HomeMy WebLinkAboutRP 12-13; Army & Navy Academy Athletic Facility; Redevelopment Permits (RP) (3)PLANNING-LEVEL GEOTECHNICAL EVALUATION
FOR PROPOSED FIELD AND ATHLETIC BUILDING PROJECT,
ARMY NAVY ACADEMY,
CARLSBAD, CALIFORNIA
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Prepared for:
ARMY NAVY ACADEMY
c/o Hofman Planning & Engineering
3152 Lionshead Avenue
Carlsbad, California 92010
Project No. 603319-001
November 29, 2011
Leighton Consulting, Inc.
A LEIGHTON GROUP COMPANY
Leighton Consulting, Inc.
A LEIGHTON GROUP COMPANY
To:
Attention:
Subject:
November 29, 2011
Arnny Navy Academy
c/o Hofman Planning & Engineering
3152 Lionshead Avenue
Carlsbad, CA 92010
Ms. Leslie Weinheimer
Project No. 603319-001
Planning-Level Geotechnical Evaluation for Proposed Field and Athletic
Building Project, Army Navy Academy, Carlsbad, California
In accordance with your request and authorization, we have conducted a preliminary
geotechnical feasibility evaluation for the subject site. In summary, it is our opinion that
the subject site does not have significant geological constraints that would require
mitigation prior to redevelopment. The purpose of our study was to evaluate geologic
conditions for the site using available geologic and geotechnical data.
If you have any questions regarding our report, please do not hesitate to contact me
directly at (858) 300-8491. We appreciate this opportunity to be of service.
Respectfully submitted,
LEIGHTON CONSULTING, INC.
William D. Olson, RCE 45283
Associate Engineer
Distribution: (4) Addressee
Robert C. Stroh, CEG 2099
Senior Engineering Geologist
3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425
858.292.8030 • Fax 858.292.0771
603319-001
TABLE OF CONTENTS
Section Page
1.0 INTRODUCTION 1
1.1 PURPOSE AND SCOPE OF SERVICES 1
2.0 SITE CONDITIONS 2
2.1 SITE RECONNAISSANCE 2
m 2.1.1 Proposed Improvements 2
H 2.1.2 Site Conditions 2
2.2 GEOLOGIC AND TECTONIC SETTING 2
m 2.3 LOCAL GEOLOGIC SETTING 3
ifi 2.3.1 Undocumented Fill 3
2.3.2 Quaternary Old Paralic Deposits 3
• 2.4 GROUNDWATER 4
• 3.0 POTENTIAL GEOLOGIC HAZARDS 5
•i 3.1 FAULTING AND SEISMICITY 5
m 3.1.1 Surface Rupture 5
3.1.2 Strong Ground Motion 6
3.1.3 Liquefaction and Seismic Settlement 6
m 3.1.4 Tsunamis and Seiches 6
3.1.5 Building Code Seismic Parameters 7
• 3.2 LANDSLIDES 8
n 3.3 FLOOD HAZARD 8
3.4 EXPANSIVE SOILS 8
3.5 CORROSIVE SOILS 9
ii 3.6 SETTLEMENT POTENTIAL 9
3.7 INFILTRATION EVALUATION 9
4.0 DISCUSSION AND CONCLUSIONS 10
^ 5.0 LIMITATIONS 11
FIGURE
ig FIGURE 1 - SITE LOCATION MAP, REAR OF TEXT
• APPENDICES
APPENDIX A - REFERENCES
•* APPENDIX B - ASFE SHEET
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ii
1.0 INTRODUCTION
In accordance with your request and authorization, Leighton Consulting, Inc. (Leighton)
has performed a preliminary geotechnical feasibility evaluation for the subject site
located off of Carlsbad Boulevard in Carlsbad, California (Figure 1). The
recommendations contained in this report are subject to the limitations presented in
Section 5.0. An information sheet prepared by ASFE (the Association of Engineering
Firms Practicing in the Geosciences) is also included as Appendix B. We recommend that
all individuals using this report read the limitations along with the attached document.
1.1 Purpose and Scope of Services
This preliminary geotechnical feasibility evaluation was completed to evaluate if
the property is potentially in an area with known (or a potential for) geologic
hazards based on existing site features and to review readily available geologic
documents. The purpose of our study was to evaluate geologic conditions for the
site using available geologic and geotechnical data (Appendix A) and to provide a
preliminary geologic hazard and geotechnical feasibility report with an evaluation
of field percolation rates for the athletic field area. We understand this information
will be used for project feasibility purposes.
