The Research On Technology Of Concrete Box Girder Being Broaden With Steel Cantilever Beam

With the social progress , national economy growth, highway traffic volume sharp rising, constant improvement of load grade and the running speed which set higher requirements on urban bridge . Especially some bridges built in the past decades in our country, became more and more remarkable. Increasing the bearing capacity of the old bridge by strengthen procedures, bridge widening , existing bridges detection and evaluation which is has already become the urgent task faced in bridge researchers.Now , there are mainly methods to widen bridge : widen directly or build another bridge . widening the bridge directly is demolition of all old anticollision warning rails and erect reinforced concrete cantilever , boundary beam , pier . Taking some city overpass for research background , this paper research on technology of concrete box girder being broaden with steel cantilever beam by ANSYS calculation program , which will be verifed by full-scale model test.The main work is follows:(1) First, through comparing with the two projects, which prestressed a hunk or two hunks of prestressing tendon ,which realize the connection of steel cantilever beam with concrete box girder ,and through erecting ansys finite element model of the two projects to analysis the stress of concrete contact ,then we can obtained project II is the optimization scheme.(2) Second, through shorting the length of anchor box slab ,keeping prestresse a hunk or two hunks of prestressing tendon, we optimize the project II and get the project III, which decrease the stress of concrete contact.(3) Third, according to the analysis results of project III, we reduce the height of steel cantilever beam , change of form of steel anchor box and setting the U ribbed slab ,We obtain the project IV whose stress reasonable an clear .(4) Then, through plan comparison and optimum design ,we confirm the final scheme which is the project IV, otherwise, using the ansys finite element model of final scheme IV to analysis the stress of steel cantilever beam's roof ,floor , web also the stress of orthotropic plate which will verify the feasibility of concrete box girder being broaden with steel cantilever beam and orthotropic plate and tensioned prestressing bar. (5) The paper will verify the validity of calculation method and calculation results by ull-scale model test. Though the summary of full-scale model widening test, this paper will provide a set of complete and practical construction technology of concrete box girder.