In this report we look at one of Saskatchewan’s iconic “bowstring” concrete arch bridges. Beautiful in design, their graceful flowing lines make them a wonderful photographic subject. This one is located near Scotsguard and is almost eighty years old. It once carried the highway over a shallow valley containing a creek and railway, but was abandoned when the road was realigned.
Somewhere between eighty and ninety of this style bridge were constructed in Saskatchewan in the 1920s and 30s, and about half still remain. Some still carry traffic, a few have been converted to pedestrian use, while others, like this one, are no longer used at all. Of the latter most were abandoned when the road they carried was rerouted. Considered too expensive to demolish, they were simply left behind. That’s lucky for us photographers and history buffs as they are a ton of fun to explore.
This structure is located just west of the small village of Scotsguard in southwest Saskatchewan and is just off the current highway.
This bridge uses a bowstring arch, aka tied arch, suspended arch, or rainbow arch, for the supporting elements. You may also hear it refereed to as a concrete arch or reinforced concrete arch bridge (like it didn’t have enough names already) which works too since it is made from that material. There is such a thing as a steel bowstring bridge, in case you were curious. No matter what they are constructed of, the roadway is basically hung from the arches.
This style of bridge has some distinct advantages. It was well suited for the low height crossings so common in flat Saskatchewan, it provides good clearance over the crossing (important when spanning railways and the like) and being made from concrete they were low maintenance. Also, the bridge structure could tolerate soft or slightly unstable soil conditions well, which are so prevalent in the province. Other types of bridges in these conditions might be susceptible to shifting but this style would essentially “float” in place and not move. Needless to say, the design was very aesthetically pleasing too.
Given the rather complicated nature of the cast-in-place concrete, building this bridge and the others like it in the province, must have been laborious. I guess during the twenties and thirties manpower was cheap however.
Most of the Saskatchewan bowstring bridges are pony style, meaning the arches are not interconnected above the roadway. At least one larger example was built, in the town of Borden, that required elements tying the two sides together. The arches on it were of course taller so the cross struts could be high and out of the way of automobiles.
You’ll notice that the two outer arches on this bridge are smaller then those in the middle. Most of the bridges built in this style in the province had either a single or double arch. Longer spans, like this one, have multiples connected arches, but these are less common.
If one looks on Google earth, the faint lines of the old road leading to and from the bridge can be seen. The highway here is #13 (lucky 13), aka the Red Coat Trail. This road roughly follows the path used by the North-West Mounted Police in the 1870s as they travelled west. That organization today is called the Royal Canadian Mounted Police and was (and is) known for their bright red uniforms, hence the nickname Red Coat.
We have not found when the road near the bridge was rerouted, but in the last few decades would be a good bet.
The bridge spans a distance of roughly 80-100 metres (a guess) and is perhaps a couple dozen metres over the creek.
Since there was a lot curves and complex elements in the design of the bridge, both making the form work and pouring the concrete must have been quite the challenges.
You’ll notice that metal bands have been added to some piers holding up the bridge. The concrete is crumbling in places and here it helps tie things all together. Other parts of the bridge are cracked, some metal reenforcing rods exposed, and some bits have fallen away. I doubt it’s structurally an issue thought. This appears to be one solid chunk of cement and I doubt it’s going anywhere soon.
A pair of Great Horned Owls were seen perched on the underside of the bridge. They did not like us being there and hooted incessantly while we explored the structure. I assume their nest was nearby and this made them nervous.
This bridge spans the slow moving Notukeu Creek and the tracks of the Great Western Railway. The latter was a former Canadian Pacific Railway grain line built about a hundred years ago. By the end of the last century however, the CPR wanted out of the branch line business – hauling grain was not profitable enough for them, but it could be for a small efficient operator and so the line was sold. The new operator took over in 2000 and seems to be doing well. I understand trains run a couple times a week, sometimes more often if traffic is heavy.
The line travels west from a point south of Moose Jaw, getting close to the Alberta border before dipping south and doubling back somewhat. The main commodity carried is of course grain. They also haul oil and other products related to the petroleum industry. Lastly, they store surplus cars. The biggest town along the line is Shaunavon, which is not terribly far from this bridge.
Nearby there is a timber trestle carrying the rail line over the creek. This style of railway bridge is very very common and not terribly photogenic when compared to its nearby neighbour (but it’s still interesting to a bridge hunter).
We found a monitoring device on the bridge. It measures how much the trestle shifts or deflects when a train passes over. This way the railway can be warned of any settling issues before they become a big problem. The set up is simple: they string a cable across the bridge and anchor it at both ends and in the middle. If a train causes the bridge to shift slightly, the cable stretches, which is them measured by a special sensor.
If you wish more information on what you’ve seen here, by all means contact us!
Date of adventure: May, 2014.
Location: near Scotsguard, SK.