Page 213 - Design of Reinforced Masonry Structures

DESIGN OF REINFORCED MASONRY BEAMS 4.77

FIGURE 4.16 Steel lintels. (Courtesy: NCMA.)

such a support is simply to act as a temporary support until the grout in the masonry sets. Some
types of supports, such as a steel plate or angles, may even be left in place permanently.
This section presents a simplified approach to analysis and designs of reinforced
masonry lintels. Regardless of the type of masonry (concrete or clay) used for lintels,
once the masonry walls are completed, the lintels become integral part of these walls and
are usually indistinguishable from the wall (Fig. 4.15a). The segment of the wall sup-
ported directly above the opening, which is an integral part of the surrounding wall, is

often referred to as a “wall beam” or “deep wall beam” and may be analyzed as a deep
beam (which is a rigorous analysis similar to that for reinforced concrete deep beams) as
discussed in the next section.

4.13.2 Design Considerations
4.13.2.1 Effective Span Lintels must bear on supporting masonry on each side of the
opening. The effective span of a lintel is assumed as the distance between the centers of
bearings on either side of the lintel. MSJC-08 Section 2.3.3.3 [4.2] requires that lintels have
a minimum bearing of 4 in. This minimum bearing length of 4 in. in the direction of span is
considered a reasonable minimum for masonry beams over door and window openings in