How come some states do not use U-channel sign posts, while I've noticed most use the square ones, or even round ones for regulatory signage. Pennsylvania uses mostly square ones. New York uses mostly U-channels, but with additional brackets seen here: https://maps.google.com/?ll=40.924206,-73.859271&spn=0.004426,0.010557&t=m&z=17&layer=c&cbll=40.924277,-73.859194&panoid=PNaGXLwfgvS8Bv_PyZXLbQ&cbp=12,160.18,,2,5.1
Not sure what these are called, though I really like these with the breakaway systems: https://maps.google.com/?ll=40.617666,-74.024892&spn=0.008893,0.021114&t=m&z=16&layer=c&cbll=40.617788,-74.024802&panoid=H2X_scDMVQOwplMdtCTolA&cbp=12,110.44,,1,-6.14
In NYC, some U-channel posts are backwards, which may be against Federal Highways standards. Also, several street signs in many states use the U-channel posts. Which are better to use, the green or galvanized ones?
Square tubular steel and round posts are more versatile than u-channel, as you can post multiple signs on a post at varying angles (not unusual for a regulatory sign to have others mounted to the same post). Without special hardware, U-channel only allows for front/back mounting, square allows for four sides, while round post allows for an infinite number of mounting angle options.
Generally, square tubular posts are easier to replace after a knock-down, as they are slid into a sleeve buried in the ground. U-channel and round poles are commonly direct-bury (pounded directly into the ground), so a knock down requires a new post and hole (bigger issue if the knock-down happens when the ground is frozen. That said, there are newer mounting methods that allow for quicker replacement of any type of metal post, but they do require more hardware: V-Loc (http://www.tapconet.com/store/products/breakaway-post-anchors/c/ydab) More hardware = higher costs.
MnDOT also has an interesting mounting system with additional braces. They typically use galvanized U-channel posts.
Quote from: J Route Z on December 22, 2013, 12:29:03 PM
Not sure what these are called, though I really like these with the breakaway systems: https://maps.google.com/?ll=40.617666,-74.024892&spn=0.008893,0.021114&t=m&z=16&layer=c&cbll=40.617788,-74.024802&panoid=H2X_scDMVQOwplMdtCTolA&cbp=12,110.44,,1,-6.14
Those look like I-beams, smaller that what is typically used for large guide signs.
WisDOT typical is a wood 4x6", but they also have square tubular steel in their standard spec book. Unless otherwise requested, they typically only use the tubular steel for signs that may need quick removal (oversized truck routes).
Ground-mounted guide, regulatory and warning signs on just about all state highways are mounted on wood posts in California. There may be a couple of odd-balls out there where signs are mounted on metal breakaway posts. HOV signage in the median of freeways are just about always mounted on round metal poles.
At the local level, I've seen everything from wooden posts to square and round poles. I think some communities are using the u-channels too.
Massachusetts uses mostly u-channel or square tube posts. The uchannel posts are breakaway design, with a u channel stub in the ground making for easier replacement. Mass also does not use the redundant braces that NY does. I have never seen a sign mounted on tube or uchannel posts fail due to wind loading, only collision.
Ohio generally uses galvanized U-channel, although some districts (like District 5) prefer tubular steel.
West Virginia is normally galvanized U-channel as well, although there tends to be significant usage of small I-beams with breakaway mounts. WVDOH District 9 tends to prefer tubular steel posts.
PennDOT generally seems to like painted U-channel, but Interstates also seem to feature a lot of tubular steel and wooden posts.
Maryland SHA uses wooden posts extensively.
TxDOT generally uses galvanized tubular steel posts with a breakaway stub. Some districts have been experimenting with fiberglass-reinforced plastic posts.
One issue with U-channel posts is that signs sometimes get crimped down into the channel.
Quote from: Scott5114 on December 23, 2013, 03:00:09 AM
One issue with U-channel posts is that signs sometimes get crimped down into the channel.
Welcome to Arkansas ;)
For years, AHTD has used steel U posts, but then has been making a gradual shift to galvanized (you don't have to back every couple years to repaint the posts and spill paint on the signs). Some areas use the square steel posts (often at expressway ramps).
Related question: how many states have a policy of bolt and rivet heads never being visible in the sign face? I am aware only of Colorado (neither) and Wyoming (bolt heads not allowed; I think rivet heads are still allowed).
Quote from: Road Hog on December 23, 2013, 01:38:45 AM
TxDOT generally uses galvanized tubular steel posts with a breakaway stub.
I'm starting to get used to the U/goal-post shape/style for multi-sign (or multi-shield) situations. BUT, I wish TxDOT could get a handle on the post assemblies that don't stay facing the direction they're supposed to without spinning around to where you can't see them.
Quote from: Road Hog on December 23, 2013, 01:38:45 AM
Some districts have been experimenting with fiberglass-reinforced plastic posts.
Would be good to see how those turn out and what kind of quality they are.
NJDOT uses U posts almost exclusively. On the other hand, NJ Transit uses square posts almost exclusively (even though I've never seen more than one side used).
Quote from: J N Winkler on December 23, 2013, 10:15:50 AM
Related question: how many states have a policy of bolt and rivet heads never being visible in the sign face? I am aware only of Colorado (neither) and Wyoming (bolt heads not allowed; I think rivet heads are still allowed).
