An energy method for earthquake resistant design of RC structures

In order to effectively design reinforced concrete moment frames to withstand earthquake ground motions, it is necessary to accurately predict the seismic demands on the building system including the effects of duration together with the usual constraints defined by building codes. In this study, the use of plastic design procedures and an energy balance equation are described. The energy balance equation becomes an additional constraint in which the energy input (energy demand) to the structure by the earthquake will be balanced by energy absorbed by the structure and by energy dissipated from the structure. Hysteretic energy is selected and employed as energy demand since it relates directly to the inelastic deformation demands of a structure subjected to earthquake ground motion.;Within this thesis, the design procedure for reinforced concrete frames that includes energy demand is presented. Reinforced concrete moment frames for low-rise and mid-rise buildings are selected and designed as case studies. Nonlinear dynamic time history analyses are conducted for two sets of earthquake records, representative of far field records and near fault records, in order to estimate the hysteretic energy demand over the height of the building. Plastic design and minimum cost concepts are developed as an objective function which is minimized subject to the constraints by using linear programming. Finally, the designed frames are evaluated and verified according to present building code and FEMA 356 requirements. This procedure is repeated until the energy demand by the ground motion is less than the energy capacity of the structure.