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CONSTRUCTION AND DESIGN DEFECT INVESTIGATION
EA staff
has performed forensic studies for over 200 litigation cases. Links to describe
our representative cases are presented below.
Click
Here to download
our Construction and Design Defect Project Sheet.
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RELATED LINKS:
EA provides management
consulting and technical services in four principal business areas:
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EXPANSIVE SOILS, PAVEMENT, & ETTRINGITE INVESTIGATIONS
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Expansive Soils Distress, FAA TRACON Building
EA staff was contracted
by the FAA to perform a geotechnical engineering investigation of the TRACON
building at Denver International Airport. Mr. Overton was the project manager,
Dr. Nelson served as corporate consultant and Dr. Chao was the geotechnical
engineer. The TRACON building had a slab-on-grade concrete floor and was
supported on a pier and grade beam foundation. The site is located in an area
with highly expansive soils. The subsoil at the site consisted of 7 to 13 feet
of fill and natural soils underlain by weathered claystone and claystone
bedrock. The natural soils, weathered by claystone and claystone bedrock,
exhibited moderate to very high swell potential. The investigation and analyses
performed included identification of design and construction deficiencies and
calculations of free field heave, pier movement and design pier length.
Additionally, conceptual repair options and costs were presented.
Foundation Movement, Woodward Governor
EA staff performed an
investigation of the heave of Woodward Governor’s 200,000 square foot
manufacturing facility in Loveland, Colorado. Mr. Overton was the project
manager and Dr. Nelson was the corporate consultant for this project. The
facility rests on 18 to 42-inch diameter piers, founded in Pierre shale bedrock,
with depths of 23 feet at the bottom of a 19 feet deep basement. Piers had
experienced heave from 0 to 11 inches at the time of the investigation. The
investigation and analyses showed the piers were being affected by deep-seated
swelling soils and that the piers should be anticipated to have a total heave of
10 to 15 inches. Analyses of groundwater flow were also performed and
groundwater flow was determined to be along fractures and bedding.
Pavement
Distress, 78th Avenue Parking Facilities,
Denver International Airport
EA staff performed an
investigation of distress to the pavement and structures at 78th Avenue, Airside
and Landside Parking Facilities at Denver International Airport. Dr. Nelson was
the corporate consultant, Mr. Overton was the project manager and Dr. Chao was
the geotechnical engineer for this project. The parking lot is underlain by
expansive clay soil and Denver formation bedrock. The subgrade soils were
lime-treated prior to construction. The parking lot has experienced distress due
to expansive soils and development of ettringite. Our in-house geochemical
expertise was used to evaluate the impact of chemical changes to the overall
expansion.
Slab and
Foundation Movements, Highlands Ranch
This project comprised a
class action lawsuit brought by approximately 950 homeowners against the Mission
Viejo Construction Company. Dr. Nelson served as the expert witness for the
plaintiffs. The project team consisting of Mr. Overton, Dr. Nelson and other
staff engineers conducted analyses of movement of slabs and design of foundation
piers. Heave predictions for the expansive soils profiles were conducted along
with general analyses of ground water movement. A large part of this project
included development of a large database in Access to facilitate analyses of
elevation surveys taken in 181 houses. The database was used to present patterns
of movement of slabs, differential movement and total movement for comparison
with heave predictions. Dr. Nelson provided testimony for two trials related to
this case. This particular case was estimated to have been one of the largest
litigation cases in Colorado dealing with expansive soils. The results presented
by EA staff led to major changes occurring in the practice of foundation
engineering on expansive soils in the Front Range area.
Distress
to Residential Structures, Powderhorn Subdivision, Littleton, Colorado
EA staff performed an
investigation of 16 residences in the Powderhorn subdivision in Littleton,
Colorado. The subdivision is underlain by steeply dipping claystone/shale
bedrock. All of the houses had structural wood floors. However, 11 of the houses
had pier foundations and five of the houses had spread pad foundations that
rested on over-excavated fill material. The investigation and analyses performed
by EA staff included prediction of pier heave, prediction of heave of the
conventional spread footing and analyses of pressure exerted on the basement
walls by expansive soil backfill. The investigation was performed by Dr. Nelson,
Mr. Overton, and Dr. Chao.
General Litigation
Support, Expansive Soils
EA staff provided
ongoing litigation support on cases involving foundation and slab failures for
houses and light structures constructed on expansive soils. To date,
approximately 150 cases have been involved. Typically, each case includes a
review of original soil reports and construction, some soil sampling and
laboratory testing, preparation of an opinion report that details the causes of
failure, factors that contribute to the failure, prediction of heave amounts and
required pier lengths, and a review of applicable or recommended repair
measures. Testimony is given at a deposition or in a trial.
