The Stress Analysis And Research On Crack Control Technology In The Whole Cycle Of Prefabrication Process Of Components Used Expressway Standard Span Beam-Bridge

The common span of highway bridge is 10m~40m,the bridge among that that the span is 20 m and below 20 m is usually simply supported hollow slab bridge,such as 10 m, 13 m, 16 m span of the assembled hollow plate beam,the bridge that span greater than 20 m is skew box girder bridge that continuous beam turned from simple beam or T beam bridge,such as 20 m, 30 m, 40 m span of the Small-box girder bridge.The small box girder due to its reasonable stress structure, high rigidity, good integrity is widely used in highway construction.Common span bridge component generally use construction method of prefabricated in advance and unified installation,this construction method can be used in mass production, and its construction period is short and cost is low. This paper take precast process of Linwei Expressway Li Jia Gou 16*40m Simple Supported-continuous Girder Bridge for engineering background,analyzing internal force deformation of component in precast full cycle and crack control technology, the following several aspects of the research work are carried out:This paper aimed at the whole period of 40 m span Simple Supported-continuous Girder Bridge,introducs briefly the process of the component and the key construction technology firstly,gets the change law of the mechanical properties of concrete after pouring with age combining with field test, to provide parameter basis for following research content. This paper establish the finite element model of 40 m box beam using Midas/Fea analysis software,take monitoring data of temperature change of environment and beam body interior of in the process of field component precast for basis,analyze the stress and strain of the component under the action of early temperature,and compare with the measured values,ensure the distribution law of stress and strain of component under the action of early temperature difference through the analysis of the temperature effect. This paper infer the effect of the interaction between the beam and the steel beam in tensioning process using theoretical knowledge,establish model to analyze the deformation and stress of member concrete in tension at different ages,simultaneously carry on simulation analysis to arch deformation of component during the storage of the beam due to creep,compare change of arch of component in the storage period after tension in different age. analysis cracking mechanism of component under conditions of prestress channel location difference,web thickness deformation,and super tension,obtain the mechanism of the crack in the process of the component is produced. According to the analysis of the previous chapters,summarizes crack prevention measures of highway bridge components in the precast full cycle. Through the research results of this paper,obtain the stress state of the component in the whole life cycle,and analysis the mechanism of the cracks in the process of the preform,summary the measures to prevent cracks in precast process.The work and research methods of this paper not only provide theoretical basis for the key technology in the process of prefabricated components,also put forward control measures for the cracks in the precast process,provide a useful reference for similar components.