Several flood events in the past few years had limited or altogether cut off access to nearly 30 homes in the Lake Shure neighborhood north of Fargo. Those residents whose homes were protected in some way from the flood waters still had to drive along overtopped roads or, at the worst levels of flooding, park their cars along the sides of the road and ferry across the floodwaters. Road access to homes was cut off for as long as 45 days at a time and a total of 170 days between 1997 and 2011.
After several back-to-back flood events, Cass County prioritized the need to replace the Lake Shure Bridge and reduce its vulnerability in future flood events. Floodwaters had regularly conquered the bridge the same as the roadway, and the County saw the importance of creating a new structure that would retain access to and from homes.
Cass County saw this project as an opportunity to improve the bridge in more ways than one. The highest priority remained bringing the new structure above the 100-year flood event. As a result, the new bridge was constructed nearly 10 feet higher than the last, eliminating the possibility of overtopping in any flood event short of Biblical proportions.
The structure itself also has a much greater length than the original. The new 375-foot, five-span structure was designed to allow for improved hydraulic flows underneath, again reducing the chance of overtopping during flood events.
After its completion in 2015, the American Council of Engineering Companies of North Dakota (ACEC/ND)
recognized the structure’s quality and its importance to residents and chose to award it the 2016 Engineering Excellence Award
in the category of Structural Systems.
By the Numbers
$2.2 million in construction costs
9,500 yards of embankment placed to raise the road
3,000 linear feet of piling driven
930 yards of riprap placed
96,000 pounds of reinforcing steel
640 cubic yards of concrete
2016 Engineering Excellence Award in the structural systems category.