Analysis of floor response spectra of an office building

Abstract

The paper deals with the analysis of an office building located in the outskirts of Bratislava, Slovakia. The building consists of one underground floor and five above ground floors that have been roofed by a steel roof structure. The steel structure represents a subtle roofing of areas with air condition units and other technological equipment. For proper design of the steel structure with respect to the seismic loading, it is necessary to prepare floor response spectra for the top floor. A computer model of reinforced concrete structure was created using the Finite Element Method - FEM. Based on the approved recommendations for dynamic loading, seismic load of the building was defined in the form of a synthetic three-component accelerogram at free field level. The calculations of seismic response spectra were made assuming a linearly elastic behavior of the building structure without considering the elasto-plastic effects during the earthquake. The calculation of transient analysis was performed for a three-component synthetic accelerometer in ANSYS software. Acceleration time responses in three orthogonal directions (two horizontal and one vertical) were obtained for 6 selected points of the top floor. The obtained values of acceleration were compiled by additional software in order to obtain the resulting floor spectra. Subsequently, the envelope of the floor spectra was created, which has been taken into account in the design of a steel roof structure.