Costco Wholesale had purchased a piece of land in Eagan, MN off Blue Gentian Road that had over 50′ grade difference from the South to North end of site. The challenge was to provide enough flat surface for a warehouse, gas station, and a 725-car parking lot. Segmental walls would be needed to break significant grade to allow for the design of two vehicular ramps at either end of the site. With the size of the parking lot, many storm utility pipes would need to be placed within the reinforced zone of the retaining walls, as well as the functionality of a new storm water management pond.
Seven segmental retaining walls of all different sizes were used around all areas of the site to balance out the grade. One wall was designed to run parallel with Blue Gentian Road and reach 30′ tall for over 1,000 LF. This single wall stretches from one entrance ramp on the East side to the other entrance ramp on the West side of the site. The wall was designed to take the live load of large semi-trucks and firetrucks while supporting the main parking lot and delivery ramp. Miragrid 5XT and 8XT from were used on every other course of block to reinforce the segmental wall and account for the global stability. To maximize space for curb and parking stalls, a Sleeve-Its system was used to install the 4′ fence directly behind the wall block. Throughout the project, close coordination was especially important for the installation of many utilities within the reinforced zone of the wall, including storm drains, man-hole structures, and electrical and fiber-optic lines that fed the building and streetlights.
It was critical that the main retaining wall along Blue Gentian Road as well as five other complex walls were complete in less than 90 days to ensure enough time for the building to be installed and Costco able to open on schedule for the 2019 holiday shopping season. With the competent experience of the Structures team and strong field communications, Structures was able to achieve this goal for Novak Construction.
Job: Costco Wholesale
City: Eagan, MN
Product: Anchor Diamond Pro H.D.
General Contractor: Novak Construction
Architect: Joseph W Kowalski, P.E.