Robustness investigation of Horizontal Bidirectional Hybrid Damping System applied to long-span bridges under near-fault pulse-like earthquakes

This paper introduces a new integrated Horizontal Bidirectional Hybrid Damping System (HBHDS) incorporating eddy current dampers, metallic yielding dampers, fuse-lock device with a spherical steel bearing, for controlling the longitudinal and transverse vibrations of long-span bridges under near-fault pulse-like earthquakes. Based on the nonlinear time history analysis, the seismic response of a long-span bridge with HBHDS is investigated under different near-fault pulse-like earthquakes and compared to the installed damping system on the as-built bridge. The numerical results indicate that the HBHDS is an effective damping system against the near-fault earthquakes and exhibits a common tendency with similar or even better reductions of structural responses in comparison to installed damping system. Besides, a series of robustness investigations for HBHDS are carried out considering the out-of-service different HBHDS' components. It is found that HBHDS presents superior robustness to considering out-of-service dampers in terms of response reduction and energy dissipation capacity.