Two-dimensional modeling of thermo-mechanical responses of GFRP box beam subjected to ISO-834 fire

During the past three decades, one-dimensional (1-D) heat transfer model was frequently used to estimate the thermal responses of glass fibre-reinforced polymer (GFRP) materials and structures. However, in real fire scenarios, beams and columns are usually subjected to multi-side fire loading, and the whole cross-sectional thermal responses can hardly be obtained when using a 1-D model. To address this issue, a 1-D model was extended to a two-dimensional (2-D) model to predict the thermo-mechanical responses of GFRP box beam subjected to one-side ISO-834 fire exposure and four-point bending. The 2-D governing heat transfer equations with thermal boundary conditions, discretized by alternating direction implicit (ADI) method, were solved by Gauss-Seidel iterative approach. Based on beam theory, the mechanical responses were obtained by the temperature-dependent Young-s modulus. The model was validated by comparing the simulated results and the available experimental data of the beam. Both temperatures and mid-span deflections of the GFRP box beam in the experiment can reasonably be predicted by this model.