Shear Walls

SHEAR WALLS:

These are simple type & these shea walls under forces & horizontal shear along its length are subjected to bending & shear. To resist the forces the uniform distribution of steel along its length is used in simple shear walls.In case of bar bell type 2 boundary elememts are provided on either side.Minimum steel is provided over the 0.7 to 0.8L & the remaining steel is placed steel is placed

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0.12 to 0.15L.These walls are designed in such a way that they never fail in shear but only by yielding of steel in bending.Shear failures are sudden & brittle.One disadvantage of this type of wall is that during EQ the shear walls attract all the earthquake forces & dissipates the forces in to the wall.The loss of energy by crackingof the wall iss difficult to repair .This can be eliminating by providing coupled shear wall.

Coupled shear wall:

If two straight walls are joined together by relatively short span beams they are called as Coupled shear wall.The stiffness of resultantwall increases in addition to the structure cqn dissipate most of the energy by yielding the coupling beams with no damage to the main walls.It is easy to repair the coupling beams than repairing the walls.

The action of the couping beams of the shear walls.The beams are displaced vertically they tend to bend in a double curvature.The consistent shear can reduce the axial force in the upwind wall by a large amount & reduce pressure can lower tne shear capacity of the wall.To take up for this force diagonal lateral steel is more effective.

The design should be taken care of to see that the system develop plastic hinges only in the coupling beams before shear failure & coupling beams should be designed to have good enrgy dissipation capacity.

Framed shear wall:

Framed shear walls can be provided with or without brick infills.