دانلود رایگان مقاله انگلیسی تحلیل مقاوم سازی لرزه ای سازه های دیوار برشی مزدوج بتنی با تیرهای اتصال دهنده فولادی - Sage 2017

Abstract

Many existing deep reinforced concrete coupling beams that have low span-to-depth ratios are not desirable for seismic design due to their potential brittle failure with limited ductility and deformability. Previous experimental and numerical studies have demonstrated that the laterally restrained steel plate retrofitting method could effectively enhance the seismic performance of deep coupling beams. This article aims to develop a nonlinear finite element model based on the OpenSees software to accurately predict the behavior of coupled shear walls with or without laterally restrained steel plate coupling beams. The numerical results reveal that the seismic performance of the laterally restrained steel plate retrofitted coupled shear walls can be significantly enhanced. Furthermore, a genetic algorithm is adopted to determine the optimal positions of laterally restrained steel plate coupling beams. It is found that desirable seismic performance can be achieved by retrofitting coupling beams in the middle and higher floors of a building with coupled shear walls. However, only retrofitting coupling beams on the lower floors should be avoided because this could result in the serious degradation of the lateral load-carrying capacity and stiffness of the coupled shear walls.

Conclusion

A finite element analysis is conducted for an optimization analysis of the seismic retrofitting of concrete coupled shear walls using LRSP to coupling beams. The main findings of this study are summarized as follows:

1. This study validates the effectiveness of a combined model formulated with the Python and OpenSees programs, which consists of a macro Vn-hinge model of coupling beams and refined model of shear walls. The model can accurately predict the overall behavior of coupled shear walls that have been retrofitted.

2. The behaviors of the retrofitted coupling beams have a significant effect on the seismic performance of coupled shear wall systems. The strength capacity, stiffness, deformability, and CR value of coupled shear wall systems are considerably enhanced after retrofitting the coupling beams with LRSP method. Moreover, the maximum IDR at the target displacement can be reduced and the uneven distribution of the IDR can be rectified after retrofitting.

3. The GA which is based on Python and OpenSees is accurate and efficient in searching for the optimal retrofitting arrangement, which is to retrofit the coupling beams in the middle and higher floors of a building. The maximum IDR at the target displacement can be reduced by about 10%–15% and the shear capacity can be increased by more than 50% after LRSP retrofitting.

4. Only retrofitting the coupling beams on the lower floors should be avoided, as they tend to reach their peak strength earlier than those on higher floors which would result in the serious degradation of the lateral strength and stiffness of the coupled shear wall system.