Passenger Railway Line Two-lane Simply Supported Box Girder Span Of Precast Lifting Construction Methods

The large-scale development of the passenger dedicated railway has driven the change of the bridge construction methods. It changes from less than 160 t of the traditional single track T-beam into 900 t double-line long span simple box girder. The changes in the upper structure part of the bridge set a higher request in bridge construction. It is impossible to meet the construction of double-line simple box girder in a large-scale passenger dedicated railway with the traditional method. The hoisting technology of full-span precast and launching in the long span simple box girder is introduced to solve the existing problems, but it is still at an early stage in domestic, and there are many issues worthy of further study.Firstly, the concepts and realizing way of the full-span precast and launching are analyzed in the essay, through the comparison of the methods which applied in the construction of double-line simple box girder in the passenger dedicated railway, the superiority of this method in the progress, economical and construction organizations are pointed out. After comprehensive analysis of its advantages and disadvantages, the obvious superiority of this method applied in the construction of double-line simple box girder in the passenger dedicated railway.Secondly, the study on the layout of the yards for precast beam is put forward, the principle of location, layout are supplemented. Through the analysis and comparison on basic lay out forms of traverse arrangement and longitudinal arrangement, the application scope as well as the merits and demerits are pointed out .In the study of scale setup , the allocation of the stands for girder fabrication and storage should be under the direct control time of erecting beam, while at the premise of assumptions and basic data, with the greatest speed of erecting beam for the goal, according to the uniform and variable speed ,the allocation of the stands for girder fabrication and storage are studied using linear programming method,. Using this method to disposition the reasonable amount of pedestal, this could provide a valuable reference to the designers. Subsequently, the multi-program comparison and construction technology research in box girder precast are researched. The allocation of formwork under variety of differential combinations is discussed in post-tensioning method in the formwork engineering; The steel reinforcement cage fabrication and the tension bed colligation, the reverse pendant as well as the sham internal model in transportation are proposed in the reinforcement engineering; The pouring concrete method and the temperature control technology in steam curing are proposed in the concrete engineering; The process, technology and distinction in the making beam with pre-tensioning method and post-tensioning are researched in the pre-stressed engineering; Sum up experiences from the control of camber, the influencing factors and control method of the camber are put forward.Finally, from the study of different construction method and construction machinery with box girder shift, transportation, the erection of bridge machine and shift in the box girder transport and erection, the merit and demerit and the application scope with the construction method and machinery are established. This concept could make some reference to constructors for making reasonable choice in method and machinery.This paper analysis the whole process of yards planning, prefabricating, hoisting with box girder, the findings are universality, and it should be valuable to designer and builder.