PRESTRESSING ANALYSIS OF ELLIPSOIDAL SUSPEN-DOME STRUCTURES BASED ON EQUIVALENT INTERNAL FORCES OF HOOP CABLES

Tension hoop cable is a high efficiency construction method for the prestressing system of suspen-domes, when equivalent internal forces of hoop cables in the same circle are ensured. Feasible prestressing distribution of three common ellipsoidal cable-strut systems are analyzed based on the equilibrium matrix theory, and the conclusion is obtained that the equivalent internal forces of hoop cables could be ensured when the degree of the indeterminacy of the cable-strut system is not less than the number of hoop cables. However the degree of the indeterminacy of rib-patterned cable-strut system is low compared with that of Lamella system and Kiewitt system, which results in unequal internal forces of hoop cables and inadaptability of tensioning hoop cables. Thus, extended force density method is adopted in the form-finding to build a modified structure. Finally, a numerical example for a modified rib-patterned suspen-dome is presented, and a comparative analysis of the modified structure and the original one using the Ansys software is performed. Suggestion is given that tensioning points should be arranged beneath the long axis of the structure, which provides a reference for both design and construction of the ellipsoidal suspen-dome in the future.