IS 11440:1985 is the Indian Standard (BIS) for precast concrete ribbed floor slabs - specification. This Indian Standard specifies the requirements for materials, dimensions, tolerances, manufacture, finish, and testing of precast concrete ribbed or cored floor and roof slabs. It covers units designed to act compositely with in-situ concrete topping.
Specifies requirements for precast concrete ribbed floor slabs, covering dimensions, materials, manufacture, and testing.
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Minimum Concrete Grade | M15 (Characteristic compressive strength of 15 N/mm²) | C30/37 (Characteristic cylinder/cube strength of 30/37 N/mm²) | EN 1168 / EN 1992-1-1 |
| Reinforcement Type | Mild steel (IS 432) and high-strength deformed bars (IS 1786). | Reinforcing steel (EN 10080) and prestressing steel (EN 10138). | EN 13369 |
| Minimum Concrete Cover (Mild/Indoor Exposure) | 15 mm (for slabs, as per IS 456:1978) | 20 mm nominal cover (c_min,dur=10mm + Δc_dev=10mm for XC1) | EN 1992-1-1 |
| Length Tolerance | ± 5 mm | ± 25 mm or L/700 (whichever is smaller) | EN 1168 |
| Overall Depth Tolerance | ± 3 mm | For a 200 mm slab: ± 6 mm (based on h/30) | EN 1168 |
| Load Test Deflection Recovery | Recovery of at least 75% of the maximum deflection after 24 hours. | Recovery of at least 90% of deflection for prestressed elements. | EN 13369 |
| Camber Tolerance | Not explicitly defined as a numerical tolerance. | Difference between adjacent units ≤ L/3000 or 15 mm. | EN 1168 |