Study On Fine Theory Of Geometric Nonlinear And Its Application For Super Long-span Cable-stayed Bridge Through Construction Stage

With the development of cable-stayed bridge striding to super long span, it is very important to study the influence of geometric nonlinear throughout its construction stage for its fine design and safety of the bridge structure. In this dissertation, firstly, study of the theory on geometric nonlinear analysis for cable-stayed bridge is comprehensively reviewed. Then, key techniques are studied deeply in the theory of geometric nonlinear analysis and construction control. Finally, the engineering of SuTong Yangtze River Highway Bridge and JingZhou Yangtze River Highway Bridge are taken as the actual engineering to verify the theoretical analysis. The main contents and conclusions of the research are listed as follows:(1) Incremental formula of stationary potential energy for Total Largrain Formulation(TL Largrain) and Updated Largrain Formulation(UL Largrain) are deduced, on the basis of which the formation rules of tangent stiffness matrix is set up by the principle of potential energy. The incremental virtual work equations of forward-constructing Co-Rotational Formulation (CR Method) are deduced in term of Kirchhoff stress tensor and Green stain tensor. The theoretical essence of CR method is found and the reason why the CR method is more exact than UL method can also be explained theoretically.(2) A more exact expression of tangent stiffness matrix is derived by twonode catenary cable element with arbitrary rigidity arms. The iteration techniques of tangent stiffness matrix are erected on two kinds of different calculations. Based on the conventional arc-length method, the arithmetic strategy and technique of accelerating iteration are put forward. This method can satisfy the demand of precise and fast calculation in the construction analysis of long span cable-stayed bridge.(3) The analysis of whole construction for SuTong Yangtze River Highway Bridge indicates that the influence must be great if we take account of the cable sag effect, beam-column effect and large deflection effect at the same time in the analysis. The influence due to comprehensive nonlinear factor is usually greater than the sum of the individual influences due to above three effects. The calculation error may be considerable if we neglect either of them. The influence on cable tension by comprehensive nonlinear factor is slight besides the cable tension near the auxiliary piers. As to the tower, the influence from the comprehensive nonlinear factor is distinctive during different construction stages. To be specific, the influence is greatest in completed bridge stage, but not so great in the longest single cantilever girder stage and the least in longest double cantilever girder stage. As to the main girder, the greatest influence may occur in the longest single cantilever girder stage, while the influence may be smaller in completed bridge stage, and the minimal influence may occur in longest double cantilever girder stage.(4) The difference of parameters on concrete shrinkage and creep are compared between the new code for design of bridge and culvert and the old one. The modes of exponent function of creep coefficients are deduced, which is convenient for FEM. The values of creep in the new. code are verified by the measurement data in the health monitoring of JingZhou Yangtze River Highway Bridge during its operation. Both the incremental virtual work equations in means of UL Formulation and the formula of equivalent joint loads for concrete shrinkage and creep are deduced. After the detailed analysis of SuTong Yangtze River Highway Bridge, we have found that the concrete shrinkage and creep would affect the internal forces and deformation of structure in a certain extent during the construction of long span cable-stayed bridge. But for cable-stayed bridge with steel main girder, the influence may be slight if the time for the construction of tower is relatively long.(5) The nonlinear iteration arithmetic of forward-construction is established to calculate the parameters of construction control for cable-stayed. The method to calculate the self-adaptive stress-free shapes is also established. The sensitivity of the main factors to installing cable tension is analyzed through the example of actual bridge engineering. A self-adaptive construction control system for cable-stayed bridge including five subsystems is put forward and has been applied in construction of JingZhou Yangtze River Highway Bridge successfully. (6) The key techniques for construction control of the long span cablestayed bridge are studied thoroughly. Firstly, a method to calculate the influence of temperature change in cable-stayed bridge is established by means of segmental polynomial function. Meanwhile the method to correct influence of temperature real time is also put forward, which is integrated with the technique of construction in site for cantilever girder. The efficiency of these methods has been validated by the actual construction control of bridge engineering. Secondly, based on the principle of vibration in the measurement of cable tension, the order of main frequency is one of the dominating factors to the measurement error of cable tension, and the relation between them can be described with the twice order parabola function. Finally, the measurement error and disposal method for concrete strain with chord-vibrating meters are researched in detail, and some instructive advice are obtained for the construction of bridge.