Research On Key Problems Of Crescent Arch-Continuous Beam Combination System

The crescent arch-beam composite system bridge is a kind of new and unique beam arch composite system bridge.Crescent arch consists of one main arch rib and two auxiliary arch ribs at the arch foot,which are arranged in the air.Each arch rib is connected into a spatial stress structure through horizontal connection.It is named after the shape of "Crescent" outside.At present,there is not much research on the composite system of crescent arch and beam arch at home and abroad,especially the number of crescent arch and beam arch composite system bridges that have been built and are under construction at home is less,so it is very meaningful to study the composite system of crescent arch and beam arch.In this paper,based on the engineering background of Chang Hushen bridge,the overall stress analysis,local stress analysis and arch rib parameters of crescent arch continuous beam composite bridge are studied.The main work and conclusions are as follows:(1)The beam grid model and single beam model of the Chang Hushen bridge are established,and the static and dynamic characteristics of the structure under different working conditions are calculated.The results of the two modeling methods are compared with the load test results,and the accuracy of the finite element simulation is verified.(2)The difference of static characteristics and stability between crescent arch-continuous beam composite system and common beam-arch composite system and continuous beam is analyzed by finite element simulation.The results show that crescent arch-continuous beam composite system can improve the mechanical performance and stability of the structure.(3)In this paper,the local solid model of the pier-beam-arch joint of the crescent archcontinuous beam composite system is established,and the local stress distribution law of the pier-beam-arch joint in the maximum double cantilever state and the completed bridge state is studied.The results show that the pier-beam-arch joint in the state of maximum double cantilevers and the state of completed bridge is basically in the state of compression,and there are tensile stresses in some places.Special attention should be paid during construction,and ordinary reinforcement can be added to prevent cracks.(4)By analyzing the static characteristics of the structure with different arch rib design parameters,the effects of the key parameters such as the rise span ratio,the angle between the vertical plane of the main and auxiliary arch ribs and the rigidity of the main and auxiliary arch ribs on the static characteristics and stability of the structure are studied.The results show that the rise span ratio and the rigidity of the main and auxiliary arch ribs affect the static characteristics and stability of the structure,while the angle between the vertical plane of the main and auxiliary arch ribs affects the static characteristics and stability of the structure The influence of qualitative analysis is small,so the appropriate rise span ratio and the rigidity of the main and auxiliary arch ribs should be selected in the design,and the included angle of the vertical plane of the main and auxiliary arch ribs can be determined according to the driving requirements and aesthetic requirements.