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coyote50
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- TL;DR Summary
- I'm looking to construct a simple rectangular 13'x17' hollow steel frame over my patio, but I'm getting conflicting beam deflection calculations.
I need to determine my beam size for my long spans of 17'. My plan was to use 3.5"OD A500 structural steel. 11 gauge (.120 in) wall thickness, 58 ksi, 5.64 lbs/ft. Beams will be sitting on and bolted (might weld) to large steel posts. So technically the ends of the beam will be free.
Hello,
I'm looking to construct a simple rectangular 13'x17' hollow steel frame over my patio, but I'm getting conflicting beam deflection calculations.
I need to determine my beam size for my long spans of 17'. My plan was to use 3.5"OD A500 structural steel. 11 gauge (.120 in) wall thickness, 58 ksi, 5.64 lbs/ft. Beams will be sitting on and bolted (might weld) to large steel posts. So technically the ends of the beam will be free.
Online calculations show deflections from .75" all the way past 6". Clearly something isn't right.
I'd like these two beams to be strong enough to handle a horizontal sunshade, and maybe a few hanging plants. I calculated a 150 lb downward force in the middle per beam just to be safe.
I guess I'm left scratching my head because they sell 16' span shade pergolas with these tiny cheap aluminum beams with no center support. Here at work I have 3"square, thin walled steel racking beams spanning 12' that can hold thousands of pounds with no real deflection. I would've thought my 3.5" structural steel beam would be ok.
Thoughts?
Thanks, Matt.
I'm looking to construct a simple rectangular 13'x17' hollow steel frame over my patio, but I'm getting conflicting beam deflection calculations.
I need to determine my beam size for my long spans of 17'. My plan was to use 3.5"OD A500 structural steel. 11 gauge (.120 in) wall thickness, 58 ksi, 5.64 lbs/ft. Beams will be sitting on and bolted (might weld) to large steel posts. So technically the ends of the beam will be free.
Online calculations show deflections from .75" all the way past 6". Clearly something isn't right.
I'd like these two beams to be strong enough to handle a horizontal sunshade, and maybe a few hanging plants. I calculated a 150 lb downward force in the middle per beam just to be safe.
I guess I'm left scratching my head because they sell 16' span shade pergolas with these tiny cheap aluminum beams with no center support. Here at work I have 3"square, thin walled steel racking beams spanning 12' that can hold thousands of pounds with no real deflection. I would've thought my 3.5" structural steel beam would be ok.
Thoughts?
Thanks, Matt.