At a later date, when more specific project data is available, a Geologic
Investigation (GI) of the subject site would be appropriate. Such an investigation
would include subsurface exploration and geotechnical design recommendations
necessary to complete the project. Specifically, our scope of work for this study
consisted of:
• A geologic reconnaissance of the site and adjacent area.
• Review of available pertinent geotechnical literature and background materials,
including geotechnical reports, geologic maps, topographic maps, and historical
stereoscopic aerial photographs.
• Review available pertinent geotechnical reports and plans on file at the City of
Carlsbad regarding previous structures located on or adjacent to the site.
• Perfonned three shallow field percolation tests for the preliminary evaluation
of an artificial turf field.
• Compilation and analysis of the data obtained; and,
• Preparation of this preliminary geotechnical feasibility report.
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2.0 SITE CONDITIONS
2.1 Site Reconnaissance
A site reconnaissance was performed on November 19, 2011 to evaluate and
document current site conditions. The site is located in the City of Carlsbad, and
is an irregular-shaped property that is occupied by an existing athletic field,
paved parking areas and storage facilities.
2.1.1 Proposed Improvements
The proposed improvements are anticipated to consist of new athletic
building, football/baseball field, viewing bleachers, press box, ticket booth,
dugouts, and maintenance building. In addition, new parking lots and other
support improvements, such as field lighting poles and utilities, are
anticipated. Proposed site grades are anticipated to remain relatively the
same.
2.1.2 Site Conditions
HP The site is located along the east of Carlsbad Boulevard, north of Beech
Avenue and west of NCTD Railroad right-of-way. The site elevation
m ranges from approximately 35 to 50 feet above mean sea level (msl).
^ Topography at the site is generally level across the existing athletic field
with ascending slopes along the western and southern perimeters. The
m site is generally covered with grass turf (i.e., playing field) and scattered
H bushes and trees along the eastern and western perimeters.
m Site Latitude and Longitude
« 33.1625° N
117.3535° W
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2.2 Geologic and Tectonic Setting
(H The project area is situated in the Peninsular Ranges Geomorphic Province. This
geomorphic province encompasses an area that extends approximately 900 miles
• from the Transverse Ranges and the Los Angeles Basin south to the southern tip
M of Baja California, and varies in width from approximately 30 to 100 miles (Norris
and Webb, 1990). The province is characterized by mountainous terrain on the
east composed mostly of Mesozoic igneous and metamorphic rocks, and relatively
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low-lying coastal terraces to the west underlain by late Cretaceous, Tertiary, and
Quaternary age sedimentary rocks. Most of the coastal region of the County of
San Diego, including the site, occur within this coastal region and are underlain by
sedimentary rock. Specifically, the project site is located in an area underlain at
depth by sediments of the Paralic Deposits (terrace deposits).
The Peninsular Ranges are traversed by several major active faults. The Whittier-
Elsinore, San Jacinto, and the San Andreas faults are major active fault systems
located northeast of the site, and the Rose Canyon, and Newport-Inglewood
(offshore) are active faults located west to northwest of the site. Major tectonic
activity associated with these and other faults within this regional tectonic
framework is right-lateral strike-slip movement. These faults, as well as other faults
in the region, have the potential for generating strong ground motions at the project
site. Further discussion of faulting relative to the site is provided in the Faulting and
Seismicity section of this report.
2.3 Local Geologic Setting
Based on our literature review, including published geologic maps and aerial
photographs, the project site is underlain by undocumented fill and the
Pleistocene-age Paralic Deposits. Brief descriptions of these units, as described
in the cited literature or as observed on the site, are presented below:
m 2.3.1 Undocumented Fill
Based on our field reconnaissance and review of referenced topographic
IP maps and aerial photographs, there are minor fills present across the site
Ig associated with the existing improvements. The fills are anticipated to be
derived from the on-site material and will generally consist of silty and
i» clayey sands. The fills are anticipated to be less than 5 feet in thickness.
• 2.3.2 Quaternary Old Paralic Deposits
The Pleistocene-aged Paralic Deposits previous known as (Quaternary
• Terrace Deposits) was observed to predominantly consist of reddish-brown,
ii brown, medium dense to dense, silty fine- to medium-grained sand. Based
on visual classification, the Paralic Deposits on the site generally have
• relatively high shear strength and a low expansion potential.
