Title: Scale Modeling of Buried Reinforced Concrete Structures Under Air-Blast Loading

Author(s): James K. Gran, John R. Bruce, and James D. Colton

Publication: Symposium Paper

Volume: 73

Issue:

Appears on pages(s): 125-142

Keywords: blast loads; blast resistant structures; dynamic loads; -- dynamic response; dynamic tests; failure; models; reinforced concrete; scale (ratio); strains; subsurface structures.

DOI: 10.14359/6777

Date: 3/1/1982

Abstract:
Two l/30-scale models of reinforced concrete cylindrical missile shelters were built and tested to study the response of buried reinforced concrete structures subjected to severe dynamic loads. To assess the applicability of small-scale modeling to this type of problem, the results of the l/30-scale model tests were compared with l/6-scale results from a parallel program. A comparison of the l/30-scale and l/6-scale tests shows that the surface loads and soil responses matched and that the structural responses agreed very well. For the elastic structures, concrete surface strains measured in the l/30-scale test and reinforcing steel strains measured in the l/6-scale test showed that the direct loading wave, the reflections from the base and the closure, the base and closure flexure, interface friction, and soil resistance to punchdown were all reproduced accurately at l/30-scale. For the inelastic structures, the responses agreed up to the time of failure of the l/6-scale structure. Failure in the l/6- scale structure occurred at an apparently locally weak section of concrete. Concrete surface strains measured in the l/30-scale test and reinforcing steel strains measured in the l/6-scale test showed excellent agreement above the failure location. The l/30 scale strains throughout the structure were also in excellent agreement with the predictions of numerical analyses.