Study On Wind Performance Of Long Span Cable Stayed Bridge Based On High Performance Materials

The traditional main span of the long-span cable-stayed bridge is made of ordinary concrete main beam,steel structure main beam or mixed beam,inclined cables are made of steel strands or parallel wires.However,the ratio of strength to density of ordinary concrete is low,its suitable span is limited,the corrosion resistance of steel structure is poor,it is not conducive to the durability of the structure,the effective elastic modulus of steel cable is low,and its anti-fatigue performance and corrosion resistance are poor,many restrictions are seriously restricting the development of long-span cable-stayed bridge.The emergence of reactive powder concrete(RPC)and carbon fiber reinforced polymer(CFRP)with high strength and excellent durability provides a new direction for the development of long span cable-stayed bridges.Based on the superior performance of RPC and CFRP materials,a new cable-stayed bridge structure system with RPC girders,RPC pylon and CFRP cable is designed to study the application of high performance materials RPC and CFRP to long-span cable-stayed bridge In the feasibility from static performance,dynamic performance,wind resistance and other aspects.The main investigations are summarized as follows:(1)Based on the design scheme of a cable-stayed bridge with a main span of 1100m,which is composed of steel cables,steel girders and ordinary concrete pylon,the steel cable is replaced by CFRP cable by considering the principle of equal strength.Considering the aerodynamic shape,stiffness,shear,anti-punching,local stability and other requirements of the original program of the main steel beam replaced by RPC main beam.Consider the tower of the force and stiffness requirements of the original program of ordinary concrete pylon replaced by RPC tower,constructed a new The same layout of the CFRP cable,RPC main beam,RPC cable tower cable-stayed bridge structure program.(2)The structural stress and deformation of the two schemes under constant load,vehicle load,temperature load and different load are analyzed and compared by finite element method.The results show that the new scheme constructed satisfies the general design requirements and has good static performance.(3)Based on the finite element software,the dynamic characteristics of the two schemes are analyzed and compared.The stability of the two schemes is analyzed and compared.The buffeting response of the structure is analyzed by time domain method.And the wind resistance of the two schemes is compared comprehensively.The results show that the natural frequencies of the two schemes are similar,and the wind resistance of the new scheme is improved obviously.(4)Considering the force of the whole structure,the modal analysis of the cable stayed in the two schemes is carried out,and the vibration characteristics and vibration amplitude of the steel cable stayed cable and the CFRP cable under different vibration types are analyzed and compared.The results show that the natural frequency of CFRP cable is much higher than that of steel cable,and its wind resistance is better than that of steel cable.