Finite Element Simulation Of The Bending Resistence Performence Of Concrete Hollow Slab Beam Strengthened With Carbon Fibre Reinforced Plastics Boards

In this paper,the finite element analysis software ABAQUS is used to numerically simulate the bending performance of the bridge hollow slab beams strengthened with prestressed carbon fiber reinforced plastics(CFRP)boards.Concrete is considered to be the constitutive model of the full curve of concrete axial tension and axial compression in GB50010-2010,and the initial damage of concrete is taken into consideration by introducing the damage coefficient α.The prestressed steel bar adopts a linear elastic model,and the loss of prestress of the prestressed steel bar is considered.CFRP board is an orthotropic material,along the fiber direction is a linear elastic material with ultra-high tensile strength.Consider the prestress loss of the CFRP board and its bond-slip effect with the concrete.The model is loaded by means of loading,and the CDP model in ABAQUS is selected to simulate concrete materials,and the stiffness reduction of the hollow slab beam due to damage and cracking during the plastic stage is reappeared.By setting the "viscosity parameter" and reducing the "initial incremental step",increasing the number of incremental steps to improve the calculation convergence ability of the plastic stage.According to the above method,a bending finite element model of a bridge hollow slab reinforced with prestressed CFRP plates was established,and the bending moment-deflection curve,mid-span section strain,stress/damage cloud diagram,etc.were obtained during the rising phase.Comparing the experimental data and calculation results,the curve fitting is better and the deviation is controlled within 5%,which proves the rationality of the finite element model.On this basis,the CFRP boards reinforcement amount and reinforced length were used as parameters,and expended model parameters for simulation analysis.The results showed that:(1)The increase in reinforced length reduced the deflection in the mid-span,with a maximum decrease of 12.3%,and the cracking moment and the ultimate bending moment are increased,and the maximum increase is 28% and 10.6% respectively;(2)The reinforcement of CFRP board is directly proportional to the ultimate bending moment and cracking bending moment,with the maximum increase of 34.4% and 93.6%respectively,and inversely proportional to the maximum deflection in the middle of the span,with the maximum decrease of 43.8%(3)From the comparison of reinforcement efficiency,the efficiency is the highest when the reinforcement length is "13m" and "3" CFRP boards reinforcement.