Comparison of Simulation and Field Tests of a Buried Concrete Arch Structure

摘要

The general objective of the study was to test a rigid structure in as large a field test as possible and to compare the results with those obtained from tests of the same type of structure in a laboratory simulation device. To accomplish the field-test part of the objective, three 30-in.-diameter reinforced concrete arches were buried in dense dry sand with 15 in. of cover over the crown and subjected to the effects of a 500-ton TNT blast (Project 3.2, Operation SNOWBALL) at overpressures of 105, 205, and 320 psi. In the laboratory, three structures were tested in the U. S. Army Engineer Waterways Experiment Station's Large Blast Load Generator, an explosively operated plane-wave loader, at overpressures of 92, 190, and 301 psi. It was found that the gross motion experienced in the field compared favorably with that obtained in the laboratory. Thrust and moment in the arch ring correlated; however, moment distribution in the arch ring appeared to be related to the impingement angle of the stress wave. Shock-spectrum comparison indicated that the free-field spectrum in the field and laboratory when compared with spectrum at a point on the structure generally exhibited an empirically predictable ratio. Consequently, the shock-spectrum envelope at certain points on these structures can be constructed for field loadings based on laboratory and free-field data. (Author)