Explanation: Response reduction factor: It is the factor by which the actual base shear force, that would be generated if the structure were to remain elastic during its response to the Design Basis Earthquake (DBE ) shaking, shall be reduced to obtain the design lateral force. Response reduction factor for building systems:
Lateral Load Resisting System
R-Value
Building Frame Systems 1. Ordinary RC moment-resisting frame (OMRF) 2. Special RC moment-resisting frame (SMRF) 3. Steel frame with ● Concentric braces ● Eccentric braces 4. Steel moment-resisting frame designed as per SP 6 (6)
3
5
−
4
5
5
Building with Shear Wall 5. Load bearing masonry wall buildings ● Unreinforced ● Reinforced with horizontal RC bands ● Reinforced with horizontal RC bands and vertical bars at corners of rooms and jambs of openings 6. Ordinary reinforced concrete shear walls 7. Ductile shear walls
1.5
2.5
3
3
4
Buildings with Dual Systems 8. Ordinary shear wall with OMRF 9. Ordinary shear wall with SMRF 10. Ductile shear wall with OMRF 11. Ductile shear wall with SMRF