The Technology Research Of Partial Prestressing Concrete Continuous Box Beam Rehabilitation And Consolidating

With the development of transportation, highway traffic and large tonnage vehicleincreases ceaselessly, early built partially prestressed concrete continuous box beam bridgeafter operation for many years, appeared to affect the structural safety of the disease, such ascracking, corrosion of steel box girder bridge structure, insufficient bearing force. In order toguarantee the safety of the bridge structure, applicable, durable, the original bridge must bereasonable and effective reinforcement.This paper introduces the existing partial prestressed concrete prismatic continuous boxbeam for double, single cell box class B component, the standard span is30m,6~8cross-linked.The main lane and overtaking lane bridge is8cm thick asphalt concrete pavement.Currently, partially prestressed concrete box beam strengthening method mainly includespassive and active reinforcement reinforcement of two types, but each reinforcement methodhas its limitations and scope of use. To improve the structure of plate bending bearing capacity,prevent the crack development effect is obvious, but the passive reinforcement of box girderYingli improvement effect is smaller; external prestress reinforcement can improve theflexural bearing capacity and improving the structure of box girder Yingli status, but the steelbeam tensioning after secondary internal force makes the steel beam reinforcement of lowusing efficiency the anchorage point size, limit the number of large steel beam, pier top innegative moment area of bridge deck pavement is smaller in thickness (8cm), the limit oflarge stocks of prestressed beam settings; only the enlarging section can enhance the structuralrigidity of section bearing capacity, but a smaller increase, and increased in the late dead load.According to the continuous box girder structure damage, fracture distributioncharacteristics, a brief introduction of the structure damage causes and reinforcement design.On the basis of detailed introduces the structural repair reinforcement construction technologyscheme and process characteristics.This paper introduces the bridge box beam structure of the comprehensive reinforcementtechnology, namely the bottom slab in box girder web plate in place, the pier top pavementlayer is additionally arranged in the prestressed steel strand, cross webs in both sides of thickened, and thickened segment set small shares of prestressed beam, structurestrengthening after the completion of the static load test, the test section structure the actualreinforcement effect evaluation summary.Finally, this paper describes the structure reinforcement process of constructionmonitoring content and before and after reinforcement of three static load tests of content, ismainly directed against the structure in the tensioning of prestressed cable during stress,deflection and structural development of cracks, comprehensive collection of prestressedcable tensioning construction process of structural deflection, key section concrete stress andcrack change condition. The test section before and after reinforcement of three static load testresults are analyzed, and the reinforcement effect is evaluated.