Shakey Lakes Park, located in Menominee County, Michigan, is
known for its great fishing and gorgeous views around the lakes. Both locals
and tourists alike take advantage of the many amenities available there, and
Menominee County takes pride in the advantages the park and surrounding lakes
afford.
In 2017, the Menominee County Road Commission looked for a
way to reline and/or replace the drawdown pipe (60-inch diameter) and six large
culvert pipes (72-inch diameter) that comprise the Shakey Lakes Dam structure.
Originally installed in 1963, these culverts were experiencing significant
corrosion and had outperformed their intended service life.
To identify the most cost-efficient solution possible, the
County looked at several potential options. Reconstruction of the existing dam
would be extremely expensive, and the County was hopeful they would be able to
identify a solution that would allow for a repair. The ability to reline the
existing pipe culverts without replacing the dam as well as the existing
concrete headwalls was the most economic solutions, and fortunately it was a
viable option. The Road Commission decided the reline of the culvert pipes was
the best option as it allowed the structure of the dam to remain intact. Smooth
Cor™ double wall pipe, manufactured by Contech Engineered Solutions, was
specified for use in the bid documents. The outside diameter of the Smooth Cor
corrugated metal pipe (CMP) was to be six (6) inches less than the diameter of
the original pipes.
This double wall CSP solution offered a polymer-coated outer
shell with a smooth, polymer-coated interior liner to increase the hydraulic
function of the culverts. With a standard Manning’s “n” of 0.012, Smooth Cor™
was again an ideal solution as the Michigan Department of Environmental Quality
(MDEQ) had limited the size of the new reline pipe that could be installed to
ensure that there would be no lasting impact on the environment or the wildlife
native to the area.
The project was bid out in 2017 and Hebert Construction,
Inc
. of Iron River, Michigan was awarded the project.
On Tuesday, July 24, 2018, a road detour was set up
and construction began on the project on Thursday, July 26, 2018. A cofferdam
was driven on the upstream side of the dam. After dewatering the site, the
actual dimensions of the existing pipes were checked against plan. It was
discovered that the first two of the southernmost culverts were deformed to the
point where a partial removal of the existing pipe crown was required for
proper installation. Consequently, the level of deformation would not allow for
the sliplining of the pipes as specified in the original bid documents.
The severe deflection of these pipes was challenging but not
insurmountable. Hebert Construction was able to remove portions of the road
structure and cut the top of the original pipe structures to facilitate the
sliplining with the Smooth Cor reline pipes. After the Smooth Cor liner pipes
were pushed into place, the top of the original culvert pipes was reattached
and then grouted.
A total of 288 LF was relined with Smooth Cor™ CSP,
diameters ranging from 54-inch to 66-inch. Smooth Cor™ is unique in that the
double wall design provides an economical and performance alternative to
concrete in difficult situations such as weak soils, poor subsurface drainage
conditions, steep slopes and high fills. Contech provided the plans and
buoyancy calculations necessary for a successful installation. The lightweight
design also made is much easier and less expensive to install when compared to
alternative concrete pipe solutions.
The installation took place over a period of roughly two
weeks. After completion of the reconstruction of the road section over the dam,
the road was paved, and the Road Commissions placed the shoulders and added pavement
markings shortly thereafter to complete the project.
Overall, the Menominee County Road Commission was able to reline
the existing culverts with a fully structural solution that would extend the
design life of the dam for 75+ years.
Menominee County Road Commission Project Engineer, Darrell
Moilanen, commented, “The use of Contech’s Smooth Cor™ pipe allowed the Road
Commission to perform maintenance on the dam structure while leaving the
upstream and downstream portions of the dam intact and complete the project in
nine weeks.”