analysis method of the mid-story isolation system is proposed, adopting the maximum story drifts of structures above and below the isolation layer and displacement of the isolation layer as performance indicators. Then, the entire process of the mid-story isolation system, from the initial elastic state to the elastic-plastic state, then to the limit state, is simulated on the basis of the incremental dynamic analysis method. Seismic fragility curves are obtained for mid-story isolation buildings with different locations of the isolation layer, each with fragility curves for near-field and far-field ground motions, respectively. The results indicate that the seismic fragility probability subjected to the near-field ground motions is much greater than those subjected to the far-field ground motions. In addition, with the increase of the location of the isolation layer, the dominant components for the failure of mid-story isolated structures change from superstructure and isolation system to substructure and isolation system.


2014 ◽  
Vol 30 (2) ◽  
pp. 867-889 ◽  
Author(s):  
Jui-Liang Lin ◽  
Manh-Tien Bui ◽  
Keh-Chyuan Tsai

This paper proposes a simple approach to the generalized optimal locations of linear viscous dampers in elastic two-way asymmetrical buildings under bi-directional ground excitations. The control target used in this optimization process is to maximize the average dissipation rate of the overall strain energy of the two-way asymmetrical building under the ground excitation of two bi-directional unit impulses. The proposed control target, referred to as the smeared damping ratio, is an intrinsic property of the building system. Two advantages of the proposed approach appeal to engineering practice. First, the proposed approach does not require a complicated optimization algorithm. Second, due to the employment of an intrinsic property rather than a certain response parameter as the target performance index, the optimal damper locations resulting from the proposed approach are generalized, which are independent on the characteristics of input ground motions.


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