Earthquake-induced lateral-torsional pounding between two equal height multi-storey buildings under multiple bi-directional ground motions

Pounding between adjacent buildings, often characterized by different material properties, can be cause of significant or even severe structural damage. The aim of this paper is to present a detailed analytical study on earthquake induced lateral-torsional pounding between two equal height multi-storey buildings with equal storey heights. Both a non-linear viscoelastic model to simulate impact and a non-linear behaviour of the storey shear forces and torques are considered in the model. Pounding-involved response is evaluated in the hypothesis of frictionless contact. Torsional effects are taken into account by implementing the most probable impact scenarios, depending on the sign of the rotations of two adjacent floor-diaphragms. Asymmetric buildings with initial eccentricities just in the transverse direction are considered, while input ground motion is incorporated in the analysis in both directions. Multiple ground motions are implemented in the analysis, in order to investigate the sensitivity of the earthquake-induced pounding to the characteristics of the seismic excitation. The dynamic equation of motion is solved by proposing a suitable MATLAB numerical algorithm.