A Case Study on Condition Assessment of Fire-Damaged RC Members of Turbo-Generator

Abstract

Many researchers across the globe have carried out fire safety risk analysis to gather evidence and pertinent data for different Reinforced Cement Concrete (RCC) members exposed to fire. Assessment of fire-damaged structures furnishes the minute details of the effect of fire on the properties of concrete.The study indicates the condition assessment of the turbo-generator (TG) unit, comprises of concrete bearing pedestals, deck and supporting columns. The research was conducted using Non-Destructive Testing (NDT) techniques using Rebound hammer test, Ultrasonic Pulse Velocity (UPV) test, Concrete Cover measurement, Carbonation and Crack depth measurements followed by microstructural studies using an X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Optical Microscope (OM), and Mercury Intrusion Porosimetry (MIP). The samples were taken from a fire-damaged concrete bearing pedestal B2 and a non-fire-damaged concrete bearing pedestal B4 of the TG unit. The approach enabled us to find the extent of damage to the RCC members exposed to fire. The above mentioned test witnessed that the concrete bearing pedestal B2 was the moderately distressed member, expressed doubtful quality of concrete, higher porosity, reduced residual compressive strength and reduction in yield strength of steel. However minor distress in form of crushing at the top grout portion was observed in concrete bearing pedestal B4, and no apparent distress was observed in supporting columns of TG unit. Based on the distress identified, repair and remedial measures were proposed to concrete bearing pedestals in order to improve the performance of the TG unit.