Shear Design in Prestressed Concrete कैसे करें? | IS 1343 Code in Hindi

Prestressed Concrete (PSC) में shear design एक critical aspect है क्योंकि beams में bending के अलावा shear forces भी act करते हैं। IS 1343 code के अनुसार PSC members में shear strength design करना necessary है ताकि diagonal cracking और failure से बचा जा सके।

Shear Design के Objectives

• Diagonal tension cracks prevent करना।
• Beam का shear failure avoid करना।
• Serviceability limits maintain करना।
• Shear reinforcement और prestressing force coordination ensure करना।

IS 1343 के अनुसार Shear Stress Limits

• Concrete shear stress τc ≤ 0.8 √fck (for rectangular sections)
• Shear carried by prestressing tendons included in design
• Minimum shear reinforcement as per code provisions

Shear Design Procedure (IS 1343)

1. Calculate factored shear force (Vf) at critical sections (supports and near concentrated loads)।
2. Compute concrete shear capacity (Vc) using:

   Vc = 0.8 √fck × b × d

   जहाँ b = beam breadth, d = effective depth

3. Check if Vf ≤ Vc।
4. If Vf > Vc, provide shear reinforcement (stirrups) along length:
   • Calculate required stirrup area Ast = (Vf - Vc) / (0.87 fy × d/s)
   • Choose spacing s according to IS 1343 minimum and maximum limits
5. Include prestressing tendon contribution in shear where applicable
6. Check deflection and serviceability limits

Important Considerations

• Stirrups placement and anchorage properly design करें।
• Shear zones में cable curvature avoid करें।
• Prestress losses consider करें।
• Minimum and maximum stirrup spacing as per IS 1343।

निष्कर्ष

Shear design PSC beams में critical है। IS 1343 code के अनुसार concrete और steel दोनों का contribution consider करके shear reinforcement provide किया जाता है। Proper design से structure safe, crack-free और serviceable रहता है।