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Author Topic: Monotube Gantries  (Read 699 times)

thenetwork

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Monotube Gantries
« on: May 23, 2020, 09:50:50 AM »

Hard to believe that montube gantries have been around for at least 45 years (saw my first ones on the TV show CHiPs).  Even harder to believe that it took so long for their design to be used regularly across the country.

What states have adopted/changed to the use of monotube gantries for their overhead signs?  Also, for the individual state, is it a sporadic placement, widespread, or is it a vanity design for a specific highway?

COLORADO:  Slowly becoming the norm state-wide as new installs and replacements of older gantries.

NEW MEXICO:  In-use Statewide.

OHIO: Sporadic, though really becoming the norm in the Toledo area.

UTAH: Seems to be the norm, and has been for quite a number of years, save for some exceptions (Legacy Parkway in SLC).

Others?
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US 89

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Re: Monotube Gantries
« Reply #1 on: May 23, 2020, 01:17:58 PM »

UTAH: Seems to be the norm, and has been for quite a number of years, save for some exceptions (Legacy Parkway in SLC).

Every overhead gantry on Legacy is still monotube:



And yes, they have been the norm since at least the mid-1980s (if not earlier). The I-80/I-215/Foothill interchange used to be full of original truss gantries, but those were all replaced a few summers ago. As far as I know, there are only five truss gantries still standing in the entire state - three at the I-15/I-70 interchange, and two at the SR 56 interchange in Cedar City.
« Last Edit: May 23, 2020, 04:24:57 PM by US 89 »
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STLmapboy

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Re: Monotube Gantries
« Reply #2 on: May 23, 2020, 07:26:52 PM »

I don't believe MO has any monotube gantries. I-15 in San Diego does have some distinctive peach-colored ones, but those are the only ones I know of in Socal.
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Scott5114

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Re: Monotube Gantries
« Reply #3 on: May 23, 2020, 08:31:20 PM »

OK seems to be installing them only in urban counties. There was a bridge project on I-35 where it crosses from Cleveland to McClain County. All of the gantries on the Cleveland side were monotubes, but the one on the McClain County side was a traditional truss.
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Brandon

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Re: Monotube Gantries
« Reply #4 on: May 24, 2020, 12:14:39 AM »

Chicago has, along the Chicago Skyway mostly.  Otherwise, ISTHA has a triangular gantry they use, and IDOT has a square gantry they use (both before and after the brown gantries of the 1980s and 1990s).
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Re: Monotube Gantries
« Reply #5 on: May 24, 2020, 01:28:31 AM »

Some newer installs along NTTA toll roads (Bush Turnpike and Dallas N. Tollway especially) have monotubes, but they haven't completely replaced traditional gantries or roadside BGSes.
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Great Lakes Roads

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Re: Monotube Gantries
« Reply #6 on: May 24, 2020, 02:09:53 AM »

None on the INDOT or the Toll Road, but three local streets uses it near Interstate 465: Keystone Parkway SB @96th Street in Carmel, 86th Street, and 71st Street.

The Tampa Region in Florida uses monotubes on I-275, I-4, and FL SR 60.

The I-80 corridor through Reno has monotubes gantries throughout the area (only place in Nevada to use monotubes gantries).
« Last Edit: May 24, 2020, 02:37:02 AM by Great Lakes Roads »
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Crown Victoria

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Re: Monotube Gantries
« Reply #8 on: May 24, 2020, 08:27:50 AM »

In general, most southeastern states donít use them, with the exception of FL.  I have seen exactly 0 in the Carolinas, GA, AL, LA, and MS.  In TN, I have only seen them on the ring road serving Nashville International Airport.  I cannot remember whether or not they exist in KY now because I want to say I saw some along the Ohio River Bridges project sites in the Louisville area.
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bing101

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Re: Monotube Gantries
« Reply #9 on: May 24, 2020, 12:57:01 PM »

California some sections uses Monotube gantries.
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ilpt4u

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Re: Monotube Gantries
« Reply #10 on: May 24, 2020, 02:04:35 PM »

Chicago has, along the Chicago Skyway mostly.  Otherwise, ISTHA has a triangular gantry they use, and IDOT has a square gantry they use (both before and after the brown gantries of the 1980s and 1990s).
ISTHA uses monotube gantries for the I-Pass ORT Toll Booth lanes. Also ISTHA has used monotube gantries at newer ramp plazas as well
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hobsini2

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Re: Monotube Gantries
« Reply #11 on: May 24, 2020, 03:47:49 PM »

Chicago has, along the Chicago Skyway mostly.  Otherwise, ISTHA has a triangular gantry they use, and IDOT has a square gantry they use (both before and after the brown gantries of the 1980s and 1990s).
I never liked those ugly brown gantries. I'm glad Illinois is going back to the trusses. Now if only the stoplights on lesser roads where you don't need 3 signals on an arm would go back to the truss.
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hobsini2

