Reinforced cement concrete lintels have practically replaced all other materials for the lintels. The RCC lintels have plenty of advantages over other materials as stated below.
- They are fire-proof, durable, strong, economical and simple in construction.
- Practically there is no restriction on length of span and loading.
- There is no need to go in for relieving arches.
- Use of precast units shall increase the speed of construction.
A concrete mix of 1:2:4 with mild steel reinforcement is usually adopted. Precast RCC lintels are preferred for a span of 2 m. While laying precast RCC units, special care has to be taken to see that the marked face of the lintel is on the top or upper side.
For large spans, lintels should be cast in place. Construction of RCC lintels is similar to any other RCC construction. Figure 19.11 shows the position of RCC lintel over a door or a passage. Adequate bearing is given for the lintel to sit well on the supports and the width is equal to the width of the wall.
Lintels with sunshades have to be planned sometimes. As stated earlier, the bearing for individual lintels should be at least one brick on each side. Window sunshades are also to be extended of this length of 23 cm on either side of the external opening. Sunshades should be projected for a length not less than that required to protect the window or door leaf which may have to be opened out from rains. As sunshade is a shading device, it is taken as a minimum of 60 cm for the windows of residence. For entrance doors, the length may be up to 1 m (Fig. 19.12).
Figure 19.11 Details of RCC lintel over door or passage
Figure 19.12 Lintel over a window with sunshade
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