👉Deflection Control in Beams and Slabs

1. Causes of Deflection

• Excessive load on the member.
• Inadequate stiffness or reinforcement.
• Creep and shrinkage in concrete.
• Long span or insufficient depth.

2. Permissible Deflection Limits (According to Codes)

• Span/250 for total deflection under all loads.
• Span/350 or 20 mm for deflection after finishes are applied.
• Codes like ACI, IS 456, and Eurocode specify these limits.

3. Methods of Deflection Control

• Increase the depth of the beam or slab.
• Provide adequate reinforcement.
• Use higher-grade concrete to reduce creep.
• Limit span-to-depth ratio.
• Provide prestressing in long spans.

4. Span-to-Depth Ratios (General Guidelines)

• Simply Supported Beam – 20
• Continuous Beam – 26
• Cantilever Beam – 7

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