Live Load Effect on Dynamic Response of Structures

Abstract

For the aseismic design of structures, the dynamic forces are generally replaced by equivalent static forces which are usually given as a function of the effective weight of the structure. The effective weight of a structure consists of full dead weight and a fraction of live loads as these are invariably spring and dashpot mounted. This paper presents the effect of such a mounting on the response of structures subjected to horizontal ground motion caused by an earthquake. The primary system as well as live load system have been idealized as single degree of freedom systems. This study indicates that only a part of the live load is effective under horizontal vibrations and this depends on the ratio of live to dead load and the amount of damping present in the live load model. The effect of various other parameters, namely, the spring mounting, undamped natural period of vibration of the primary system and the ground motion has also been investigated.