Study On Assembly Rapid Reinforcement Method For Fatigue Cracking Of U-rib And Transverse Stiffener Detail In Orthotropic Steel Bridge Deck

The orthotropic steel bridge deck has many advantages as the bearing structure system widely used in modern steel bridge.However,due to the lack of experience in the initial design and construction,the study of welding details is not enough,the traffic flow during the service period is increasing,and the load of the vehicle is increasing.Orthotropic steel bridge panels have different degrees of fatigue cracking,therefore,for orthotropic steel bridge deck maintenance and reinforcement research is imperative.The traditional method of fatigue cracking is complicated,the working conditions are demanding,the implementation is difficult and the traffic is interrupted,the cost is high,the adverse social impact caused by the interruption of traffic and the direct and indirect economic losses are inevitable.It is an important research topic to solve the sustainable development of bridge engineering.It is very important to improve the service quality of steel bridge structure and reduce the cost of maintenance and repair.It is an important research topic which is urgent to be solved in the sustainable development of bridge engineering.In this paper,we focus on the fatigue crack reinforcement of the orthotropic steel bridge deck and the longitudinal ribs,and carry out the following research work:(1)This paper reviews the fatigue crack initiation and cracking causes of orthotropic steel bridge panels.The research on the maintenance and reinforcement technology of the corresponding fatigue cracking of orthotropic steel bridge panels is studied and studied.Problems and methods to be solved.(2)The finite element model of the experimental model was established by ANSYS finite element software,and the finite element model was used to calculate the U-rib and transverse ribs.And the experimental model at two points of the measured value of the test comparison,analysis of the fatigue and fragmentation.(3)The fatigue crack at the joint of the U-rib and the longitudinal ribs of the orthotropic steel bridge was established.A series of initial crack lengths were selected and the crack simulation was carried out based on the fracture mechanics.The crack tip stress intensity factor at different initial crack lengths,the equivalent stress intensity factor and the initial length of crack are analyzed.(4)The fatigue crack produced by the combination of the U-ribs and the transverse ribs of the orthotropic steel bridge panels with fastening of the assembled angle steel was used to evaluate the reinforcement effect by comparing the equivalent stress intensity factor at the crack tip before and after the assembly reinforcement.The influence of the length,width and angle of the angle on the reinforcement effect of the assembled steel is as follows:It is found that the length and width of the reinforced angle have no significant effect on the reinforcement effect,and the thickness of the angle has a significant effect on the reinforcement.(5)This paper analyzes the new stress concentration after the reinforcement of the steel and the base metal,and evaluates the thickness of the reinforcement plate,and analyzes the effect of the mechanical properties of the reinforced angle on the rapid reinforcement effect of the assembled steel.For the improvement of the stress concentration,it is concluded that the thicker angle has obvious effect on the tensile and compressive stress concentration zones produced on the angle steel.