Thermo-mechanical analysis of pultruded GFRP slabs subjected to elevated temperatures using finite element modeling

Purpose This study aims at investigating the fire performance of pultruded Glass Fiber-Reinforced Polymer (GFRP) slabs under combined elevated temperatures (20–200°C) and mechanical loading. It provides new insights into how support conditions, fire exposure sides and load ratios affect structural behavior – an area with limited quantitative analysis in the current literature. Design/methodology/approach Finite element (FE) models are developed in ABAQUS temperature-dependent orthotropic properties and validated against previous experimental deflection–temperature curves with <10% deviation. A parametric study was then conducted to investigate the impact of support types (pinned vs fixed), fire exposure (bottom-only vs three-sided) and applied load ratios on the midspan deflection and failure thresholds. Findings Temperature-induced deflection increased sharply near the glass transition temperature. Fixed supports improved fire resistance by 40–60% over pinned supports. Failure temperatures declined significantly with rising load ratios (from 190°C at 0.25 P to 30–60°C at 0.75 P). Three-sided fire exposure showed faster stiffness loss and thermal softening. Originality/value This study provides quantitative insights into the combined effects of mechanical loading and elevated temperatures on the structural performance of pultruded GFRP slabs. The findings provide practical engineering guidance for boundary condition selection, span optimization and offer validation data for advanced FE models that incorporate realistic fire scenarios and time-dependent material degradation.