Study Of Load Transmission Performance Of High Strength Bolt In Steel Trussed Girder Bridges

In recent years,with the heavy haul running,making all kinds of existing railwaysteel bridge disease still happen,severely affected the life of the bridge and thesecurity of driving.In this paper, based on the ministry of railways to fund projects ofthe detection and evaluation and remediation technology research of existing steelbridges under heavy haul train(2011G016-C),as the background of ChangdongYellow River Bridge in line Xin Yan replace about1200broken high strength boltsevery year at the part of steel truss continuous beam,the finite element model werebuilt by software ANSYS to analysis the effect of bolt damage or missing of steeltruss, the main conclusions are as follows:(1) The influence range of bolt missing in high strength bolt friction grip shortjoint on the force transmission ratio and splice plate stress are only limited in twoand one bolt space respectively,but the bolt missing will result in the frictional forceand load transfer factors of the rest bolts in this row increase; The stresses of spliceplate significantly reduced at where the bolts are missing,but keep no changeapparently at other position.The stresses along the axial and transverse direction ofcore plates increase,but the change is not significant;(2) The bolt of load transfer factors of the high strength bolt friction grip shortjoint will slip in turn followed the increase of the load and the one of which biggerload transfer factors comes first; After the bolt missing, the load transfer factors ofeach row keep no change when added by smaller loads, but when the load continuesto increase, the load transfer factors changes and the rest of bolts come to slip in turnby the load transfer factors;(3) The regularities of load transfer factors of the high strength bolt friction griplong joint under axial load is distribution saddle types, the uneven arrangement ofthe bolts in actual gusset plate leads to the mutations of load transfer factors inindividual locations;(4) The single bolt of every row has an inconsistent order of slip, the bolt which near the middle has a large amount of slip and reduce in turn to the edge; The shearforce of each row along the width direction is uneven on design, which is reducefrom the middle to both sides.After entering the local slip state, the nonuniformity ofshear force along the width direction increase and achieves uniform distribution afterthe row of bolts come to full slip.