超大型冷却塔钢管混凝土交叉支柱截面选型研究

To solve the problems of current reinforced concrete X-columns such as large cross-section size, long construction period and considerable usage of the scaffold during the construction process, it is proposed that concrete-filled steel tube (CFST) can be effectively used as the X-column in the ultra-large cooling tower project. Two types of CFST X-columns with different sections (circular section and the long-circular section) were designed and both of them had the same bearing capacity as the rectangular reinforced concrete X-column in the original scheme of prototype cooling tower project. The finite element models of the cooling tower with the aforementioned three types of X-column (i.e., the rectangular reinforced concrete X-column, the circular and the long-circular CFST X-column), were established using ABAQUS. The accuracy of the finite element models were verified by comparing with the tested natural frequency of a practical project. The responses of structures under gravity load, wind load and earthquake action were obtained, and the influence of different cross sections of X-columns, including different cross-section shapes and material components, on the structural performance of cooling towers was studied. Finally, the axial force-moment capacity interaction curves of the aforementioned three types of X-column were obtained based on the fiber model method. The results show that the displacement of tower using circular and long-circular CFST X-column are both less than that using rectangular RC X-column under different loads, which indicates that using CFST X-column can improve the structural stiffness of the cooling tower. Under the same axial load, the bending performance of circular and long-circular CFST X-column is better than rectangular RC X-column. Based on the simulation results, the circular CFST X-column is recommended to be adopted.