Situation: In the early 1980s a group of apartments was constructed in Carrollton,
Texas with all the earmarks of a great investment property for the developer.
Once completed, the apartments proved to be just that: not only from revenue
generated by occupancy but by exceptional gains in equity caused by the
booming real estate market in the Dallas-Fort Worth metropolis. Amidst
all of the positive return being realized, however, concerns began to
surface, quite literally. Sheetrock cracks, sticking doors, windows that
didn’t work and uneven ﬂoors indicated that something was terribly
amiss. Although the complex was built using the latest and most innovative
construction methods, featuring a waffle slab and post-tension foundation
and ﬂoor systems, signs of foundation distress were still occurring. The
cause of the problems was neither the methods nor the materials used in
the construction of the apartments themselves, but rather the ground on
which it had been constructed. To gain the most efficient use of the square
footage of the site, the property had been altered using the cut-and-ﬁll
method of leveling; over the years, this contributed to the problem through
settling of the under-compacted 10 to 18 feet of ﬁll soils, and the release
of overburdened soil pressures in an already active soil condition. A
creek-bed adjacent to the property extending 30 feet below the normal
surface level of the site provided an opportunity for soil creep due to
the lack of soil retention along the creek bank area. Compounding these
issues was the largest contributing factor of all: the Eagle Ford Formation.
This soil formation is one of most active soil types found in the United
States, running from the Red River to San Antonio. With soil plasticity
levels of between 50 and 80 combined with the extensive seasonal moisture
changes in the region, the Eagle Ford Formation has wrought havoc on all
types of structures within its reach. From small residential structures
to massive commercial properties, billions of dollars have been spent
trying to counteract the negative inﬂuence of the Eagle Ford Formation.
One of the most recognizable properties affected by the phenomenon is
the DFW International Airport. The elaborate maze of runways, taxiways,
highways and buildings throughout the property must be continually maintained
and adjusted to ensure the safety of the airport patrons. Likewise, the
Carrollton apartments were not immune to the inﬂuences of the Eagle Ford
Formation. All of these conditions combined allowed the buildings to settle
dramatically; due to the rigidity of the waﬄe slab foundations, however,
the structures primarily experienced tilting and not as much deformation
as might be expected in structures settling as much as 10 inches!
Solution: Concerned for the safety of their tenants as well as with protecting their
investment, the apartment owners experimented with several foundation
repair contractors, trying to remedy the problems they were experiencing.
These contractors used a variety of different repair methods utilizing
concrete. The problem with using concrete as a repair method in this type
of scenario, however, is that you typically cannot get beyond the active
zones in the soil and the downward pull of negative skin friction on the
concrete piers, so they are not able to resist the soil’s activity.
With an overwhelming need to ﬁnd a solution to their problem, apartment
owners set out to ﬁnd a company with a history of success in dealing with
this type of soil condition. Ram Jack® of Texas was contacted and
inquiries were made into their history and experience with this scenario.
With its proven track record for repairing structures in and along the
Eagle Ford Formation and their roots in the formation of an international
network of Ram Jack foundation contractors extending from Canada to Costa
Rica and all points in between, Ram Jack of Texas was contracted to repair
the structure. Ram Jack’s history began in 1968 with the formation
of its parent company, Gregory Enterprises, and now includes fourth generation
employees. The history and reputation of Ram Jack gave the owners of the
apartments the conﬁdence they needed to enlist Ram Jack to provide the
long-awaited solution to their problems. Ram Jack of Texas sent in a team
of experts led by Jim Roberson, a 20-plus year employee of Ram Jack, to
evaluate the property. Ram Jack’s vast experience in dealing with
these types of problems and its innovative, state-of-the-art product line
made it easy to prescribe a remedy. A number of piers were ﬁrst installed
inside and around the structures. With 70,000 pounds of driving force,
the piers were driven to an average depth of 35 feet into the unweathered
shale formation below the creek bed to form a permanent bearing element,
ensuring that the piers would have a stable point of resistance to counter
the soil’s activity. Once all of the piers had been driven, a manifold
lift system was used to raise the structure. This manifold system eliminates
unnecessary stress to the foundation and slab caused by point loading,
enabling a more accurate and reliable lifting process. During the lifting
procedure, interior and exterior elevations were monitored to ensure a
uniform recovery. In some areas the slab and foundation were raised over
10 inches with only minor damages resulting, helping to regain much of
the elevation loss in and around the structures.
Conclusion: The Ram Jack piers are constructed of high carbon custom-manufactured
steel. Ram Jack adheres to the strictest guidelines in its manufacturing
process. Many of Ram Jack’s products carry ICC-ES approval; this
ensures code compliance for engineers and municipalities across the country.
The use of steel as a piering material allows for easy installation with
minimal disruption to the property and landscaping and eliminates the
likelihood of pier failure caused by friction with the soil.
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