Effectiveness Of Energy Dissipation Devices For Seismic Response Of Building

Abstract

In order to control the vibration response of buildings during earthquakes, passive energy dissipation devices are most commonly used.These devices provide an additional damping to building, which helps in reducing seismic response of it. There are a number of types of dampers available, which use a variety of materials to obtain di erent levels of damping. These include dampers like viscous, viscoelastic(VE), Metallic, friction and magneto-rheological(MR) damper. These dampers are usually placed between framing elements at various storey. Present study considers seismic response reduction of three storey shear building using passive energy dissipation devices i.e. friction damper and semi-active device, magneto-rheological(MR) damper used passively placed at ground oor only. Behaviour of friction and MR damper was studied by characterizing these devices under sinusoidal and random elicitation, analytically. A three storey shear building has been considered. A lump mass model approach is used to obtain mass and sti ness matrices. Damping is assumed to be Rayleigh's type and damping matrix is determined considering 5 % critical damping co-e cient for all modes. Equation of motion for three storey building with damper attached at G.F. The equation of motion derived, are solved using Newmark-Beta and Runge-Kutta method respectively for building with friction and MR dampers through MATLAB. Four di erent type of earthquakes namely, El centro(1940), Kobe(1995), Loma Prieta( 1989) and Northridge(1994) are used to determine uncontrolled(building without damper) response for the building. Response quantities like displacement, velocity, acceleration, inter storey drift were extracted for uncontrolled and controlled(with dampers) building. The response quantities of uncontrolled building have been compared with the controlled building in order to establish efficiency of friction and MR damper. It has been found that all response quantities shows reduction for controlled building as compared to uncontrolled building. It was found that friction damper is most e ective under Northridge type of excitation. It is also noted that MR damper considered in present study reduces response quantities of controlled building marginally when used in "Passive O " condition, i.e. like viscous damping. However, MR damper keeps in reducing response quantities of controlled building substantially when used as "Passive On" condition, i.e voltage of 2.5 V applied continuously.