Research On The Pre-stressed Concrete Hollow Slab Bridge Reinforced By CFRP Sheets

With the steady growth of highway transportation in China,highway bridges bear loads gradually more than the design one.It is necessary to do the bridge reinforcement.Therefore,research on CFRP reinforced bridge is the important subject in the study of bridge reinforcement.This article uses the finite element simulation and field test method to calculate CFRP reinforced hollow slab bridge bearing capacity and loading process.The main research produces and results are as below.(1)This paper summarizes the present hollow slab is the main disease and CFRP cloth and the basic construction technology of pre-stressed CFRP reinforced,provide a basis for parameter setting in finite element simulation of later.(2)To verify reinforcement effect of the CFRP sheets and pre-stressed CFRP sheets on hollow plate,hollow slab through the field static load test in this paper.On the basis of field test results are analyzed the influence of the process of the hollow slab stress CFRP cloth.The static load test results show that with the increase of CFRP cloth layer reinforcement effect is obvious.However,normal stress of CFRP cloth hysteresis phenomenon resulting of common CFRP reinforced hollow slab effect is not significant.Through the pre-stressed tensioning pre-stressed CFRP cloth to overcome the stress of CFRP cloth hysteresis phenomenon improves the reinforcement effect.Compared to common CFRP reinforced,pre-stressed CFRP cloth significantly improves the bearing capacity and rigidity of pre-stressed concrete hollow slab and other mechanical properties,can inhibit the development of cracks and deflection.(3)After taking a simply hollow slab bridge as an example of CFRP cloth and pre-stressed CFRP reinforced hollow slab bridge finite element calculation and the analysis of bearing capacity.In order to further Finite element simulation results show that the bearing capacity limit state for hollow slab bridge reinforcement in damage of steel strand there is no problem,but in under the action of uniformly distributed load and concentrated load across the concrete do not meet the design requirements.CFRP hollow slab after structural strengthening can improve the edge of the hollow plate tensile properties,and inhibit the development of cracks and deflection.However,the phenomenon of stress hysteresis of CFRP cloth resulting of common CFRP reinforced hollow slab effect is not significant.Using a layer of CFRP reinforced cannot meet the demand of strengthening,using two layers and three layers of common CFRP reinforced after the basic meet the requirements of reinforcement.Pre-stressed CFRP reinforced concrete hollow slab after improve the bearing capacity improvement.Use 1 or 2 layers of CFRP reinforced concrete hollow slab steel strand maximum stress were 1134.2 MPa and 1049.8 MPa,the largest maximum stress of concrete suffered 15.681 MPa and 14.201 MPa,can satisfy the requirements of reinforcement.