Abstract:In order to more accurately analyze the coupled lateral-torsional seismic responses of a structure whose mass centers at different floors are not located on a single vertical axis, a basic framework of analyzing the seismic dynamic interaction of the soil-general mass eccentric structure is presented here. First, use the polar coordinates to develop the dynamic equations of a two-storey general asymmetric-plan structure (GAS) with the 6-degree-of-freedom (6DOFs) under the bi-directional earthquakes. Then, with resorting to the 5DOF soil impedance functions,characterize the soil-general asymmetric-plan structure interaction (SGASI). Finally, integrate the dynamic equations of both the GAS and soil-foudation+superstructure (whole) interaction. The normalized root-mean-square (RMS) seismic displacement and acceleration responses of the SGASI system are derived. Numerical study on the effects of both the single-axis and non-coaxial mass eccentricities on the coupled lateral-torsional seismic responses are analyzed through setting up different locations of mass eccentricity under the bi-directional earthquakes.