DYNAMIC SHEAR STRENGTH OF REINFORCED CONCRETE BEAMS, PART 1
Rept. for Jun 1962-May 1965
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA
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A series of reinforced concrete beams were tested to study shear and diagonal tension in beams under dynamic load. The tests constitute the first phase of a study designed 1 to determine criteria for the minimum amount of web reinforcement required for developing the ultimate flexural resistance of beams and 2 to evaluate the difference between these criteria for static and dynamic loading. It was found that 1 the shear resistance at diagonal tension cracking and at first yielding of the stirrups increased under dynamic load, and 2 the formulas presented in a definitive report by a joint committee of the American Concrete Institute ACI and the American Society of Civil Engineers ASCE adequately predicted the static shear resistance but grossly underestimated the dynamic shear resistance. Evidence is cited which attributes the increase in shear resistance under dynamic load to an increase in the tensile strength of the concrete and yield strength of the stirrups. An effective amount of web reinforcement rfy, 69 percent less than the amount required by the ACI-ASCE formula, resulted in flexure failures under static and dynamic load. Equations are presented which permit prediction of the dynamic shear resistance corresponding to diagonal tension cracking and first yielding of the stirrups. A dynamic response chart is developed for estimating the maximum shear at the supports of a simple supported beam under a uniform dynamic load.
- Ceramics, Refractories and Glass
- Structural Engineering and Building Technology