I was looking thru some old pictures today and saw these two pictures of doghouses that were damaged during strong winds which brings me to this question... how sturdy are 5-section doghouses on span wire, and their strength with or without a backplate, and if backplates are used, if the full square or outline varients are best in terms of durablility? Based on my experience... doghouses are the least sturdy on span wire if they don't have a backplate...
I can name three instances of span wire doghouses in Maine that were damaged due to strong winds...
1. Around August 28, 2011 (Sanford ME), at Main at Shaws Shopping Center. This doghouse was damaged (https://www.google.com/maps/@43.4141405,-70.7474738,3a,45y,133.04h,92.63t/data=!3m6!1e1!3m4!1sk3MD5a6PSrYjn5QoPhLlow!2e0!7i13312!8i6656) becuase of strong winds due to Hurricane Irene of around 65-80 km/h (40-50 mph), and I believe the green and yellow sections broke off during the storm. The doghouse was then reinforced with a brace around the red light supporting the yellow and green sections (https://www.google.com/maps/@43.4141071,-70.7474943,3a,17.2y,126.22h,93.41t/data=!3m6!1e1!3m4!1sIS5PSbVP_-zePlu9dRAzaw!2e0!7i13312!8i6656) and has been holding strong ever since.
2. November 2, 2019 (Old Town ME) at Stillwater at College Ave (https://www.google.com/maps/@44.9147374,-68.6834625,3a,16.5y,44.77h,94.95t/data=!3m6!1e1!3m4!1svWlYBh-k8bw8KZgy_TK3zA!2e0!7i16384!8i8192). We had a strong windstorm with gusts up to 80 km/h (50 mph) that knocked out power around the local area which cancelled UM classes for a couple of days. In my first few weeks as a freshman, I noticced that the right turn doghouse was on the verge of collapsing and it seems like this storm was the straw that broke the camel's back. A brace was not erected here... they just put up newer parts, but it still looked like the doghouse would collapse despite the replacement part. Then sometime in March 2022... the doghouse was replaced with an entirely new doghouse (with a retroreflective square backplate) and it seems to be a lot more stable than it was before.
(https://i.ibb.co/JzjxBwJ/IMG-5963.jpg) (https://ibb.co/P5GTmvH)
3. July 23, 2020 (Sanford ME), at Main St and Walmart Driveway (https://www.google.com/maps/@43.3998115,-70.7027675,3a,15y,187.35h,93.21t/data=!3m6!1e1!3m4!1sucdyHu_HSObPMtDoOMlT5Q!2e0!7i13312!8i6656). We had a strong microburst come thru the area on that day (I was in RI at the time) and it left a lot of hail and other widespread damage during the time. It also left this right turn doghouse damaged and it was also reinforced with a similar brace in Example 1.
(https://i.ibb.co/M2BHHyp/broken-sanford-doghouse.jpg) (https://ibb.co/mDNKKrt)
Almost all of the new span wire doghouses I've seen on roads in Ohio are ones with a backplate, with both square (https://www.google.com/maps/@39.2876508,-84.3051639,3a,41.3y,105.57h,98.5t/data=!3m6!1e1!3m4!1sZWug9sMwsF_VWGEB6phksg!2e0!7i16384!8i8192) and outlines (https://www.google.com/maps/@39.292781,-84.3137206,3a,36.3y,249.35h,100.23t/data=!3m6!1e1!3m4!1s32uBzXaCkgOjPNd0yFob2g!2e0!7i16384!8i8192) existing. I'm pretty sure the stability is one reason why they switched over. Still a lot of older doghouses without a backplate, though personally I haven't seen one rip apart during strong winds yet.
Quote from: SkyPesos on April 12, 2022, 06:25:19 PM
Almost all of the new span wire doghouses I've seen on roads in Ohio are ones with a backplate, with both square (https://www.google.com/maps/@39.2876508,-84.3051639,3a,41.3y,105.57h,98.5t/data=!3m6!1e1!3m4!1sZWug9sMwsF_VWGEB6phksg!2e0!7i16384!8i8192) and outlines (https://www.google.com/maps/@39.292781,-84.3137206,3a,36.3y,249.35h,100.23t/data=!3m6!1e1!3m4!1s32uBzXaCkgOjPNd0yFob2g!2e0!7i16384!8i8192) existing. I'm pretty sure the stability is one reason why they switched over. Still a lot of older doghouses without a backplate, though personally I haven't seen one rip apart during strong winds yet.
I'm pretty sure Ohio switched over for enhanced visibility as a safety measure. If they were just doing it for stability, they wouldn't have replaced essentially every single ODOT-owned signal head in the state but instead would have just changed things over as needed.
ODOT and WVDOH have used doghouse signals extensively for years without backplates. I've never seen any indication they are more likely to be damaged than other configurations.
I would say backplates are mor subjective to damage because of increased wind loading, though louvered backplates help alleviate this problem.
5 Section Towers look funnier on Span Wire installations
I drive by one almost daily that has been wind-blown to a funky angle instead of straight verticle. I'll grab a picture sometime
Nothing as bad as blowing half the doghouse away, tho, like some of these pictures