Research On Dynamic And Static Characteristics Of Long Span V-shaped Arch Beam Arch Bridge

With the development of the economy and the emergence of new materials about steel and concrete,the construction method has gradually broken through.In the field of bridges,there are some special-shaped beam-arch composite bridges with rich cultural heritage and unique shapes.These structures are unique in shape and their force characteristics are relatively complex.The force of different modeling structures also has its uniqueness.The study of its force characteristics has certain necessity and reference.Based on the Hailan Lake Bridge,this paper studies the reasonable bridging state and dynamic and static characteristics of long-span V-shaped arch-girder arch bridges,which provides theoretical basis for the design and research of similar bridges.The tensile force of the pull-down cable of the reasonable bridge state of the Hailan Lake Bridge is calculated by the method of rigidly supporting the continuous beam.Under the condition that the tensile tension of the cable is relaxed,the principle of proportional force of the pull-down cable based on the constant load of the bridge is proposed.The initial tension of the cable makes the tension of the cable meet the requirements of the tension。The static characteristics of the structure are studied,and the structural design parameters such as the thickness of the steel arch rib,the angle of the V-shaped arch plane,the span ratio,and the tensile force of the cable are compared and analyzed.The finite element software is used to calculate the static and dynamic characteristics of the structure.The deformation,internal force and stress of the structure under various changing parameters,comparative analysis of the various trends show that the thickness of the arch rib,the angle of the V-shaped arch plane and the tension of the cable have a great influence on the deformation and stress of the arch rib and the main beam.The specific shadow has a great influence on the stress of the main beam and the deformation of the arch rib,and has little influence on the deformation of the main beam and the stress of the arch rib.The section of the main girder is optimized to reduce the consumption of steel and achieve the goal of economic saving.The dynamic characteristics of the structure are studied.The vibration period and frequency of the Hailan Lake Bridge are calculated by Lanczos method.The natural vibration characteristics and the characteristics of each mode are analyzed.The out-of-plane stiffness of the V-shaped arch bridge is less than the in-plane stiffness.At the same time,using finite element software to study the influence of arch rib thickness,V-shaped arch plane angle and span-to-span ratio on the natural vibration characteristics of the structure,it is found that the influence of V-shaped arch rib thickness is relatively large.Then the time history analysis method is used to simulate the influence of vehicle load on the structure,and the time history dynamic response of the structure under different vehicle speeds and different distances is obtained.The analysis shows that the greater the vertical deflection of the main beam and arch ribs,the greater the vehicle speed is.When the critical speed of the bridge and the vehicle is reached,the critical speed will be reduced;the larger the distance,the smaller the vertical deflection of the main beam and the arch rib,which is beneficial to the safety of the vehicle and the impact of the vehicle on the bridge.It is beneficial to the normal use and durability of the bridge.