(https://i.redd.it/0g2wn0h4tni81.jpg)
I don't know if it was wind, bad engineering, or something hit the pole. It was a massive sign and must have been pretty heavy. People were driving under it.
https://twitter.com/TarynJonesCBS/status/1494786381360644103?s=20&t=qD7olsvy-Tlp3shBBUpnQQ (https://twitter.com/TarynJonesCBS/status/1494786381360644103?s=20&t=qD7olsvy-Tlp3shBBUpnQQ)
Missed opportunity not to have the theme of Toad's Turnpike as the background music in that Twitter post.
Wow.
As a side note, it seems to me Texas has more issues than other states with the wind blowing over their BGSs. I visited Austin and San Antonio in 2019 and recall seeing at least 2 or 3 toppled BGSs on the way there.
In any other state, a BGS that big would probably be on a full gantry.
Quote from: CoreySamson on February 24, 2022, 08:20:59 PM
Wow.
As a side note, it seems to me Texas has more issues than other states with the wind blowing over their BGSs. I visited Austin and San Antonio in 2019 and recall seeing at least 2 or 3 toppled BGSs on the way there.
The ones you are talking about if I am correct are not the ones like the one on the picture above. They are the ones that are on two posts. The reason those blow over is they are break-away signs. They are designed to fold in half on impact. The bottom part of both posts will often remain standing while the top folds over or gets loose and hangs.
Sure looks like a post failure. Extreme wind can and will bring down a sign, but I don't think it's been any windier in North Texas than usual this month, and it's always windy. Probably a flaw in the steel that developed over time.
This particular sign structure collapse appears to have resulted from failure of the welds that secure the upright column to the anchor plate. Something must have gone seriously awry for this to happen. It is common for structures to be designed to tolerate cyclic loading from all causes (wind, buffeting by large vehicles, thermal expansion and contraction, etc.) without failure over a period of time well in excess of the expected service life.
If this event isn't a one-off or attributable to a fabrication/workmanship issue, I'd expect it to lead to at least a second look at the design criteria and possibly an overhaul of TxDOT's cantilever overhead sign structure standard plans. About 15 years ago, NCHRP sponsored a major research project dealing with wind buffeting of cantilevers, but I think that focused primarily on horizontal truss elements.
Quote from: Road Hog on February 26, 2022, 01:09:59 AM
Sure looks like a post failure. Extreme wind can and will bring down a sign, but I don't think it's been any windier in North Texas than usual this month, and it's always windy. Probably a flaw in the steel that developed over time.
I agree. The one in the picture is concerning. A failure that should not have happened. One would hope that this one was an anomaly. Like someone else suggested, probably a failure in a weld.
Loose nuts on the anchor bolts can be a proximate cause of this type of failure. When a nut loosens, which happens even on new installs, that concentrates the load on the other bolts and can also lead to the structure moving more than designed, which sets the stage for crack initiation in the welds that connect the anchor plate to the upright column. This is enough of a problem that in 2018 Minnesota DOT sponsored a research study (https://www.dot.state.mn.us/research/reports/2018/201827.pdf) on maintenance procedures for re-tightening anchor bolts.
I drive up 75 every third day, one day I noticed this a little wonky, didn't think much of it, next (3rd) day, I see it in pieces on the ground. What a hoot.