Page 217 - Design of Reinforced Masonry Structures

DESIGN OF REINFORCED MASONRY BEAMS 4.81

4.13.2.2 Arching Action in Masonry Walls Because the exact load distribution in a wall
above an opening is uncertain, the load carried by a lintel is really indeterminate. The span
of a lintel varies depending on the width of the wall opening (for doors and windows). The
height of the wall above a lintel may be small or large relative to its span, which depends
on the building configuration (heights of doors, and floor-to-floor, or floor-to-roof heights,
see Fig. 4.13a).
Design loads for lintels can be estimated based on certain assumptions. For a lintel
supporting a wall at least as high as its span, and when there are also substantial piers
(wall-segments) on both sides of the openings, it may be assumed that arching action
develops in the wall, which transfers a good portion of the wall load over the lintel to the
masonry on either sides of the openings as shown in Fig. 4.22a, and only a small triangular

FIGURE 4.22 Load distribution on lintels.