INVESTIGATIONS OF SEISMIC JOINT AND POUNDING EFFECT ON ADJACENT BUILDINGS

Abstract

Earthquake-induced structural pounding phenomenon, which is the collision between two adjacent buildings subjected to earthquake ground motion, has been the concern of numerous studies in recent years. Such phenomenon may cause severe damage to colliding buildings’ element that may lead to their collapse. As such, the international seismic provisions and standards have proposed a minimum separation distance between adjacent buildings in order to avoid seismic pounding. However, such provisions have considered only the peak floor drift, but not the relative movement between the buildings to determine, which provides excessive gap distance between adjacent buildings in some cases. This study aims to evaluate the accuracy of different methods (proposed by international seismic provisions and guidelines) used in determination of seismic joint distance. In order to identify peak floor drift of analysed buildings, nonlinear pushover analysis is conducted to four reinforced concrete frames utilizing three earthquake recodes with five peak ground accelerations which varies from 0.10 g till 0.30 g. Then, the detailed dynamic analysis is performed using nonlinear time history (NLTH) techniques considering same earthquake records and peak ground accelerations to calculate the critical required gap distances and compare them with the results of the studied methods. In general, the results show that the use of absolute sum rule always provides overestimation of separation distance, while square root rule may provide more accurate separation distance but in few cases provides insufficient separation distance between adjacent buildings. Furthermore, the effect of aligned slabs pounding on the behaviour of colliding structures has been numerically simulated with the use of linear viscoelastic model. A large number of nonlinear numerical simulations were performed, in which the critical separation distance is reduced monotonically and floor impact force is determined using NLTH technique. It is found that reducing separation distance increases the number of colliding floors, axial compression force of beams, and slightly increase of total base shear in some cases. The results of this study are expected to contribute to the growing reinforced concrete seismic performance database and to the future development of reinforced concrete structures’ design provisions under lateral loads in Egypt.