Seismic Performance Evaluation of a Fire-Damaged Reinforced Concrete High Rise Building by Non-linear Time History Analysis

Abstract

Concrete is widely used worldwide for the construction of buildings and infrastructure that remain stable under fire. It shows some damage and deformations that require maintenance. Although rehabilitation and restoration procedures for fire-damaged buildings are usually time-consuming and costly, the post-fire resilience of the structure is very important for understanding its capacity and condition. In the seismic zone, the buildings must satisfy the seismic demand after the potential repair and retrofitting of the fire-damaged building. A simple, verified simulation procedure for post-fire seismic analysis is necessary to advance understanding of the seismic performance of RC structures after fire. However, individual computer programs that can perform well in both thermal and seismic analysis may help structural engineers make decisions. This study presents an in-depth seismic performance evaluation of a fire-damaged high-rise reinforced concrete (RC) building in Dhaka, Bangladesh. The building, which suffered severe fire damage on the 7th to 9th floors, underwent rigorous structural investigation and testing, including core extraction and rebar tensile testing. According to ACI 562, the residual strengths of concrete and reinforcement were calculated. A comprehensive finite element model was developed in ETABS to simulate the structure’s static and dynamic behavior. Nonlinear Time History Analysis (NLTHA) was performed using nine ground motion records scaled to Bangladesh National Building Code (BNBC 2020) spectra. The comparative results are presented in terms of storey drift and displacement, stiffness, and demand /capacity ratios of column and shear wall. In most cases, it meets the allowable limits for different performance criteria. The proposed assessment procedure can capture the actual conditions of a fire-damaged building at different performance levels, helping stakeholders make further strategic decisions about the damaged structure.