Study For Ultimate Bearing Capacity Of Heterotypic Hybrid Girder Cable-stayed Bridge

Hybrid girder cable-stayed bridge is a framework in which concrete composite beams and steel ones combine. Since it improves performance of mechanical structure and reduces cost, it has been widely used in practice projects. As demand for bridge landscape increases heterotypic hybrid girder cable-stayed bridge has gradually been applied to engineering practice. However, there are only a few documents available in literature and it is necessity for engineers to understand mechanical characteristics of the bridge. Therefore, we propose an innovative approach for analysis of ultimate bearing capacity of the bridge. The characteristic of this paper is study of prominent robustness problems in this structure.After thorough literature overview in approaches for analysis of ultimate bearing capacity of heterotypic hybrid girder cable-stayed bridge, this paper starts with summary of present research situation in the world. Thereafter, it describes current analysis approaches based on geometric nonlinearity, materials nonlinearity and dual nonlinearity theory and structure analysis program.This paper investigates the setup of the numerical model, the simplified simulation of constitutive relation of different materials, and the finite element simulation of structure nonlinearity, and finally suggests an efficient simulation implementation method.Using allowable stress theorem and limit state theorem as principles for judging the state of ultimate bearing capacity, a numerical analysis simulation model is designed. It loads the structure in conventional load mode with the ultimate bearing capacity and the most unfavorable processing load of each controlling cross section of the structure. After comparing several analysis results of load?ˉs material nonlinearity, dual nonlinearity and robustness and analyzing the ultimate bearing capacity in multiple-load mode, it is found that characteristics of the geometric nonlinearity characteristics of the small span heterotypic hybrid girder cable-stayed bridge are not significant, and materials?ˉnonlinearity has dominant effect in the structure.Under allowable stress control, theoretical analysis indicates that the bearing capacity of structure is substantial larger than the design capacity in the range of linear elasticity. The structure is locally instable in robustness analysis, and the eigenvalue is large.