Construction Control And Force Analysis Of No.0 Block Of Dagang Extra-large Bridge

Prestressed concrete continuous beam bridge is one of the bridges widely used in practical engineering,mainly because of its advantages such as small deformation,good mechanical performance,strong anti-seismic ability,smooth and comfortable driving and so on.Cantilever pouring method is a commonly used construction method for long-span prestressed concrete bridge.Because of the complicated construction process,the construction of long-span prestressed concrete bridge should be controlled.It is also an important link to ensure the quality and safety of construction as well as to ensure that the completed state of the bridge meets the design requirements.Based on the construction background of Dagang Bridge,the main research contents and conclusions are as follows:(1)This paper summarizes the development of prestressed concrete continuous beam bridge and its cantilever pouring characteristics,the significance of bridge construction monitoring and the current research situation at home and abroad.(2)The related theory of construction control is introduced,including construction control content,construction control method,structural analysis and calculation method and so on.(3)The finite element simulation software Midas/Civil is used to establish the simulation model of the bridge,and the simulation analysis of each construction stage of the bridge is carried out to obtain the theoretical elevation value of the main girder.By using the model to analyze the sensitivity of parameters affecting the alignment of the main girder,such as concrete bulk density,concrete elastic modulus,initial tension stress,pipeline friction coefficient and pipeline deviation coefficient,it is concluded that concrete bulk density,elastic modulus and initial tension stress are sensitive parameters,so as to strengthen the control of these parameters in construction.(4)Through comparative analysis of the measured data from the field and the theoretical data calculated by the model,it can be seen that the bridge shape control is good and meets the design and specification requirements;the measured stress value of test sections are basically consistent with the theoretical calculation values,and the error is within the allowable range of the specification.(5)Using Midas/FEA finite element software to establish the local solid model of zero block,the distribution of the transverse,longitudinal and principal stresses of the roof,floor,web and diaphragm in the maximum cantilever state and bridge-building state of zero block are analyzed.It is found that there are different degrees of tensile stresses at the joints of roof,floor,web and diaphragm,and the joints between web and diaphragm,which are prone to cracks.Measures should be taken to strengthen the control of these parts during construction.