An experimental and numerical study of brace-type long double C-section steel slit dampers

Abstract

In this research study, a novel double C-section steel slit damper (DCSSD) was proposed. Six cyclic loading tests of DCSSD specimens were carried out to study the effects of strip aspect ratio, thickness of flange, damper length and steel grades on the hysteretic behaviour and resistance of the DCSSD. Test results showed that the proposed DCSSD exhibited good structural performance in terms of initial stiffness, resistance, ductility and energy dissipation capability. The equivalent damping ratio of all DCSSD specimens exceeded 0.45 while that of the DCSSD using Q160 was over 0.50. Moreover, the cumulative displacement of the DCSSD using Q160 could approach 1500 mm. Subsequently, numerical models of test specimens were built to further investigate load transfer mechanism of the DCSSD. Good agreement was observed between the numerical simulations and the test results. The distribution of the moment and shear over the strips were extracted from the FE database, and the effectiveness of the long DCSSD was confirmed by the even moment and shear distribution profile. Finally, the accuracy of the available design equations of slit steel damper (SSD) documented in the literatures for predicting the initial stiffness and resistance of DCSSD was evaluated. In general, the design models produced inconsistent predictions of the initial stiffness of the test specimens. The existing design equations for predicting the ultimate strength of the DCSSDs were relatively conservative.