The Effectiveness of Using Seismic Gap as a Simple Solution to Enhance the Seismic Resilience of RCC Buildings on Sloped Terrain

Abstract

Abstract Reported literature on the potential use of the seismic gaps in reinforced cement concrete (RCC) buildings on hill slopes as a simple solution to enhance seismic resilience is limited. While previous studies by the authors identified the optimal configuration and the critical threshold ground slope for hillside RCC buildings, the present work extends this understanding by evaluating, for the first time, to the best of our knowledge, how the inclusion of seismic gaps influences slope-dependent seismic performance. In the present study, a detailed comparative analysis of stepback–setback building models with and without the seismic gap across varying slope angles is presented. Key response parameters, including roof displacement, drift, base shear, overturning moment, and hysteretic energy dissipation of both types, were evaluated. The results reveal that in buildings with the seismic gap, roof displacement and drift increase uniformly due to enhanced flexibility, but there is a notable reduction in base shear, a more uniform force distribution, and improved energy absorption through nonlinear hysteretic damping. The study highlights the unique role of seismic gaps in redistributing internal forces and enhancing energy dissipation, thereby improving configuration-specific seismic resilience of hillside structures. The seismic response transitions from higher-mode effects to a more fundamental mode-controlled behavior, ensuring greater predictability and stability if seismic gaps are provided. However, in buildings with seismic gaps, the increase in overturning moments at higher slopes suggests the need for supplementary structural reinforcement to maintain overall stability. These findings establish that the seismic gap offers a viable strategy for mitigating the adverse effects of hillside building configurations, preventing localized overstressing, improving dynamic response, and reducing seismic force demands on foundations. While seismic gaps significantly enhance seismic resilience, their effectiveness is slope-dependent. This study provides a new perspective on seismic design for sloped terrain, presenting a novel approach for improving the performance of hillside structures in seismically active regions.