Per §10.5, the Himsworth constant K (multiplier of σ) used to obtain t…

Question

Per §10.5, the Himsworth constant K (multiplier of σ) used to obtain target mean strength under the Indian Standard's 5 percent risk factor is:

Accepted Answer

D. {'text': '1.65', 'label': 'D'}

1. §10.5: 'ftarget = fck + 1.65σ' for IS at 5 percent risk; the value 1.65 is Himsworth's constant. American Standard accepts a 2 percent risk factor whose Himsworth constant is 2.2 (Eq. 10.5B).
2. Lower the risk factor, higher the Himsworth constant and the larger the target strength against the same characteristic strength.
_Source: IGNOU ET-522 Block-3 Unit-10 Concrete Mix Design, §10.5, Eq. 10.5/10.5A/10.5B, p. 10_

Answer

{'text': '1.00', 'label': 'A'}

Answer

{'text': '3.00', 'label': 'B'}

Answer

{'text': '2.20', 'label': 'C'}