# Aluminum post/base strength

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• 04-10-2018, 10:00 AM
dave_blackburn
Aluminum post/base strength
Hi!
I'm building a driveway gate and I'm having a hard time finding info on aluminum strength for the posts.
Gate will be aluminum tube, approximately 57" x 104" and should weigh about 100lb. I want to install a 6x6" .250 wall post on the footing. It will be about 96" tall with a welded base plate 14" square (3/8 or 1/2) to bolt through and swing the gate on hinges 2 at approximately 36" and 84" from the bottom.
Will the 6x6 and base plate support a 100lb cantilevered load?
Thanks for any help!
Dave
• 04-10-2018, 02:00 PM
Kelly Bramble
There are statics calculators available on the following webpage.

[U][B][URL="https://www.engineersedge.com/beam_calc_menu.shtml"]Beam Deflections and Stress Equations and Calculators[/URL][/B][/U]

For simplicity, I recommend concentrating the load calculations at one point to compensate to the FOS.

See:

[U][B][URL="https://www.engineersedge.com/beam_bending/beam_bending10.htm"]Cantilevered Beam with Load at Location Between Support and Load Equations and Calculator[/URL][/B][/U]

You could also use this Flagpole Base Design Calculator to determine the bearing loading in the ground.

[U][B][URL="https://www.engineersedge.com/calculators/flagpole-base-design-calculator.htm"]Flagpole Base Design Calculator[/URL]
[/B][/U]
• 04-10-2018, 02:07 PM
Kelly Bramble
Also, to determine the area moment of inertia (to determine the section modulus) of your poles see..

[U][B][URL="https://www.engineersedge.com/section_properties_menu.shtml"]Section area moment of inertia equations and calculators[/URL][/B][/U]

Specifically, [U][B][URL="https://www.engineersedge.com/material_science/moment-inertia-gyration-3.htm"]Section properties of pipe[/URL]

[/B][/U]or for [U][B][URL="https://www.engineersedge.com/materials/aisc_structural_shapes/aisc_structural_shapes_viewer.htm"]AISC Shapes[/URL][/B][/U]

and, material engineering characteristics.

[U][B][URL="https://www.engineersedge.com/manufacturing_spec/properties_of_metals_strength.htm"]Aluminum and Steel Engineering Properties[/URL][/B][/U]
• 04-11-2018, 09:54 AM
dave_blackburn
Thanks, tried my best with those calculators. I think I figured it out.