Experimental Research On The Mechanical Performances Of Double-box Steel-concrete Continuous Curved Composite Girders

With the continuous progress of society,bridge engineering is also developing towards higher requirements.Because of the advantages of steel-concrete composite structure in mechanical performance and other aspects,it has been widely used in practical engineering.Double-amplitude curved continuous composite box girder is a structural form of steel-concrete composite structure used more in Bridges.Although there are more studies on the application of this kind of straight girder,the research on the mechanical performance of the corresponding curved girder is not deep enough,so the research on the stress analysis of the corresponding curved girder is very necessary.In this paper,three continuous steel-concrete composite box test beams with different curvature radii and diaphragms are designed based on the engineering background of Hangzhou ring viaduct.Through loading test,theoretical analysis and finite element simulation,the mechanical properties of such test beams are analyzed,and the corresponding results are obtained.Specific research contents and conclusions are as follows:1.Through the loading test,the influence of the curvature radius on the mechanical performance of the beam is analyzed.The analysis results show that the ultimate bearing capacity of the specimen decreases,the ultimate deflection increases,the torsion Angle increases,and the crack spacing increases.It can be concluded that the bending resistance,torsion resistance and mechanical properties of the specimen decrease with the smaller radius of curvature.2.Through the loading test,the influence of changing the type of diaphragm connection on the mechanical performance of the beam is analyzed and studied.The test shows that the ultimate bearing capacity of the specimen is increased,the ultimate deflection is reduced,the torsion Angle is reduced,and the crack spacing is reduced after the use of high-strength bolted diaphragm instead of welded diaphragm.It can be concluded that the bending and torsion resistance of the specimen can be enhanced and the mechanical properties of the specimen can be improved by changing the high-strength bolted diaphragm.3.The theoretical values of ultimate bearing capacity,crack spacing and deflection of steel-concrete continuous composite box girder with double amplitude curve were obtained through theoretical derivation and analysis,and compared with the experimental results,the results show that the theoretical calculation results are close to the experimental values,and can be used in practical engineering calculation.4.The finite element software ABAQUS was used to model and analyze the specimen,and the results obtained from the finite element model simulation were compared with the test data.Meanwhile,a larger curvature radius model was simulated for force analysis.The results show that the finite element simulation can accurately express the stress state.Through more comparison of curvature radius,the trend is that the smaller the curvature radius,the weaker the mechanical performance of the specimen.