INVESTIGATION OF THE FUNDAMENTAL PERIOD OF REINFORCED CONCRETE MID-RISE BUILDINGS

Abstract

The determination of fundamental period of vibration for structures is essential to earthquake design. The current codes provide empirical formulas to estimate the approximated fundamental period and these formulas are dependent on building material, height of structure or number of stories. Such a formulation is excessively conservative and unable to account for other parameters such as: length to width ratios, vertical element size and floors area. This study investigated the fundamental periods of mid-rise reinforced concrete moment resisting frames and shear wall buildings. A total of 13 MRFs and 13 shear walls buildings were analyzed by ETABS 15.2.2, for gross and cracked eigenvalue analysis and Extreme Loading® for Structures Software or ELS, for nonlinear dynamic analysis. The estimated periods of vibration were compared with empirical equations, including current code equations as well as equations proposed in recent literature. Based on the results obtained from the analyzed models, equations for calculating period of vibration are proposed. These proposed equations will allow design engineers to quickly and accurately estimate the fundamental period of MRFs and shear wall buildings with taking different length to width ratios, vertical element size, floors