Analysis of Static Performance and Construction Process of Bi-Directional Cable-Supported Composite Floor Structure

With the large-scale construction of large public buildings, multi-storey large span structure comes into being. The biggest feature of the structure is that the span of floor structure is large. At present, there are four kinds of structural systems that can be applied to long-span floor, namely hollow sandwich floor, steel truss(net rack) composite floor, cable-supported floor and prestressed floor. In order to further improve the span capacity of floor structure and improve the force transmission efficiency, a new type of long-span floor structure, namely bi-directional cable-supported composite floor structure(BCSCFS), is presented in this paper. Through the numerical simulation method, the static performance of new type of structure system and the force transmission mechanism had carried out firstly, and the law over space and time in the construction and service phase in terms of the support reaction force, cable force, steel beam force and the internal force of concrete slab were discussed. Secondly, by comparing with the conventional composite floor structure, the improvement effect of the new floor structure in span capacity was studied. Finally, the design method of the new structure was discussed, and the influence of neglecting the construction process on the design result was studied.
The results show that:the horizontal normal support reaction force in the concrete construction stage increased significantly, and the horizontal reaction direction at the middle position and side position of the boundary is opposite. In the use stage, the normal horizontal support reaction force is the largest, followed by the vertical reaction force, tangential horizontal reaction force is the smallest. In the construction process, the horizontal displacement of sliding support changes little. The general trend of the cable force in the construction process is gradually increased, but there is a certain drop in the tension stage in the middle position. Except the tension stage, the cable force in the middle position is large and that in the two sides is small in the other construction and service stages. The axial force of steel beam is pressure in the stage of steel structure assembling and cable tensioning. In the stage of concrete construction and service, the middle part of steel beam is strained and the two sides are pressed. The bending moment of steel beam is mainly positive bending moment in steel structure assembling stage and negative bending moment in cable tensioning stage. In the concrete construction stage and the use stage, the middle of the steel beam is positive bending moment, the two sides are negative bending moment. The concrete slab is under pressure at all stages, and the bending moment is small. Compared with the conventional bi-directional composite floor, the horizontal reaction force, structural axial force, bending moment and vertical deformation of the support are greatly reduced, and the static performance is better than that of the conventional bi-directional composite floor. When analyzing the static performance of BCSCFS, there is a large deviation between the calculation results of the direct method and the actual situation, and most of the internal forces of the key structure part are relatively small. There is a certain safety hazard for the structure design, so it is recommended to adopt the method considering the construction process in analysis of structure in the design.