Study On Construction Control Of Long Span And Long Unit Prestressed Concrete Continous Girder Bridges

With the development of science, technology, communications and transport, the prestressed concrete girder bridge has been growing up rapidly in recent years with its unique predominance of handy construction, economical cost, reasonable internal force and riding comfort. At present, the prestressed concrete box grider bridge occupies the dominant place in the bridge whose span ranges from 40m to 150m. The longer span of continuous girder bridge is, the more diffcult construction is. It is an essential step and important measure to execute process control in long-span prestressed concrete continuous girder bridge construction, which can ensure not only the quality and safety in construction, but also the final state meeting the design requirement.Based on the construction of the TuoketuoZhunge'er Yellow River Bridge, the study uses the grey predictive control theory to control the cantilever construction process of the main bridge and makes an analysis about the elevation of the main girder through establishing the GM(1,1). Therefore, the study successfully fulfilled prediction of the elevation of formwork erection of the main girder during the next construction stage. The result of construction control indicates that the application of grey predictive control in the long span and long unit prestressed concrete continuos girder bridge can effectively ensure the construction safety, attain the ideal alignment and make the main girder internal force meet the design requirement when the bridge is built. Such methods can be applied in the construction control of similar bridges.Temperature variation exerts great influence on the bridge alignment during the long-span prestressed concrete continuos girder bridge construction. The longer the length of main girder, the greater the deformation caused by sunshine temperature difference. So, the influence of temperature must be taken into consideration in construction control. Based on the temperature distribution of the critical section of box girder that is measured on site, the thesis calculates and analyses the temperature effect of continous girder bridge in a specific construction state. Furthermore, it analyses and calculates theoretically thetemperature effect of continous girder bridge in the finished state. The analysis result indicates that temperature variation is a very important influential factor in the design and construction of long-span and long unit prestressed concrete continuos girder bridge, and it deserves much concern. The rectification of temperature difference of elevation of framework erection should be paid close attention to in the construction control.