•i Experience with similar units on nearby sites indicate that the Paralic
Deposits and sandstone unit of the underlying Santiago Formation are
• generally massive in this area with no significant geologic structure.
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Pertinent geotechnical literature (Appendix A) indicates that the
sedimentary soils are generally flat-lying to gently dipping to the west. No
major folding of the sedimentary units is known or expected to exist at the
site.
2.4 Ground Water
Seeps, springs, or other surface indications of shallow ground water were not
indicated in our background review or observed during our site visit. Therefore,
based on our literature review and site reconnaissance, the depth to ground
water is anticipated to be greater than roughly 30 feet below the existing ground
surface. The ground water table is expected to fluctuate with seasonal variations
in rainfall, irrigation practices, and local perched ground water conditions may
exist.
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3.0 POTENTIAL GEOLOGIC HAZARDS
•* These hazards include, surface rupture, seismic shaking, landslides, liquefaction,
^ seismically induced settlement, flooding, and expansive and corrosive soils. The following
sections discuss these hazards and their potential at this site in more detail:
** 3.1 Faulting and Seismicitv ii
^ Our discussion of faults on the site is prefaced with a discussion of California
' legislation and policies concerning the classification and land-use criteria
associated with faults. By definition of the California Mining and Geology Board, an
IP active fault is a fault which has had surface displacement within Holocene time
^ (about the last 11,000 years). The state geologist has defined a potentiallv active
fault as any fault considered to have been active during Quaternary time (last
m 1,600,000 years). This definition is used in delineating Earthquake Fault Zones as
ig mandated by the Alquist-Priolo Geologic Hazards Zones Act of 1972 and most
recently within an interim revision in 2007 (Hart, 2007). The intent of this act is to
m assure that unwise urban development and certain habitable structures do not
^ occur across the traces of active faults. The subject site is not located within any
mapped Earthquake Fault Zones as created by the Alquist-Priolo Act.
IP Our review of available geologic literature (Appendix A) indicates that there are
no known major or active faults on or in the immediate vicinity of the site. The
m nearest active fault is the off shore segment of the Newport-Inglewood Fault
n located west of the site.
3.1.1 Surface Rupture
The nearest active fault is the off shore segment of the Newport-
Inglewood Fault located west of the site. Therefore, the potential for
ground rupture due to faulting at the site is considered low.
Ground lurching is defined as movement of low density soil materials on a
bluff, steep slope, or embankment due to earthquake shaking. Since the
site is generally level with no sloping terrain present, the risk of ground
lurching is low.
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3.1.2 Strong Ground Motion
Like all of Southern California, severe ground shaking is most likely to
occur during an earthquake on one of the regional active faults in the area.
As discussed above, the Newport-Inglewood Fault, located west of the
site, is the 'active' fault considered having the most significant effect at the
site from a design standpoint due to the close proximity.
3.1.3 Liguefaction and Seismic Settlement
The term liquefaction describes a phenomenon in which saturated,
cohesionless soils temporarily lose shear strength (liquefy) due to
increased pore water pressures induced by strong, cyclic ground motions
during an earthquake. Structures founded on or above potentially
liquefiable soils may experience bearing capacity failures due to the
temporary loss of foundation support, vertical settlements (both total and
differential), and undergo lateral spreading. The factors known to influence
liquefaction potential include soil type, relative density, grain size,
confining pressure, depth to groundwater, and the intensity and duration of
the seismic ground shaking. The cohesionless soils most susceptible to
liquefaction are loose, saturated sands and some silts.
Due to the lack of shallow ground water and relatively dense nature of the
underlying formational materials, the potential for liquefaction and dynamic
settlement of the site are considered nil.
p 3.1.4 Tsunamis and Seiches
" Tsunamis are long wavelength seismic sea waves (long compared to the
PI ocean depth) generated by sudden movements of the ocean bottom
^ during submarine earthquakes, landslides, or volcanic activity. A seiche is
an oscillation (wave) of a body of water in an enclosed or semi-enclosed
•i basin that varies in period, depending on the physical dimensions of the
ll basin, from a few minutes to several hours, and in height from several
inches to several feet. A seiche is caused chiefly by local changes in
m atmospheric pressure, aided by winds, tidal currents, and occasionally
if earthquakes.