In general,
Dr. Nelson has served as the expert witness and technical director, and Mr.
Overton or Dr. Chao was project manager for the projects. Projects have been
located in areas ranging from the flat-lying bedrock areas in the eastern parts
of the Front Range area to steeply dipping bedrock areas near the foothills.
EA’s staff work has had a significant impact on the successful settlement or
trial of these cases. Also, the work conducted by EA staff has formed a basis
for publications that have advanced the state-of-the-art in heave prediction and
has had a significant impact on the state-of-the-practice.
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Photo of Buckled Partition Wall
Stud,
TRACON Building, Denver, Colorado
Photo of Pier Shear
Failure, Woodward Governor Building, Loveland, Colorado |
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Photo of Basement Slab
Cracks, Denver, Colorado |
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Photo of Pavement
Distress,
Littleton, Colorado
Photo of Drywall
Crack, Denver, Colorado |
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COMPACTION AND SETTLEMENT INVESTIGATIONS
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Roadway Fills and Landslide Stabilization, Cedar Heights Subdivision
EA staff performed an
investigation of approximately seven miles of distressed roadways for a large
private housing development in Colorado Springs, Colorado. The major distress of
the roadways was from inadequate compaction of fill soils where the roadway
crosses drainages. Additionally, 23 active landslides were present within the
development. The estimated repair cost was 9.4 million dollars. The project team
consisted of Dr. Nelson, Mr. Overton, Dr. Chao, and others.
Foundation and Slope Movement, Patel Residence
The Patel residence is a
house that cost approximately $700,000 to build. The original lot consisted of
sloping ground. To extend the limits of the constructable area of the lot, a
fill approximately 20 feet deep was constructed. The foundation consisted of
drilled piers advanced through the fill to expansive bedrock. Because of poor
compaction of the fill, the slope underwent large plastic downhill deformation,
which exceeded 18 inches in some areas, causing severe distress to the house.
The project team included Mr. Overton, Dr. Nelson and others. A field
investigation was undertaken to analyze the cause of distress, the degree of
compaction of the fill, the nature of the slope movement and the movement of
water in the slope. Costs for repair were estimated to be approximately one
million dollars.
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Roadway Distress, Colorado
Springs,
Colorado |
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LANDSLIDE INVESTIGATIONS
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Landslide Mitigation Plan, Colorado Springs, Colorado
EA staff performed a
geotechnical investigation and developed a mitigation plan for the stabilization
of a 175-acre landslide at a recreation facility in Colorado Springs, Colorado.
The project team consisted of Dr. Nelson, Mr. Overton, Dr. Chao and others.
Surface water, groundwater and geotechnical aspects of the landslide were
studied in detail, and the proposed mitigation plan consisted of extensive
surface water and groundwater controls.
Landslide Causation and Mitigation Plan, 6th Avenue Estates, Jefferson County,
Colorado
EA staff performed a
forensic study into the causes of a landslide on the north facing slope of Green
Mountain. The landslide traversed two streets and caused damage to six
residences. EA staff also reviewed a mitigation plan for stabilization on the
landslide using tie-back anchors. The project team consisted of Dr. Nelson, Mr.
Overton and others.
Landslide Causation Study, The Redlands, Grand Junction, Colorado
EA staff performed a
study to determine the causes of a landslide in the Redlands area of Grand
Junction, Colorado. The landslide is located south of the Colorado River, and
has caused one residence to be condemned. The project team was comprised of Dr.
Nelson, Mr. Overton and Ms. Dornfest.
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Photo of Entrance
Slab Separation,
6th Avenue Estates, Jefferson County,
Colorado
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HYDROCONSOLIDATION INVESTIGATIONS
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Unstable Subgrade Soils,
Parker Market Place
EA staff performed an
investigation of distress at the Parker Market Place, Parker, Colorado. Dr.
Nelson, Mr. Overton, and Dr. Chao comprised the project team. The site was
underlain by seven feet of fill and alluvial natural soil. Both the fill and
alluvial soils had low densities and were subject to large immediate settlement
upon loading, hydroconsolidation and long-term deformation of the soils.
Hydroconsolidation
Investigation, Riverbend Subdivision
EA staff performed an
investigation of hydroconsolidation of five residences of the Riverbend
Subdivision in New Castle, Colorado. The site was underlain by approximately 100
feet and alluvial soils. These soils experienced settlement, movement and ground
cracking shortly after release of water onto the site by an up-gradient
irrigation ditch. Several of the houses in this project had significant distress
and have since been vacated.
