FEMA P55 Coastal Construction Manual, Fourth Edition - Mad Cad

13 CONSTRUCTING THE BUILDING Volume II
Figure 13-22.
Full-height sheathing to
improve transfer of shear
The design drawings may show tiedown connections between large shearwall vertical posts and main girders.
Especially in larger, taller buildings, these connections must resist thousands of pounds of overturning
forces during high winds. See Section 8.7 for information regarding the magnitude of these forces. The
connections must be accomplished with careful layout, boring, and assembly. Shear transfer nailing at the
top plates and sills must be in accordance with the design. Proper nailing and attachment of the framing
material around openings is very important; see Section 9.2.1 for a discussion of the difficulty of transferring
large shear loads when there are large openings in the shearwall.
It is very important that shearwall sheathing (e.g., plywood, oriented strand board [OSB]) with an
exterior exposure be finished appropriately with pigmented finishes such as paint, which last longer than
unpigmented finishes, or semitransparent penetrating stains. It is also important that these finishes be
properly maintained. Salt crystal buildup in surface checks in siding can damage the siding. Damage is
typically worse in siding that is sheltered from precipitation because the salt crystals are never washed off
with fresh rainwater.
To meet the design intent, walls must:
Be plumb and square to each other and to the floor
Be lined up over solid support such as a beam, floor joists, or a perimeter band joist
Not have any more openings than designated by the plans
Not have openings located in places other than designated on the plans
Consist of material expected to resist corrosion and deterioration
Be properly attached to the floors above and below the wall, including the holddown brackets required
to transfer overturning forces
13-26 COASTAL CONSTRUCTION MANUAL