^ Specifically, southern California is oriented obliquely (i.e., not directly in
ii line) with the major originating tsunami zones, and it has a relatively wide
(about 220 kilometers) and rugged continental shelf (or borderland) that
• acts as a diffuser and reflector of remotely generated tsunami wave
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energy (Joy, 1968). These conditions, in addition to the geologic and
seismic conditions (such as the strike-slip fault regime and the infrequent
large submarine earthquakes) along the coastline, also tend to minimize
the likelihood of a large tsunami at the site. For example, tsunami wave
heights and runup elevations experienced along the San Diego coastline
during the last 170 years have fallen within the normal range of tidal
fluctuations.
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Based on the factors discussed above and a site elevation of
approximately 50 feet msl, there is a very low potential for flood damage to
occur at the site from a tsunami or seiche.
3,1.5 Building Code Seismic Parameters
The effect of seismic shaking may also be mitigated by adhering to the
California Building Code or state-of-the-art seismic design parameters of
the Structural Engineers Association of California. The following
geotechnical design parameters have been determined in accordance with
the 2010 CBC (CBSC, 2010) and the USGS Ground Motion Parameter
Calculator (Version 5.1.0):
CBC (2010) Seismic Code - Parameters for the Site
Description Values CBC Reference
Site Class D Table 1613.5.2
Short Period Spectral Acceleration Ss 1.338 Figure 1613.5(3)
1-Second Period Spectral Acceleration Si 0.504 Figure 1613.5(4)
Short Period Site Coefficient Fa 1.0 Table 1613.5.3(1)
1-Second Period Site Coefficient Fv 1.5 Table 1613.5.3(2)
Adjusted Short Period Spectral
Acceleration SMS 1.338 Equation 16-36
Adjusted 1-Second Period Acceleration SMI 0.756 Equation 16-37
Design Short Period Spectral
Response Parameter SDS 0.892 Equation 16-38
Design 1-Second Period Spectral
Response Parameter SDI 0.504 Equation 16-39
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3.2 Landslides
Landslides are deep-seated ground failures (several tens to hundreds of feet
deep) in which a large arcuate shaped section of a slope detaches and slides
downhill. Landslides are not to be confused with minor slope failures (slumps),
which are usually limited to the topsoil zone and can occur on slopes composed
of almost any geologic material. Landslides can cause damage to structures both
above and below the slide mass. Structures above the slide area are typically
damaged by undermining of foundations. Areas below a slide mass can be
damaged by being overridden and crushed by the failed slope material.
Several formations within the San Diego region are particularly prone to
landsliding. These formations generally have high clay content and mobilize
when they become saturated with water. Other factors, such as steeply dipping
bedding that project out of the face of the slope and/or the presence of fracture
planes, will also increase the potential for landsliding.
No active landslides or indications of deep-seated landsliding were noted at the
site during our field reconnaissance or our review of available geologic literature,
topographic maps, and stereoscopic aerial photographs. Furthermore, our field
reconnaissance and the local geologic maps indicate the site is underlain by
favorable oriented geologic structure. In addition, the site has no significant
slopes. Therefore, the potential for significant landslides or large-scale slope
instability at the site is considered nil.
H 3.3 Flood Hazard
p According to a Federal Emergency Management Agency (FEMA) flood insurance
H rate map (FEMA, 1997); the site is not located within a 100-year floodplain.
HI 3.4 Expansive Soils
*• Expansive soils are characterized by their ability to undergo significant volume
^ changes (shrink or swell) due to variations in moisture content. Changes in soil
moisture content can result from precipitation, landscape irrigation, utility
•* leakage, roof drainage, perched groundwater, drought, or other factors and may
*w result in unacceptable settlement or heave of structures or concrete slabs
supported on grade. At the time of our site reconnaissance, we noted no
*^ indications of expansive soils movement, such as distress to flatwork, or
desiccation cracks within the site area soils. Therefore, based on the results of
our background review and site reconnaissance, we anticipate that the impact of
"** expansive soils to the site is generally low.
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3.5 Corrosive Soils
Corrosive soils are characterized by their ability to degrade concrete and corrode
ferrous materials in contact with water or soil. In particular, concrete is
susceptible to corrosion when it is in contact with soil or water that contains high
concentrations of soluble sulfates which can result in chemical deterioration of
the concrete. In addition, regarding ferrous metals, electrical resistivity of the soil
can affect the soils corrosive effects.
