| The stay cable,as an important part of the overall stiffness of the cable-stayed bridge,which coordinated by the tower and the beam through the pre-tension to make it in a stable and balanced state.At present,The stiffness of the cable structure determines the cable stay area based on the deflection value of the main span and the maximum total cable force.On the other hand,compliance with the overall stiffness requirements of cable-stayed bridges through the deflection span ratio,displacement and internal force indicators specified in the code.At present,many excellent properties of carbon fiber composite materials(CFRP)are driving the development of cable structures.When CFRP cables are used in cable-stayed bridges,the cable stiffness problem is more prominent.This article combines the discussion of the parameters of the cable stiffness,and analyzes the influence of the parameters of the cable on the stiffness characteristics of the cable structure,which will help the continuous optimization and improvement of the cable structure.Reasonable design is essential.Therefore,this paper focuses on the research direction of the stiffness characteristic parameters of steel cables and CFRP cables from the following aspects::(1)This paper analyzes the requirements of bridge stiffness in the relevant highway bridge codes at home and abroad,compares and analyzes several analytical methods,scope of application and respective characteristics of cable geometric nonlinearity,analyzes the influence of cable structural stiffness on structural parameters of cable-stayed bridge,and puts forward that displacement index and internal force index can be used to express the overall stiffness of cable-stayed bridge.(2)According to the mechanical parameter characteristics of the cable,the influence of each parameter under the condition of the cable stiffness is explored and analyzed.The design principle of the cable structure,the theory of the cable pretension,the influence of the cable structure stiffness characteristics and the classification of the overall structure stiffness of the cable are obtained.(3)Based on the above theoretical analysis,according to the design method of the mechanical parameters of the stay cables,the steel cables are replaced by CFRP cables in different ways,and the finite element model of the cable-stayed bridge under various analysis conditions is established.Based on the theoretical analysis above,the structural rigidity of the steel cables and CFRP cables is analyzed,and the sensitivity of the mechanical parameters that may affect the overall rigidity of the cable-stayed bridge is analyzed,The influence of the change range of stiffness of steel cable and CFRP Cable on the vertical displacement of tower top,internal force of tower bottom and the vertical displacement of main beam is analyzed,and the reasonable limit range of structural stiffness of steel cable and CFRP Cable is given respectively.the structural stiffness of the cable and the CFRP Cable is analyzed,and the sensitivity of the key mechanical parameters affecting the overall stiffness of the cable-stayed bridge is analyzed The reasonable limits of the structural rigidity of steel cable and CFRP Cable are given.(4)Based on the advantages and disadvantages of steel and CFRP,three kinds of steel and CFRP Composite Cable schemes are compared and analyzed.For the steel and CFRP Composite cross-section,two different cross-sectional area ratios of different materials are obtained for parameter analysis,and the cross-sectional ratio within the reasonable use range under different cable length is obtained.Finally,according to the supporting engineering example,the reasonable application scheme is given and the overall analysis of the cable-stayed bridge is carried out.(5)The finite element analysis model of cable-stayed bridge with steel cable,CFRP Cable and composite cross-section cable is established to compare the change trend of horizontal displacement of tower top,internal force of tower bottom and vertical internal force and vertical displacement of main beam span with the change of cable tower height under the action of live load.Finally,by adjusting the structural rigidity of cable-stayed,the influence change trend of steel cable,CFRP Cable and composite cross-section cable is compared and analyzed to prove the composite cross-section cable The superiority of the rope. |
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