Simplified approaches for estimation of required seismic separation distance between adjacent reinforced concrete buildings

Abstract

This study aims to investigate the determination of seismic separation gap of adjacent low and mid-rise reinforced concrete (RC) buildings with no structural irregularity using nonlinear time history analysis. The low and mid-rise RC buildings were reflected using 3, 4, 5, 6, 7, 8, 9 and 10-story buildings designed per 2018 Turkish Building Earthquake Code (TBEC-2018). Beam and column elements are modeled as nonlinear frame elements with lumped plasticity by defining plastic hinges at both ends of beams and columns. The adjacent threedimensional (3D) building models are connected to each other by link elements at the floor levels. 1232 nonlinear dynamic (time history) analyses were performed using 56 different building pairs and 11 different earthquake record pairs (22 records) compatible with TBEC-2018 to obtain the required seismic gap distances. The distances necessary to avoid pounding obtained from the analyses were compared with the minimum seismic gap requirements of the current earthquake codes, provisions (Eurocode-8, ASCE 7-16 and TBEC-2018) and several proposed methods (ABS, SRSS and DDC) in the literature. The outcomes indicate that the ASCE 7-16 and EC-8 significantly overestimate the required seismic gap distances for the buildings with similar dynamic characteristics while they provide reasonable estimates for the buildings with significantly different dynamic characteristics. However, the TBEC-2018 requirements are insufficient for the neighboring building period ratios greater than 1.25. Although both the ASCE 7-16 and EC-8 requirements are acceptable for the design of new buildings as being on safe side, they are not useful for the evaluation of existing buildings. Two different simple approaches were proposed to estimate the required seismic gap distances between neighboring buildings. The first approach requires linear static analysis of the buildings subjected to the reduced seismic design forces while the second simplified approach does not need any analysis. The proposed equations in this study are simple and useful for the evaluation of existing low and mid-rise RC buildings with no structural irregularity. Besides, their estimates are acceptable for the design purposes.