Research On Design Parameters Of Hinged Piecewise Steel Arch Rings Reinforced Arch Bridge

Arch bridge is an important component of traffic.Arch bridge strengthening helps improve social operation efficiency.Arch bridge reinforcement technology can be divided into passive reinforcement and active reinforcement.Reinforcement design must consider staged forces.Active reinforcement is beneficial to joint forces between old structures and new structures,reducing strain lag,and improving material utilization.Research on design parameters optimization of hinged piecewise steel arch rings is conducive to the realization of active reinforcement of arch bridges.Based on the experiment and the finite element analysis,this paper studies the technique from the aspects of effect evaluation and the aspects of design parameters.The main research contents include:(1)The technique mainly realizes reinforcement from the aspects of improving pressure line and arch axis coincidence,and pre-deformation.The reinforcement process unloads and closes the structural cracks on the main arch,and exerts the original arch bearing potential.It is particularly suitable for arch bridges with poor bridge formation,reinforcement,and temporary overloading.(2)Combining the finite element analysis,the stress characteristics of the arch bridge,and the constraint conditions,the relationship between the effect evaluation index and the main design parameters was analyzed.The results show that when the hinges on the two sides of the four-section steel arch are arranged near the peak cross section of the positive moment of the main arch circle in the unconsolidated state,the reinforcement efficiency is high.Leading the concept of critical thrust,exceeding the critical thrust is not conducive to the arch bridge.(3)The dead load was simulated by the lever,and the experiment was designed.The relationship among strain,deformation,number of hinges,position of hinges,and thrust was analyzed.The hinges could be arranged by the efficiency of section deformation recovery,and the thrust could be analyzed by the critical jacking force of the main arch circle under load.The change rule of experiment data is basically consistent with the finite element analysis.Reinforcement design should combine geometric analysis and mechanical analysis.(4)Derived the friction loss and anchor deformation loss formula of this reinforcement technique.Combined with the experiment data,the relationship between the friction loss and the axial force,friction coefficient,and angles of the compression rod was analyzed.It is recommended to reduce the friction loss through the backing plate and lubricating oil.(5)According to the experiment,a finite element nonlinear analysis model was established.The relationship between cracking load,plasticity development,bearing capacity and the thrust,the arrangement of the hinges was analyzed.It indicates that the reinforcement should make the connection reliable between the arch foot and the abutment surface,and the pushing reaction force should be far away from the arch foot to avoid stress concentration.It shows that the efficiency of arch deformation recovery can reflect the reinforcement effect.