The Construction Safety And Pre-Camber Controlling Technology Of The Bridge Constructed By Long-Span Combined Movable Scaffolding System

Movable scaffolding system construction method possesses the advantages of high degree of automation, high quality concrete construction, short construction period, economically viable, little damage to the surrounding ecological environment, etc, widely used in the construction of small and medium span prestressed concrete girder bridge. However, through the analysis of the previous engineering examples, we can find that there are still many problems on construction safety and pre-camber controlling technology of the bridge, especially in the use of long-span movable scaffolding system. The above problems restrict the promotion and the application of movable scaffolding system method.In view of problems on construction safety and pre-camber controlling technology of the bridge, based on the construction of the Dongting lake bridge, this paper focus on the construction technology of the movable scaffolding system method, scheme of preloading test, construction safety, pre-camber control, etc, in order to ensure the safety of construction and guarantee the final shape of the bridge will meet the requirement of design. Details work is as follows:(1)The development of movable scaffolding system method is reviewed.The necessity of research on construction safety and pre-camber controlling technology of the movable scaffolding system is discussed. Then a brief introduction of engineering background is made.(2) The basic structure, modular construction techniques, precautions of the MSS55 combined movable scaffolding system is summarized. And it can provide materials for writing guidelines of the movable scaffolding system method.(3) The analysis model of the movable scaffolding system is established by using the finite element software. The results under the most unfavorable conditions of the program is calculated. Then compare the results with the requirements of the design specifications. The results show: Except the pre-lifting beam, all the key component of the movable scaffolding system meet the requirements of the design specifications.The measures to solve the stress shortage of the pre-lifting beam is took.(4) This paper briefly describe the preloading test plan of the movable scaffolding system. Then the deflection and stress of the measuring points under each load levels is record. By comparing the theory data with the measured data, we can verify the accuracy of the theory results and initially identified parameters of the model. At the same time, we can ensure the construction safety once again.(5)The whole process analysis model of the bridge which is constructed with movable scaffolding system is established by using the finite element software. The model of movable scaffolding system is modified according to the comparing data. Then the pre-camber is calculated to guide the construction and the calculated parameters of the model is modified based on feedback information.