Seismic energy response of a 42-story reinforced concrete tall building

Earthquake input energy imparted to a building is dissipated by hysteretic behavior and other mechanisms usually represented by viscous damping. Hysteretic energy is particularly important as it is an indicator of potential damage. In this study, a 42-story reinforced concrete dual-system building was analyzed at two different ground shaking intensity levels (serviceability and maximum considered earthquake) to investigate energy components and distribution of energy in the building. Analyses were conducted using Perform 3D as it allows to obtain energy break-down for the entire structure. Based on analysis results, seismic energy response of the building is obtained in terms of elastic (kinetic energy and strain energy) and inelastic energy (hysteretic energy and structural damping energy) components for each structural member (e.g. beams, columns, shear walls) at each floor level. Hysteretic energy distribution is a critical tool for energy-based seismic design of tall buildings. Distribution of hysteretic energy indicates parts of building where irrecoverable energy demands are high, showing which particular members require higher energy absorption capacity. This information is essential in design process of structural members. Ratio of hysteretic energy to input energy is also provided, which will be helpful for designers to have an estimate for the expected hysteretic energy demand once the input energy is known. Energy demands can be used in seismic performance assessment of tall buildings when compared with associated energy capacities, although not discussed in this paper but is considered in future studies.