Gantry Style/Design Between The States

[Scott5114]

Minnesota has kept it nice and simple over the years. Like many states at the dawn of the interstate age MNDOT used howe gantries.

Those are actually Pratt trusses, not Howe. (Pratt trusses have the opposing diagonals meet at the bottom-center of the truss, while Howe trusses have them meet at the top-center.)

[hobsini2]

Minnesota has kept it nice and simple over the years. Like many states at the dawn of the interstate age MNDOT used howe gantries.

Those are actually Pratt trusses, not Howe. (Pratt trusses have the opposing diagonals meet at the bottom-center of the truss, while Howe trusses have them meet at the top-center.)

Sorry Scott.

https://youtu.be/sTDENzpW7tw

[andrepoiy]

Ontario uses a few gantry types, and I'm not well versed in gantries so I don't know what their names are, so if you do, please let me know.

Here is a picture with a side-span as well as a full-span, and these appear to be the most common ones and also the current standard of gantry:


These two styles are being phased out from my understanding, and the one with the 407 ETR signs have largely disappeared from Ontario-maintained freeways.

Older:


Oldest:

[roadman65]

These are common in IL.

The poles are above the truss and seem to lean on each other with a connector beam.

[hbelkins]

Kentucky is the only state I know of that uses this style. I've heard it called "Erector set."

2017 Various KY pics Jan-June - 0033 by H.B. Elkins, on Flickr

[thenetwork]

These are common in IL.

The poles are above the truss and seem to lean on each other with a connector beam.

Kentucky uses this style as well.

[TheArkansasRoadgeek]

My short time in Omaha, I noticed NEDOT doesn't have a particular design they stick to. I saw box, monotube, and a few others.

[ztonyg]

Arizona once used Pratt truss, but now uses monotubes.  Some older portions of the Phoenix area freeway system still have some of the truss gantries intact.

I've always seen Arizona as a monotube state, same as California. I don't know.... Movies?

There are still plenty of trusses on many of the older freeways in the Phoenix area. I don't recall seeing many trusses in the rural areas of the state though.  They are still very common on I-10 and SR 143 in the Phoenix area, with a small number still on I-17 and US 60; most of those surviving on the latter being full-widths (I think the one-sided ones were replaced by monotubes in a construction project in the early 2000s), although some one-sided trusses still survive east of Loop 202.

Arizona has a few interesting ones although most everything built within the last 20 - 25 years by ADOT itself is a monotube (the South Mountain Freeway supports were built by the partnership that built and maintains the road).

ADOT standard one sided truss:

SR 51: https://goo.gl/maps/19y2VNNtgYyufQkEA

I-17: https://goo.gl/maps/kXS2tudxHA1cAGx68

ADOT standard full width truss:

I-10: https://goo.gl/maps/kjepjMjf5MRiMoU37

I-17: https://goo.gl/maps/4SXB9DNMgB7AYS299

ADOT nonstandard one sided truss (used only on I-10 near the I-10 / I-17 stack):

I-10: https://goo.gl/maps/Wz1z9RS3tSWYVdJYA


ADOT nonstandard full width truss (used only on I-10 near the I-10 / I-17 stack):

I-10: https://goo.gl/maps/DB5uGUf4wo6Kg3Bv5

City of Phoenix installed one sided truss (used only on older portions of SR 51):

https://goo.gl/maps/D5W9kLHYHaU6N1hG8

https://goo.gl/maps/g1WaYZzbzYHCsgzp6

South Mountain freeway one sided truss (used only on Loop 202 South Mountain Freeway):

https://goo.gl/maps/n56PSXxmrmnPxBNj6

South Mountain freeway full width sign support (used only on Loop 202 South Mountain Freeway):

https://goo.gl/maps/8PqDkPSNUNiox4MD7