Prestress Design of Ellipsoid Hybrid Form and Parameter Analysis of Design Factors

Abstract

New types of hybrid cable domes combining Geiger and Levy forms are presented in this paper. Their basic configuration and geometry are proposed and discussed. The partition-assembly method for a prestress design of the hybrid-form cable dome is proposed. This method obtains the prestress of each unit by solving equilibrium equations and assembles them by the force-density method and genetic algorithm. The partition-assembly method enables prestress of hoop cables in the same ring to equal each other for an ellipsoid hybrid-form cable dome. Examples of ellipsoid hybrid-form and Geiger-form cable domes are established. Prestress of the examples are calculated by the partition-assembly method. Mechanical properties of hybrid-form and Geiger-form cable domes are analyzed and compared, and the results show that the hybrid form has better properties under nonuniform loads and larger overall stiffness than the Geiger form. Influence of prestress and proper ratio of prestress of middle to outermost hoop are discussed in the last part of the paper.