Answers:
31.7 inches
Explanation:
Given:
Diameter = 3ft
Let D = Diameter
So, D = 3ft. (Convert to inches)
D = 3 * 12in = 36 inches
Coss-sectional area of the steel = 0.2in²
Gauge Pressure (P) = 4psi
Stress in Steel (σ)= 11.4ksi
Force in steel = ½ (Pressure * Projected Area)
Area (A) = 2 * Force/Pressure
Also, Area (A) = Spacing (S) * Wood Pipe Diameter
Area = Area
2*Force/Pressure = Spacing * Diameter
Substitute values I to the above expression
2 * Force / 4psi = S * 36 inches
Also
Force in steel (F) = Stress in steel (σ) × Cross-sectional area of the steel
So, F = 11.4ksi * 0.2in²
F = 11.4 * 10³psi * 0.2in²
F = 2.28 * 10³ psi.in²
So, 2 * Force / 4psi = S * 36 becomes
2 * 2.28 * 10³/4 = S * 36
S = 2 * 2.28 * 10³ / (4 * 36)
S = 4560/144
S = 31.66667 inches
S = 31.7 inches (approximated)