Effects of different prestress intensities on the displacement of membrane structures under point loads

摘要

Membrane structures exhibit large displacements under external loads. These are a consequence of the low stiffness of the membrane. One of the ways to increase the stiffness of the structure is to increase the prestress intensity of the membrane or of the cables. This paper presents a research done on the influence of the prestress intensities on the displacements under point loads since point loads have a significant impact on the displacements in membrane structures. In this research the prestress of the membrane and the prestress of the edge cables have been investigated separately. Ten different intensities of the membrane prestress, and five different intensities of the cable prestress, combined with four positions of the point load have been modeled. The intensity of the point load has been kept constant in all loads cases. The research is conducted on numerical models in software Sofistik. Displacements under given parameters of the membrane structure and the point loads were recorded and maximal displacements were compared. The obtained results provide a better understanding of the relation between the prestress intensities and displacements of saddle shaped membranes. The outcome of the research can be used to better predict and to reduce the displacements of membranes under point loads.