Seismic modal response histories of two-way asymmetric adjacent buildings with soil-structure interaction effects subject to earthquake excitations
The seismic response history analysis of multi-storey asymmetric elastic or inelastic adjacent buildings with soil-structure interaction (SSI) during impact is investigated in this study. The coupled multi-degrees of freedom differential equations of motion for two way asymmetric shear buildings are derived and solved using a step by step solution by the fourth-order Runge-Kutta method with and without impact. The SSI forces are modelled in the form of the frequency-independent soil springs and dashpots with modelling the coupled buildings resting on the surface of an elastic half-space. Two extreme cases of shear wave velocities of soils are created to investigate the SSI effects onto the adjacent buildings. A numerical example of twoway asymmetric five and four-storey adjacent buildings with large and small SSI effects is investigated under the excitation of two directional 1940 Elcentro Earthquake. The study was also carried out for two different cases assuming the couple buildings to be inelastic and elastic in order to investigate the influence of interaction forces and pounding force. The results from this study show that the lateral torsion response of the couple buildings is affected when impact takes place with the adjacent buildings. The modal response histories of both the lighter and the heavier buildings are significantly reduced due to the effect of the small SSI. Further, it is also observed that the roof twist of the lighter building which is assumed to be inelastic is decreased for the large SSI effect compared to the small SSI effect. At high shear wave velocity, the couple buildings are slightly on the conservative side. Finally, in increased shear wave velocity, the impact response of buildings is significantly severe.