Experimental Investigation of Slit Damper Subjected to Combined Flexure-Shear Actions

Previous earthquakes have demonstrated that collapse of RC precast frame buildings is mostly due to failure of beam-column joints. The precast beam-column joints exhibited insufficient strength, ductility, stiffness, and energy dissipating capacity of the connection region. Use of passive energy dissipation systems at beam-column joint of RC precast frame buildings is an effective and reliable solution to improve seismic performance of these buildings. Energy dissipation through these systems can be accomplished in various mechanisms such as friction sliding, yielding of metal, and deformation of viscoelastic fluids. The most popular mechanism for the dissipation of input energy is through metallic yielding. In the available study, the metallic slit dampers are tested for yielding of steel slits through bending or shear deformation modes under shear action. Studies were also carried out using the dedicated shear and flexural steel plate arrangement to combine bending and shear deformation modes for the yielding of steel. This paper discussed development of slit damper for dissipation of input seismic energy through combined bending and shear deformations in RC precast frame buildings. The proposed damper comprises multiple steel slits cut from steel plate. The steel slits will yield under combined shear and flexural actions and consumes the portion of the input seismic energy. The energy dissipation characteristics of the proposed passive devices are studied using experimental testing. The seismic performance is evaluated in terms of strength degradation ratio, equivalent viscous damping ratio, strength index ratio, displacement ductility, and the failure modes.