Overview

G2 Consulting was retained by McCarthy and Smith, Inc., to design a support system so the construction team could excavate underneath the original “natatorium wing” of the 1930s historic clubhouse. The renovation plans called for relocation of the club’s popular bowling facility to the lower level location previously occupied by an indoor swimming pool, which had been out of use for decades.

Club management’s direction that the building’s architectural character and footprint not be altered in any way created an interesting engineering challenge since the team would need to excavate underneath the existing structure without disturbing it.  Adding to the challenge, the underlying soil conditions were poor with clay along one side of the structure and wet sand along the other.  After considering numerous approaches, the team decided on a series of underpinnings, essentially putting the building on stilts, and then pouring concrete foundation walls to encapsulate the stilts, providing stability for the renovations to occur in the short term and adequate bearing for the long term.

G2 Consulting Group provided underpinning design of three (3) perimeter walls and one interior column line.  G2 designed temporary shoring consisting of “push piles” along the perimeter piles and an open cut excavation along with support beams for the interior column line. G2 also provided design of backfill methods which employed Reinforced Earth Technology.

Challenges/Solutions:

• Ground conditions prevented traditional underpinning techniques. G2 designed and developed an earth retention system to access exterior footing. A unique backfill technique utilized reinforced earth to reduce wall pressures on Country Club of Detroit perimeter wall resulting in significant savings to the project.
• G2 maintained traffic flow to the Country Club of Detroit entrance while working on the project.