IS 2950:2000 (Part 1) is the Indian Standard (BIS) for design and construction of raft foundations, part 1: design. This code establishes the criteria for the design of raft (mat) foundations. It provides detailed guidance on evaluating soil-structure interaction, selecting between rigid and flexible methods of analysis, calculating the modulus of subgrade reaction, and properly proportioning the foundation to limit differential settlements and ensure safe stress distribution.
Code of practice for design and construction of raft foundations, Part 1: Design
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Design Philosophy | Working Stress Method (WSM) | Limit State Design (LSD) / Load and Resistance Factor Design (LRFD) | EN 1997-1 / ACI 336.2R-19 |
| Global Factor of Safety (Bearing Capacity) | 2.5 to 3.0 | Not used; partial factors on resistance (e.g., γR ≈ 1.4) and actions are applied instead. | EN 1997-1 |
| Minimum Concrete Cover (against earth) | 50 mm (for foundations, from IS 456) | 75 mm (3 in.) for concrete cast against and permanently exposed to earth. | ACI 318-19 (used with ACI 336.2R-19) |
| Permissible Total Settlement (Rafts) | 75 mm on sand/hard clay; 100 mm on plastic clay (from IS 1904) | No single prescribed value; depends on structure, but 50 mm is a common serviceability limit. | EN 1997-1 (Informative Annex) |
| Permissible Angular Distortion | 1/500 to 1/750 for avoiding cracking in panel walls (from IS 1904) | 1/500 is a common limit for frames with brittle finishes. | BS 8004:2015 |
| Minimum Shrinkage & Temperature Reinforcement | 0.12% of gross area for HYSD bars (from IS 456) | 0.18% of gross area (for Grade 60 rebar). | ACI 318-19 (used with ACI 336.2R-19) |