Located in the Blufflands of southeastern Minnesota, Beaver Creek Valley State Park is over 1,200 acres in size. It is known for its clear streams fed by the "Big Spring" and is frequented by hikers and campers.
When an existing low water vehicular crossing was determined to be affecting the water quality, a replacement structure was needed. In search of the best solution, Minnesota Department of Natural Resources (MnDNR) turned to Contech Engineered Solutions for help. Contech assisted MnDNR with the preliminary design plans and since the plans were used during the bid process, upfront design time was saved.
As the best solution, a 30' span x 6'-4" rise x 30' long CON/SPAN® O-Series® Bridge System was selected for its aesthetic appeal and clear span which maintained the natural stream bottom. The system also included two precast headwalls and four precast wingwalls. To further expedite the installation, the CON/SPAN structure was placed on 5' wide x 2.4' thick x 30' long precast EXPRESS® Foundations.
Prior to the installation of the structure, Zenke, Inc, the project's contractor, built a full bypass channel, as the stream flows were too difficult to bypass pump. While the stream was temporarily re-routed, the EXPRESS Foundations and CON/SPAN system were installed via a double drum crane to further speed up installation.
"The MnDNR had studied and looked at many different alternatives over the years to replace the low water crossing at Beaver Creek Valley State Park which provides the only access to the campground," stated Yancey Stam, Senior Engineer, with MnDNR. "The existing low water crossing caused many safety issues for pedestrians, bicyclists and motorcyclists crossing the creek. The CON/SPAN structure provided the best cost effective solution to provide a safe, low profile, aesthetically pleasing structure with a natural stream bottom. The precast foundations and structure allowed for the entire project to be completed within a month during a short window in which the campground could be closed."