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Monotube Gantries

Started by thenetwork, May 23, 2020, 09:50:50 AM

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Pink Jazz

In Texas, they are pretty much standard in the El Paso District, but are less common in other parts of the state.


tolbs17

Comparing the west coast to the east coast, they are definitely more common there compared to the east coast with absolutely no such signage in states like GA, SC, NC, VA, MD, DE, NJ, etc.

I wonder what the advantage of using monotube signs are but they look uglier compared to the traditional trusses we use.

Scott5114

They're easier to fabricate, and probably use less material. Both of those would make them cheaper.
uncontrollable freak sardine salad chef

zachary_amaryllis

Quote from: Scott5114 on February 02, 2022, 11:25:59 PM
They're easier to fabricate, and probably use less material. Both of those would make them cheaper.

i think the ones here in colorado are just ... funny looking. there's probably structural/technical details that are beyond what i know, but they just look weird to me.
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ran4sh

Quote from: tolbs17 on February 02, 2022, 11:14:36 PM
Comparing the west coast to the east coast, they are definitely more common there compared to the east coast with absolutely no such signage in states like GA, SC, NC, VA, MD, DE, NJ, etc.

I wonder what the advantage of using monotube signs are but they look uglier compared to the traditional trusses we use.

I also don't encounter monotube gantries on a regular basis, but I've never heard anyone say they're uglier than the trusses used in the Southeast.
Control cities CAN be off the route! Control cities make NO sense if signs end before the city is reached!

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thenetwork

One surprising monotube design I've seen that didn't last too long are some of the monotubes in Southern California (especially along I‐15 between San Bernardino and San Diego) that start at a slight angle from the ground then a not-so-tight horizontal turn up top.

Was that design not as reliable as the most common monotube designs?

tolbs17

I have to exclude Delaware. More monotube gantries are coming up when looking at the recent sign placements.

jaehak

It seems like they are really common on I-15 specifically, at least more so than any other x0 or x5.

US 89

Quote from: jaehak on February 22, 2022, 11:56:54 AM
It seems like they are really common on I-15 specifically, at least more so than any other x0 or x5.

Eh, 25 might edge it out given all of its major population centers are in Colorado and New Mexico, which make heavy use of monotubes. I-15 has plenty in the California and Utah cities it passes through, but the other states along 15 (including Nevada with Las Vegas) don't really use them as far as I know.

skluth

Quote from: zachary_amaryllis on February 02, 2022, 11:35:07 PM
Quote from: Scott5114 on February 02, 2022, 11:25:59 PM
They're easier to fabricate, and probably use less material. Both of those would make them cheaper.

i think the ones here in colorado are just ... funny looking. there's probably structural/technical details that are beyond what i know, but they just look weird to me.
Personally, I think trusses are far uglier than monotubes which I find simple and elegant.

SkyPesos

#35
Quote from: jaehak on February 22, 2022, 11:56:54 AM
It seems like they are really common on I-15 specifically, at least more so than any other x0 or x5.
Now I'm kind of wondering which interstate is the longest without monotubes. So far, with the longest overall...

I-90: box monotubes in WA
I-80: monotubes in UT, and possibly CA as well
I-40: monotubes in NM
I-10: monotubes in NM and AZ, and possibly CA?
I-70: monotubes in CO and PA
I-95: monotubes in PA, and maybe FL?
I-75: monotubes in OH, and maybe FL?
I-94: and... i'm stuck here


Pink Jazz

#36
Quote from: SkyPesos on February 22, 2022, 02:04:20 PM
Quote from: jaehak on February 22, 2022, 11:56:54 AM
It seems like they are really common on I-15 specifically, at least more so than any other x0 or x5.
Now I'm kind of wondering which interstate is the longest without monotubes. So far, with the longest overall...

I-90: box monotubes in WA
I-80: monotubes in UT, and possibly CA as well
I-40: monotubes in NM
I-10: monotubes in NM and AZ, and possibly CA?
I-70: monotubes in CO and PA
I-95: monotubes in PA, and maybe FL?
I-75: monotubes in OH, and maybe FL?
I-94: and... i'm stuck here


I-10 uses monotubes in the El Paso district of Texas.  The El Paso district seems to like monotubes.

I-40 also has monotubes in Arizona.

Scott5114

I-35, I-40, and I-44 all have monotubes at various places in OK.
uncontrollable freak sardine salad chef

Great Lakes Roads

Quote from: SkyPesos on February 22, 2022, 02:04:20 PM
Quote from: jaehak on February 22, 2022, 11:56:54 AM
It seems like they are really common on I-15 specifically, at least more so than any other x0 or x5.
Now I'm kind of wondering which interstate is the longest without monotubes. So far, with the longest overall...

I-90: box monotubes in WA
I-80: monotubes in UT, and possibly CA as well
I-40: monotubes in NM
I-10: monotubes in NM and AZ, and possibly CA?
I-70: monotubes in CO and PA
I-95: monotubes in PA, and maybe FL?
I-75: monotubes in OH, and maybe FL?
I-94: and... i'm stuck here

The Chicago Skyway in IL also uses monotubes.

TheHighwayMan3561

Quote from: Scott5114 on February 22, 2022, 02:49:35 PM
I-35, I-40, and I-44 all have monotubes at various places in OK.

I-35W in Minneapolis has monotubes, the only such in Minnesota.