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Re: Monotube Gantries
« Reply #12 on: May 24, 2020, 03:58:35 PM »

Chicago has, along the Chicago Skyway mostly.  Otherwise, ISTHA has a triangular gantry they use, and IDOT has a square gantry they use (both before and after the brown gantries of the 1980s and 1990s).
ISTHA uses monotube gantries for the I-Pass ORT Toll Booth lanes. Also ISTHA has used monotube gantries at newer ramp plazas as well
For the toll plazas, yes. and it makes sense for the to use them for the I-Pass lanes. But ISTHA never uses them for the green sign gantries. They had the opportunity to switch to it recently with the widening of I-90 and the extension of the Elgin O'Hare 390 Tollway but didn't. BTW, the plazas on the Elgin O'Hare 390 Tollway are not the same style as the I-Pass lanes on say 294 or 355. Those are more rounded. These are more squared. https://www.google.com/maps/@41.9868679,-88.1300475,3a,75y,38.68h,95.25t/data=!3m6!1e1!3m4!1sqTrAUdZD1ngrKP7cdP1VMA!2e0!7i16384!8i8192?hl=en or this https://www.google.com/maps/@41.9844772,-88.0070691,3a,75y,262.62h,89.67t/data=!3m6!1e1!3m4!1ssZqBQg5kHfNuQS9G_UNlXw!2e0!7i16384!8i8192?hl=en

One thing ISTHA has changed recently is the Plaza signs. They used to be green like this at Boughton Rd Plaza 89 for the non I-Pass lanes. https://www.google.com/maps/@41.7332056,-88.0352473,3a,75y,163.41h,89.51t/data=!3m6!1e1!3m4!1sCFNgOLAdVFwANzH4eg_goA!2e0!7i16384!8i8192?hl=en
They are blue now at that plaza as of a feww weeks ago. Unfortunately, I do not have a pic of it yet.
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Roadwarriors79

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Re: Monotube Gantries
« Reply #13 on: May 24, 2020, 05:16:39 PM »

For Arizona, monotube gantries are used almost everywhere. The South Mountain section of Loop 202 is the only new stretch of freeway that does NOT use the monotube style.
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ErmineNotyours

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Re: Monotube Gantries
« Reply #14 on: May 24, 2020, 11:32:50 PM »

Chicago has, along the Chicago Skyway mostly.  Otherwise, ISTHA has a triangular gantry they use, and IDOT has a square gantry they use (both before and after the brown gantries of the 1980s and 1990s).
ISTHA uses monotube gantries for the I-Pass ORT Toll Booth lanes. Also ISTHA has used monotube gantries at newer ramp plazas as well
For the toll plazas, yes. and it makes sense for the to use them for the I-Pass lanes. But ISTHA never uses them for the green sign gantries. They had the opportunity to switch to it recently with the widening of I-90 and the extension of the Elgin O'Hare 390 Tollway but didn't. BTW, the plazas on the Elgin O'Hare 390 Tollway are not the same style as the I-Pass lanes on say 294 or 355. Those are more rounded. These are more squared. https://www.google.com/maps/@41.9868679,-88.1300475,3a,75y,38.68h,95.25t/data=!3m6!1e1!3m4!1sqTrAUdZD1ngrKP7cdP1VMA!2e0!7i16384!8i8192?hl=en or this https://www.google.com/maps/@41.9844772,-88.0070691,3a,75y,262.62h,89.67t/data=!3m6!1e1!3m4!1ssZqBQg5kHfNuQS9G_UNlXw!2e0!7i16384!8i8192?hl=en

One thing ISTHA has changed recently is the Plaza signs. They used to be green like this at Boughton Rd Plaza 89 for the non I-Pass lanes. https://www.google.com/maps/@41.7332056,-88.0352473,3a,75y,163.41h,89.51t/data=!3m6!1e1!3m4!1sCFNgOLAdVFwANzH4eg_goA!2e0!7i16384!8i8192?hl=en
They are blue now at that plaza as of a feww weeks ago. Unfortunately, I do not have a pic of it yet.

Strange that PA uses monotubes for toll plazas, because the last latticework gantry I saw in Washington was for the photo toll equipment near Evergreen Point Bridge here.  This turned out to be a very temporary installation and they moved the equipment at bit to the west on to the same square monotubes the state has put up since the 80s.

