Performance Analysis Of Masonry Arch Bridge Strengthened With FRP

Masonry arch bridge has a history of thousands of years and is a kind of bridge with cultural value.Most masonry arch bridges have been in a long period of time.Due to the influence of natural environment and the increase of vehicle load,masonry arch bridges can not meet the requirements of use.However,FRP(Fiber Reinforced Plastics)reinforced masonry arch bridge can not only satisfy use requirements but also meet its aesthetic.Based on the separated modeling method,this paper takes FRP type,width and reinforcement position as variables,and establishes 12 finite element models of FRP strengthened masonry arch bridge.The main contents of this paper are as follows:1)The failure models of unreinforced masonry arch bridge and FRP reinforced masonry arch bridge are analyzed.The result show that the failure mode of unreinforced masonry arch bridge with four hinges is brittle failure.The failure mode of four-hinge mechanism is changed and the brittle failure of unreinforced masonry arch bridge is avoided by using FRP arch back or arch abdomen to reinforce masonry arch bridge.With the increase of FRP width,the failure mode of masonry arch bridge strengthened with FRP arch abutment of different widths is changed from FRP stripping failure to that of block crushing and FRP stripping.However,the bonding width of FRP has no effect on the failure mode of arch bridge strengthened with arch back.2)The influence of FRP type,width and reinforcement position on the carrying capacity and deformation capacity of masonry arch bridge is discussed and the optimal reinforcement scheme is selected by orthogonal test.The results show that the deformation capacity and carrying capacity of masonry arch bridge strengthened with FRP are improved.The larger thepaste width of FRP,the greater the carrying capacity and deformation capacity of the arch abutment reinforcement,and the greater the capacity of the arch back reinforcement,but the increase is very small,and the ductility is not improved very well.The carrying capacity of the arch abutment reinforcement is greater than that of the arch back reinforcement,while the deformation ability of the arch back reinforcement is greater than the deformation ability of the arch abutment reinforcement.The carrying capacity of CFRP strengthened masonry arch bridge is greater than that of GFRP,while the deformation capacity of GFRP strengthened masonry arch bridge is greater than that of CFRP.Reinforcement of masonry arch bridge with arch back based on orthogonal test CFRP(2x50mm)is the best scheme.3)Three lateral horizontal loading modes are applied to the optimal reinforcement scheme.The Pushover analysis of longitudinal and lateral direction is carried out to obtain the performance points of masonry arch bridge and the shear force of arch foot and the displacement of arch top.Finally,the results are compared with the results of the time history analysis.The results show that the top displacement error along the bridge direction is less than8% under multi vibration load model and the top displacement error of the transverse bridge is less than 10% under inverted triangular load model.Therefore,it is a reasonable loading mode to adopt multi vibration load model along the bridge direction.Using inverted triangular load model in the transverse bridge direction is a reasonable loading mode.