Last reviewed 16 Sept 2026 · 5 min read
What reinforced brickwork is
Reinforced brickwork (RB work) is brick masonry in which steel bars are embedded in the mortar joints (or in grout-filled cavities) so that the masonry can resist tension and bending, which ordinary brickwork cannot. The bricks and mortar take compression; the steel takes tension, similar in principle to RCC.
It was widely used in India before RCC became economical and is still found in low-cost and rural construction for short spans.
Uses
| Element | Purpose |
|---|---|
| RB lintels over doors and windows | Carry masonry above the opening |
| RB slabs (floors, roofs, sunshades) | Short spans, commonly up to about 3 m |
| RB beams | Light loads, short spans |
| RB walls | Resist lateral loads (wind, earth, earthquake) and tension; grade beams, retaining walls of small height |
| RB columns / piers | Improved strength and ductility |
| Seismic bands | Horizontal reinforcement in joints or bond beams at plinth, lintel and roof levels |
Materials
- Bricks: good-quality, well-burnt bricks of adequate compressive strength, true in shape, with low water absorption.
- Mortar: rich cement mortar (commonly 1:3 cement : sand) — lime mortar is not used because the steel needs an alkaline, dense cover against corrosion.
- Steel: mild steel or HYSD bars, commonly 6–12 mm for slabs and lintels; hoop iron or wire mesh in wall joints.
- Cover: bars fully surrounded by mortar; adequate cover (at least about 15–20 mm of mortar) to prevent corrosion.
Construction of an RB slab
- Erect centering (formwork) at the soffit level, as for an RCC slab.
- Lay bricks on edge (or flat, for thin slabs) with gaps of about 25–40 mm between rows along the span for the main bars, and smaller gaps across.
- Place the main bars in the joints parallel to the span, with distribution bars in cross joints.
- Fill all joints with 1:3 cement mortar (or 1:2:4 concrete for wider joints), compacting well so the bars are fully embedded.
- Provide a top layer of concrete or plaster as wearing surface if required.
- Cure for at least 7–10 days; remove centering after the mortar has gained enough strength (commonly about two weeks for slabs).
Reinforced brick concrete (RBC)
In RBC slabs, bricks are placed with wider gaps (about 75–100 mm) filled with concrete containing the bars — a hybrid of RB and RCC. Bricks act as fillers in the tension zone and reduce the quantity of concrete and the self-weight. RBC is used for roofs of low-cost buildings; the bricks in the compression zone are designed to share compression.
Design approach and limitations
- RB members are designed like RCC members by the working stress concept, with permissible compressive stress in brickwork much lower than in concrete, and bond stress in mortar lower still.
- Joints must be wide enough for bars plus cover; this limits bar sizes and steel percentage.
- Spans are short (slabs about 3 m, lintels over ordinary openings).
- Quality depends heavily on workmanship — incompletely filled joints cause corrosion and loss of bond.
- Suitable where bricks are cheap and loads light; RCC is preferred for larger spans and important structures.
Load on lintels
A lintel below a wall with enough masonry above and beside the opening carries only the masonry within an equilateral triangle over the opening (60° lines from the ends), because the masonry above arches over it. If the height of masonry above is less than the triangle height, or if floor loads fall inside the triangle, the lintel carries the full load of masonry and those loads.
Worked example
An RB lintel spans a 1.2 m window opening in a 230 mm brick wall; bearing 150 mm each side. The wall rises well above the opening. Brickwork unit weight 19 kN/m³. Find the maximum bending moment in the lintel from the triangular masonry load (ignore lintel self-weight).
Solution. Effective span ≈ clear span + bearing m (taking centre of bearing).
Height of equilateral triangle on the clear opening m.
Load of the triangle per m of wall thickness: total weight kN.
For a triangular load of total on span (peak at centre), :
This small moment is why modest RB or RCC lintels suffice over ordinary windows.