Q138
For M 150 grade concrete (1 : 2 : 4) the moment of resistance factor is
A.
0.87
B.
8.50
AnswerC.
7.50
D.
5.80
Answer: Option B
Solution
Answer: Option B
Solution:
M150 grade concrete refers to a mix ratio of 1:2:4 (Cement : Sand : Aggregate), where the characteristic compressive strength (fck) is 15 N/mm². The moment of resistance factor (R), also known as the limiting moment of resistance per unit width and square of effective depth, is a design parameter used in the limit state method for RCC beam design.
According to standard design aids and tables based on IS 456:2000, for M15 grade concrete, the commonly referred value of the moment of resistance factor is approximately 8.50.
Option A: 0.87 is incorrect, as it usually refers to the partial safety factor or percentage of steel yield stress, not the moment of resistance.
Option C: 7.50 and Option D: 5.80 are not the correct standard values for M150/M15 grade concrete.
Therefore, the correct answer is Option B: 8.50.