When I was commuting to a job in 1994 I noticed something odd in the construction of a monotube sign.  Where the horizontal and vertical tube met was connected with a cast aluminum bracket.  Nothing odd about that, but when the installation was complete, they covered it with a sleeve that made it look like the tubes were welded together directly.  Or maybe I'm imagining things, but I swear I saw that bracket and I now can't see any indications that the tubes aren't welded together.
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tdindy88

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Re: Monotube Gantries
« Reply #15 on: May 25, 2020, 12:29:30 AM »

In general, most southeastern states donít use them, with the exception of FL.  I have seen exactly 0 in the Carolinas, GA, AL, LA, and MS.  In TN, I have only seen them on the ring road serving Nashville International Airport.  I cannot remember whether or not they exist in KY now because I want to say I saw some along the Ohio River Bridges project sites in the Louisville area.


I'm pretty sure the Ohio River Bridges projects did not feature any monotube gantries. I don't think I've ever seen any kind of signage like that in Kentucky at all, or Indiana for that matter.
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bing101

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Re: Monotube Gantries
« Reply #16 on: May 25, 2020, 12:47:17 AM »


Here is the first known case of a monotube gantry in California at the CA-118 freeway.


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MarkF

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Re: Monotube Gantries
« Reply #17 on: May 25, 2020, 04:04:16 AM »

The first monotubes I saw in CA were when the I-15 Escondido bypass opened in 1977, the streetlights had a similar design:

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jakeroot

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Re: Monotube Gantries
« Reply #18 on: May 25, 2020, 04:10:52 AM »

^^^^
The first monotubes I saw in CA were when the I-15 Escondido bypass opened in 1977, the streetlights had a similar design:
https://i.imgur.com/A7b8bQQ.jpg

Those almost appear to be rounded version of the welded box monotubes that WSDOT uses prolifically. Unless I'm seeing the image incorrectly.
« Last Edit: May 25, 2020, 04:31:07 AM by jakeroot »
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jakeroot

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Re: Monotube Gantries
« Reply #19 on: May 25, 2020, 04:19:06 AM »

WSDOT uses their welded box monotube standard that doesn't seem to have a domestic equivalent (at least not full width). They are very similar to the gantries used in some European countries like Germany, France, Austria, Norway, or Sweden, although only in appearance. How WSDOT constructs their gantries, I really don't know. They must weld them on the spot or something.

There have been traditional monotubes installed in Washington State, but none for a good twenty years or so; examples here and here (and all along the WA-14 Freeway in general). All examples I'm familiar with are in Clark County, just across the river from Oregon.

So, to add to the list:

WASHINGTON STATE: curved monotube gantries used sparingly in southwest part of state; box monotube structures are current standard for all overhead gantries.

Here's a picture of Washington's current highway gantries...obviously not a traditional monotube design, but does it count for the purpose of this thread?

« Last Edit: May 25, 2020, 04:28:17 AM by jakeroot »
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ErmineNotyours

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Re: Monotube Gantries
« Reply #20 on: May 25, 2020, 11:30:42 PM »

Also a curved monotube near Wenatchee.  https://goo.gl/maps/YgdBkDwKyLm1D4g66
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EpicRoadways

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Re: Monotube Gantries
« Reply #21 on: May 25, 2020, 11:44:31 PM »

The only ones in MN were installed in 2008 along the I-35W St. Anthony Falls Bridge in Minneapolis. AFAIK they haven't been used since.

https://goo.gl/maps/JnHKdvZSTEesMn3f9
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jakeroot

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Re: Monotube Gantries
« Reply #22 on: May 26, 2020, 03:25:11 AM »

Also a curved monotube near Wenatchee.  https://goo.gl/maps/YgdBkDwKyLm1D4g66

Sweet find! I had no idea there were any curved monotubes outside of Clark County. Although this is rather strange with the double monotube setup. This has to have been a one-off assembly.
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deathtopumpkins

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Re: Monotube Gantries
« Reply #23 on: May 26, 2020, 06:08:40 AM »

Massachusetts used monotubes throughout the Big Dig project area, but hasn't put up a new one since, switching back to more traditional trusses.

Example: https://goo.gl/maps/jqu6EkNq1Srdp93D6

MassDOT did use single or double mast arms for overhead signs for a while, e.g.: https://goo.gl/maps/DnDB7jQhGH34Ax6o9 though it seems new installations usually use traditional trusses.
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Re: Monotube Gantries
« Reply #24 on: May 26, 2020, 10:14:24 AM »

CTDOT seemed to use the curved monotube gantries from around 2000 to about 2010-2015.  They are quite prominent on I-95, including the Q-Bridge project.  However lately, they seem to have switched to a mixture of single chorded trusses (mostly to replace bridge mounted signage) and squared off tube gantries.  It looks like the full chorded truss May be making a comeback, as I see several newish ones in a storage area that look like theyíre reserved for the CT 72 sign replacement/exit renumbering.
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