Automated Seismic Design of Reinforced Concrete Buildings

Keywords: Reinforced Concrete Buildings,  Design For Seismic Stability, Seismic Excitation, Dynamic Analysis, and Dissipation Of Earthquake Energy.

Abstract: A new automatic method for the seismic design of reinforced concrete frame buildings is presented. A new damage index is reviewed, which serves as a measure of a member's residual energy dissipation capacity and is suitable as a control parameter in an automated design method. The method proposed aims for a uniform energy dissipation throughout the building frame, as measured by the individual member damage indices. The new damage index is modeled on the low-cycle fatigue phenomenon exhibited by reinforced concrete members subjected to strong inelastic cyclic loads. It accounts for the observed stiffness and strength deterioration, includes a modified Miner's Rule for variable amplitude loading, and considers the effect of load history. These features make the damage index a useful measure of a member's capacity to resist further cyclic loading. The automatic design method is based on a thorough study of the effects of three important design variables, the longitudinal reinforcement, the confinement steel, and member depth. Design rules derived for the large number of numerical studies allow an iterative improvement of a preliminary design until the distribution of damage indices has reached a user-specified degree of uniformity. The usefulness of this design method, which incorporates aspects of a knowledge-based expert system, is demonstrated with a typical four-story, three-bay office building.