Method for constructing models of complex shell structures

Structural mechanics

Shell structures made of reinforced concrete are one of the most elegant and at the same time cost-effective architectural solutions but have a huge deficiency namely the difficulty of the calculations in their design. Today thanks to the introduction of modern computer technologies in the processes of design of building structures, increased speed of calculations and their accuracy. Finite element method in conjunction with modern computer technologies creates opportunities for modeling and calculation of structures of any complexity. One of the possible decision is to use in tandem PC Revit and PC SCAD. PC Revit is one of the most popular program complexes for 3D modeling of constructions. PC SCAD is the most common calculating program in Russia. In the article on the example of shell with double positive Gaussian curvature is proposed and described method of exporting a model from PC Revit to PC SCAD using at intermediate stages PC Autocad and satellite of PC SCAD Forum. The result of application of this method is the finite element model of the reinforced concrete shell, which is fully prepared for further calculation and analysis. To verify the correctness of the method we compared the model obtained by the method of export and model made in PC SCAD. Moreover, it was conducted evaluation of time spent of the construction of models in both methods. The comparison showed that the time spent on getting the model with proposed method was 10 min while for the construction of the same structure only in PC SCAD took 40 min. In addition, this shell has a simple geometry respectively in the formation of more complex models the advantage in time consumption will be more sensible. At the same time, the comparison revealed a drawback in the process of approximation of the surfaces on the flat elements. This caused the formation of cracks in the joints of the top cover with lateral edges in the final model and as a consequence the difference in bending moments at the points of supporting of the cover on the racks. However, the uneven splitting was obtained only on the side faces and this shortcoming can be corrected in the PC SCAD with a small investments of time. Then there were illuminated other possibilities of the proposed method in the export of various forms of shells. Modeling of more complex shapes have shown that the proposed method of export gives large possibilities in the formation of structures of complex shapes, which are technically difficult to build in PC SCAD. Especially, proposed method allow to model qualitatively curved shells without joints, which are difficult to build only in PC SCAD.