360R-06 Design of Slabs-on-Ground
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- DESIGN OF SLABS-ON-GROUND 360R-47 10.3.2.6
| 10.3.2.4 Impact resistance—The impact resistance of
steel FRC has been determined to be as much as three to 10 times greater than that of plain concrete when subjected to explosive charges, dropped weights, and dynamic flexural, tensile, and compressive loads (Williamson 1965; Robins and Calderwood 1978; Suaris and Shah 1981). The degree of impact resistance is directly related to the mixture proportion and all mixture constituents, including fiber type and quantity. 10.3.2.5 Fatigue resistance—The fatigue strength at two million cycles for plain concrete is approximately 50% of the static rupture modulus. This is the basis for the well-known safety factor of 2.0 shown in the PCA design document (Spears and Panarese 1983). Steel FRC mixtures have shown fatigue strengths of 65 to 90% of the static rupture modulus at two million cycles when nonreversed loading is used (Ramakrishnan and Josifek 1987; Ramakrishnan et al. 1987). The fatigue strength is slightly less when full reversal of loads is used (Batson et al. 1972). The degree of fatigue resistance is directly related to the mixture proportions and all mixture constituents, including fiber type and quantity. DESIGN OF SLABS-ON-GROUND 360R-47 10.3.2.6 Shear resistance—Steel FRC can provide higher punching shear resistance and anchor bolt pullout resistance as compared with plain concrete. The degree of shear resistance is directly related to the mixture proportion and all mixture constituents, including fiber type and quantity. 10.3.2.7 Freezing-and-thawing resistance—Steel fibers do not inherently increase freezing-and-thawing resistance of concrete. The same mixture proportion principles as those discussed in ACI 201.1R should be followed for steel FRC (for consistency) exposed to freezing and thawing. tải về 2.35 Mb. Chia sẻ với bạn bè của bạn:
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