Based on our previous laboratory testing of the sandy Paralic Deposits (terrace
deposits) soils and professional experience with similar soils in the area, the on-
site soils should possess negligible soluble sulfate content. However, additional
laboratory testing should be performed on the soils placed at or near finish grade
to ascertain the actual corrosivity characteristics.
3.6 Settlement Potential
Undocumented fill soils, such as those underlying the middle portions of the site
may be subject to future consolidation (settlement) when subjected to new loads
and other factors such as changes in subsurface moisture content. Generally,
when such materials are encountered beneath any proposed improvements and
are not removed by the proposed grading, recommendations are provided
regarding the removal of those materials. The thickness of these unsuitable soils
may vary across the site and may be locally deeper in certain areas. Therefore,
mitigation of unsuitable undocumented fill may be necessary prior to new
development at the site.
3.7 Infiltration Evaluation
m We performed three field percolation tests on the site to evaluate the existing on
li site soils for potential infiltration of storm water. The results of the field
percolation tests indicated that the site soils have a percolation rate ranging from
P approximately 5 to 30 minutes per inch (mpi). It should be noted that generally, a
In percolation rate less than 120 mpi is considered necessary to consider a site
suitable for onsite surface infiltration of storm water.
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4.0 DISCUSSION AND CONCLUSIONS
Based on the results of our preliminary geotechnical feasibility evaluation, it is our
opinion that the subject site does not have significant geological constraints that would
require mitigation prior to redevelopment. In our opinion, the following geotechnical
factors should be considered in the planning and implementation of possible future
projects at the subject site:
• The site, like much of San Diego County, could be subjected to relatively strong
shaking due to earthquakes on active faults in the region. Thus, the potential for
relatively high seismic forces should be considered in the design of additional site
development.
• Localized minor undocumented fill soils are present at the site. Undocumented
fills are considered unsuitable to support foundation elements or settlement
sensitive structures in their current condition. Remedial grading of these
materials will be required prior to redevelopment.
• Corrosive soils may be present at the subject site. Additional testing will be
necessary following development and grading at the site.
• The site soils have a percolation rate ranging from approximately 5 to 30 minutes
per inch (mpi).
• Conventional foundations (i.e., continuous or isolated spread footings) founded in
firm, compacted fill or competent formational material may be used to support
proposed buildings and structures.
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5.0 LIMITATIONS
The geologic analyses presented in this preliminary geotechnical feasibility evaluation
have been conducted in general accordance with current practice exercised by geologic
consultants performing similar tasks in the project area. No other warranty, expressed
or implied, is made regarding the conclusions, recommendations, and opinions
presented in this report.
Please also note that our evaluation was limited to assessment of the geologic aspects
p of the project, and did not include evaluation of structural issues, environmental
^ concerns or the presence of hazardous materials. Our conclusions, recommendations
and opinions are based on an analysis of the observed site conditions, and our review
m of the referenced geologic literature and reports. If geologic conditions different from
^ those described in this report are encountered, our office should be notified and
additional recommendations, if warranted, will be provided upon request.
^ The recommendations contained in this report are subject to the limitations presented in
Section 5.0. An information sheet prepared by ASFE (the Association of Engineering
m Firms Practicing in the Geosciences) is also included as Appendix B. We recommend that
^ all individuals using this report read the limitations along with the attached document.
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APPENDIX A
REFERENCES
California Building and Safety Commission (CBSC), 2010, California Building Code
" (CBC).
CDMG, 1995, Landslide Hazards in the Northern Part of the San Diego Metropolitan
Area, San Diego County, California, Open-File Report 95-04.
^ FEMA, 1997, Panel Map 761F, dated June 19.
mm Hart, E.W., 2007, Fault-Rupture Hazard Zones in California, Alquist-Priolo Earthquake
Fault Zoning with Index to Special Study Zones Maps: Interim Revision 2007.
Jennings, C.W., 1994, Fault Activity Map of California and Adjacent Areas, with Locations
p and Ages of Recent Volcanic Eruptions: California Division of Mines and Geology,
California Geologic Data Map Series, Map No. 6, Scale 1:750,000.
m Kennedy, M.P. and Tan S.S., 2005, Geologic Map of the San Diego 30'x60'
Quadrangle, California, compiled by Michael P. Digital Preparation by Kelly R.
» Bovard, Anne G. Garcia and Diane Burns, California Geological Survey.
Norris, R.M., and Webb, R.W., 1990, Geology of California, Second Edition: John Wiley
* & Sons, Inc.
