Abstract: This study investigates the mechanical behavior of glass fiber-reinforced polymer reinforced concrete (GFRP-RC) columns under high temperature and impact loading,aiming to address the damage assessment of GFRP-RC structures under fire and impact conditions.Finite element models were developed to simulate the response of GFRP-RC square and circular columns under combined high temperature and impact loading,and the accuracy of the models was validated against experimental data.The results show that circular columns exhibit lower peak displacement,impact force,and reaction force compared to square columns due to their smaller contact area and reduced contact stiffness,resulting in less severe damage under both ambient and high-temperature conditions.The damage caused by high temperature increases significantly with prolonged exposure,and the combined effect of high temperature and impact loading leads to a nonlinear accumulation of damage.Furthermore,a relationship between the damage index and lateral residual displacement was established based on the residual axial load-bearing capacity,providing a reference for rapid damage assessment of GFRP-RC columns in engineering applications.