| Orthotropic steel bridge decks are widely applied to long-span bridges because of their characteristics such as light weight,high load-carrying capacity,wide application,rapid construction and beautiful appearance.However,with the increase of traffic,especially the increase of heavy vehicles and overloaded vehicles,the fatigue of bridge decks has become increasingly prominent in recent years.A large number of surveys show that orthotropic steel bridge decks have appeared fatigue-cracking problem during service.One of the key factors affecting the fatigue performance of orthotropic steel bridge decks is the the form of the rib-to-deck weld,of which the controversial one is the penetration of groove welding.In order to analyze the penetration of groove welding,this study intended to carry out experimental and numerical studies on the influence of the penetration of groove welding on the fatigue performance of the rib-to-deck welded joint.Firstly,the static and fatigue tests of nine orthotropic steel bridge deck double-rib specimens were tested.Based on the test of Zhuankou bridge in Wuhan,the fatigue performance of double-sided weld was further studied by comparing the performance of the single-side weld.With the help of a static strain collector and a non-contact full-field strain measurement system,the data of strain and displacement were measured.The test results showed that the change of the weld penetration of groove welding had insignificant effect on the fatigue life of the double-sided weld joint specimens.The stress amplitude had great influence on the speed of crack propagation.The strain and displacement values of the control points measured by the non-contact full-field strain measurement system were basically the same as those measured by the traditional measurement method.Secondly,finite element analysis(FEA)model was established using ANSYS to simulate the static test,which considered the material properties,the boundary conditions and grid size.In addition,the FEA models were validated against the experimental data.Based on the validated model,the FEA were conducted to investigate the effefct of penetration to rib-to-deck welding structure considering static load.The weld penetration of groove welding,the influence of other parameters and different load positions on the fatigue performance of the rib-to-deck joint intended to be further studied.These conclusions provided basis for fatigue life assessment.Finally,the evaluation results of the master S-N curve method and the test results were compared and the applicability of the evaluation method was verified.The master S-N curve method was used to evaluate and analyze the fatigue life of the rib-to-deck welded joint of the double-rib specimens.The fatigue life assessment was carried out for the weld penetration of groove welding,the ratio of weld toes and the load positions.The evaluation results showed that the total cyclic number of the double-sided weld joint specimens was closer to the evaluation value of fatigue life under the statistical mode of median,and total cyclic number of the single-sided weld joint specimens was closer to the evaluation value of fatigue life under the statistical mode of-2σ.With the increase of penetration,the fatigue life evaluation value of the double-ribb model decreased slightly,and the ratio of two weld toes and the loading position had greater effect on the evaluation value of fatigue life. |
