Research Into Construction Control Of Long-span Beam Bridge With High Pile-Cap And Deepwater Pier

With the rapid development of highways in our country, long-span bridges are needed to span big rivers and bayous. And among the various bridge types, the concrete beam bridges with long spans are widely used for their advantages. The long span bridge such as continuous bridge, arch bridge and cable-stayed bridge, most of these use self-erection system to be constructed. That is, bridge span is cast by segment or by course, later fragment or later course is supported by former fragment or former course, i.e. the construction continue by self-structure of no formwork. Concrete bridge construction is influenced by temperature, moisture, time and concrete's nonhomogeneous quality and unstable property, besides the influence of between the fragments and the courses. All these infections influence each other. So these influences must make internal force and displacement of each fragment or each layer deflect the value of design following the argument of the casting concrete or the concrete fragment. To guarantee the quality of the construction, the whole process of the construction must take construction control.To the long span prestressed concrete continuous beam bridge, the main work of the construction control is the control of the beam elevation. Designer make use of some empirical parameters and several supported numerical model to calculate elastic total displacement and total precamber, generally based on the length of cantilever, mechanics property of the reinforce concrete, the magnitude of stretching force which is surveyed in practice. Displacement happened by hook-basket in the test is measured. Then construction elevation is calculated by the formula that is 'construction elevation= design elevation+ elastic total displacement+ precamber+ displacement by hook-basket'. Whereas, empirical parameters and supported condition always have some difference with factual condition, and some errors may happen in construction such as error of the weight of concrete fragment, error of reinforcement, error of stretching force,error of measurement and other errors that are considered, all which could make the mechanics property of the factual beam fragment change. Then displacement that is not agreed with design value may happen. So if it continues to construct with former design value, there will be deviation between the alignment in , construction and the design alignment. The deviation takes some difficulty in connection of the fragments, what's more, it influences the quality of the bridge that has been built.Gray system theory is adopted as the predictive method of the construction control of continuous beam bridges with long-spans in this paper. Traditional equip gap gray predictive model GM(1,1) is amended. Non-equip gap gray prediction model NGM(1,1) is put forward. This paper also proposes a normalized mapping rule of raw gray series. Then the gray system theory is applied in the construction control of long-span prestressed concrete continuous beam bridge.In this paper, based on the study of the key engineering of Hubei province - Danjiangkou Er Qiao , construction technology and construction skill of long-span prestressed concrete continuous beam bridge with high-rise pile cap and deepwater pier are researched. Also this paper fully analyse construction control of big-span prestressed concrete continuous beam bridge with high-rise pile cap and deepwater pie in theory. Through the description of gray system theory, the gray system theory is applied in the construction control of long-span prestressed concrete continuous beam bridge.