Dynamic Behavior of RC Buildings with Viscous Dampers under Surface Blast

Effectiveness of fluid viscous dampers on blast resistance of Reinforced Concrete (RC) buildings is numerically evaluated in the present study. An Iranian viscous damper, designed and manufactured by Behsazan Larzeh Davam Co. is used to improve stability of a ۵ -story RC building. Thorough experimental studies have been carried out on the considered damper and obtained results have indicated that the damper have reliable and stable behavior under dynamic loading with different frequencies and amplitudes. The building is designed per Iranian seismic code with no explicit consideration for blast loading. Five surface blast scenarios with T NT masses of ۱۰۰ kg, ۲۰۰ kg, ۵۰۰ kg, ۱۰۰۰ kg, and ۲۰۰۰ kg all with a standoff distance of ۵m are considered. Full ۳ -D finite elements models of the building with and without viscous dampers are used to simulate behavior of the structure under the considered surface blasts. The models are able to explicitly account for fracture and disintegration of concrete and rebar elements. It turned out that viscous dampers can reduce the imposed demands in terms of inter-story drifts and structural damages under minor to moderate blast scenarios. Under severe blast loads, viscous dampers cannot meaningfully improve stability of the building and the progressive collapse would be inevitable for the adopted building configuration. In other words, viscous dampers are able to reduce demands caused by structural vibrations and they have no effect on demands directly triggered by the incident blast wave.