| The half-through steel box basket arch bridge,like the conventional arch structure,has the advantages of arch rib compression and strong spanning ability.In addition,because of its beautiful shape,light structure and small self-weight,it also has the characteristics of a beam-type structural system,which reduces the amount of engineering when the bearing capacity is guaranteed.At the same time,the arch ribs are inclined inwards,the lateral rigidity of the structure is improved and the stability is better.The force transmission path of the half-through arch bridge is relatively simple and clear,and the exertion of the overall mechanical performance of the structure is affected by the structural parameters of each component.The robustness of the bridge reflects the ability of the bridge structure to resist continuous collapse under local damage.At present,there is no recognized and feasible robust evaluation method in domestic and foreign codes and literatures.In order to evaluate the robustness,this paper proposes a robustness evaluation index under unexpected loads for the half-through arch bridge structure.Based on the background of Yinshui pedestrian arch bridge,this paper establishes a finite element model for structural sensitivity analysis and application description of robustness evaluation under unexpected loads.The content of this article is as follows:(1)Briefly introduce the characteristics of the arch bridge and the development overview at home and abroad.(2)Introduce the engineering overview of Yinshui pedestrian arch bridge,establish the finite element model of the whole bridge with the help of finite element software,use the rigid support continuous beam method and the rigid suspender method to find the tension of the suspender in the bridge state,and determine the appropriate by comparing and analyzing In the state of bridge completion,the tension of the suspender is used to analyze the stress characteristics of the full bridge.(3)Change the structural parameters of different components,establish the corresponding finite element model,and discuss the influence of arch rib inclination angle,wind bracing quantity and arch rib stiffness on the internal force of half-through steel box basket arch bridge,and get the half-through steel box The change law between the internal force of the basket arch bridge structure and each structural parameter can give suggestions on the value of each structural parameter.(4)Briefly describe the problems that the robustness aims at,and the differences from the traditional design requirements,and propose reasonable principles of robustness assessment.Select the boom as the most important component,comprehensively consider the impact of boom failure on the whole and the part,put forward a component importance formula,and according to the characteristics of the component’s importance and the negative correlation of robustness,a deterministic mid-through steel box Evaluation index of the robustness of the X-shaped arch bridge.Then,the robustness calculation under the accidental load is carried out,and the static analysis of single boom failure and the static analysis of failure of the boom assembly are carried out respectively.Based on the results obtained,the robustness of the bridge was evaluated.In view of the fact that the bridge is a pedestrian bridge,accidental loads refer to objective factors such as fire,non-motor vehicle impact,and corrosion of the boom. |
