This paper presents the seismic responses of a l:5-scale five story reinforced concrete building model, which represents a residential apartment building possessing high irregularities of weak story, soft story. and torsion simultaneously in the ground story, subjected to a series of uni- and bi-directional earthquake simulation tests. Analysis of the test results leads to the following conclusions: (1) The model survived the table excitations simulating the earthquakes with the PGA's up to 0.187g without any significant damages, though it was not designed against earthquakes; (2) The torsion mode appears to be the fundamental mode with the period of the second translational mode being close to that of the first mode. The two orthogonal translational modes acted independently while the torsion mode frequently coincided with the next close translational mode, thereby leading to large inelastic responses: (3) The maximum torsion and torsion deformation remained almost constant regardless of the exclusion into inelastic behavior in two orthogonal translational motions: And. (4) the resistance and stiffness of the columns and wall increase or decrease greatly with the variation of acting axial forces.