Truss vs. tubular gantries by state

[davewiecking]

Wow, clearly I need more coffee.

I did grow up in the 80s, and can't believe that one slipped by me! 

I read it with a Southern California accent...and for some reason have seen part of Valley Girl on TV recently...

[roadman]

Box truss and trichord uprights for cantilever supports used to be common in Massachusetts until the mid-1970s.  Massachusetts stopped using the design, principally for asethetic reasons, when they stopped allowing aluminum sign supports (due to issues with premature fatigue).

There are a small number of trichord upright cantilever supports still in place on sections of I-495 - they are planned to be replaced as part of current and future sign replacement projects.

Aren't there still some trichord cantilever supports along I-95 between Topsfield/Danvers (Exit 50/US 1) and Byfield/Newbury (Exit 55/Central St.)?  GSV still shows them circa 2011. 

You (Roadman) know this, but for those that don't; those date back to when I-95 was widened to 8-lanes during the mid-1970s. 

The trichord cantilever supports on I-95 north of 97 in Georgetown were replaced under the Salisbury to Georgetown sign replacement project completed in late 2013.  The trichord cantilever supports on I-95 south of 97 in Georgetown will be replaced in early to mid 2015 under the Peabody to Georgetown sign replacement project currently underway.

[PHLBOS]

Wow, clearly I need more coffee.

I did grow up in the 80s, and can't believe that one slipped by me! 

I read it with a Southern California accent...and for some reason have seen part of Valley Girl on TV recently...

Let's go with the original, shall we? 

[JakeFromNewEngland]

What is the name for this type of support (from kurumi.com)?

Monotube cantilever, I believe? Oregon uses both these and trusses.

I've always thought those gantries looked unappealing. I prefer tubular or the cantilever truss gantries that have been showing up recently.

[Gnutella]

That looks like a good PennDOT sign.
(Think District 2 or District 11, not District 1 or District 4.)

[wriddle082]

Speaking of Kentucky, it's the only place I've seen that uses what I've seen called an "erector set" support for overheads.

I've seen a couple of older overheads similar to this only in NC.  One of them might still be standing on I-40 west at the ramp for US 25 south in Asheville.  I can't remember where I saw the other one.  The horizontal component of this one was prism-shaped instead of rectangular-shaped.

Also, KY used to have a "T" variant of that gantry that I once saw on US 60 westbound at New Circle Rd in Lexington, long before they rebuilt that 40's or 50's era cloverleaf into a SPUI.  I might have seen another one somewhere in the Louisville area, like maybe on I-264 at US 31W/60 in Shively?

[hbelkins]

Maybe the exit signage for River Road and 3rd Street/4th Street, where there are two signs, one for thru westbound I-64 and one for the ramp from I-65?

[roadman65]

I always liked Kentucky's overheads with the truss support posts on their half sign bridges.

You could actually start another thread with truss gantries as there are many different designs of them.

[kphoger]

Wow, clearly I need more coffee.

I did grow up in the 80s, and can't believe that one slipped by me! 

I read it with a Southern California accent...and for some reason have seen part of Valley Girl on TV recently...

Let's go with the original, shall we? 

Good ol' Moon Unit!

[riiga]

Not a US state, but Sweden uses truss gantries, as does Norway.


Older signs were mounted on rectangular tubelike gantry.

[kphoger]

^^ I'm pretty sure that Y-RING is should be a brand of birth control.

[riiga]

^^ I'm pretty sure that Y-RING is should be a brand of birth control.

Heh, it's short for "Yttre ring" = Outer Ring. We have a C-RING too, the (City) Center Ring.

[Gnutella]

Not a US state, but Sweden uses truss gantries, as does Norway.

The truss gantry itself looks fine, but when they're used also as supports, they look kind of insubstantial, like they could be twisted easily in high winds. I could be wrong, though. Maybe I'm just used to big, beefy gantry supports, I guess.

[The High Plains Traveler]

Minnesota is almost all truss, one notable exception being the gantries on the "new" (if six years old isn't really new anymore) I-35W bridge which features tubulars.

I attribute the monotube sign supports on the I-35W bridge as being due to the fact that the bridge was reconstructed by a Colorado construction company (Flatiron). Tubulars are being used on virtually all new sign installations in Colorado.

[riiga]

The truss gantry itself looks fine, but when they're used also as supports, they look kind of insubstantial, like they could be twisted easily in high winds. I could be wrong, though. Maybe I'm just used to big, beefy gantry supports, I guess.

It's just looks, they're very stable for their size and I'm yet to hear of any ones failing or falling due to only wind. Then again, we don't have extreme weather like tornados, tropical storms, or supercell thunderstorms here.

[roadman65]

I just remembered, that here in Orlando we have one tubular gantry on the east end of World Center Drive where it defaults onto FL 417. 

AA Roads here has a photo of it in the FL 536 page.

https://www.aaroads.com/guide.php?page=s0536fl

[ztonyg]

I would like to know, what type of gantries are current standard installation by each state - truss or tubular?

Here is what I know:

• Arizona - Tubular
• California - Mostly truss, but some tubular gantries installed as well.
• Nevada - Truss
• New Mexico - Tubular
• Virginia - Truss

Does anyone know about other states?

Arizona uses both Truss and Tubular.  Older gantries are truss, newer installations are tubular. 

[Scott5114]

Oklahoma has been using more tubular gantries in recent years. The new I-40 near downtown Oklahoma City uses them, along with I-35 through Norman and I-44 through part of Tulsa. All these sections of highway have been reconstructed or built during this decade.

As always, though, nothing is simple with ODOT. It seems to be a county-by-county thing, because the I-35 Canadian River bridge project used tubular gantries on the bridge and Cleveland County soil, and a brand new truss cantilever on McClain County soil.

