A modified DEB procedure for estimating seismic demands of multi-mode-sensitive damage-control HSSF-EDBs

The core objective of this research is to develop a modified dual-energy-demand-index-based (DEB) procedure for estimating the seismic demand of multi-mode-sensitive high-strength steel moment-resisting frames with energy dissipation bays (HSSF-EDBs) in the damage-control stage. To rationally quantify both the peak response demand and the cumulative response demand which are essential to characterise the damage-control behaviour of the system subjected to ground motions, the energy factor and cumulative ductility of modal single-degree-of-freedom (SDOF) systems are used as core demand indices, and the contributions of multi-modes are included in the proposed method. A stepwise procedure based on multi-mode nonlinear pushover analysis and inelastic spectral analysis of SDOF systems is developed. Based on the numerical models validated by test results, the proposed procedure is applied to prototype structures with a ground motion ensemble. The satisfactory agreement between the estimates by the proposed procedure and the results determined by nonlinear response history analysis (NL-RHA) under the ground motions indicates that the modified DEB procedure is a promising alternative for quantifying the seismic demands of tall HSSF-EDBs considering both peak response and cumulative effect, and the contribution of multi-modes can be reasonably estimated.