| Cable-stayed bridges with inclined arch-shape pylon have attracted increasing interests from government and engineer communities owing to their aesthetic characteristics as well as the improvement to cityscape.However,the novel and special structure form of such cable-stayed bridge makes its structural analysis and construction management of great challenges.Taking Wangpeng Bridge in Shenzhen-Shanwei Special Cooperation Zone as the background,the objective of this research is to determine the reasonable state and the global static stability of cable-stayed bridge with wide composite girder and inclined arch-shape pylon in the completed and constructing stages,so as to ensure the safety and reliability of Wangpeng Bridge in its construction and operation.The outcomes of this research can provide reference for the design and construction of similar bridges.The main research works include:(1)Two finite element(FE)models of Wangpeng Bridge are developed with ANSYS and MIDAS/Civil programs respectively.The accuracy and reliability of the two FE models are verified by comparing the static and dynamic behaviours computing by the two models with each other.(2)A cable force optimization method for cable-stayed bridge based on genetic algorithm is established,which is implemented on MATLAB platform,by calling ANSYS program externally for structural analysis.The developed optimization method was employed to determine the reasonable completed state of Wangpeng Bridge.(3)Based on the unstressed state method,a method combining the modification of material properties and the function of birth-death elements is proposed,so as to simulate and optimize the construction process.The reasonable construction sequence and cable force of constructing bridge is determined.The reasonability of the construction procedure for the closure of pylon and girder is discussed.The frame removal procedure and construction safety for the pylon and main girder is verified.(4)The static stability of Wangpeng Bridge during construction and completion was investigated.The elastic and nonlinear stability safety coefficients are calculated,and the instability modes under typical working conditions are analyzed.The bearing capacity of main stressed components is evaluated,and the influence of tower construction support on the global nonlinear stability is discussed.With the preceding studies,the following conclusions can be drawn:(1)The static and dynamic behaviours predicted by the two FE models were in consistence with each other,indicating the accuracy and credibility of the FE models developed on ANSYS and MIDAS/Civil program.The ANSYS FE model can be used for the analysis of stresses,deformation and static stability of structure in completed and constructing stages,and the MIDAS/Civil FE model can be used to verify the accuracy and reliability of the results.(2)Compared with the in-built zero-order optimization algorithm of ANSYS program,the developed cable force optimization method for cable-stayed bridge based on genetic algorithm is superior in optimization results,iterations and computational efficiency.The obtained completed state of Wangpeng Bridge is reasonable.(3)The results show that the construction procedure of Wangpeng Bridge determined by unstressed state method is reasonable.The stress status in the constructed structure can meet the requirements during the construction process.The obtained cable forces and stresses of the completed structure after construction sequence simulation are consistent with the desired reasonable state of the completed bridge,and the structure alignment is reasonable.(4)The elastic and nonlinear stability safety coefficients are greater than 4 and 2respectively in the constructing and completed state,and the loading multiple of each component is greater than 2 when yield or failure occurs.The results demonstrat that the global static stability can meet the requirements of the specification.The outcomes can provide reference for the design and construction of Wangpeng Bridge. |
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