Effectiveness of passive response control devices in buildings under earthquake and wind during design life

The effectiveness of passive vibration control devices used to retrofit multi-storied steel buildings during their design life is investigated under the dynamic forces induced by earthquake and wind. The passive vibration control devices include steel bracing, viscous and viscoelastic dampers. The buildings without and with the retrofitting devices are modelled as multi-degree of freedom (M-DOF) systems, with inertial masses lumped at each floor level. The governing differential equations of motion for the uncontrolled and controlled buildings are solved using Newmark's time marching scheme. The obtained dynamic responses for the buildings exposed to the earthquake- and wind-induced forces are subsequently compared. It is concluded that upon retrofitting, the modified dynamic properties, such as modal frequencies and damping ratio play an active role to attract forces during the two hazards, which in turn influences the response reduction achieved. It may be worth noting that the buildings retrofitted for earthquake tend to attract more forces under wind load and vice versa. Therefore, a retrofit strategy providing beneficial effects against a particular hazard may prove to be catastrophic for the other, which underlines the need for careful selection of the retrofit solution and design for a structure considering such multi-hazard scenario.