A Technology Research On Monolithic Reinforcement For Concrete Hollow-slab Girder Using New Modified Polyuethane-cement(MPC)

Transportation is the artery of national economic development.Bridges are an essential part of transportation facilities.Since the reform and opening up,the country's national economy has been developing and our country has made remarkable progress in the construction of bridge projects.However,as the use of concrete Bridges in the service roads,heavy load and the volume of traffic increase,most of the concrete highway Bridges in small and medium sizes have concrete structure cracking,reinforcement corrosion,concrete loss and the function of hinged seam invalidated.This is not only severely restricts the development of the national economy,but also greatly endangers the safety of people's lives and property.To this end,the author has developed a lightweight,high-strength and flexible MPC composite,which is suitable for rapidly reinforcing bridge structure.First of all,through the test of materials this paper determines the optimum mixture ratio of MPC composites and establishes the MPC composite flexural tensile strength,compressive strength,flexural modulus of elasticity and the reinforced concrete interface bonding strength between the mechanical parameters for its application in bridge reinforcement project to provide the necessary technical support.Secondly,classic hinged plate beam method and finite element method to calculate the load transverse distribution coefficient are compared with each other and this paper puts forward the concept of hinged injury tolerance,then discusses load transverse distribution in the condition of different injury tolerance.Thirdly,based on slabs of hinged joint damage bridge,this paper studies on reinforcement effect which is influenced by thickness of reinforcement,location of MPC composite materials and thickness of deck pavement.At the same time,the calculation of stiffness parameters in the hinged slab method is modified,and the formula for calculating the lateral distribution of the load is derived.Finally,through the experiment of bridge reinforcement design,construction,the comparative analysis of the load test results and long-term observation,this paper verifies the actual effect of using MPC composite material to reinforce the bridge of active highway.