Basic principle for the Seismic design of building: Avoid bracing offsets

Avoid bracing offsets

Avoid bracing offsets

 Horizontal bracing offset, in plane or out of plane, result when the position of the bracing changes from one storey to another. The bending moments and the shear forces are induced by the offset. The offset disturb direct flow of forces, weaken the resistance and reduce the ductility of the bracing. Moreover, they cause large additional forces and deformation in other structural elements (e.g. slabs and columns) during an earthquake. 

Compare to bracings that are continuous over the height of the building, bracings with offsets increase the vulnerability of the construction and usually reduce its seismic resistance.

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