Gypsum-board fire protection for fiber reinforced polymer strengthened concrete slabs

Abstract

Fiber reinforced polymer (FRP) has been widely used for strengthening concrete structures. However, the glass transition temperature of FRP is low at which point the material may begin to soften and lose its capability to transfer loads to the fiber reinforcement. This can result in a significant deterioration of the structural load-bearing capacity which may lead to the structural failure. It is therefore essential to protect the material against the high-temperature conditions, e.g. fire, to ensure safety. In this research, a series of fire tests are conducted on the gypsum-board suspended ceiling systems, which consist of gypsum-board and rock wool layers as well as metal frame sections, for FRP protection. The tests are conducted in accordance with the ISO 834 standard time-temperature relationship. The test results are compared with the numerical results obtained from the finite-element analysis to determine a 2-hr fire rated gypsum-board suspended ceiling system required by the Ministry of Interior Regulation 60, B.E. 2549. The fire resistance capability of the tested configurations of the gypsum-board fire protection systems for FRP material subjected to the time-temperature relationship according to ISO 834 was assessed by using a commercially available finite element computer program, Abaqus/CAE. The fire resistance of the fire protection systems is assessed based upon their insulation by using temperatures on the FRP surface as the criteria. It was found that the fire resistance ratings for the tested gypsum board assemblies were 104 minutes and 83 minutes for assembly 1 and assembly 3, respectively. It is also reasonable to state that if there was no equipment malfunction during the fire test of assembly 2, the assembly would have the best fire rating. Based on the comparison between the modeling results and the experimental results, it was found that the Abaqus/CAE model could predict the temperatures within the gypsum board assemblies during the fire test with reasonable accuracy, when the correct material properties were used and when the gypsum boards and insulation material remained in place.