Research On Crack Control Method Of Super Wide Prestressed Concrete Box Girder Cable Stayed Bridge

With the establishment of more and more super-wide and super-large Bridges,the crack control technology of Bridges has become a hot topic for researchers.Combined with the structural characteristics of Ligui super-wide prestressed concrete box girder cable-stayed bridge and the key technical problems existing in the concrete construction,this paper studies the crack control technology of this kind of bridge.The main contents are as follows: Through the establishment of the bar system model and solid model of Ligui bridge,analyze the possible crack location of the super-wide prestressed concrete box girder cable-stayed bridge;By establishing the fine finite element model of the whole bridge,the specific crack location and stress size of the bridge are defined,and the optimal design scheme is put forward by increasing the prestress,adjusting the tensioning sequence and strengthening the reinforcement of ordinary steel bars,and the stress value after the optimal design is calculated and analyzed to verify the effectiveness of the optimal design method;By analyzing the construction control means of Ligui bridge and the monitoring and measurement results,the effective construction means of controlling cracks of ultra-wide prestressed concrete box girder cable-stayed bridge is defined.The bar model and solid model of Ligui bridge are established,and the possible crack location of super wide prestressed concrete box girder cable-stayed bridge is analyzed.Firstly,the model of cable-stayed bridge is established,and the stress calculation of main beam and tower is carried out.Then,the physical model of the main tower with complex forces is established,and the stress distribution of each part of the area is clarified.Finally,the solid model of beam at the consolidation point of tower beam is established,and the stress distribution of beam is analyzed.It provides reference for the analysis and optimization design of fine simulation space model.A fine simulation model of Ligui bridge is established and the spatial effect of fine simulation is analyzed.Analyzes the super wide the location of the prestressed concrete box girder cable-stayed bridge cracks may be produced,from increasing prestressed,adjust the tensioning sequence,the increase of ordinary steel reinforcement and concrete material improved to optimize the design of the Bridges,to design means to control bridge cracks,fine effect analysis of the simulation of the reentry after optimization design,the optimized the danger zone of stress value,compared with that before optimization to verify the effectiveness of the optimization design.The stress under permanent action is calculated and the optimal design scheme is put forward for the crack area with large stress value.According to drain the cassia bridge lasting status checking,short-term crack checking serviceability limit states and the need of local calculation,the selection of working condition checking,after got the optimized design of structure under the combined stress check stress distribution,stress is still too large area for crack control scheme is put forward,ultra-wide crack control of prestressed concrete box girder cable-stayed bridge in the aspect of design means to provide the reference.The construction measures of crack control of super wide prestressed concrete box girder cable-stayed bridge are studied.The construction scheme of the main parts of the bridge,the construction scheme of concrete temperature control and the monitoring scheme of the bridge,including the construction principle,process and construction measures,are clarified.The effectiveness of the construction method to control cracks is verified by the construction monitoring results.It provides a reference for the crack control of the super wide prestressed concrete box girder cable-stayed bridge in terms of construction methods.