Page 422 - Design of Reinforced Masonry Structures

WALLS UNDER AXIAL AND TRANSVERSE LOADS 6.73

Caulking
No. 2
bar

Courses Courses Courses
Alternate Alternate
Control Alternate
Mortar
joint

24 × 20 24 × 24 24 × 24

Special

Courses Courses Courses
Alternate Alternate Alternate

24 × 20 24 × 24 24 × 16

FIGURE 6.41 Unbonded and bonded 24-in. pilasters [6.31].

walls spanning between horizontal supports was discussed in previous sections. It was
tacitly assumed that the wall was simply supported at top and bottom. While this approach

is simple and straightforward from design standpoint, it ignores the influence of end-
restraints at lateral supports when such supports (e.g., pilasters) are present. Also, such a
procedure may be overly conservative if the ratio of horizontal distance between lateral
supports and the height of wall (called the aspect ratio) is relatively small, and end-fixity
is developed.
This section describes a method to determine lateral forces on walls supported on three
or all four sides, and pilasters to which they may transfer their loads. In the following
discussion, the wall segments between pilasters will be referred to as wall panels. From a
structural design perspective, wall panels are assumed to function as thin plates or slabs.
In the presence of pilasters, wall panels may be thought of as panels bounded by roof and
foundation as horizontal supports, and pilasters as vertical supports. Under these support
conditions, a wall can be assumed as a vertical two-way slab and designed for two-way