Research Article
Bhatti AQ and Naqash MT
Abstract
Dynamic stresses generated by geological agents such as earthquakes, sand storms and hurricanes causes great damages to the structures. In this research dynamic loads the effect of generated by these geological agents have been taken into account for the performance base evaluation and design of rigid steel frames. The effect of fundamental periods on the design of these frames taking into account the variation in the behaviour factor and drift limitations is highlighted. The periods are obtained from the modal dynamic analysis; their performances were tested through nonlinear pushover analysis and these are then compared with the periods obtained from codified formulations. The weight of the designed frames are normalised with respect to the modal periods. It is observed that as the drift limitation varies from the lower limit (relaxed one) to the upper limit (stringent one); the fundamental period of the frames decreases and so the stiffness of the frame increases due to the members (beam and columns) sizes. Furthermore, it can be noted that the periods calculated from the codified formulations are in the same range to the one obtained from the modal analysis when the strict drift limit is incorporated.