REINFORCED BRICK MASONRY

Ordinary brick masonry can not take tensile stresses as the mortar joints separate out and the bricks pulled out. In order to increase the load-carrying capacity, in particular tensile stresses, of ordinary brick masonry steel reinforcement is introduced in between mortar joints. This type of construction can withstand tensile and shear stresses for moderate loading.

Reinforced brick masonry is recommended in the following cases:

1. When excessive compressive loads are to be supported
2. When the brickwork has to withstand tensile and shear stresses
3. When the supporting soil may be subjected to differential settlement
4. When the brick masonry is to be provided over openings of doors, windows and passages
5. When the brick masonry has to sustain lateral stress
6. When it is intended to strengthen the longitudinal bond
7. When constructions in earthquake-prone areas are to be made

The following points should be kept in mind:

1. All the bricks should be structurally sound and of uniform size.
2. In order to bond the brickwork, a cement mortar of 1: 3 should be used.
3. The joints have to be constructed carefully such that the reinforcement gets sufficient cover and is also prevented from corrosion.

Typical reinforced brick masonry are discussed below.

Reinforced Brick Masonry Walls

Here the reinforcement may be iron base or expanded metal mash provided at every third or fourth course. Flat bars of section about 25 mm × 2 mm may be used as hoop iron reinforcement for walls. They are hooked at corners and junctions. In order to increase the resistance against rusting, the bars are dipped in tar and sanded immediately. Reinforcement in vertical direction is provided by using special bricks or blocks. Mild steel bars of 6 mm diameter may also be used as longitudinal reinforcement in walls. A detailed discussion is made in Chapter 7.

16.5.2 Reinforced Brick Masonry Columns

These columns are made with special-purpose bricks and vertical bars running through them. In order to keep the bars in position and to strengthen the brickwork, steel plates of 6 mm thick are introduced. Bent bars of small diameters of about 12 mm can be used in the horizontal joints (Fig. 16.13).

Figure 16.13 Reinforcement of brick masonry column

Reinforced Brick Masonry Lintel

In lintels, bars are provided longitudinally in between the vertical joints and extending from joint to joint. Further, to resist the vertical shear, additional 6 mm diameter steel stirrups may be used (Fig. 16.14).

Reinforced Brick Masonry Slab

Floor slabs of brickwork with reinforcement is also done. The conventional centring is made. The centring is covered with earth for a depth of about 20–25 mm and well compacted and sand sprinkled on the top.

Figure 16.14 Reinforcement in brick masonry lintels

Then the reinforcement is placed in the correct direction. The bricks are laid in one or two directions. The joints are then filled with mortar such that the reinforcement is fully closed. The work is kept moist for a period of two days and then kept fully wet for 14 days. The centring is then removed. The top and bottom surface of slab are then suitably finished (Fig. 16.15).

Figure 16.15 Slab with reinforced brickwork