| Title |
Torsional Response of Multistory Building with Unsymmetric Plan |
| Abstract |
Buildings with unsymmetric plan such as Fig(1), when subjected to the y-component of ground motion, would simultaneously undergo lateral motion in two horizontal(x and y) directions and torsion about the vertical(z) axes.In this paper, the equation of governing such coupled lateral-torsional motion are formulated for multistory buildings by means of finite element method.For this purpose, the lateral stiffness of each plan and inertia forces matrix on the mass component of the structures are defined.Each floor diaphragm, assumed to be rigid in its own plane has three DOFs defined at the center of mass.The DOFs for the jth floor are : translation ujx along the X-axes, translation ujy along Y-axes, and torsional rotational uj about the vertical axes ; ujx and ujy are defined relative to the ground.Combining the response contribution of all the modes gives the total response of the unsymmetric-plan building to earthquake excitation. The structural dynamics programs by Mario Paz are used to determine the natural frequency and natural mode of vibration. |