| Recently,the damage of highway bridge expansion device frequently ocuurs in bridge engineering,which seriously affects the driving comfort and the safety of bridges in normal operation.Moreover,the traffic disruotion and traffic control in the maintenance and replacement process of the traditional expansion device will comsume a lot of time and cost,also bring great impact on society.Therefore,it is necessary to study a type of new bridge expansion device and rapid repair materials.In this paper,on the basis of summarizing and analyzing the disease,damage causes and durability of the bridge expansion device at domestic and abroad,a series of repair materials research results of the existing bridge expansion device are summarized.The main work of this paper is to develop a new type of epoxy resin concrete(ERC)and design a bridge expansion device structure which is applied in the small and medium span bridge for rapid maintenance and repair of bridge expansion devices.Combined the laboratory experiment,numerical simulation,theoretical analysis and engineering application,the following research were carried out in this paper.(1)The compression strength,tensile strength and bending strength of ERC materials were tested at high temperature,normal temperature and low temperature.The basic mechanical properties of ERC materials were analyzed by compression elastic modulus test and dry shrinkage test at room temperature.Combined with the loading curves of the whole process of compression test and tensile test of ERC,the modified stress-strain relationship model suitable for uniaxial compression and uniaxial tension of ERC is proposed.(2)The influences of three factors on the bonding properties of ERC-NSC interface,including the age of ERC,the water content of the normal strength concrete(NSC)and the inclined angle of the bonding interface,were evaluated by direct tensile test,split tensile test,bi-shear test and slant shear test.Based on the interface test results,the cohesive and friction coefficient were deduced to predict the bonding properties of similar ERC-NSC interfaces.The experimental results indicate that the bonding strength of ERC-NSC interface increases with the increase of the age of ERC material.The moisture on the surface of NSC substrate will reduce the bonding strength of ERC-NSC interface.For ERC-NSC slant shear specimens,the larger the inclination angle,the higher the bond strength in inclined shear test,and the lower the possibility of interface failure.(3)The finite element model of the ERC expansion device was established to study the influence law of the number of bridge lanes,width of expansion joint,transverse and longitudinal slope of bridge deck,the speed of vehicle,the axle load of vehicle on the static and dynamic response of the ERC expansion device.The results show that small width of expansion seam causes the most adverse effect on the static of ERC expansion device.The impact coefficient of the ERC expansion device exceeds the standard value with a lower vehicle speed,smaller vehicle axle load,or larger width expansion seam.The finite element analysis results show that the traffic of small and medium-sized vehicles could be opened one day after ERC is poured.(4)The equivalent model fatigue test of ERC-NSC composite components was carried out in this research.The experimental results show that the ERC-NSC interface has good anti-fatigue performance.Combined with the traffic statistics of a bridge in Guangdong Province,the cumulative fatigue damage of ERC expansion device under the varying amplitude vehicle load spectrum was analyzed,and the theoretical fatigue life of each component of ERC expansion device was estimated.The application of the ERC expansion device on Pengjiang Bridge in Guangdong Province indicates that it has good applicability and durability.It can be used as a reference and suport for the rapid replacement of highway bridge expansionc device. |
