Page 212 - Design of Reinforced Masonry Structures

4.76 CHAPTER FOUR

FIGURE 4.15 Wall loads on lintels.

and b). In addition, a lintel might have to support concentrated loads from roof joists/floor
beams, or other beams framing into the wall.
A variety of schemes are used to provide lintels in masonry buildings. Lintels may be
constructed from materials such as steel, reinforced concrete (precast or cast-in-place),
wood, and reinforced masonry. Figure 4.16 shows several schematics of steel lintels used
in masonry structures. Those shown in Fig. 4.16a, b, and c are made up of steel angles, and
are used for relatively small openings. For longer spans and heavier loads, steel W-shapes
with suspended soffit plates (Fig. 4.16d) may be used. Figure 4.17 shows steel W-shapes
installed as lintels in a masonry building under construction.
Figure 4.18 shows reinforced concrete masonry lintels under construction. Figures 4.19
to 4.21 show several commonly used schemes of concrete and brick masonry lintels. In
general, masonry lintels make it easy to maintain the bond pattern, color, and surface tex-
ture of the surrounding masonry, an important consideration for a building’s aesthetics and
architecture. Masonry lintels provide an advantage over steel or precast concrete lintels in

that no special lifting equipment is required for their construction.
Masonry lintels must be reinforced because of the masonry’s inherent weakness in
tension. Typical reinforced brick and concrete masonry beams and lintels are shown in
Figs. 4.18 to 4.20. Figure 4.20a and b show lintels that can be constructed from single or
multiwythe bricks to attain the desired widths. Note the special U-shaped lintel units that
can be used to construct reinforced masonry lintels (Fig. 4.21c). To carry tension in the
bottom fibers of a masonry lintel, it is a common practice to provide typically one or two
reinforcing bars which are grouted, which enables them to act in unison with masonry lintel
blocks after the grout sets. In general, masonry lintels are integral part of the masonry walls,
and therefore, their widths are same as that of the wall of which they are a part.
With the exception of steel and precast concrete lintels, some sort of temporary support is
required as the masonry is laid for a lintel or a beam as shown in Fig. 4.18. The function of