Finite Element Analysis On Shear Behavior Of Reinforced Concrete Continuous Beams After Fire

The accurate test of the residual mechanical properties of RC members after fire is the foundation of the structural damage assessment and reinforcement design after fire.As the main load-bearing member,it is necessary to study the performance of beam after fire.At present,domestic and foreign scholars have made some analysis and summary on the mechanical properties of RC beams after fire,but there are few achievements on the shear performance of continuous beam after fire.By ABAQUS simulation,the article analysed the variation of shear properties of continuous beam under different parameters.ABAQUS was used to establish the temperature field model of RC three-face fire beam,and the thermal analysis results were imported into the static model for calculation.The shear properties of continuous beam under different parameters were summarized by analyzing the residual bearing capacity and load deflection curves.The thermal coupling model was established to simulate and analyze the shear performance of simply supported beams under different conditions after fire,and the results were compared with the shear properties of continuous beams.The rationality of model is proved by comparing with the experimental data.By extracting the temperature at different positions of thermal analysis model,it is found that,because of the influence of thermal inertia of concrete,the temperature rises more obviously in the position close to the fire surface,and the internal temperature of the beam is generally lower than that of the fire surface.In a reasonable range,the shear performance of continuous beam is improved by increasing the stirrup reinforcement ratio,but the effect of prolonging the fire time,increasing the shear span ratio and the thickness of protective layer is opposite.For two-span beam,the residual bearing capacity of partial fire is lower than that of the whole fire,while for three-span beam,the shear performance decreases due to the increase of fire range.By comparison,it is found that the ductility of continuous beam is better than that of simply supported beam because of the redistribution of internal forces in the continuous beam.Figure 36;Table 20;Reference 65...