Photoelastic Model Studies of WYE Manifold Branches

Analytical stress analysis of branch openings reinforced by various means is only approximately possible and several simplifying assumptions are necessarily used. Nomographs and empirical formulae guide designers with significant incertitude. Structures designed on existing nomographs exhibited yielding during the proof test. A simple method of photoelastic model fabrication that makes possible accurate experimental analysis prior to the fabrication of the prototype is developed. The methods of model fabrication are described, including procedures adopted for measurements and data reporting. Examples of the application of these techniques are given, including investigation of the stress distribution in the vicinity of the large opening in the Brooklyn and Richmond Shaft Caps of the Richmond Project.