Construction Technological And Experimental Research Of Post-tensioned Prestressed Concrete Hollow Beams

Prestressed concrete hollow beam bridge is the bigger and one of the widest used medium span bridges in China, as for it clear stress, simple struction and easy to precast production standardly or construction. For now, with the economy developed swiftly, stransportation becomes heavy-duty, high rate, large capacity modern transportation structure which gives so many higher and newer requires to the design and construction of prestressed concrete hollow beam bridge. But for these kinds of conponents and the construction control is not spesification, they have so many problems in precasting and using. Therefore,improving the construction technology of hollow beams and evaluating the real loading capacity of finished beams rightly can decrease loss, save the project cost and also has important theoretical and real meaning to save the project investment.This article integrates the characteristics of precasting hollow beams, analyses the advantages and disadvantages of some often uesd internal mold,designs steel core mold that can assurant the size of the internal cavity and proposes the making and fixing methods which can solve the problems that the roofs are so thin often in construction. That the article instructs the design and construction of this kind of hollow beams, and establish the foundation of the design and the quality of construction from the technical aspect.The control technic of prestressing tension is the key in the whole prestressed concrete structure. The building of prestressing tension is derectly influncing the prestressing effect and the components quality. This article analyses the technological process of post-tension applying prestress method and analyses the shortages and mistakes in the construction. Also it gives some suggests on prestressed calculation methods and checks the measured value,thus reflects the real quality of construction objectively.This article tests and calculates the load-carrying ability of prestressed concrete wide-span hollow beams, analses the stress and detemplateation features of these beams, collects the datas of prestressing, deflection and crack width hollow beams from step loading to design loading. It not only provides evidence for the load capacity of homogeneous prestressed concrete beams, also certificates some quizzical local in the beams designing.And evaluates the designing rationality of finished product beams and real loading capacity and structure.