Tan, S.S. and Kennedy, M.P., 1996, Geologic Maps of the Northwestern Part of San
W Diego County, California, California Division of Mines and Geology Open-File
i Report 96-02, Scale 1:24,000
• Treiman, J.A., 1993, The Rose Canyon Fault Zone, Southern California: California
• Division of Mines and Geology, Open-File Report 93-02, 45 p.
A-1
I mportant Information about Your
GeotechnlGal Engineering Report
Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes.
While you cannot eliminate all such risks, you can manage them. The following information is provided to help.
Geotechnical Services Are Perfopmed for Specific Purposes, Persons, and Projects
Geotechnical engineers structure ttieir services to meet ttie specific needs of
ttieir clients. A geotecfinical engineering study conducted for a civil engi-
neer may not fulfill ttie needs of a construction contractor or even anottier
civil engineer. Because eacti geotectinical engineering study is unique, eacti
geotecfinical engineering report is unique, prepared so/e/yfor the client. No
one except you should rely on your geotechnical engineering report without
first conferring with the geotechnical engineer who prepared it. And no one
— not even you—should apply the report for any purpose or project
except the one originally contemplated.
itead tiie Fuii Report
Serious problems have occurred because those relying on a geotechnical
engineering report did not read it all. Do not rely on an executive summary.
Do not read selected elements only
A Geoteclinicai Engineering Report is Based on A Unique Set of Project-Specific Factors
Geotechnical engineers consider a number of unique, project-specific fac-
tors when establishing the scope of a study Typical factors include: the
client's goals, objectives, and risk management preferences; the general
nature of the structure involved, its size, and configuration; the location of
the structure on the site; and other planned or existing site improvements,
such as access roads, parking lots, and underground utilities. Unless the
geotechnical engineer who conducted the study specifically indicates
otherwise, do not rely on a geotechnical engineering report that was:
• not prepared for you,
• not prepared for your project,
• not prepared for the specific site explored, or
• completed before Important project changes were made.
Typical changes that can erode the reliability of an existing geotechnical
engineering report include those that affect:
• the function of the proposed structure, as when it's changed from a
parking garage to an office building, or from a light industrial plant
to a refrigerated warehouse,
• elevation, configuration, location, orientation, or weight of the
proposed structure,
• composition of the design team, or
• project ownership.
As a general mie, always inform your geotechnical engineer of project
changes—even minor ones—and request an assessment of their impact.
Geotechnical engineers cannot accept responsibility or liability for problems
that occur because their reports do not consider developments of which
they were not informed
Subsurface Conditions Can Ciiange
A geotechnical engineering report is based on conditions that existed at the
time the study was performed. Do not rely on a geotechnical engineering
reporfwhose adequacy may have been affected by: the passage of time; by
man-made events, such as construction on or adjacent to the site; or by
natural events, such as floods, earthquakes, or groundwater fluctuations,
/l/ways contact the geotechnical engineer before applying the report to
determine if it is still reliable. A minor amount of additional testing or
analysis could prevent major problems.
Most Geoteciinicai Findings Are Professionai Opinions
Site exploration identifies subsurface conditions only at those points where
subsurface tests are conducted or samples are taken. Geotechnical engi-
neers review field and laboratory data and then apply their professional
judgment to render an opinion about subsurface conditions throughout the
site. Actual subsurface conditions may differ—sometimes significantly—
from those indicated in your report. Retaining the geotechnical engineer
who developed your report to provide construction observation is the
most effective method of managing the risks associated with unanticipated
conditions.
A Report's Recommendations Are yvof Finai
Do not overrely on the construction recommendations included in your
report. Those recommendations are not final, because geotechnical engi-
neers develop them principally from judgment and opinion. Geotechnical
engineers can finalize their recommendations only by observing actual
subsurface conditions revealed during construction. The geotechnical
engineer who developed your report cannot assume responsibility or
liability for the report's recommendations if that engineer does not perform
construction observation,
A Geoteclinicai Engineering Report is Subject to Misinterpretation
Other design team members' misinterpretation of geotechnical engineering
reports has resulted in costly problems. Lower that risk by having your geo-
technical engineer confer with appropriate members of the design team after
submitting the report. Also retain your geotechnical engineer to review perti-
nent elements of the design team's plans and specifications. Contractors can
also misinterpret a geotechnical engineering report. Reduce that risk by
having your geotechnical engineer participate in prebid and preconstruction
conferences, and by providing construction observation.
