Research On Mechanical Properties Of Oblique Curved Special-Shaped Box Girder Bridge

With our urban planning and requirements of route alignment,driving comfort and aesthetics,many different-shaped bridge structures with different shapes have built.However,change in the shape of the special-shaped bridge leads to complex stress behavior,which leads to many complicated problems encountered in the design stage of the project.At present,there are few analysis studies on the mechanical characteristics of inclined-bent special-shaped box girder bridges at home and abroad..Therefore,this paper takes the cross-Wanrongjiang bridge of Jinping Road project in the high-speed railway area of Jishou City as the research object to carry out the research on the mechanical properties of the special-shaped prefabricated box-girder bridge.Curved continuous small box girder bridge,the article uses the finite element calculation software Midas/Civil to establish different analysis models,not only combined with experimental research to study and analyze the mechanical performance of the full bridge,but also to the internal force lateral distribution calculation method of the bridge Modification and optimization are of certain significance and engineering application value for improving the design calculation method of special-shaped bridges,further probing the bearing mechanism of special-shaped bridges,and ensuring the performance of special-shaped box girder bridges.The main research work of this paper is as follows:1.Introduced the status quo of domestic and foreign researches such as special-shaped assembled box-girder bridges,summarized the characteristics of the mechanical performance of skew-shaped curved continuous beam bridges,briefly described the finite element analysis methods commonly used in scientific research and engineering today According to the characteristics of the bridge,three methods for calculating the transverse distribution coefficient with certain characteristics are introduced.2.Discussing the grid division of the box girder model which based on the characteristics of the bridge structure.The large-scale general-purpose finite element analysis software Midas Civil is used to establish the single-beam model,the beam grid model,and the plate element solid model of the superstructure of the special-shaped assembled box girder bridge.Numerical simulations to verify the accuracy of the three finite element models;3.Carring out field load test research of the bridge after the engineering completion.Collectting field test data to study the static performance of deadweight dead load,live load partial load and live load.Verifing the correctness and accuracy of the three finite element models,and selecting the static performance of the bridge Representative combined working conditions.The beam grid model and the plate element solid model were used to compare and analyze the bending moment,deflection,and stress.It was learned that the relative error of the support reaction is generally less than 6%,the maximum relative error is 10%,and the sum of the reaction forces of each support is basically equal The distribution law of deflection calculation is basically the same,the maximum relative error is within 5%,the stress distribution law of the top and bottom of the mid-section of each main beam is basically the same,the maximum relative error is controlled within 10%,and the external force effect of the bridge under constant load Greater than internal measurement,the effect of the inner edge beam under live load is the most significant,and the effect of temperature load is mainly reflected at the edge beam;the modal of the eigenvalue vector method(Lanczos method)is used to analyze and study the bridge modal and discuss the bridge Through the comparative analysis;4.Using the equivalent stiffness simply supported beam(slab)method,the single beam method is combined with three traditional transverse distribution coefficient calculation methods to calculate the lateral load distribution of the bridge,and the calculation results of the rigid beam method are compared with such bridges.The horizontal distribution of the load is the closest,but there are results of relatively large errors in the L/4 and 3L/4 cross sections.Therefore,it is recommended to use the rigid beam method to calculate the transverse distribution coefficient:the correction coefficient at the cross section of the side span and mid-span fulcrum can be taken as 0.94,The correction coefficient at the mid-span section can be 1.03,and the L/4 and 3L/4 section correction coefficients can be selected in the range of 1.06 to 1.23 according to the number of the main beam;for eccentric and intermediate load conditions,eccentric load Correction of working conditions.The coefficient is the same as that of the 1#side beam,and the correction factor for medium load conditions is reduced by 0.9 times on the basis of the 3#beam.