overhead sign support angle top and bottom chord
overhead sign support angle top and bottom chord
(OP)
i design pipebridge (not an actual bridge see pic attached) from time to time and in all cases i had to use wide flange beam for bottom and top chord because of bending.
i'm confused because i see these sign supports all the time in freeway some even around 100' and angles are working fine.
can someone link me the analysis of these supports. are the bottom and top chord assumed as axial only because i cant see these angles passing if it were to take bending.
i'm confused because i see these sign supports all the time in freeway some even around 100' and angles are working fine.
can someone link me the analysis of these supports. are the bottom and top chord assumed as axial only because i cant see these angles passing if it were to take bending.






RE: overhead sign support angle top and bottom chord
RE: overhead sign support angle top and bottom chord
RE: overhead sign support angle top and bottom chord
I like your pipebridge much better.
RE: overhead sign support angle top and bottom chord
The only sign structures we design in NY are ones carrying VMS. They're quite heavy at times and the size of the sign is specific to the location. These are quad trusses, which we design as a space truss. The truss is simply supported. The members are always round sections. I attached the NYSDZOT sign structure design manual for reference. I'll also post the VMS design manual.
RE: overhead sign support angle top and bottom chord
RE: overhead sign support angle top and bottom chord
RE: overhead sign support angle top and bottom chord
RE: overhead sign support angle top and bottom chord
Anyway, the whole thing was built from angles. 6x6x1/2" for the (4) chords and 3x3x3/8" for the diagonals. It was 4'-5" wide and 5'-9" deep.
Link
RE: overhead sign support angle top and bottom chord
I model mine as one continuous beam for top and bottom chord, shear connected at the column. Vertical and horizontal brace as truss member.
Is there another way of analysis for this truss? Can this be analyze as one built up shape basically just one member?
I haven't read the PDF I downloaded. I'm curious how those angle top and bottom chord are passing.
RE: overhead sign support angle top and bottom chord
RE: overhead sign support angle top and bottom chord
My guess, in no particular order:
Aesthetics;
No horizontal projections to accumulate snow, debris or provide a home for pigeons;
More torsional rigidity with a tube versus angle;and
That's what the DOT tells us to use
From a fabrication standpoint gusset plates with angles is easier.
RE: overhead sign support angle top and bottom chord
RE: overhead sign support angle top and bottom chord
The telecom industry does use round solid or pipe type legs with welded gusset plates on their 3 sided free standing towers. They do sometimes use 60° angles as legs.
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I have been called "A storehouse of worthless information" many times.
RE: overhead sign support angle top and bottom chord
And it's still there to this day.
RE: overhead sign support angle top and bottom chord
I'll see your monotube and raise you 3 monotubes. This one's about 15 miles from my house. It was erected about 12 years ago and one of the first uses of a monotube sign structure in the region.
RE: overhead sign support angle top and bottom chord
RE: overhead sign support angle top and bottom chord
RE: overhead sign support angle top and bottom chord
RE: overhead sign support angle top and bottom chord
RE: overhead sign support angle top and bottom chord
RE: overhead sign support angle top and bottom chord
Yes. That's essentaially what a truss model is, with some shear flexibility thrown in, right?
That is what I would do for physically continuous chords. Hopefully the shear stiffness of the truss is high enough that it wouldn't matter much either way.
I believe that sign structures are allowed to be designed rather aggressively with regard to their flexibility. Perhaps that accounts for some of the difference. Locally, we've had some issues with resonant vibration.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: overhead sign support angle top and bottom chord
RE: overhead sign support angle top and bottom chord
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.