مقاله انگلیسی مطالعه عملکرد لرزه ای قاب های RC مقاوم سازی شده
Highlights
Abstract
Keywords
1. Introduction
2. Studied building
3. Testing program
4. Test results
5. Conclusions
CRediT authorship contribution statement
Declaration of Competing Interest
Acknowledgements
Funding
References
Abstract
This paper proposes a novel arrangement of RC infill walls made possible by RC infill wall mega braces (RCIWMBs). The seismic behavior of a reinforced concrete (RC) frame structure retrofitted by the RCIWMB was investigated through 1/5-scale shaking table tests. The seismic damage characteristics and the dynamic responses of the model structure under different input ground motions are presented in detail. The results show that the presence of the RCIWMB has a slight effect on the failure of beam-column joints, but it can lead to punching shear failure of its connected frame columns. When the RC walls are arranged diagonally, the RCIWMB can form a macroscopic brace effect, serving as the first seismic line of defense. Compared with traditional RC infill wall retrofitted frame structures, the drawback is obvious failure, which appears on the lower stories of this novel type of structure and is prone to forming a weak story. This indicates a poor structural story ductility and more severe damage to the integral structure. However, the addition of the RCIWMB resulted in a substantial increase in the integral lateral bearing capacity, integral lateral stiffness and integral ductile behavior, a decrease in lateral displacement, and a reduction in damage to the original frame structure. The novel structural system performed better under extensive seismic tests, providing a new method for upgrading the seismic performance of existing buildings.
1. Introduction
Reinforced concrete (RC) frame structures have been widely used worldwide in multistory buildings because of their light weight, flexible space division and material savings. In recent years, earthquakes have inflicted severe damage, including collapse, on many RC frame structures because of their lack of sufficient ductility, bearing capacity, and energy dissipation capacity [1,2]. Although there are many novel strengthening methods for RC framed structures [3–7], such as using cross laminated timber panels as infill shear walls, the addition of RC infill walls remains a relatively feasible and popular technique for retrofitting existing RC buildings, which do not comply with current seismic requirements [8–10]. Tests and numerical simulation studies on the seismic performance of RC frame structures infilled with RC walls have been conducted by many researchers who typically handle the RC wall frame design by aligning RC infill walls in a continuous arrangement in a multistory building from the bottom to the top [11–14]. Previous studies have shown that adding RC walls can effectively improve the lateral stiffness and bearing capacity of a structure, thereby limiting its displacement. However, structural engineers have found it more advantageous to stagger the RC walls as they evenly disperse them along the building’s height, similar to the inclined web members of a truss, rather than continuously extending the shear walls from the bottom to the top [15–19]. Few shaking table tests have been conducted to test RC frames retrofitted with staggered RC infill walls; thus, the understanding of the seismic behavior of this arrangement is limited. Therefore, a shaking table test was used to measure the seismic performance of the retrofitted RC frames under earthquake conditions and provide more reliable information on their structural mechanics and behaviors.