Bending of Main post:

• 70 in from concrete to top hinge pin

• Gate volume was 772in^3

• Gate mass then should be 219 for metal and 40 for the wood, so about 260lbs

• Center of mass is around 40in from post centerline

  • Moment generated = 260lbs*40in = 10,400in-lbs

• Distance between hinges

  • 56in between them

  • 70.25in from concrete to top hinge

  • 14.0in from concrete to lower hinge

• Lateral Force on each hinge

  • 10400in-lbs/56in = 185.7

    • Lower hinge = +185.7

    • Upper hinge = -185.7

• Super position Upper hinge Deflection

  • Defl = PL^3/(3EI) = -185.7lbs * (70.25in)^3/ ( 3 * 29Msi * 8.83in^4) = -0.084in

• Super position Lower hinge Deflection

  • Defl = Pa^2(3L-a)/(3EI) = 185.7lbs* 14in^2 (3**70.25in-14in)/(329Msi * 8.83in^4) = 0.0093in

• Total Def from one post= 0.084in - 0.0093 = 0.0745in

WOW that’s less than expected, benefit of using 1/4inch thick tubing