Foundation Failure, Rangely Middle School
The Rangely Middle
School is a heavy multi-story masonry building constructed on a pier and grade
beam foundation. The soil profile consisted of a 60 to 70 feet deep deposit of
silty clay and clayey silt (ML/CL), underlain by a claystone/clayshale bedrock.
Between the bedrock and the ML/CL soils was a layer of gravel approximately 2
feet thick. Foundation piers were designed and constructed to a depth that was
approximately 15 feet short of the bedrock (45 feet +). As a result of water
movement into the collapsible subsoils, extensive movement of the piers
occurred, causing severe structural distress to the grade beams and
superstructure. EA staff was retained to determine causes of movement, sources
of subsurface water and movement of groundwater at the site. Dr. Nelson served
as the project manager and engineer, and represented the owner on the mitigation
design. The remedial repair that was instituted consisted of pressure grouting
the soil between the bottom of the piers and the bedrock. Dr. Nelson reviewed
the building performance for approximately one year after completion of the
repairs.
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RETAINING WALL INVESTIGATIONS |
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Retaining Wall Failure,
Port Moody, British Columbia, Canada
EA staff performed a
forensic investigation of the collapse of a 35-foot-high stress wall retaining
system in Port Moody, British Columbia. The investigation focused on the crib
design and construction, the wall backfill, analyses of rainfall events, seepage
analyses and stability analyses. It was determined that the wall failed due to
excess pore pressures in the wall backfill. Dr. Nelson, Mr. Overton and Dr. Chao
worked on the investigations.
Distressed Retaining Wall, Calabasas, California
Prior to employment with
EA, Mr. Overton investigated a distressed crib wall system located near the City
of Calabasas City Hall. Mr. Overton investigated the design and construction of
the wall, and identified several items that were contributing to distress of the
wall, including but not limited to inappropriate backfill soils, poor internal
crib compaction and use of shimming on the crib members.
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SURFACE GRADING AND DRAINAGE INVESTIGATIONS |
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Surface Grading and
Drainage Investigation, Colorado Springs, Colorado
EA staff performed a
surface grading and drainage survey of 47 town homes located in Colorado
Springs, Colorado. The survey consisted of measuring the slope away from the
units within the first 10 feet for each unit at 219 locations within the entire
development. The Soils Report specified a slope of 10% in the first 10 feet away
from the structures. Sufficient grade is necessary to direct water away from the
foundation and soils around the buildings to reduce infiltration of water into
the soils around the buildings. Failure to obtain this grade will result in an
increase in infiltration of water into the backfill and natural soils around the
buildings, which increases the risk of foundation movement. The results of the
grading survey indicate that the current grading at 181 out of 217 locations
does not meet the minimum 10% grading specified by the Soils Report. It was
recommended that the slopes at the site be regraded to 10 percent in the first
10 feet around the structures. EA provided cut and fill volume estimates for
remediation of the drainage conditions. We also provided a third party review of
proposed drainage improvement at the site. The investigation was performed by
Dr. Nelson, Dr. Chao, and Mr. Andrews.
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Photo of Poor Grading
and Drainage,
Colorado Springs, Colorado |
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TAILINGS DAM FAILURE
INVESTIGATIONS |
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Tailings Dam Failure,
Talache Mine Site, Idaho
EA staff performed an
investigation of a tailings dam failure at the Talache mine site in Idaho.
Analyses were performed to determine the quantity of tailings from different
mine operations that were involved in the breach of the dam. The project team
consisted of Dr. Nelson, Mr. Overton and others.
Church
Rock Tailings Dam Failure, Church Rock, New Mexico
Prior to employment at
EA, Dr. Nelson was the chief technical reviewer for the United States Nuclear
Regulatory Commission in review of the failure of the Church Rock Tailings Dam.
Failure occurred as a result of cracking of the dam caused by large settlement
of collapsible foundation soils. Failure to maintain a beach allowed tailings
water to enter the cracks in the dam directly, thereby causing the dam to fail
from the piping of highly dispersible compacted embankment fill. Improper
construction of the drainage zone of the dam exacerbated the problem. Dr. Nelson
conducted analyses of the failure and reviewed the proposed repairs.
Subsequently, he was retained as an expert witness on this case on behalf of
Sphere Insurance Company.
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Engineering Analytics, Inc.
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Fort Collins, Colorado 80525
Phone: (970) 488-3111
Fax: (970) 488-3112
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