The Flexural Performance Research Of The Segmental Prefabricated Continuous Box Girder With Corrugated Steel Webs

As a rapidly developing form of bridge structure at home and abroad,the composite box girder with corrugated steel webs takes full advantage of the mechanical properties of steel and concrete.Compared with the traditional reinforced concrete bridge,the box girder with CSWs has the advantages of reducing the structural self-weight and improving the prestress efficiency.Besides,the economic and social benefits are more obvious.The combination of box girder with CSWs and prefabricated construction technology not only improves the utilization rate of materials but also realizes the efficient and rapid construction of the bridge,which has a broad application prospect.Based on the methods of model test,simulation and theoretical analysis,the flexural performance of segmental prefabricated box girder with corrugated steel web is experimentally studied.The main jobs and conclusions are as follow:(1)Static load tests were carried out on segmental precasted box girder with CSWs and integral cast corrugated steel web box girder,and the variation laws of mechanical indexes such as load-displacement,strain distribution and prestressed increment of the test beams were analyzed.The test results show that: 1)The ultimate bearing capacity of segmental beams is reduced by 16.25% compared with that of integral beams.The cracks of integral beams are mainly distributed at the mid-span and mid-support positions,and the width of the crack is small and dense.While the segmental beams are concentrated in the joints on both sides of the loading segment and the middle support segment.The width of the crack is large but the number is relatively small;2)In the elastic stage,the load-displacement curves of the two beams are basically similar,and the strain changes of the top and bottom concrete of the segmental beams are basically consistent with the assumption of "Quasi plane";3)The cracking load of the integral beam is similar to that of the segmental beam,and the stiffness degradation rate of the segmental beam is significantly greater than that of the integral beam after concrete cracking;4)The increment of the internal and external prestressed stress changes slowly in the elastic stage,and the change rate becomes faster after cracking.In the ultimate state,the prestressed increment of segmental beams changes significantly compared with that of integral beams,providing a greater contribution to flexural resistance.(2)The numerical model of the test beam was established by using ABAQUS finite element software,and the whole process of the static loading of the test beam was simulated by considering the material nonlinearity and geometric nonlinearity.Based on the numerical model,the influences of the number of segments,the thickness of the rubber joints and the initial tension of the prestressed tendons on the load-displacement curve and the ultimate bearing capacity of the segmental box girder with corrugated steel webs were discussed.(3)Considering the effect of joint bonding strength on cracking moment,a method for calculating cracking moment of segmental assembled corrugated steel web box girder is proposed.Based on the idea of energy equivalent,the calculation method of joint opening width and rotation Angle is proposed.Based on the analysis of the failure section,the calculation method of the flexural bearing capacity of the segmental composite box girder with corrugated steel webs is proposed,and the correctness of the method is verified by the test results.