Research On Construction Monitoring And Local Stress Analysis Of Cable-stayed Bridge With Single Cable Plane And Wide Span And Low Tower

The wide box-girder and low-tower cable-stayed bridge is a new bridge type derived from the increasingly heavy traffic volume.With the high-quality development of my country’s economy and science and technology,the overall national strength continues to increase.The low-tower cable-stayed bridge occupies a greater advantage in the current bridge construction and development.Relying on the background project Jingyuan Jintan Yellow River Bridge,this paper focuses on the cable-stayed cable force control on the construction monitoring of a single-cable-plane wide and low-tower cable-stayed bridge.The 0# block is combined with the two cable beams at the point where the cable force is the largest.The important local structure analyzes the change law of the top and bottom plate stress.Aiming at the particularity of the diaphragm beam,the theoretical calculation and stress analysis of the diaphragm beam are studied separately.Block 0 is the most complicated stress structure of the whole bridge.The cable stays will cause a large stress concentration on the box girder.The transverse beam is the key structure for the use of the whole bridge,which determines the durability and service life of the bridge structure.At the same time,it is also a structure with many hidden quality hazards,which will bring varying degrees of damage to the strength and stiffness of the structure,so it is of great significance to conduct force analysis and research on it.The main conclusions drawn in this article are:(1)Under the condition of complete background engineering data,the overall model is established through Midas Civil software,and through the calculation and analysis of the most important stages,it is concluded that the location of the maximum shear force,the maximum bending moment and the maximum stress are in a safe state required by the specification.By changing the main parameters,running and analyzing the corresponding background project Midas Civil model,and comparing the changes in stress and deflection,it is concluded that bulk density,cable force,and prestress are sensitive parameters of the bridge structure,which need to be paid attention to during the construction process.(2)Comparing the measured and theoretical bridge cable forces,it is concluded that the equivalent tension method can be better applied to the tension control of the epoxy-coated unbonded steel strands of the wide and low-tower cable-stayed bridge.The stress of the main beam and the main tower is basically consistent with the theory in the construction control,highlighting the "four controls",namely the cable elongation,the beam lifting,the corresponding main beam and the main tower stress,and the cable force test on the accuracy of the cable force.Lift and control.(3)In the important construction stage,the top and bottom plates of block 0# are mainly under compression,and the horizontal and vertical directions along the centerline of the support and the longitudinal centerline of the box girder show certain changes.The maximum compressive stress and local tensile stress meet the corresponding requirements.The limit value required by the specification.The top plate of the cable-beam junction is mainly subjected to tension,and the bottom plate is mainly subjected to compression,and the maximum tensile and compressive stresses all meet the limit value required by the specification.(4)Diaphragm beams tend to cause stress concentration effect at the center of the bottom box room.The middle diaphragm beams at 2m and 4.5m have a significant impact on the stress of the top plate at the web.The increase trend of the compressive stress of the top plate at the mid-span closing stage is less than Maximum cantilever stage.Through the analysis and research of the concrete cracking of the diaphragm,the calculation analysis of the tension and compression bar model is safer in the calculation of the force of the diaphragm.The longitudinal prestress is the cause of the main cracks of the diaphragm.