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Frequently Asked Questions

Sawn Lumber

Wood Design consists of finding the allowable design stress for each mode of failure by multiplying the reference stress by the appropriate adjustment factors to find the design allowable stress. The breakdown for sawn lumber and structurally glued members is in Tables 4.3.1 and 5.3.1 respectively.

Structural Glued Laminated


Connections are similar to other modes of failure in which the reference value is multiplied by adjustment factors to determine the design allowable stress. Dowel Type Fastener (bolts, lag screws, wood screws, nails, spikes, drift bolts, drift pins) stresses are determined from Table 11.3.1

For Lateral Loads:

Z’ = Z x CD CM Ct Cg CD Ceg Cdi Ctn


W’ = W x CDCM2CtCegCtn

CD = Duration Factor 11.3.2

CM = Wet Service Factor 11.3.3

Ct = Temperature Factor 11.3.4

Cg = Group Action Factor 11.3.6

CD = Geometry Factor 12.5.1

Ceg = End Grain Factor 12.5.2

Cdi = Diaphragm Factor 12.5.3

Ctn = Toe Nail Factor 12.5.4