| The concrete-filled steel tube arch bridge has the advantages of large spanning capacity,strong bearing capacity,good ductility,rapid construction,and beautiful appearance.It was favored by bridge engineers at home and abroad when it first appeared.However,the early structural design and calculation theory of concrete-filled steel tube arch bridges in our country were not mature,which led to many diseases during the operation period.In particular,some mid-through and through-type concrete-filled steel tube arch bridges with suspended deck structures are used.The bridge deck structure of this type of bridge has a single force transmission path and poor integrity.Therefore,it is necessary to add steel longitudinal beams to improve the robustness of the bridge deck structure and avoid the bridge deck collapse accident caused by the cable break.This article is mainly based on a mid-through concrete-filled steel tube arch bridge in the southwest region.It focuses on the parameter change of the steel longitudinal beam section and the different bridge deck structure to co MPare and analyze the effect of improving the static and dynamic characteristics of the structure before and after reinforcement,and discuss the steel The problem of the influence of the different connection modes between the longitudinal beams and the transverse beams on the original structure.The main research content,methods and research results are as follows:(1)Under the premise of meeting the minimum cross-sectional area and minimum bend-resistant moment of steel beam required when the boom breaks and the beam does not fall,it is obtained that the reinforcement effect of the steel girder is better than that of the truss-type,type-type steel girder reinforcement on the original structure by co MParing and analyzing the static dynamic characteristics of the truss-type and type-type steel beams.Secondly,through the analysis of the effect of the variation of the parameters of the cross-section height,width and cross-sectional area of the steel girder on the effect of reinforcement improvement,it is concluded that the change of the cross-sectional area of the steel girder has the greatest i MPact on the improvement effect,followed by the cross-sectional height,but the difference between the effects of the reinforcement improvement of the two is not significant.(2)The static dynamic characteristics of the three different forms of bridge surface system structure,such as simple branch system,first simple branch and then continuous system,are reinforced by co MParative analysis of steel girders.It is concluded that the static dynamic characteristics of the three forms of bridge system structure have been significantly improved after reinforcement,and the improvement efficiency of the bridge surface structure of the simple branch system is the highest,while the improvement efficiency of continuous architecture is the lowest.On this basis,the suspender stress of the three structural systems after the suspender fracture is compared and analyzed,and it is concluded that the suspender stress change range of the simply supported system bridge deck structure is the largest,and the suspender stress change range of the continuous system bridge deck structure is the smallest.(3)Combined with the actual engineering and using Ansys Workbench finite element analysis software,the physical modeling and analysis of the different connection methods between steel vertical beams and beams are carried out,the influence of different connections between steel beams and beams on beam structure is discussed,and the force of steel vertical beams under each connection is analyzed.It is concluded that the material strength limit requirements can be met by holding hoops or bolting between steel girders and beams under the most adverse load action,but the influence of the beam structure is greater by means of the central through bolt connection when the boom breaks. |
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