Construction Control Calculation And Mechanical Properties Analysis Of Long-Span Steel Box Basket-Handle Arch Bridge

The main purpose of the construction control of the long-span steel box basket-handle arch bridge is to ensure the safety of the construction process and to make the line shape and the stress state of the bridge to the maximum to meet the design and standard requirements.In this paper,taking the Caijiapo East Fourth Road bridge crossing Wei River(hereinafter referred to as the bridge)as the engineering background,the simulation calculation analysis,the sensitivity analysis of the parameters,the setting of the pre arch,the calculation of the cable force and the tension of the construction,and the stability of the arch bridge of the key construction stage of the steel box basket-handle arch bridge are analyzed by the simulation model.The main works are as follows.(1)the structure characteristics and development course of the long span steel box basket arch bridge are introduced,and the common construction methods and construction calculation methods for the long span steel box basket arch bridge are briefly expounded.Long-span X-style steel box arch bridge structure characteristics and construction control theories are analyzed and concluded;(2)The general situation and construction plan of the bridge are briefly introduced.Based on the established construction scheme,the simulation model of the structure is built with the finite element software MIDAS/CIVIL,and the key construction stages and postcs of the bridge are simulated and analyzed.The stress and deformation of the structure during the critical construction stage are calculated by the positive calculation method,which provides theoretical basis and guidance for construction monitoring.(3)On the basis of simply introducing the construction monitoring scheme of the bridge,the sensitivity analysis of the design parameters of the long span steel box basket arch bridge is carried out.The main analysis objects are the elastic modulus and the bulk density of the arch rib material.The analysis result shows that the bulk density of the steel is the main parameter of the bridge.At the same time,the method of setting the pre arch degree commonly used in the project is summarized and analyzed.The practicability and accuracy of various methods are verified with the bridge as the engineering background.The result shows that the method of using the proportional distribution of the impact line by the arch foot thrust is closest to the result of the simulation analysis.The reason is that the method is not only considered by other methods,but not only considering the other methods.The relative position of each section of the arch rib is also considered,and the geometric characteristics of the arch ring are also taken into account.(4)For the suspender arch bridge,the determination of the reasonable cable force and the tension force is an important part in its design and construction.The main procedure is to determine the bridge cable force under the reasonable bridge state by the elastic support continuous beam method and the minimum strain energy method,and take the cable force as the internal force,and determine the suitable construction tension by the influence matrix method and the iterative method.The calculation results show that the final state of the suspended rod applied above is in agreement with the design state,and it can be used for reference for the determination of the tension of the construction of the similar arch bridge hanger.(5)The basic concept and type of the arch bridge stability problem,the basic concept of the nonlinear theory of arch bridge,the analysis method,the solution method of the nonlinear problem and the finite element analysis method of the stability problem are introduced.In the analysis process,the selection of incremental load and the problem of crossing the extremum point should be paid attention to.Based on these theories,the stability analysis of the Caijiapo East Fourth Road Bridge Crossing Wei River is carried out.The results show that the first order stability coefficient of the Wei River bridge is 49.1 under the most unfavorable load conditions,which is far greater than the standard specified by 4-5,and the overall structure meets the requirements of stability.