Out-of-plane Sheathing Capacities

The table below indicates where to find the out-of-plane wind capacities of the sheathing material used in Shearwalls, in pounds per square foot on exterior surfaces of the building, for the following materials

• wood structural panels
• fiberboard
• lumber siding

from the

• AWC Special Design Provisions for Wind and Seismic (SDPWS)
• Wood Frame Construction Manual (WFCM).

These values represent the maximum component and cladding wind loads which create allowable bending and shear stresses in the sheathing material.

Values from WFCM

Values for lumber siding are taken from the 2001 (and later) WFCM , as SDPWS does not list these values. Values for 5/16” sheathing are taken from the 1995 WFCM as they are in neither the SDPWS nor the 2001 WFCM.

Wind Load Duration Factor

The SDPWS values incorporate a wind load duration value of 1.6, so Shearwalls does not apply a further load duration factor. WFCM does not include the load duration factor, so lumber siding values from the WFCM are multiplied by the 1.4 factor given in WFCM table 4A.

ASD Design Factor

The values are divided by 1.6 for ASD design in Shearwalls, in accordance with SDPWS 3.2.1

Continuous Support Assumption

The WFCM values were based upon the assumption of three span stud support, the SDPWS is based on two spans. SDPWS C3.2 says that the reason for this change is that two span conditions often exist at end zones where the forces are highest.

The program allows you to select which assumption you prefer based on the characteristics of your building, via 2-span and 3-span buttons in the Out-of-plane sheathing assumption data group in the Design settings. The span assumption appears in the legend below the Components and Cladding by Shear Line table.

The default value for new files is 2-span, in accordance with SDPWS.

When 3-span is selected, the factored tabulated values are multiplied by 1.25.

Output

These values are shown in the Components and Cladding Design table of the Design Results.