Do Not Redraw the Engineer's Logs
Geotechnical engineers prepare final boring and testing logs based upon
their interpretation of field logs and laboratory data. To prevent errors or
omissions, the logs included in a geotechnical engineering report should
neverbe redrawn for inclusion in architectural or other design drawings.
Only photographic or electronic reproduction is acceptable, but recognize
that separating logs from the report can elevate r/s/r.
Give Contractors a Complete Report and
Guidance
Some owners and design professionals mistakenly believe they can make
contractors liable for unanticipated subsurface conditions by limiting what
they provide for bid preparation. To help prevent costly problems, give con-
tractors the complete geotechnical engineering report, ^bu/preface it with a
clearly written letter of transmittal. In that letter, advise contractors that the
report was not prepared for purposes of bid development and that the
report's accuracy is limited; encourage them to confer with the geotechnical
engineer who prepared the report (a modest fee may be required) and/or to
conduct additional study to obtain the specific types of information they
need or prefer. A prebid conference can also be valuable. Be sure contrac-
tors have sufficient time to perform additional study Only then might you
be in a position to give contractors the best information available to you,
while requiring them to at least share some of the financial responsibilities
stemming from unanticipated conditions.
Read Responsibility Provisions Closely
Some clients, design professionals, and contractors do not recognize that
geotechnical engineering is far less exact than other engineering disci-
plines. This lack of understanding has created unrealistic expectations that
have led to disappointments, claims, and disputes. To help reduce the risk
of such outcomes, geotechnical engineers commonly include a variety of
explanatory provisions in their reports. Sometimes labeled "limitations"
many of these provisions indicate where geotechnical engineers' responsi-
bilities begin and end, to help others recognize their own responsibilities
and risks. Read these provisions closely Ask questions. Your geotechnical
engineer should respond fully and frankly
Geoenvironmental Concerns Are l\lot Covered
The equipment, techniques, and personnel used to perform a geoenviron-
mental s\u6y differ significantly from those used to perform a geotechnical
study For tfiat reason, a geotechnical engineering report does not usually
relate any geoenvironmental findings, conclusions, or recommendations;
e.g., about the likelihood of encountering underground storage tanks or
regulated contaminants. Unanticipated environmental problems have led to
numerous project failures. If you have not yet obtained your own geoenvi-
ronmental information, ask your geotechnical consultant for risk manage-
ment guidance. Do not rely on an environmental report prepared for
someone else
Obtain Professional Assistance To Deal with Mold
Diverse strategies can be applied during building design, construction,
operation, and maintenance to prevent significant amounts of mold from
growing on indoor surfaces. To be effective, ail such strategies should be
devised for the express purpose of mold prevention, integrated into a com-
prehensive plan, and executed with diligent oversight by a professional
mold prevention consultant. Because just a small amount of water or
moisture can lead to the development of severe mold infestations, a num-
ber of mold prevention strategies focus on keeping building surfaces dry.
While groundwater, water infiltration, and similar issues may have been
addressed as part of the geotechnical engineering study whose findings
are conveyed in this report, the geotechnical engineer in charge of this
project is not a mold prevention consultant; none of Oie services per-
formed in connection witti ttie geotectinical engineer's stutly
were designed or conducted for tlie purpose of moid preven-
tion. Proper implementation of the recommendations conveyed
in this report will not of itself be sufficient to prevent mold from
growing in or on ttie strucbire involved.
Rely on Your ASFE-Member Geotechnical Engineer for Additional Assistance
Membership in ASFE/The Geoprofessional Business Association exposes
geotechnical engineers to a wide array of risk management techniques that
can be of genuine benefit for everyone involved with a construction project.
Confer with your ASFE-member geotechnical engineer for more information.
THE GEOPROFESSIONAL
BUSINESS ASSOCIATION
8811 Colesville Road/Suite G106, Silver Spring, IVID 20910
Telephone: 301/565-2733 Facsimile: 301/589-2017
e-mail: info@asfe.org www.asfe.org
Copyright 2004 by ASFE, Inc. Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with ASFE's
specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of ASFE, and only for
purposes of scholarly research or book review. Only members of ASFE may use this document as a complement to or as an element of a geotechnical engineering report. Any other
firm, individual, or other entity that so uses this document without being an ASFE member could be committing negligent or intentional (fraudulent) misrepresentation
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