What Is A Shear Wall? | Where it is needed the most?

A shear wall is a vertical structural member constructed to resist lateral forces of wind and seismic (earthquake) activity.

 So, shear walls are a vertical member which resists horizontal forces (wind and seismic), while walls and columns carry the compression of the structure down to the foundation.

 

How Does Shear Wall Work?

Shear walls transfer the lateral forces (caused by wind, earthquake, uneven settlement loads, etc.) from exterior walls, floors, and roofs to the ground foundation, where those forces get re-distributed in the soil in the direction parallel to the plane.

Shear walls are simply reinforced concrete walls.

 

Where is Shear Wall Needed?

Shear walls are much more needed in a high-rise building. The greater the height of the building, the greater the need for the lateral force-resisting system i.e. shear wall.

This is because lateral forces caused by wind, seismic and uneven settlement loads, create powerful twisting (torsional) forces. These forces lead to the failure of the structures by shear i.e. it can tear the building apart. Shear Walls provide required strength and stiffness to those lateral forces. And higher the height of the structure more the lateral forces (especially wind). Hence, shear walls are much needed in a high-rise building.

 

Where Should the Shear Wall Be Placed?

The best position for the shear wall would be the center of each half of the building. But it utilizes a lot of space, so they are best positioned at the ends. Usually, the walls around the lift shaft and stairwells are made of shear walls, since no windows are needed in those areas.

 

It is mandatory that, if shear walls are built in the building, then they must be built symmetrically around the building's central axis. This means, if a shear wall is constructed on the north side of the building, then the identical shear wall must be constructed on the south side of the same building. 

 

Differences Between Shear Wall and Column.

Shear walls	Columns
They are designed for lateral forces.	They are designed for compressive forces.
The breadth to width ratio should be greater than 0.4.	The breadth to width ratio should be smaller than 0.4.
They are highly resistant to seismic (earthquake) loads.	They are less resistant to seismic loads.
They are highly preferred in a high-rise building.	They are highly preferred in low-rise buildings.

 

Important Question

Q. Is it possible to construct a 25 storey building without any columns?

Ø The answer is Yes. We can construct a 25 storey building without any column by simply constructing a shear wall. The structure might not be as strong as with column but, still, it is possible to construct without column by using a shear wall.