Twin City Hardware Case Study | Grip-Tite Manufacturing Co.
  • Twin-City Hardware Case Study

    New Hope, Minnesota
    November 2009

Grip-Tite Products Used

Before calling one of our certified Grip-Tite dealers, the existing Twin-City Hardware building in New Hope, Minnesota needed to build an addition.The 100'x220' concrete addition was to include both warehouse and office space for employees and products. Before the build, the soil was inspected. Beneath the new addition, geotechnical borings indicated up to 20 feet of very soft, swamp-deposited peat and organic silt overlying stiff sandy clay glacial till soils. Wall loads were estimated to be on the order of 7 to 11 kips per lineal foot and column loads were estimated to be 90 kips.

The Building Plan

Prior to the building construction, it appears that earthwork operations included a partial over-excavation and replacement of the unsuitable organic soils.

It is understood that the building started to settle and construction crews re-leveled the walls multiple times during the construction process. Within a few years of completion, portions of the building had experienced an additional 6 inches of settlement.

The Twin City Hardware Building Solution

Our dealer in New Hope, Minnesota was awarded the project and installed 93 helical piles and 39 floor slap piers to support the distressed areas of the building. The helical piles were installed alternating inside and outside under the east foundation wall and were installed from the outside along the south exterior foundation wall.

The Foundation Repair Process

Due to the heavy foundation loads, the project included installing Grip-Tite's Heavy Duty Retrofit Brackets and utilizing lead sections with 10", 12" and 14" helices on all of the helical piles. Galvanized material was selected due to the presence of high groundwater levels and organic soils. The helical piles were installed to ultimate capacities on the order of 76 kips and pushed within the glacial till soils near depths of 30 to 55 feet below the bottom of footings.

Preparing the footings included core-drilling through 18 to 24 inch thick footings in order to place the retrofit bracket beneath the foundation walls. In addition, installing the floor-slab piers included working in limited space around office desks, interior walls and built-in drafting tables.

The building was lifted to near-vertical all at once, which took a huge effort by the Grip-Tite team.

American Engineering Testing, Inc. provided continuous observation and testing throughout the entire project to ensure accurate testing and the overall success of the project.

Choose Grip Tite

If the Twin-City Hardware issues sound similar to your own business or home, don't hesitate to call Grip-Tite today. We can help you get in touch with a certified dealer or installer and get you started on a plan to fix your foundation until it's good as new. You should feel safe wherever you work and live. Call us today to get started!