The Calculation and Analysis of the Spatial Mechanical Behavior for Steel Truss Bridge Considering the Effect of Integral Joint Rigid Zone

Integral joint technology is widely used in modern steel truss bridge.In establishing full-bridge FE model,how to handle the problem of joint rigid zone is an essential problem related to the calculation accuracy of the results.Taking Dongjiang Bridge in Dongguan as engineering background,beam elements with rigid arms were used to simulate the stiffness enhancement of integral gusset plate of steel truss bridge,and full-bridge calculation model was established to carry through mechanical analysis.Comparisons between FEA results and dynamic and static loading test results of this bridge indicate that the influence of joint rigid zone on the mechanical behavior of the bridge structure cannot be neglected.Without regard to the influences of joint rigid zone,the relative errors between the tested deflections and the calculated deflections of the bridge's middle and side main truss are up to 30%.If the influence of the joint rigid zones is considered using beam elements with rigid arms,these errors will be reduced by about 50%.Moreover,the calculated stresses of the upper and lower chord and the stiffening chord are more close to the measured results.The relative error between the calculated results of modal frequency and the tested ones is no more than 5%,and the calculation accuracy is remarkably improved.