Experimental study on seismic performance of steel slit damper under additional tensile load

Hysteretic steel dampers of the flexural/shear yield-type may resist unanticipated tensile load because of their installation pattern, boundary conditions, and scale difference with the frame. In this study, the effect of unexpected additional tensile loads on a flexural yield-type steel slit damper was experimentally analyzed. To this end, two experimental boundary conditions were applied as the experimental variables: 1) shear loading only, and 2) combined shear and tensile loading. Experimental results showed that the damper hysteresis under shear load has a typical parallelogram shape, whereas that under combined shear-tensile loading shows a butterflyshaped curve. The effect of additional tension is proportional to the aspect ratio and maximum deformation angle of the damper. The plastic deformation capacity according to the cyclic hysteresis of the damper under additional tensile load was found to be similar to that of the damper under shear loading only, and the amount of plastic energy absorbed until failure was measured to be equal or higher. However, the dissipated energy of the damper under additional tensile load contains a substantial amount of unstable energy owing to out-of-plane deformation. According to the test results, the hysteresis of the damper under additional tension was found to be lower than the existing predicted curve for the evaluation of the plastic energy, and a design value was proposed for the predicted curve of the flexural yield-type steel slit damper under an additional tensile load.