Page 248 - Design of Reinforced Masonry Structures
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DESIGN OF REINFORCED MASONRY BEAMS 4.111
4.16 DIAPHRAGM ACTION
4.16.1 In-Plane Loads in a Diaphragm
To understand the mechanism by which axial force is developed in a bond beam, it is
essential to understand the diaphragm action in a building. Essentially, walls are sub-
jected to lateral loads due to wind or earthquakes as shown in Fig. 4.32. These loads are
transmitted to the lateral load resisting elements of a building on the tributary area basis.
Typically, in a single-story building, lateral loads on the lower half of the wall are trans-
mitted to the floor, whereas those from the upper half of the wall, including those from
the parapet, are transferred to the roof. The roof then acts as a large horizontal member
resisting lateral loads in its own plane (i.e., acts as a diaphragm)—this mechanism is
known as diaphragm action, and causes in-plane loads in the diaphragm. The roof, in
turn, transfers these in-plane loads to shear walls through the connection hardware. And
finally, the shear walls transfer all loads to the foundation.
FIGURE 4.32 Diaphragm action in a roof due to lateral loads.
