Civil Engineering ETDs

Publication Date

1969

Abstract

A series of tests was conducted to obtain information concerning the effectiveness of a shock shield of reinforced concrete between ground surf ace and a buried structure as a means of reducing the shock transmitted to the structure due to airblast loading. Two shock shields were used. The diameter of both shields was 20 inches and the thicknesses were 6 inches and 2 feet. The structure was 20 inches in diameter with a thickness of 5 feet. Tests were performed in a 2- by 40-foot shock tube without shock shield and structure, with structure only, and with different thicknesses of shock shield at various depths above the structure but not in contact with it. The shields and the structure were buried in 20-30 Ottawa sand and subjected to a dynamic pulse with a maximum pressure level of approximately 500 psi and a positive-phase duration of 20 msec. Air pressure gages were mounted in the walls of the shock tube at the surface. The shock shields and the structure were instrumented at the top with stress gages, accelerometers, and velocity gages. Stress gages were also mounted in

the bottom of the shock shields. Stress gages and accelerometers were placed at various depths in the sand above the structure. Comparison of experimental results with theory was done by use of a plane, one-dimensional, finite-difference analog of the basic conservation laws of continuum mechanics

(mass, momentum, and energy). The boundary conditions at the surface was chosen to represent the predicted pressure pulse from the shock-shield tests, a 500-psi input pressure. A linear stress-strain curve was used for the concrete, and a nonlinear stress-strain curve was used for the sand.

Document Type

Thesis

Language

English

Degree Name

Civil Engineering

Level of Degree

Masters

Department Name

Civil Engineering

First Committee Member (Chair)

Marion Marvin Cottrell

Second Committee Member

Gerald William May

Third Committee Member

Cornie Leonard Hulsbos

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