Response of deep reinforced and unreinforced concrete slabs to static and dynamic loading
Albritton, Gayle E.
Miscellaneous paperAbstract: The objectives of this investigation were to study experimentally the response of deep, two-way reinforced and plain concrete slabs subjected to static over-pressures and to determine the response to failure of deep slabs subjected to airblast overpressure. In the static program, tests were conducted on twenty-one deep-slab specimens having a constant span-to-thickness ratio of 4.12. The parameters varied during the tests were the steel percentage and concrete strength; also the study included tests on plain concrete slabs. Six additional deep slabs were included in a field test, with three slabs having a span-to-thickness ratio of 3.5 and three a ratio of 2.6. All of the slabs had a model scale ratio of 1/7 of the assumed prototype deep slab, had a constant square length of 30.25 inches, and were supported flat over a 24-inch-diameter clear span. The magnitude of static failure overpressures ranged from 695 psi for the low strength plain concrete slabs to 1,432 psi for the slabs containing reinforcement and having a high concrete strength of 4,590 psi. The slabs tested in the field were subjected to an apparent airblast overpressure of approximately 5,000 to 6,000 psi. Collapse of the slabs was instantaneous and very catastrophic, and the mode of failure for all slabs was shear. The results from the static tests indicated that the slabs had low ductility ratios of approximately 2 to 3. The tests have shown that increase in tensile reinforcement from 0.99 1.49 percent does not appreciably change the resistance of the slab. The failure overpressures for plain concrete deep slabs were less, although not significantly, than those for reinforced concrete slabs, with comparable concrete strengths. In the field test, the airblast overpressure was greater than that required to fail the slabs; however, there was no evidence to indicate that the dynamic load capacities were lower than the static load capacities.
Weapons Effects Laboratory (U.S.)Engineer Research and Development Center (U.S.)
Airblast; Concrete slabs; Concrete reinforced
Miscellaneous paper (U.S. Army Engineer Waterways Experiment Station) ; N-68-5.
Approved for public release; distribution is unlimited.