Nonlinear response of two-way asymmetric single-story building under biaxial excitation

Findings from nonlinear dynamic analyses investigating the torsional response of a two-way asymmetric single-story building under biaxial excitations are reported. Ground motions of increasing intensities, characterized by varying angles of incidence, are used to show the evolution of the seismic behavior with the increase of the inelastic demand. Results of the numerical simulations indicate that the parameters governing the nonlinear response of the asymmetric-plan building are associated with the centers of resistances (CRs) of the system. These CRs correspond to the "base shear-torque" (BST) combinations producing the plastic mechanisms that provide in each direction the maximum lateral strength of the building. The location of such CRs can be evaluated through the analysis of the BST surface, that is, the BST interaction surface of all the different plastic mechanisms that can develop in the building. Comparisons of the obtained results with those from incremental dynamic analyses on systems characterized by different stiffness and resistance distributions are also shown.