Study Of Mechanical Properties And Influence Parameters Of Steel Ring Restrainer Under Monotonic Loading

The bridge structures are traffic lifeline projects and significant national infrastructures.A large number of seismic damage data show that under the ground motions,the bridge structure suffers from the superstructure earthquake damage,the bearing damage,and the substructure damage,which result in casualties and economic losses.If unseating damage occurs in earthquake,it will hamper the rescue work and further expand the loss.Therefore,many scholars significant value the unseating prevention study.Based on the research of unseating prevention system,a new type of restrainers is proposed-the steel ring restrainer.The steel ring restrainers consist of three parts:energy dissipation steel ring,upper guide steel wheel and lower guide steel wheel,which can be placed at the joint between the main girder and abutment,main girder and pier to restrain the relative displacement between them and prevent the unseating damage from earthquake.For the new type steel ring restrainer,the author has carried out experiment and simulation analysis.The main contents and results are as follows:(1)The experimental study on the steel ring restrainer is carried out.The mechanical properties and failure mode of the steel ring restrainer under the monotonic loading are studied.According to the deformation,stress,strain and load-displacement curve of specimens obtained from the experiment,the paper studies the whole process of the mechanical behavior and the failure mode of the steel ring restrainer,and then sketch the working and simple seismic design principle of the restrainer.Two groups of 26 steel ring specimens were designed to investigate the influence of steel material,diameter D of guide wheel,thickness t of steel ring,radius R arc section of steel ring and length of straight section a on the mechanical properties of the steel ring restrainer.The reference point displacement,ultimate force and ultimate force point displacement were analyzed and compared-The results show that:with other parameters remaining the same,the thickness increase 8mm,the ultimate force increase 68%;the length increase 45mm,the reference point displacement increase 27%?28%;radius increase from 120mm to 170mm,the displacement increase 46%?58%;the guide wheel diameter increase from 40mm to 140mm,the displacement decrease 30%?32%.Therefore,the ultimate force of the steel ring restrainer can be effectively improved by increasing the thickness;the displacement of the steel ring restrainer can be changed by changing the length of the straight section,the radius of the arc section and the diameter of the guide wheel.(2)The finite element simulation of the steel ring restrainer is carried out.The three-dimensional finite element model of the steel ring restrainer is established by using the finite element software ABAQUS.The static analysis is performed using the calibrated ductile fracture steel constitutive model.By comparing the results of load-displacement curve,deformation strain,initial stiffness K1,secondary stiffness K2,ultimate force and ultimate force point displacement between simulation and experiment,the results of simulation analysis are well consistent with the experimental results within 10%errors which verifies the accuracy of finite element model.In order to expand the range of influence parameters,and to supplement the parameters of the width w of the steel ring,the finite element quantitative analysis of the steel ring restrainer is carried out with considering the limitations of the test The influence of the diameter D of the guide wheel,the thickness t of the steel ring,the radius R of the steel ring arc section,the length of the straight line section a,the width w of the steel ring on mechanical properties are investigated.The results show that:With other parameters remaining the same,the thickness and width each increase 4mm,the ultimate force increase 13.8%?24,5%and 14.3%?25.2%;the length each increase 25mm,the ultimate force displacement increase 8.2%?11%;the radius each increase 20mm,the ultimate force displacement increase 13.2%?16.5%;the diameter each increase 40mm,the ultimate displacement decrease 15.6%.It is summarized that the ultimate force of steel ring restrainer can be improved by increasing the width of steel ring,and the trend of change is consistent with the test results when the parameter range is expanded.