Design of cable net-membrane roofs with reverse curvature by nonlinear analysis

Abstract

INTRODUCTIONThe cables are very high in tensile strength, but they have very low flexural stiffness occurring in large deformation. Therefore, the structural system with a small deformation as much as possible should be considered at building design, and the analysis considering geometric nonlinearity should be performed. In order to minimize the deformation of the cable roof system, it is should be ensured the necessary rigidity, a roof system with upward and downward curvatures is very effectively structural system. The cable roof system has that the ridge and valley cables are connected by bracing cables to resist the up and down load. The structural concept of a radial cable roof system is consists of outer compression ring and continuous radial truss cables. The outer circular ring acting compression forces is setting in equilibrium with the tensile forces of inner radial cables. The upper ridge cables and the lower valley cables with a large prestress are connected to ensure structural stability and rigidity. The ridge cables and the valley cables are prestressed in the reverse direction [1][2][3][4]. This paper is carried out analyzing and comparing the tensile forces of cables and deflection of curved roof systems by vertical loads. The elements for analysis uses a tension only cable element and a triangular membrane element with 3 degree of freedom in each node. The authors will estimate that the curved cable-membrane roof system with reverse curvature is one of a very effectively structural system according to the sag ratio of ridge cables and the rise ratio of valley cables.