An enhanced modal pushover analysis procedure for seismic evaluation of single-layer latticed shell structures

Nonlinear static analysis procedures on seismic assessment arc mainly studied and retrofitted specific to frame buildings. This fact hinders the application of such methods on the widely-adopted latticed shell structures featured with strong geometrical nonlinearity and multi-dimensional coupling. This paper proposes a novel enhanced modal pushover analysis procedure aiming at giving a better consideration of the multi-dimensional coupling effects associated with single-layer latticed shells. Within this proposal, modal stiffness is derived to describe the nonlinearity using overall loads and displacements, based on which an equivalent single-degree-of-freedom system is established as well as the capacity curve derived in A-D format. Then by the aid of capacity spectrum method or response history analysis method, the overall responses are obtained. The novelty of this proposal is to conquer the drawback of conventional pushover method that the capacity curve is described resorting to base shear and roof displacement. Seismic responses of a spherical single-layer latticed shell are calculated by means of the proposed procedure. The results demonstrates that the nodal displacements, element stresses, as well as the yielding members, arc estimated accurately.