Mechanical Analysis of a Type of Hybrid Spatial Structure Composed of Cables,Bars and Beams

Abstract

The computational analysis method of a hybrid structure composed of cables, bars and beams and its preliminary mechanical properties are presented in this paper. At first, based on the local analysis method, the distribution and magnitude of pre-stress of this hybrid structure is analysed using the optimal theory. Then, the optimal pre-stress distribution is obtained. The outmost ring of cable and bar has the largest pre-stress compared with the middle one and the inner one. Second, nonlinear static analysis is carried out with induction of the pre-stress in beams as self-equilibrated initial internal force. The tensegric system and pre-stress in the whole structure could not reduce the deflection dramatically. However, the pre-stress can significantly affects the distribution of the axial forces in beams. Also, linear and nonlinear dynamic analysis is conducted by taking account of the pre-stress of beams as self-equilibrated initial internal force. With the decrease of the stiffness of the upper reticulated structure the effect of pre-stress on natural frequencies of the whole structure becomes larger. The fluctuation of the internal force in the cables and bars is not very large under vertical frequently meeting earthquake load (not over 7%) and smaller under horizontal frequently meeting earthquake load. At last, buckling analysis is carried out. Comparing to single-layer reticulated shell, this type of hybrid structures has much higher limit load capacity ability.