I-94 unless it has some in downtown Detroit might qualify. I've driven all of it except there, basically.
self-certified as the dumbest person on this board for 5 years running

SkyPesos

Quote from: TheHighwayMan394 on February 22, 2022, 06:45:14 PM
Quote from: Scott5114 on February 22, 2022, 02:49:35 PM
I-35, I-40, and I-44 all have monotubes at various places in OK.

I-35W in Minneapolis has monotubes, the only such in Minnesota.

I-94 unless it has some in downtown Detroit might qualify. I've driven all of it except there, basically.
I don't see any monotubes on a GSV look on I-94 in downtown Detroit. So I think that makes it the longest interstate without monotubes, with the second and third longest to be I-20 and I-55 to the best of my knowledge. Someone can correct me on either (or both) if necessary.

wriddle082

#41
I don’t believe that I-64 has any monotubes, and it’s a pretty long interstate.

Also add Tennessee, or at least TDOT, to the list of who doesn’t use monotubes.  There may still be some custom monotubes being used on roads serving Nashville International Airport (BNA), but these are not TDOT installs.  And they look(ed) a bit different than most other states’ monotubes in that the 90° curve was a little sharper and they were painted white.

tolbs17

Quote from: skluth on February 22, 2022, 01:18:47 PM
Quote from: zachary_amaryllis on February 02, 2022, 11:35:07 PM
Quote from: Scott5114 on February 02, 2022, 11:25:59 PM
They're easier to fabricate, and probably use less material. Both of those would make them cheaper.

i think the ones here in colorado are just ... funny looking. there's probably structural/technical details that are beyond what i know, but they just look weird to me.
Personally, I think trusses are far uglier than monotubes which I find simple and elegant.
Clearly not all states are on board to use them.... But I will say this: They are nicer compared to the trusses used in Connecticut.

jdbx

Caltrans D4 uses a lot of monotubes. I-680 in Contra Costa County is almost all monotube, with very few exceptions.  Example from the exit nearest my home:

https://www.google.com/maps/@37.9372089,-122.0601197,3a,75y,11.16h,92.13t/data=!3m6!1e1!3m4!1shoCoAopZ968L9xEZGCMBqw!2e0!7i16384!8i8192


tolbs17

#44
Disadvantages of monotube gantries is that this can happen.

https://www.cnn.com/videos/bestoftv/2012/08/21/vo-calgary-highway-sign.global-news

Now you know why some states (especially coastal ones) don't use them.

jakeroot

Quote from: tolbs17 on February 23, 2022, 02:03:19 PM
Disadvantages of monotube gantries is that this can happen.

https://www.cnn.com/videos/bestoftv/2012/08/21/vo-calgary-highway-sign.global-news

Now you know why some states (especially coastal ones) don't use them.

That monotube is much smaller (thinner) than the monotubes used in places like California or Utah, and are much less likely to flex in a manner like that.

US 89

Quote from: jakeroot on February 23, 2022, 03:42:39 PM
Quote from: tolbs17 on February 23, 2022, 02:03:19 PM
Disadvantages of monotube gantries is that this can happen.

https://www.cnn.com/videos/bestoftv/2012/08/21/vo-calgary-highway-sign.global-news

Now you know why some states (especially coastal ones) don't use them.

That monotube is much smaller (thinner) than the monotubes used in places like California or Utah, and are much less likely to flex in a manner like that.

Yep. Here's the monotube in question. Compare it to a typical Utah example and you'll almost instantly notice the difference. A lot of monotubes in states that use them are also this even beefier variant when they have to carry larger signs (of course, CA probably doesn't have any signs tall enough for that).

The wind argument is also silly when you consider a state like New Mexico. The state has enough of a wind concern that they mount 99.5% their traffic signals horizontally on mast arms, yet they are also pretty much exclusive monotube users...

Scott5114

I wish more states would use the double-tube variant (duotube gantry?) more often. It just looks more visually pleasing and sturdy to me. I know intellectually that a monotube is usually strong enough to hold a sign just fine, but visually the signs look way too big for the pole.
uncontrollable freak sardine salad chef

plain

Quote from: Scott5114 on February 23, 2022, 04:29:02 PM
I wish more states would use the double-tube variant (duotube gantry?) more often. It just looks more visually pleasing and sturdy to me. I know intellectually that a monotube is usually strong enough to hold a sign just fine, but visually the signs look way too big for the pole.

I used to dream about such. It would definitely look pleasing to the eye, even if the lower tube was smaller than the upper.
Newark born, Richmond bred

roadfro

Quote from: SkyPesos on February 22, 2022, 02:04:20 PM
Quote from: jaehak on February 22, 2022, 11:56:54 AM
It seems like they are really common on I-15 specifically, at least more so than any other x0 or x5.
Now I'm kind of wondering which interstate is the longest without monotubes. So far, with the longest overall...

I-80: monotubes in UT, and possibly CA as well

Monotubes are also on I-80 in Nevada through Reno/Sparks. To date, it's Nevada's first and only foray with montube gantries. I'm pretty sure it was part aesthetic design choice with the rebuild circa 2010, and part because NDOT hadn't yet figured out the best way to mount a large APL to their standard truss (that project also had NDOT's first 2009 MUTCD compliant APLs).
Roadfro - AARoads Pacific Southwest moderator since 2010, Nevada roadgeek since 1983.



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