Retrofitting Existing Residential Building Structures to Increase Earthquake Resistance: A Case Study of Golpogriho, Shewrapara, Dhaka

Abstract

Dhaka, one of the world’s most densely populated megacities, lies within Seismic Zone III of Bangladesh, characterized by moderate to high earthquake risk. The prevalence of soft-story residential buildings—where ground floors are left open for parking—has created a critical structural vulnerability. This study investigates the retrofitting potential of Golpogriho, a soft-story residential building in Shewrapara, through structural modeling, architectural evaluation, and inspiration from case studies such as SPL Serenity and Century City Medical Plaza. Using ETABS simulations and field documentation, the research evaluates multiple retrofit strategies, including shear walls, infill walls and steel bracing, to determine optimal performance improvements under seismic loads of magnitudes 5–6. The study defines the soft-story phenomenon more precisely and describes architectural and structural techniques to mitigate its impact, proposing an acceptable 30% openness ratio for seismic resilience. Results demonstrate that integrating infill and bracing increases lateral stiffness by up to 150%, reducing inter-story drift within BNBC (2020) safety limits. The findings provide guidelines for seismic retrofitting strategies adaptable to Dhaka’s residential sector while maintaining architectural integrity.