Nails Spikes Withdrawal Load

Overview

Engineering reference data for Nails Spikes Withdrawal Load in mechanics.

Key Formulas

Newton's Second Law

$F = ma$

Force = mass × acceleration.

Work

$W = Fd\cos\theta$

Work = force × displacement × cos(angle).

Kinetic Energy

$E_k = \frac{1}{2}mv^2$

Energy of motion.

Potential Energy

$E_p = mgh$

Gravitational potential energy.

Variables

Symbol	Description	Unit
$F$	Force	N
$m$	Mass	kg
$a$	Acceleration	m/s²
$v$	Velocity	m/s

Formula: Allowable Withdrawal Load

The allowable withdrawal load or force for a common nail or spike driven into side grain perpendicular to the fibers of seasoned wood can be estimated using the following formula:

$F = 1380 \cdot SG^{5/2} \cdot D$

Where:

• F = allowable withdrawal load or force per inch of penetration (lb/in)
• SG = specific gravity of oven dry wood
• D = diameter of nail or spike (inches)

Note: The allowable load calculated is 1/5 of the ultimate withdrawal resistance (USDA document FPL-0100). This safety factor is applied to determine the design allowable value.

Example Calculation

For Canadian Spruce (SG = 0.45) with a 20D nail (D = 0.203 in): $F = 1380 \cdot (0.45)^{5/2} \cdot 0.203 = 38 \text{ lb/in}$

Nails and Spikes - Withdrawal Force Data

US Wire Nails (Spruce, SG = 0.5)

Metric Wire Nails (Spruce, SG = 0.5)

Interactive Charts

References

• Original Source