Engineering Inc - January/February 2018 - 23

MULTI PROJECT
PROJECT: COUNTRY CLUB OF
DETROIT, GROSSE POINTE FARMS
MICHIGAN
FIRM: G2 CONSULTING GROUP
ANN ARBOR, MICHIGAN

n December 2016, the Country Club
of Detroit completed a major renovation of its historic Tudor-style clubhouse, but not without some clever
geotechnical and structural engineering.
Located on 212 acres in Grosse Pointe
Farms, Michigan, the club was founded
in 1897, although the clubhouse was not
built until 1927.
The renovation was part of a long-range
plan to offer club members a resort-like
experience. It consisted of reconfiguring
what was originally the natatorium wing
by moving a first-floor bowling alley down
to the basement level in place of a longunused swimming pool and providing a
new first-floor fitness center.
Although club management specified
the project could not alter the building's

architectural character or footprint, additional headroom was required for both the
bowling alley and fitness center. That left
just one way to go: down.
"So, there was the challenge: to build
something underneath an existing facility, maintain its look and not damage it
during the process," says project manager
Mark Stapleton, associate with the geotechnical engineering firm G2 Consulting
Group, Ann Arbor, Michigan.
Providing the taller ceilings and larger
interior spaces in the basement and on the
main level meant the bowling alley would
be moved seven feet below the existing
foundation. The challenge was further
complicated by the variability of the soils
on-site.
"Our borings confirmed that the ground
conditions couldn't have been worse,"
Stapleton says. "It's a small footprint, but
the soil conditions varied wildly. On one
side of the building we had water-bearing
sand, and on the other side
we had clay."
G2 designed a system

The bowling
alley was
moved
down to the
basement
level, now
seven feet
below the
original
foundation.

Deeper
Foundations
Support New
Facilities

of 120 steel mini piles to underpin the
building. Using open cut excavation, the
underpinning proceeded in 25-foot increments. Pipe piles attached to the existing
foundation were hydraulically pushed
down into place, essentially putting each
section of the building foundation on stilts
while not subjecting the historical structure to damaging vibrations of traditional
pile installation.
Concrete foundation walls were then
formed and poured to encapsulate the
stilts, thus providing stability for the renovations in the short term and adequate
bearing for the long term. Throughout the
underpinning, sensors monitored foundation displacements, which amounted to
only 1/100th of an inch throughout the
entire construction process.
Backfilling the excavation presented
another challenge because of the horizontal soil pressure it would create on the
newly extended foundation walls. By using
geofabrics, crews minimized
active soil pressure on the
foundation.

Mark Stapleton

Table of Contents for the Digital Edition of Engineering Inc - January/February 2018