Experimental Research On Prefabricated Simply Support Beam With Prestressed CFRP Plate

With the increasing of traffic,the prefabricated simple support beam is prone to many diseases due to its insufficient flexural capacity to withstand heavy vehicle and even overloaded vehicles.There are many ways to strengthen the flexural capacity,and the prestressed CFRP plate reinforcement is of higher quality,simple construction and higher material strength than other reinforcement methods.However,the existing research is mainly for small proportion section,which is not suitable for the study of large proportion section of bridge structure,and there is no explicit formula for calculating flexural capacity and flexural rigidity of simply support beam with prestressed CFRP plate.In order to study the effect of simply support beam with prestressed CFRP plate,the main work and main conclusions of this paper are as follows:(1)The 8m span simply support hollow slab beam model test,the results show that the hollow slab strengthened with prestressed CFRP plate damage can be divided into four stages of elastic work,beam crack,viscose failure and hollow plate plasticity;because of the small span of the hollow plate and the large bending stiffness,the failure form of the prestressed CFRP reinforced hollow slab is the strength failure,adhesive failure between CFRP plate and concrete when ultimate load is reached.Compared with the unreinforced hollow slab,the cracking load of hollow slab strengthened with prestressed CFRP plate increases by 167%,the ultimate bearing capacity is increased by 226%,and the deflection decreases by 32%,which indicates that the flexural capacity and flexural rigidity of hollow slab strengthened with prestressed CFRP plate are significantly improved.(2)The 20m span simply support T beam model test,the results show that the T beam strengthened with prestressed CFRP plate damage can be divided into three stages of elastic work,beam crack and beam plasticity;because of the large span of the T beam and the small bending stiffness,the failure form of the prestressed CFRP reinforced T beam is flexural failure.When the damage load is reached,the adhesive tensile strain between the concrete and the carbon fiber board is close to the disintegration limit.Compared with the unreinforced T beam,the cracking load of T beam strengthened with prestressed CFRP plate increases by 13%,the ultimate bearing capacity is increased by 100%,and the deflection decreases by 7%,which indicates that the flexural capacity of T beam strengthened with prestressed CFRP plate are significantly improved,but the increase of flexural rigidity is not obvious.(3)The nonlinear finite element analysis of prefabricated simply support beam is made by the general software ABAQUS.The reliability of the finite element model is verified by comparing with the experimental results.Analysis of the effect of performance,force on force and control the number of prefabricated beam strengthened with CFRP plate compared with that before reinforcement girder with prestressed CFRP plates,each increase of one piece of 100mmx 1.4mm specifications,cracking moment and ultimate bearing capacity of hollow slab beam and T beam are increased by at least 12%,11%and 6%,12%;The cracking moment and ultimate bearing capacity of the hollow plate and T beam increased by 8%,4%and 4%,5%for each increase of 5%of the control stress,the increase of the amplitude decreases with the increase of the control stress.(4)Considering the influence of prestress in prestressed CFRP,the calculation method of flexural capacity and flexural rigidity of Prestressed CFRP reinforced simple supported beam is established.The accuracy analysis with finite element calculation results shows that the error of flexural capacity and flexural rigidity of the strengthened main girder is less than 11%and 12%,which indicates that the formula for calculating the flexural capacity and flexural rigidity of the strengthened girder has high accuracy.