Iterative Equivalent Modal Pushover Method for Seismic Displacement Demand Calculation of Cylindrical Latticed Shells

Abstract:

A modified modal pushover method is proposed to improve the efficiency and accuracy of seismic displacement demand calculation of cylindrical latticed shells. First, based on the energy equivalence rule, an equivalent single-degree-of-freedom (ESDF) system for spatial structures is established, in which the equivalent force and displacement of the ESDF system can be directly calculated without using interim parameters or step-by-step calculation. Then, according to the equal-energy rule, an iterative equivalence method is proposed to calculate the target displacement of the ESDF system. Finally, the overall structural seismic demand is obtained by combining the peak responses of dominant modal ESDF systems using the complete quadratic combination (CQC) rule. The numerical results show that compared to the results obtained by using the traditional pushover method, both the maximum and the envelope nodal displacement obtained by using the proposed method yield less error. The accuracy of the proposed method remains stable when structural response is dominated by multiple modes.