Application Research Of UHPC Pavement In Improving Bearing Capacity Of Existing Concrete Beam Bridge

In recent years,the traffic volume has increased and the serious overload of vehicles has increased sharply.The diseases and damages of highway bridges have been increasing day by day.For the existing concrete beam bridge structure,because the load level is insufficient,the load-carrying capacity does not meet the traffic needs,and it needs to be reinforced.In the past,due to insufficient attention to bridge deck pavement,it caused premature destruction of bridge deck pavement,which brought hidden dangers to vehicle driving comfort and safety.The load directly acts on the bridge beam under long-term heavy or overload The above will reduce the bearing capacity of the bridge,accelerate the degradation of the function of the bridge,and affect the function of the bridge.Therefore,it is necessary to study the design,calculation,use and replacement of bridge deck pavement.Based on UHPC's superior mechanical properties such as better tensile,compressive strength and low permeability than ordinary concrete,this paper proposes a scheme of using UHPC bridge deck pavement to reinforce existing concrete beam bridges.The stiffness of the bridge,the method of strengthening the overall bearing capacity of the bridge,provides scientific guidance for bridge reinforcement.The main research contents and results of this article are as follows:(1)Analyze the mechanical behavior of bridge deck pavement,and get the mechanics of bridge deck pavement.Based on the reliability theory of bridge structure,a method of using UHPC bridge deck pavement to improve the bearing capacity of bridge is proposed.At present,there are few studies on the constitutive model of UHPC bridge deck pavement loading and reinforcement of existing concrete beam bridges.In view of this situation,this paper establishes the constitutive relationship of UHPC bridge deck pavement,loading and strengthening existing bridges.(2)Although there are many studies on UHPC to enhance the integrity of the structure,there is no unified and effective method for the bond strength at the interface.On the basis of previous studies,this paper analyzes the calculation of bond strength.On this basis,the paper puts forward a method to calculate the thickness of bridge deck pavement with the control value of tensile reinforcement and prestress.(3)Based on the constitutive relationship of the UHPC bridge deck pavement reinforcement to load the existing concrete beam bridge,the UHPC bridge pavement reinforcement method of bending capacity and shear load capacity calculation formula was deduced.The reinforcement mechanism was analyzed.(4)The existence of cracks in the existing concrete structure has a non-negligible effect on the ultimate bearing capacity after reinforcement.In this paper,the parameters of the existing concrete structure strengthened by UHPC are analyzed through experiments under the consideration of the cracks in the existing concrete structure,so as to obtain the most Construction parameters.(5)Applying the research results of this paper to the reinforcement design,dynamic and static load tests were carried out on the reinforced prestressed concrete box girder bridge,and the deflection,strain and natural frequency of the UHPC deck decking structure on the bridge were analyzed through the load test And the impact coefficient,proved that the reinforcement effect is good.