Methodology for the elaboration of the design table of GFRP structures subjected to fire

Abstract

The main objective of this study is to establish a fire protection design method for pultruded Glass Fiber Reinforced Polymer (GFRP) structures exposed to fire. The method is based on the development of tables similar to those already available for steel structures. The structural designer may use these tables to determine the minimum required thickness (of any type of insulation), so that the structure maintains its mechanical properties above the over-dimensioning coefficient. The method used to draw up these tables follows four steps; i) First, the limit temperatures are determined or the temperature ranges within which the application of pultruded GFRP is permitted; ii) Second, the behavior of certain physical properties (density, specific heat, thermal conductivity, emissivity...) are defined as a function of the temperature; iii) Third, the method to determine the fire resistance temperature of the pultruded profile sections is defined; iv) Finally, the mechanical properties and ultimate resistance values of these profiles at different temperatures are also estimated. The behavior of the mechanical properties is analyzed as a function of the massivity of each section and the ratio between the thermal conductivity of the insulation and its thickness. In addition, a practical example is given of the application of the tables to a pultruded GFRP structure.