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+--- Thread: Homer Watson and Ottawa Three Lane Roundabouts (/showthread.php?tid=339)
RE: Homer Watson and Ottawa Three Lane Roundabouts - Canard - 09-26-2017
Pretty sure they are not lights. They are just shields to prevent the accumulation of snow. They have them at Franklin/Pinebush too. I wondered what they were so took a look and they're just inert shields.
RE: Homer Watson and Ottawa Three Lane Roundabouts - KevinL - 09-26-2017
Ah, I stand corrected then. Was sure I saw something installed, but I never managed to get up close.
RE: Homer Watson and Ottawa Three Lane Roundabouts - embe - 09-26-2017
Wow, hadn't seen this pics until now. What the heck are those signs made of? The metal structure itself (not to mention the footing) is huge !
Long gone are the days of pressure-treat 4x4 for this type of thing I suppose, lol. Huge signs for Huge roundabouts
RE: Homer Watson and Ottawa Three Lane Roundabouts - Canard - 09-26-2017
They're made by B&M
RE: Homer Watson and Ottawa Three Lane Roundabouts - The85 - 09-27-2017
(09-26-2017, 05:33 PM)Canard Wrote: Pretty sure they are not lights. They are just shields to prevent the accumulation of snow. They have them at Franklin/Pinebush too. I wondered what they were so took a look and they're just inert shields.
They are not lights. These fins are only used on single mount gantry signs for wind loading. The MTO's single mount gantry on Highway 8 West for the Weber Street exit also has them. They are not used on double mount overhead gantries as the double support can better withstand high winds.
RE: Homer Watson and Ottawa Three Lane Roundabouts - Canard - 09-27-2017
What do the snow shields do for wind loading? I don't understand...
RE: Homer Watson and Ottawa Three Lane Roundabouts - trainspotter139 - 09-27-2017
(09-27-2017, 05:51 AM)Canard Wrote: What do the snow shields do for wind loading? I don't understand...
Like a spoiler on a car creates more downforce on the rear of the car these shields can reduce exerted torsion on the structure by redirecting the air flow.
RE: Homer Watson and Ottawa Three Lane Roundabouts - timio - 09-27-2017
(09-27-2017, 05:51 AM)Canard Wrote: What do the snow shields do for wind loading? I don't understand...
I don't see how those could be snow shields. Unless the snow is falling straight down, they'd be useless.
RE: Homer Watson and Ottawa Three Lane Roundabouts - Canard - 09-27-2017
I guess, as we just learned, they are not!
RE: Homer Watson and Ottawa Three Lane Roundabouts - KevinL - 09-27-2017
So they alter the way the wind flows around the sign, so there's less structural strain? Intriguing.
RE: Homer Watson and Ottawa Three Lane Roundabouts - JCnb - 09-27-2017
Always wondered what those "fins" were for on gantry signs, now I know!
This MTO Sign Standards document confirms this. Curious why they are used on the double supported gantry on Franklin however?
Edit: Just realized these are two independent single supported signs... odd.
RE: Homer Watson and Ottawa Three Lane Roundabouts - KevinT - 09-27-2017
(09-27-2017, 02:56 PM)JCnb Wrote: Always wondered what those "fins" were for on gantry signs, now I know!
This MTO Sign Standards document confirms this. Curious why they are used on the double supported gantry on Franklin however?
Nice find! Here's the key excerpt that explains the fins:
MTO Sign Support Manual Wrote:An aerodynamic damper along the full width of all sign boards is required to suppress vortex shedding and galloping instabilities of the structure under various wind conditions. The damper is attached to each Z-bracket by means of stainless steel bolts. The damper assembly is fabricated from structural aluminum and is comprised of a damper plate, gusset plates and support angles
RE: Homer Watson and Ottawa Three Lane Roundabouts - boatracer - 09-27-2017
"This MTO Sign Standards document confirms this. Curious why they are used on the double supported gantry on Franklin however? "
The signs are two single sided signs. They do not connect in the middle
RE: Homer Watson and Ottawa Three Lane Roundabouts - Canard - 09-27-2017
Took a good look today at the Franklin ones while waiting in line. They are just flat plates. It's amazing this does anything - but I guess that's what wind tunnel testing and real-world experience do with design. What isn't obvious to us is absolutely obvious to those who design and build these things all day, every day.
RE: Homer Watson and Ottawa Three Lane Roundabouts - KevinL - 09-27-2017
Got some pics this morning - wasn't able to post them until now.
![[Image: 1hbm.jpg]](http://i.thinimg.com/img/1hbm.jpg)
![[Image: 1hbn.jpg]](http://i.thinimg.com/img/1hbn.jpg)
![[Image: 1hbp.jpg]](http://i.thinimg.com/img/1hbp.jpg)
THERE. ARE. NO. LIGHTS.
![[Image: 1hbq.jpg]](http://i.thinimg.com/img/1hbq.jpg)