Deep beams — minimum total area of side face reinforcement For a reinforced concrete deep beam (depth beyond the codal trigger), the total area of side face reinforcement provided along the two faces should not be less than what percentage of the web area?

Introduction / Context:
Deep beams experience disturbed-region (D-region) behavior where conventional plane-section assumptions do not strictly apply. To control side face cracking from shrinkage and tension fields, codes require a minimum distributed reinforcement on both side faces.

Given Data / Assumptions:

• Beam qualifies as a deep beam per codal trigger (e.g., depth and span/depth limits).
• Side face steel must be distributed on both faces.
• Web area refers to b_web × overall depth used for percentage calculation.

Concept / Approach:
Minimum side face steel provides crack control and enhances ductility. Standard practice stipulates that the total side face reinforcement (both faces combined) be at least 0.1% of the web area, placed approximately equally on the two faces with appropriate spacing limits.

Step-by-Step Solution:
Step 1: Determine web area A_web = b_w × D.Step 2: Compute minimum total side face steel A_sf,min = 0.001 × A_web.Step 3: Distribute A_sf,min roughly equally on both faces, respecting bar spacing and cover requirements.

Verification / Alternative check:
Handbooks echo 0.1% as the baseline minimum for deep beams; higher percentages may be used where exposure or crack-width limits are stringent.

Why Other Options Are Wrong:
0.2–0.6%: Higher than required minimum; may be used for severe exposure or design judgment but not the codal baseline.

Common Pitfalls:

• Calculating percentage on gross section including flanges in T-beams; use web area.
• Providing all steel on one face, leading to asymmetric crack control.

Final Answer:
0.1% of web area