Shear Wall Positioning

How should I position the shear wall? These is a question that comes up all the time among structural designers. To answer this question let me clarify what shear walls do. Shear walls provides extra stiffness to the structure to resist against lateral loads. So the dimension of shear walls must be large enough to have enough stiffness.

The overall center of stiffness of the building is a point on the plan. If the center of stiffness be far away from the center of gravity the building become weaker as we need to design stronger cross sections to compensate it. Stronger cross sections mean spending more money. So a wise designer always try to make the center of stiffness as close as possible to the center of gravity.

Here is the center of stiffness in different shear walls. In figure 2 ,for example, the stiffness center is closer to the U-shaped shear wall. One solution is to increase the length of the other shear wall. as it is illustrated in figure 2 using a longer shear wall at the left side of plan helps to reduce the distance between gravity center and stiffness center.