DYNAMIC SHEAR STRENGTH OF CONCRETE KEYS
A research program was conducted to study the comparative behavior of shear keys under static and dynamic loading and to obtain information on the ultimate load carrying capacity of shear keys as influenced by various parameters, such as the aggregate strength, the number of keys, and the transverse compression on the shear section. The following categories of tests were made: (I) Specimens with the variation in the strength of coarse aggregate. (II) Specimens with keys under direct transverse compressive stresa (50 psi). (III) Specimens with the variation in number of shear keys. All these three categories were tested for both static and dynamic loads, the dynamic loads simulating an initial peak triangular blast loading. These tests have shown that (1) plain concrete keys have a high strength in shear--of the order of 1000 psi under static loads and 1300 to 1700 psi under dynamic loads; (2) the use of stronger or weaker aggregate, compared to a normal aggregate seems to be beneficial for dynamic load cases; (3) the effect of transverse compression on shear strength of concrete is significant only when transverse compression is of the order of 300 psi; (4) the total strength of a joint does not increase in direct proportion to the number of shear keys. With the increase in the number of keys (in the direction of the load application) the average shear strength decreases; and (5) failure of shear keys is quite brittle in general for both static and dynamic loadings. (auth)
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge. School of Engineering
- NSA Number:
- NSA-17-040956
- OSTI ID:
- 4632547
- Report Number(s):
- DASA-1339; AD-297927
- Country of Publication:
- United States
- Language:
- English
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