Question

Arrange the following checks in the correct order during R.C beam design:
A. Deflection check
B. Flexural strength design
C. Crack width control
D. Shear strength check
Choose the correct answer from the options given below :

• A. B, A, D, C
• B. B, D, A, C
• C. D, B, A, C
• D. B, C, D, A

Hint:

Always remember: "Safety first, Comfort second." Collapse checks (Flexure/Shear) must be satisfied before Serviceability checks (Deflection/Cracking).

Answer 1

The Correct Option is B

Concept: Reinforced Concrete (RC) design follows the Limit State Method, prioritizing "Limit States of Collapse" (safety) before "Limit States of Serviceability" (functionality).

Step 1: Primary Strength Design.
The first and most critical step is to ensure the beam can carry the primary bending loads. This involves calculating the longitudinal reinforcement. Therefore, B (Flexure) is the first step.

Step 2: Secondary Strength Design.
Once the beam is sized for flexure, it must be checked for diagonal tension. Stirrups are designed to prevent sudden shear failure. Therefore, D (Shear) follows B.

Step 3: Serviceability Check - Deflection.
After ensuring the beam won't collapse, we check if it is too "flexible." In RC beams, this is usually done using span-to-effective depth ratios. Therefore, A (Deflection) follows D.

Step 4: Serviceability Check - Cracking.
The final step is checking crack widths to ensure durability and aesthetic requirements are met, often through bar spacing rules. Therefore, C (Cracking) is the final step. The sequence is B-D-A-C.