Calculate Withdrawal Strength of Dowel-type Fasteners

The following is for calculating withdrawal strength of connection made up of lag screws, wood screws or nails and spikes.



N - Number of fasteners
G - Specific gravity of wood member
D - Fastener diameter
L - Average Length of fastener penetration into side grain of member
Cd - Load duration factor
Cm - Wet service factor*
Ct - Temperature factor*
Ceg - End grain factor*
Ctn - Toe-nail factor*
TEF -  - Time effect factor
*Note if the factor is not required leave the default value set at 1.00.

W(LS) - lag screws, withdrawal strength
W(WS) - wood screws, withdrawal strength
W(NS) - nails and spikes, withdrawal strength
W' -  adjusted withdrawal strength
WR - Connection withdrawal resistance

W(LS) - lag screws
W(WS) - wood screws
W(NS) - nails and spikes