Enhancement of Seismic Performance Using Shear Link Braces in a Building Designed Only for Gravity Loads

Abstract

The present work attempts to study the behaviour of building designed for gravity loads only under the effect of lateral seismic load. Such a building is generally deficient against lateral forces and need to be retrofitted against lateral earthquake forces. A retrofitting scheme by providing aluminium shear link with chevron braces is suggested to improve its performance. Past earthquakes have shown a great deal of damages to the deficient RC frame buildings designed without any consideration to the lateral earthquake forces. Chevron braces with the aluminium shear link can be implemented as an effective retrofit measure. A comparison of the performance of building initially designed for gravity load only with the retrofitted building using chevron braces with the aluminium shear link is presented in this paper. The behaviour of building is worked out by performing nonlinear static pushover analysis and nonlinear time history analyses. A parametric study has also been carried out to study the effect of shear link and braces on the retrofitted building. The performance of RC building designed for gravity loads only as evaluated from the nonlinear static pushover analysis lies in life safety and collapse prevention range for DBE and MCE level of earthquakes respectively. The same building when retrofitted by using chevron braces with aluminium shear link show improved performance. This device is very simple, economic, effective and can be placed in a building very easily. The dissipation of damaging energy/damage is localised in shear link which can be replaced after a major earthquake.