IS 10440:1983 is the Indian Standard (BIS) for construction of rb and rbc floors and roofs. This code of practice covers the construction of reinforced brick (RB) and reinforced brick concrete (RBC) floors and roofs. It details the requirements for materials, workmanship, formwork, reinforcement placement, and construction procedures for this composite system.
Code of practice for construction of RB and RBC floors and roofs
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Minimum Concrete Grade (for RBC fill) | M 15 (15 N/mm² characteristic cube strength) | Performance-based; typically C20/25 (20 N/mm² cylinder strength) is a practical minimum for reinforced concrete elements. | EN 1992-1-1 (referenced by EN 1996) |
| Minimum Brick Compressive Strength | 10.5 N/mm² (average) | No absolute minimum; design is based on the normalized compressive strength (fb) of the unit, allowing for a wide range of materials. | EN 1996-1-1 |
| Minimum Reinforcement Cover | 15 mm or bar diameter, whichever is greater. | Depends on exposure class; for mild indoor exposure (MX1), nominal cover is typically ≥ 20 mm. | EN 1996-1-1 |
| Mortar Specification | Prescriptive mix: 1:3 (cement:sand) by volume. | Performance-based: Specified by compressive strength class (e.g., Class M4, M6, M12). | EN 1996-1-1 |
| Reinforcement Lapping | As per IS 456, often simplified to a multiple of bar diameter (e.g., 40d for tension in M15 concrete). | Calculated based on a formula considering steel stress, bond strength, bar diameter, and concrete strength. | EN 1996-1-1 |
| Design Philosophy | Working Stress Method (permissible) / early Limit State Method. | Exclusively Limit State Design (LSD) with partial safety factors. | EN 1996-1-1 / TMS 402 |