The Effect Of Freeze-thaw On Mechanical Properties Of Stud Shear Connection

Stud connectors are mainly used in composite structure of wet joint,that plays an important role in the process of stress in the composite beam bridge.Because of our vast,great regional difference,the temperature difference between day and night in winter in northern China,long winter,building bridges susceptible to freezing and thawing load influence,while the wet joint is the weak part of combined beam bridge,so the research on freezing thawing under cyclic loading is very important for the wet joint composite beam bridge.The significance and necessity of the process,but the related research in China and abroad mainly focus on the research of concrete freeze-thaw and carrying capacity of studs,the stud in the freeze-thaw research under cyclic loading is still in the blank.This paper mainly through the freeze-thaw test and test of stud connectors,the freeze-thaw cycle load and damage.A total of 12 test pouring diameter 22 stud connectors.The specimens were divided into four groups,respectively 0,50,100,150 times of freeze-thaw,freezing test the load displacement curve after thawing.At the end of the experiment was simulated by finite element analysis software.Effectiveness of the first through the test results of numerical analysis were carried out to verify that the numerical analysis can effectively simulate the experimental results,through the finite element results of variable parameter analysis.The main results are as follows:(1)through the freeze-thaw damage of concrete with high strength concrete,the surface is more obvious,after freezing and thawing loss rate of quality basically is zero,the elastic modulus decreased,the strength decreased in the early stage of slow down later soon.(2)the freeze-thaw test and launch experiment based on stud specimens,and finally get the stud specimens with the increase of the number of freeze-thaw,decreasing the ultimate bearing capacity of the test specimens mainly for concrete cracking.The 22 diameter of stud connectors in different freeze-thaw cycles under the load-displacement curve.(3)by numerical analysis software for modeling,verify the validity of the model,the finite element model parameters were analyzed by fitting the data obtained,finally put forward the freeze-thaw damage coefficient for shear connectors,and get the mathematical formula.