The stress distribution in, and stability of, space frames with particular reference to radial ribbed domes

Abstract

The research project is concerned with the stress distribution in, and stability of, space frames. Particular emphasis is placed on the study of radial ribbed domes. The development and classification of the main types of space frame are discussed and a brief history of dome construction is included. Braced dome systems are detailed comprehensively. Methods for determining the stresses in space frames are given. These include analysis procedures for statically determinate and statically indeterminate pin-jointed structures. The solution of statically indeterminate space frames without pin-joints is also considered. Specific methods for analysing the stresses in braced domes are reviewed. Radial ribbed dome stress analysis methods are discussed. in detail. In particular, the analysis of three-pinned unstiffened semicircular radial ribbed domes, by the method of Makowski and Gogate, is reproduced. The method has been modified to simplify the analysis of low rise-to-span domes with three-pinned unstiffened circular arc radial ribs. A computer program, based on this method, has also been developed. Literature relating to loads on domes is reviewed. Special reference is made to snow loading and wind pressure distribution. To compare radial ribbed dome theoretical stress analysis values with results obtained experimentally, a model dome has been constructed. Calculations and design drawings for the prototype structure are included along with details of the model. Results of tests on the materials employed in the construction of the model dome are also presented. By using a displacement technique on the model, indluence line diagrams of force have been obtained with, and without, bracing. Rib strains and apex ring deflections are tabulated. An assessment of the analysis methods for space frames is given and comments on dome loading are included. ThP test results are discussed and conclusions are drawn. Suggestions are also made for further research.