This report we’ll be looking at another of Saskatchewan’s iconic bowstring arch bridges. In the 1920s and 30s around eighty of these graceful structures were built, and fair number remain today. Some are still being used for road traffic, some are pedestrian use only, and others have been abandoned like the one seen here. This example was found pretty much in the middle of nowhere, along Highway 37 between Gull Lake and Shaunavon.
Constructed in 1938, at some point unknown to us, but likely no more than a couple decades ago, give or take, the highway that it carried was realigned and a new bridge built to replace it. Today, the two structures sit side by side. The old bridge was not demolished, probably because it was too costly to do so. In fact a good number of extant bowstring bridges, those that are no longer being used that is, still survive because they are simply so well built that it’s uneconomical to tear them down.
In a bowstring arch bridge (aka tied arch, suspended arch or rainbow arch), the roadway is basically hung from the arch members. This allows for good clearance on the underside, an important factor, not so much here, but in other locations where a bridge may have to span a railway track or another road.
Given the complex nature of the cast-in-place concrete, one would think it would be costly to make such a bridge. Back in those days, labour was fairly cheap though and so that was not a huge factor. Material costs were low too, since most of the structure is made from plain old gravel which was often sourced nearby.
This design bridge offered some distinct advantages over say a wood structure – the concrete was durable, strong and low maintenance. And while labour intensive, it was still lest costly then steel.
The bowstring design was well adapted to the soft and often unstable soil found in the province. It would “float” in conditions where other design would shift.
Aesthetically the design was very pleasing in form, which makes them wonderful photographic subjects. A side benefit I guess.
This is a pony style bridge, meaning the arches are not interconnected, and most in the province were built this way. At least one bowstring bridge however was made in a through style – the arches were higher and were tied together with crossbeams above the roadway.
The current highway is only short distance from the structure. The old road that was bypassed, leading to and from the old bridge, can still be seen.
The bridge is about 40 metres long and sits perhaps five to ten metres over Swift Current Creek. It is comprised of two equal length spans – most bridges of this design seem to take this two-span form and are roughly this size. We’ve noted others however that have a single arch span and some with three or more, but they seem less common.
Many cliff swallows could be found living under the new highway bridge. They dart about in a chaotic fashion, chasing down flying insects. They congregate in large colonies, building mud nests under bridges and the like…and on cliffs, but few of these exist in Saskatchewan as you know. I wonder how each bird knows which home is theirs? Oddly, only a small number of nests were found under the old bridge. I guess they don’t like it as much for some reason.
This bridge was photographed in the spring of this year, while we toured southwest Saskatchewan. We came to record grain elevators, ghost towns, railways lines, old trucks and vehicles, and of course structures like this. It was an amazing trip and it provided us much fodder for many BIGDoer.com blog posts. There are still more to come!
If you wish more information on what you’ve seen here, by all means contact us!
Date of adventure: May, 2014.
Location: Middle of nowhere, SK.