Research On Experiment And Relative Problems Of Prestressed Variable Cross-section Eight Cells Single Box Girder Bridge With Corrugated Steel Webs

The Prestressed concrete box girder bridge with corrugated steel webs has been developed for several decades,Its form gradually changed from constant section to variable section,from single-box single-cell to single-box multi-cell,but the real stress condition under the action of prestress and load is less at home and abroad.In this paper,relying on Zhengzhou South Sanhuan East extension line-107 auxiliary road project,and carry out a real bridge test of the prestressed variable cross-section eight cells single box girder bridge with corrugated steel webs.Building the finite element model,analyze the force characteristics of the bridge,focus on the research of the efficiency of prestressing force and the shear force sharing of corrugated steel webs,the following are the main research and conclusions:1.A refined Midas/FEA finite element model is established,and calculated the basic mechanical characteristics of structure under prestresse and load,comparing the measured value with the finite element calculation result,the calculation result matched well with measured values and the theoretical results.2.Comparing the effective prestress values at two different stages of the same section,the internal prestress stage is higher than the external prestress stage.In internal prestressed stage,the effective prestressing of the mid-span section is higher.In external prestressed stage,the effective prestresseing of section 1/2 and 1/4 is higher.The prestressed application efficiency of each section is 0.81~0.96under internal prestress by the calculation and the measurement;Under external prestressing,the prestressed application efficiency of each section is 0.80~0.92.3.Under the internal and external prestress action,the largest difference of shear stress distribution of webs is the mid-span section,the end section and 1/4 Section are second,the 3/4 section is smallest.Under the symmetrical load,the webs of loading area and the loading section bears greater shear force and is more average.The average shear force sharing of the 7 web at the middle side is about 12%~13%,and the transmission force of the side web is smaller at 4%~6%,and the maximum C_?is about 1.21;Under the action of eccentric load,the webs of the loading area and the loading section share more than 90%of the total shear,and the maximum value of the distribution coefficient is above 3.0.Under symmetric and eccentric loading,the web shear is gradually balanced from the loading section to the non loading section.Overall,under the symmetrical load,the corrugated steel webs shear stress distribution of loading beam segment and non loading beams segment are different,but the difference is small;Under the eccentric load,there is a big difference in shear stress distribution between the loading section beam section and the non loaded section beam section.The conclusions by measurement and research can provide reference for the similar engineering design.