Operation Upshot-Knothole, Nevada Proving Grounds, March - June 1953. Project 3.1. Tests on the Loading of Building and Equipment Shapes,

This report deals with pretest and post-test work on the Air Force Structures Test, Project 3.1, Tests on the Loading of Building and Equipment Shapes. The test was designed to check and improve upon previously developed methods of predicting blast loadings on simple structures representative of targets of military interest. The specific objectives dealt with the influence of certain geometric and blast parameters on the loading of solid structures (e.g., the effects of shock strength on building height, width, shielding, orientation, etc.). The test items consisted of a series of 17 cubical structures of reinforced concrete construction which were designed to rigidly withstand the effects of the blast. The structures were rather extensively instrumented with pressure gages and were included in both Shots 9 and 10. Most of the structures were located in the Mach reflection region on both shots; two structures were located in the regular reflection region of Shot 9 and in the precursor region of Shot 10. Primary emphasis was placed on the study of diffraction phenomena since the pressure gage data were not expected to be sufficiently accurate to resolve the relatively small drag forces. A comparison between measured and predicted diffraction loads served to confirmmore » certain aspects of the pretest load prediction methods and led to revisions of others. In the remaining instances the form of the data was inadequate to either confirm or revise the methods. This latter category includes those cases in which the test data clearly disagreed with predictions but was too sparse to warrant revision of the prediction scheme.« less