Research On Key Technology Of Closure Of A Prestressed Concrete Rigid Frame-Continuous Beam Combined Bridge

Now,the number of bridges crossing the river in China is rapidly increasing.The combined rigid frame-continuous beam bridge in prestressed concrete has the characteristics of continuous beam and continuous rigid frame bridge.In other words,the support reduces the static and uncertain internal force,and the use of the St.Regis frame counterpart in the span is both satisfactory and convenient for the cantilever structure.The structure is stable,while reducing the manufacturing cost,it also reduces the mature technology of the cantilever method,reduces the amount of support used,and reduces the cost,and the overall bridge type is simple and beautiful.being widely used.At present,there are relatively few studies on multi-span,long-connected prestressed concrete rigid frame-continuous beam composite beam bridges.Closure is the top priority in the entire bridge construction process.It is essential for the structural stability and linearity after the bridge is completed.The closed plan is essential for the construction of the bridge.This paper takes a large bridge:?77+8×120+77?m multi-span long prestressed concrete rigid frame-continuous beam composite bridge as the engineering background,and focuses on the impact of key closure technologies on the bridge structure.The main research contents are as follows:1.According to the engineering background,7 kinds of closure sequences are proposed,and the main girder axis of each closure sequence is completed in the three stages of closure,completion of the bridge?loading of the second phase?,and ten years of completion of the bridge by using the MIDAS/Civil finite element software.The force,shear,bending moment,stress,and vertical deflection are analyzed,and the force and deformation of the seven closing sequences in the bridge completion stage are compared,and the law of the influence of the closing sequence on the bridge structure is analyzed.At the same time,it is necessary to consider the difficulty,construction period,cost and other factors of the actual construction to select a more reasonable closure sequence plan suitable for the case background.2.In view of the difference between the design closing temperature and the actual closing temperature of a large bridge,the initial temperature is 10?,15?,4?,20?,and 24?respectively.Through the overall temperature rise and fall simulation of these four initial temperatures,the comparison and analysis are carried out.The influence of the overall temperature change on the stress and deformation of the bridge,and the influence of the temperature load on the linearity and force of the bridge is obtained.3.The 4^th to 7^th spans of a prestressed concrete rigid frame-continuous beam composite beam bridge are rigid frame systems.In order to adjust the linearity and force of the bridge,it needs to be pushed when closing,and the amount of pushing is proposed for the closing scheme of a large bridge.The method of pushing force,and the temperature effect optimization of the designed pushing force,the axial force,shear force,bending moment,horizontal deformation of the pier top and the bending moment of the rigid frame pier top and bottom of the bridge before and after the jacking By comparison,the meaning of Helong's push is drawn.Through the above exploration,it provides reference for the construction of the same type of bridge.