How does
that work? Bolt from the back? That would look worse, in my opinion.
Quote from: Scott5114 on December 23, 2013, 02:39:05 PMQuote from: J N Winkler on December 23, 2013, 10:15:50 AMRelated question: how many states have a policy of bolt and rivet heads never being visible in the sign face? I am aware only of Colorado (neither) and Wyoming (bolt heads not allowed; I think rivet heads are still allowed).
How does that work? Bolt from the back? That would look worse, in my opinion.
There are many ways to make it work. Britain uses clips in channel rails secured to the back of the sign panel. (When this mounting method was introduced with the Worboys signs in the mid-1960's, the rails were riveted to the panels with the rivet heads standing proud of the sheeting. When the no-bolt-through-signface requirement was introduced around 1995 or so, sheeting began to be lapped over rivet heads instead, and it may also have become more common to spot-weld the rails to the panels.) Other European countries with similar no-bolt-through-signface requirements use framed panels (France and Germany do so extensively in urban areas), extrusheet construction similar to that used by some American state DOTs (Spain does this), or flat-sheet panels with crimped edges and mounting clips that bolt through the edge (a dated approach, but very common with smaller signs in France, Spain, and Mexico). Colorado and Wyoming do it by spot-welding angle braces to the back of flat sheet sign panels and then securing the mounting hardware to the braces rather than the panels themselves.
There are some advantages to not having bolts or rivets running through the signface:
* Better aesthetics (nothing on the signface but the sign message)
* Better readability (sheeting is more likely to weather or go bad around bolt holes)
* Better distribution of wind loads; mounting bolts no longer function as stress raisers
* Flat sheet sign panels become less likely to warp around posts
* No need to use nuts or washers to spread the load around bolt holes, which in many states are so obtrusive they detract from the sign message if they don't occlude parts of it (KDOT, for example, used to use very large opaque square nuts as washers in western Kansas)
The main disadvantage is cost and added complexity of installation.
Massachusetts used to have some fairly complex installations.
(//www.aaroads.com/shields/img/MA/MA19300202i1.jpg)
theoretically, those four bolts were painted the same color as the sign face and, being flush, were intended to be "invisible". the backplate which held the reflectors in also had slots for bracket mounting.
(//www.aaroads.com/shields/img/MA/MA19300202i2.jpg)
In Nevada, NDOT is using tubular breakaway posts almost exclusively along state-maintained highways. There are some cases along freeways where if a larger sign is behind a jersey wall, they might use I-beams instead (especially if there isn't the room for the typical 3-point tubular wind-braced mount).
The municipalities in Nevada tend to vary sign post types. In urban areas, they'll actually affix signs to street light poles wherever possible. Failing that, square channel posts are most common. Non-breakaway tubular posts seem to be the older standard that is becoming less common. For rural areas, the counties tend to mimic NDOT standards nowadays, but there's all sorts of things out there.
Generally speaking, though, U-channel posts are not very common in Nevada for some reason. Wood posts are typically only used in temporary/construction situations and never anything permanent.
Quote from: J N Winkler on December 23, 2013, 10:15:50 AM
Related question: how many states have a policy of bolt and rivet heads never being visible in the sign face? I am aware only of Colorado (neither) and Wyoming (bolt heads not allowed; I think rivet heads are still allowed).
I've noticed on *some* newer NDOT projects that the bolt heads are painted to match the color of the sign at the mounting hole location. It's by no means universal, but I feel like I've seen it enough that it seems like some kind of standard.
Quote from: mass_citizen on December 22, 2013, 10:06:51 PM
Massachusetts uses mostly u-channel or square tube posts. The uchannel posts are breakaway design, with a u channel stub in the ground making for easier replacement. Mass also does not use the redundant braces that NY does. I have never seen a sign mounted on tube or uchannel posts fail due to wind loading, only collision.
MassDOT standards for support posts for smaller aluminum signs (0.080 inch thick panels) are generally more conservative than most states as well. However, although failure due to excessive wind loading is quite rare, failure due to gusting can be a problem for larger signs (like 4' X 4' and 5' x 4' panels) on Interstates and freeways.
For those who are interested, the current Massachusetts small sign support loading standards for both u-channel and square tube posts (called P5 posts in MassDOT speak) can be found at:
http://www.massdot.state.ma.us/Portals/8/docs/construction/SupplementalSpecs20120615.pdf - Page 93
Quote from: DaBigE on December 22, 2013, 01:18:21 PM
Square tubular steel and round posts are more versatile than u-channel, as you can post multiple signs on a post at varying angles (not unusual for a regulatory sign to have others mounted to the same post). Without special hardware, U-channel only allows for front/back mounting, square allows for four sides, while round post allows for an infinite number of mounting angle options.
Generally, square tubular posts are easier to replace after a knock-down, as they are slid into a sleeve buried in the ground. U-channel and round poles are commonly direct-bury (pounded directly into the ground), so a knock down requires a new post and hole (bigger issue if the knock-down happens when the ground is frozen.
* * *
Colorado uses almost exclusively round signpost, but it is attached to a base buried in the ground. There appears to be a set screw that allows the sign to be rotated to the desired angle and secured. Sometimes seasonal signs are rotated away from the road, or speed limit signs are rotated during construction. The downside to this is that wind can also rotate the signs, especially larger ones.