AN EVALUATION OF THE DISPLACEMENT CONTROLLED DESIGN PROCEDURES

When yielding occurs in a structure during extreme earthquakes formation of a desired earthquake resistant mechanism does not in itself guarantee that repair cost would be tolerable. By controlling inter-story drift we can reduce the expected damage and economic risk. It has been proved in many research works that adequate strength does not have a decisive influence on expected structural drift. Therefore, maximum displacements, rather than maximum stresses, represent the proper design criteria. This differs from current force-based design philosophy that is based on acceleration spectra, code performance factors that correlate poorly with damage potential, and displacement checks to ensure that non-structural drift limitations are not exceeded.