RESISTANCE OF TUBULAR STRUCTURES TO DYNAMIC LOADING.
Final rept. Apr-Nov 65.
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CALIF
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Static and dynamic experimental investigations were conducted to validate the NFEC computer program used to predict the behavior of microwave towers subjected to blast loading. Five small-scale towers representative of the prototype were made of composite sheet steel and microconcrete. The inside and outside diameters were 10.7 and 12.4 inches, respectively, and the height was about 39 inches. The following tests were conducted static and dynamic tests on steel and concrete specimens static tests on a simply supported tubular beam and on a cantilever model and dynamic tests on three model towers - free-vibration tests, base-acceleration shock-pulse tests on a vibration machine, and air-blast tests in a 6-foot shock tube. The failure mode for the statically loaded beam and cantilever tower was of the same type as for the dynamically loaded cantilever tower a semicircular bulge occurred in the inside and outside steel cylinders at the location of maximum moment in the compression zone. Models tested in the shock tube failed at peak overpressures of 44.4 psi. The model tests showed the NFEC computer program can predict the behavior of small cantilever towers under different types of dynamic loading, thus increasing the level of confidence in the programs prediction of strength for the prototype tower. Author
- Structural Engineering and Building Technology