[SSOWorld]

Iowa and WI are Truss states. 

[Pink Jazz]

Arizona uses both Truss and Tubular.  Older gantries are truss, newer installations are tubular.

This thread is specifically about current standards.  Current installations are tubular.

FYI New Mexico also used truss a very long time ago.  Truss gantries are now very rare in NM.

[Greybear]

I've seen tubular gantries in parts of Colorado and Texas. It's been rare to see tubular gantries in the Northeast.

I think the El Paso district of TXDOT uses tubular gantries as standard installation; not sure about the rest of the state.

North Texas districts use truss gantries.  North Texas Tollway Assoc. (NTTA) pretty much uses tubular on new gantries but still have some truss still in use.

[shadyjay]

CT seems to have stopped using the tubular only if the design of the project is being built today but was designed 10 years ago.  No new designs seem to have them.

This one is fairly recent (within the last 3 years).

Nope, that one goes back farther than you'd think.   Sometime around 2005.  It just looks newer because of the signs applied to it, but it replaced one of the green-colored supports similar to the one linked on the I-91 Exit 15 photo.  Apparently the official name is "Tubular Bridge" for one that spans the highway, or "Tubular Cantilever" only spanning one lane / one support. 

The current standard throughout CT on new projects seems to be the heavy duty truss gantries, some being capable of supporting two signs but with only a right hand support.  See an example here:
http://www.goo.gl/maps/xjOsR
Official name:  4-Chord Truss Cantilever (mounts on one side) / 4-Chord Truss Bridge (spans full length of roadway)

I-84 in Danbury seems to be the only sighting of the heavy duty steel angled posts (tubes without the angles).  See here:
http://www.goo.gl/maps/1bf4h
Official name:  Monotube Bridge. 
I-91 will be getting one SB at Exit 40 and NB at Exit 10, both which are missing signs/gantries altogether presently, and have been for a little while now. 

And of course there are plenty of these around, in a variety of color schemes (brown/green/yellow/grey):
http://www.goo.gl/maps/IXOaY
If I'd have to put $$$ on it, I'd guess all Exit 15 signs will go to the ground when it comes time to replace them.  Same with Exit 14.  Exit 13 as well.  ConnDOT is on a real kick to eliminate overheads. 

[JakeFromNewEngland]

CT seems to have stopped using the tubular only if the design of the project is being built today but was designed 10 years ago.  No new designs seem to have them.

This one is fairly recent (within the last 3 years).

Nope, that one goes back farther than you'd think.   Sometime around 2005.  It just looks newer because of the signs applied to it, but it replaced one of the green-colored supports similar to the one linked on the I-91 Exit 15 photo.  Apparently the official name is "Tubular Bridge" for one that spans the highway, or "Tubular Cantilever" only spanning one lane / one support. 

The current standard throughout CT on new projects seems to be the heavy duty truss gantries, some being capable of supporting two signs but with only a right hand support.  See an example here:
http://www.goo.gl/maps/xjOsR
Official name:  4-Chord Truss Cantilever (mounts on one side) / 4-Chord Truss Bridge (spans full length of roadway)

I-84 in Danbury seems to be the only sighting of the heavy duty steel angled posts (tubes without the angles).  See here:
http://www.goo.gl/maps/1bf4h
Official name:  Monotube Bridge. 
I-91 will be getting one SB at Exit 40 and NB at Exit 10, both which are missing signs/gantries altogether presently, and have been for a little while now. 

And of course there are plenty of these around, in a variety of color schemes (brown/green/yellow/grey):
http://www.goo.gl/maps/IXOaY
If I'd have to put $$$ on it, I'd guess all Exit 15 signs will go to the ground when it comes time to replace them.  Same with Exit 14.  Exit 13 as well.  ConnDOT is on a real kick to eliminate overheads.

There is another monotube bridge design at Exit 87 on I-95 southbound: https://www.google.com/maps/@41.359867,-72.050842,3a,75y,281.39h,90.93t/data=!3m4!1e1!3m2!1sbKwUtvJzGwX35rXtK458Ug!2e0?hl=en

[PHLBOS]

CT seems to have stopped using the tubular only if the design of the project is being built today but was designed 10 years ago.  No new designs seem to have them.

This one is fairly recent (within the last 3 years).

Nope, that one goes back farther than you'd think.   Sometime around 2005.  It just looks newer because of the signs applied to it, but it replaced one of the green-colored supports similar to the one linked on the I-91 Exit 15 photo.  Apparently the official name is "Tubular Bridge" for one that spans the highway, or "Tubular Cantilever" only spanning one lane / one support.

So you're saying that the signs are newer than the gantry; am I correct?  That LEFT EXIT tab clearly screams MUTCD 2009; something that ConnDOT's only recently fully adopted.

I remember the old (80s-vintage) green gantry (I do travel this road several times a year during the last 24 years) and signs (all button-copy w/reflectorized sheeting).  I just do not recall an older set of signs on that tubular gantry.

This one looks definitely newer than 2005.

[shadyjay]

So you're saying that the signs are newer than the gantry; am I correct?  [/quote]

Yup, that's exactly what I'm saying....
(not my photo, though)


Back when it went up, it must've been just a support replacement, as CT was well out of the button copy "Phase III" era by then.  Now, most support replacements involve new signs as well. 

The other photo in the "canyon" in Hartford, WB, is new, installed only within the past couple of years.  Big giveaways there are the aligned exit tabs with borders.  Of course that's the new standard for signs in CT.  Those on I-95 west of New Haven missed the "border revolution", while those on the "Q" are getting the full border treatment.

There is also a new cantilever pipe gantry going on I-95 SB down in Fairfield County, in the current (2014) spot overhead replacement project.  It's actually being relocated from I-84 WB in Waterbury, so that's why.