IS 4326:1996 is the Indian Standard (BIS) for earthquake resistant design and construction of buildings - requirements for masonry buildings. This code establishes guidelines for the earthquake-resistant design and construction of buildings, with a primary focus on unreinforced and reinforced masonry structures. It provides essential prescriptive detailing requirements, such as seismic bands and vertical corner reinforcements, to ensure buildings exhibit box-like action and avoid brittle failure during seismic events.
Lays down requirements for earthquake resistant design and construction of masonry buildings.
Seismic-resistant masonry construction — bands, openings, corner reinforcement, mortar grades and storey limits for low-rise load-bearing buildings.
| Reference | Value | Clause |
|---|---|---|
| Applicability — building category | Load-bearing masonry up to 3 storeys (zones III, IV, V) | Cl. 1.2 |
| Min wall thickness — load bearing (1 storey) | 200 mm (brick) / 230 mm (depending on units) | Cl. 8.1 |
| Plinth band — required (zones III, IV, V) | Yes (RC band, full perimeter) | Cl. 8.4.1 |
| Lintel band — required | Yes (continuous over openings) | Cl. 8.4.2 |
| Roof / gable band — required (zones IV, V) | Yes | Cl. 8.4.3 |
| RC band — min depth × steel | 75 mm × wall width with 2 × 8 mm bars (zone III) up to 150 mm with 4 × 10 mm (zone V) | Cl. 8.4 (Table 4) |
| Stirrup in RC band | 6 mm @ 150 mm c/c | Cl. 8.4 (Table 4) |
| Max opening size — door (% of wall length) | ≤ 30 % (zone V); 35 % (zone IV) | Cl. 8.5 (Table 5) |
| Max total openings (windows + doors) per wall | ≤ 50 % (zone IV); 42 % (zone V) | Cl. 8.5 (Table 5) |
| Min pier width between openings | ≥ 600 mm (zone IV/V) | Cl. 8.5 (Table 5) |
| Distance — opening from corner (min) | ≥ 600 mm | Cl. 8.5 |
| Vertical reinforcement at corners — bar size | 10–12 mm (zone IV); 12 mm (zone V) | Cl. 8.4.5 |
| Vertical reinforcement at jambs — bar size | 10 mm (zone IV); 12 mm (zone V) | Cl. 8.4.5 |
| Mortar — min grade | M1 (1:4 cement-sand for zone V) or H2 | Cl. 7.1 / IS 1905 |
| Anchorage of RC band steel at junction | Continuous, overlap ≥ 60 φ | Cl. 8.4 |
| Through-stones — required (rubble/random masonry) | 1 per 0.5 m² of wall area | Cl. 7.4 |
| Roof slab anchorage (RCC) — to wall | Mandatory continuous bond to lintel band | Cl. 8.4.4 |
| Buttresses — required spacing (long walls) | ≤ 6 m or every cross-wall | Cl. 8.6 |
| Height of building — max load-bearing brick (zone V) | 2 storeys (≤ 7 m) | Cl. 8.1 |