Truss vs. tubular gantries by state

[KEK Inc.]

I know it's been mentioned, but specific areas tubular gantries seem to be used thematically in California are the Walnut Creek area, Fresno area, and parts of the Escondido area.  Otherwise, its use is pretty random. 

Since the late 90s, Washington uses a boxed 90º-jointed monotube, and Oregon uses a jointed monotube only for cantilevered signs.   Vancouver, WA, has a unique mix of traditional monotubes and square curved monotubes.  The traditional monotubes on I-5 in Hazel Dell and WA-14 by Pearson Field are the only ones I know in the state to date, and it seems like they were installed in the early 2000s due to the constant-slope barriers and the fact that I've seen them there in 2004.  I'm not sure when WSDOT abandoned the F-shape barrier, but it seems to be commonplace in the country by 2005 for single-slope barriers to replace jersey/F barriers.

I think my favorite truss design is Oregon's.  It uses a Warren truss design which I find more aesthetically pleasing than most gantries in the country. 

[brownpelican]

Truss in Louisiana and Mississippi.

[Darkchylde]

Truss in Kansas (KDOT and KTA) and Missouri.

[jakeroot]

The traditional monotubes on I-5 in Hazel Dell and WA-14 by Pearson Field are the only ones I know in the state to date

Interesting. It's a bit of a trip to see traditional monotube in Washington.

Taking a brief glance up and down WA-14 makes it clear to me that WSDOT SW Region is completely nuts. They apparently have an active remove-all-full-width-exit-tabs-and-replace-them-with-traditional-tabs program whereby they remove perfectly good traditional WSDOT exit tabs and replace them with the standard MUTCD exit tabs. For what it's worth, I prefer the WSDOT style so I'm none too pleased with the SW region.

[PHLBOS]

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

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

Thanks for posting that photo.  I knew there was only two generations of that signage over the last 25 years.  I have to wonder if the gantry (but not the signs) replacement was indeed due to the original gantry getting struck in an accident.

The other photo in the "canyon" in Hartford, WB, is new, installed only within the past couple of years.

And that was my earlier point.  ConnDOT is still using (or at least was) using pipe gantries post-2005.

[adventurernumber1]

Definitely truss gantries around here, but I also find tubular gantries to be very cool.

[hm insulators]

I think truss gantries tend to be on older roads, and tubular ones on newer roads.

[KEK Inc.]

Look at high voltage transmission lines.  Before around 2003, they were generally all lattice tower designs except for urban areas where there was limited space.  Now brand new transmission lines are all monotube.  The main reason is that monotubes are easily sectional and can be manufactured, whereas lattice structures generally have more complex assembly on site -- especially on odd terrain where helicopters install them.  Lattice structures are great and still used for high crossings (i.e., over rivers with ships).   



Look at path 15 or path 61 in California.  You can see all arrays of transmission lines from different decades. 

I still haven't seen HVDC monotubes.  Path 65 and the North Dakota lines were built in the 80s.

[cpzilliacus]

Look at high voltage transmission lines.  Before around 2003, they were generally all lattice tower designs except for urban areas where there was limited space.  Now brand new transmission lines are all monotube.  The main reason is that monotubes are easily sectional and can be manufactured, whereas lattice structures generally have more complex assembly on site -- especially on odd terrain where helicopters install them.  Lattice structures are great and still used for high crossings (i.e., over rivers with ships).

I have seen "tube" transmission lines that date back to well before 2003 in Maryland.

Two 500 KVA transmission lines were built side-by-side in the early 1970's to link Baltimore Gas and Electric's then-new Calvert Cliffs Nuclear Generating Station with high-voltage transmission lines closer to Baltimore, and "tube" structures were used at points where the line crossed a public road, example here (from near the northern terminus of the line in Gambrills, Maryland off of Md. 3).

in the 1980's, in another part of the state, two 500 KVA circuits were built on "unified" structure, example here crossing Md. 97 north of Sunshine.

After decades of obstructionism and opposition by NIMBYs and environmental groups, these two lines were linked with a new circuit about 10 years ago, part of which used a style of monotube poles I had never seen before here (this line is also 500 KVA).