Correct Answer - Option 3 : 3.35 bd
2
Concepts:
The limiting Moment of Resistance of a RCC Beam is given as:
Mu,lim = 0.362Bfck Xu,lim (d-0.42 Xu,Lim)
Where symbols have their usual meaning
Further, the Xu,lim/d ratio depends on grade of steel being used, which is referred from the below table:
Grade of Steel
|
Xu,lim/d
|
Fe 250
|
0.53
|
Fe 400
|
0.48
|
Fe 500
|
0.46
|
Calculation:
Given:
Grade M 25 ; fck = 25 MPa
Grade of Steel is Fe 500 ; Xu,Lim/d = 0.46
Now,
Mu,Lim = 0.362 × 25 × 0.46 × (1-0.42× 0.46) Bd2
Mu,Lim = 3.358 Bd2
Note:
The limiting moment of resistance for a beam is that factored moment due to loads on it which a beam can safely resist. This term is used in the Limit State Design method. In the working state method of Design, it is simply called Moment of Resistance.