Question

If the building is having more stiffness is it exerts less base shear quora

Answer 1

Let us try to understand structural dynamics using some static approaches.

Building is heavy -> High Base Shear

Building is stiff -> High Base Shear

Building located near fault -> High Base Shear

Building Weight

Imagine you have two buildings. One weights 50,000 kips while the other weights 20,000 kips. And let us say that the ground is excited at 0.4g of acceleration. Now in no way the entire building will be shaked at this value of acceleration, but just for the sake of simplifying we say that it is.

So building 1 will have a base shear of 50,000 * 0.4 = 20,000 kips

Building 2 will have a base shear of 20,000*0.4 = 8,000 kips

So there you have variation of building base shear with respect to weight of the structure.

2. Building Stiffness

Oh, this one is the ultimate parameter to understand the building base shear. Now, each structure has its own natural period of vibration. Some buildings have 0.5 seconds, some have 1.5 seconds and some have 8 seconds of natural period. Higher the natural period of structure means the more flexible the structure is. A flexible structure generally experiences lower accelerations than a stiff building. This is called response of a structure. ().

Now because a flexible building is hard to excite, it will have lower base shear as compared to a stiff building. For example if you compare a shear wall building and a moment frame building for the same building height and weight, then the base shear of moment frame building will be lower than that of a shear wall building.