Study On The Mechanical Properties Of The Modular Expansion Joints Of Highway Bridges

The increasing number of vehicles will lead to the failure of the bridge telescopic devices.That has given rise to problems,For example,uneven roads reduce driving comfort and reduce the safety of bridges.There are many failure forms of modular expansion device of highway bridge,mainly as follows: load bearing steel plate is deformed and shedded under heavy pressure;The welding fracture of embedded Anchorage steel bar is broken;the anchor bolt is cut and cracked;the concrete in Anchorage zone is cracked loosely.According to the investigation,the cracking and breakage of expansion joint Anchorage concrete is the most common,and the frequency of fracture of expansion joint steel beam is small.On the basis of summarizing the main diseases of modular expansion joints as anchoring systems and supporting systems,this paper focuses on the study of the mechanical properties of modular expansion joints.In this paper,taking the concrete surface of a highway bridge in Jiangxi Province as an example,the concrete surface of the anchoring area of the modular expansion joint is cracked during the replacement of the support.The modular expansion joint structure is simulated and analyzed by finite element software ANSYS.In this paper,the construction and force transfer mechanism of modular expansion joint are introduced,and the disease of modulus expansion joint is summarized.Secondly,the important parameters of this research object are defined,and the stress analysis of the middle beam and the whole expansion joint of the modular expansion joint is carried out by using the ANSYS finite element software.The finite element model of expansion joint is established.The width of transverse bridge with continuous four-span continuous beam is closer to the expansion joint under the wheel load.Then the static analysis and dynamic analysis of the expansion joint are carried out respectively,and the concrete force situation of the components under the wheel load is clarified.Based on the basic assumptions,the formulas of geometric relation and shear force at the two ends of the simplified model of braced crossbeam in the state of simultaneous lifting on both sides are obtained.At last,the finite element parameter analysis of modulus expansion joint under the condition of one side beam lifting is carried out.The results show that:Under the wheel load,the main stress location of modulus expansion joints is concentrated in a fixed range.The stress of each component increases with the increase of axle load.The influence of simultaneous lifting on both sides of the beam is relatively small,and the single side uplift of the beam will be damaged by the factors such as the height of jacking,the stiffness of support,the quality of concrete,and so on,which will cause damage to the concrete in Anchorage area.