The effect of the presence of a concrete shear wall on the seismic performance of structures:
In all structures, especially in tall structures, it is necessary to provide adequate stiffness to resist lateral wind and earthquake forces. Otherwise, it is possible to create too much tension and vibration in various organs when the lateral loads are applied; This can cause severe discomfort to the occupants of the building, or even serious damage to the building. Appropriate lateral stiffness to resist lateral loads may be provided by bending frames, shear walls, or a combination of bending frame and shear wall. Shear walls are actually reinforced concrete walls that have a very high intra-plate stiffness. These walls act like a vertical and deep cantilever beam that provides lateral stability for the building and resists shear and bending anchors caused by lateral loads. They carry it to the ground. However, since shear walls are like vertical beams, their main function is bending, and therefore the shear wall is not very lateral to their function. In contrast, bent frames have a shear function against lateral load, contrary to their name, and transfer lateral loads to the ground by changing their shear shape. In shear walls with a small height-to-length ratio, shear is more important than bending. In contrast, in taller shear walls, the bending anchor is much more important. Because of the similarity of the function of shear walls with deep beams, shear steels are placed in them both horizontally and vertically. In shorter shear walls, horizontal shear steels are less effective and vertical shear steels play a more effective role. In contrast, in taller shear walls, horizontal shear steels have a greater effect on shear endurance.
A few points:
1- Using a shear wall is not always the most appropriate method because it concentrates the force in certain points of the foundation.
2- In tall structures with regularity and appropriate openings, the use of bending frames may lead to a better design unless special considerations are made in relation to displacement control.
3- In structures shorter than 4 floors, the use of shear walls is often unreasonable.
4- In tall structures, the presence of walls increases the base shear. This is due to the increased stiffness of the frame
This post is written by AminNajafgholizadeh