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AMERICAN
CEOSER\1ICES
Geotechnical Evaluation Report
33 4 Wheel Drive Rd, Carbondale, CO 81629
Date: February 12,2024; Project No: 0125-WS24
AMERICAN
GECSERVICES
CFOTFCHNICAL & MATERIALS
ENVIRONMENTAL
STRUCTURAL
ct\4t.
F,NCINEERING AND SCIENCE
8882764027
February 12,2024
PROJECT NO: 0314-WS20
CLIENT: Mr. Scott Hankinson
Reference: Geotechnical Evaluation Report, 33 4 Wheel Drive Rd, Carbondale, CO 81623
Dear Mr. Hankinson,
At your request, we have completed the geotechnical evaluation for the referenced project in
accordance with the American GeoServices, LLG (AGS) Proposal. Results of our evaluation and
design recommendations are summarized below'
PROJECT INFORMATION
The site is located as shown in Figure 1 and Figure 2. The proposed development will consist of
residential pool/spa construction. We do not anticipate significant site grading for this project' We
anticipate the proposed structure will be constructed with light to moderate foundation loads.
SCOPE OF WORK
Our scope of services included the geologic literature review, soil explorations, geologic hazards
evaluation, geotechnical evaluation, and the preparation of this report. Evaluation of any kind of
existing structures on and adjacent to the site was beyond our scope of services.
ln February 2024,we performed two soil explorations (81 and 82) at approximate locations shown
in Figure 2 and collected soil/rock samples. Our soil exploration included logging of soils from
soil boring and evaluation of the exposed driveway cuts and other ground cuts. Our explorations
extended to a maximum depth of 5 feet below existing ground surface (BGS). All soil/rock
samples were identified in the field and were placed in sealed containers and transported to the
laboratory for further testing and classification. Logs of all soil explorations showing details of
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subsurface soil conditions encountered at the site are included in an appendix. The Legend and
Notes necessary to interpret our Exploration Logs are also included in an appendix. Data
obtained from site observations, subsurface exploration, laboratory evaluation, and previous
experience in the area was used to perform engineering analyses. Results of engineering
analyses were then used to reach conclusions and recommendations presented in this report.
SURFACE CONDITIONS
The site is roughly an irregularly shaped parcel of land as shown in Figure 2. Currently the site
topography is gently to moderately sloping downwards to the north. At the time of our site visit,
there was no visual indication of active slope instability or active landslides in the site vicinity.
However, our review of available geology maps and geologic hazards information revealed the
presence of landslide geologic hazards and evaporite-related hazards at or immediately adjacent
to the site.
SUBSURFACE CONDITIONS
Subsurface conditions encountered in our explorations and noted in our literature research are
described in detail in the Exploration Logs provided in an Appendix and in the following
paragraphs. Soil classification and identification is based on commonly accepted methods
employed in the practice of geotechnicalengineering. ln some cases, the stratigraphic boundaries
shown on Exploration Logs represent transitions between soil types rather than distinct lithological
boundaries. lt should be recognized that subsurface conditions often vary both with depth and
laterally between individual exploration locations. The following is a summary of the subsurface
conditions encountered at the site.
Alluvium: Site is primarily underlain by generally medium stiff mixtures of sand-silt (SM, ML)
extending to depths of about 1.5-2.5 feet. These soils exhibited low plasticity in the field and in
the laboratory. These soils do not represent old debris flow deposit or ancient landslide deposit.
Gompfetely to Partially Weathered Bedrock: Below about 1.5-2.5 feet, the site is generally
underlain by completely to partially weathered sandstone/mudstone/siltstone formations
extending to depths of several tens of feet.
Groundwater: Groundwater was not encountered during exploration or at the time of completion
of our soil explorations. This observation may not be indicative of other times or at locations other
than the site. Some variations in the groundwater level may be experienced in the future. The
magnitude of the variation will largely depend upon the duration and intensity of precipitation,
temperature and the surface and subsurface drainage characteristics of the surrounding area.
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February 12,2024
Page No: 2 of 18
GEOLOGIC HAZARDS EVALUATION
Expansive/Gollapsible Soils: The site is not underlain by highly expansive clayey soils or clayey
sedimentary bedrock materials. The site location is not near known swell hazard zones that pose
a significant geotechnical concern. However, local pockets of 'collapsible' soils/materials can
occur through the site and may cause settlement in the foundations or flatwork around the site.
This is typical of many areas along the Roaming Fork River corridor.
Flooding: Proposed construction area is not located within 1O0-yearflood hazard zone; however,
a flood hazard evaluation was beyond our scope of services. We recommend hiring an
experienced hydrologist to evaluate the flood hazards for the site, or an in-depth evaluation of
published flood hazard maps, considering the proximity of the site to the river.
Debris Flow: Site is not located within alluvial fans or flood channels. Debris flow hazard at the
site is minimal under normal site, topographic, geologic, and weather conditions. However, the
site vicinity area may consist of ancient debris flow or ancient landslide deposit, which is currently
inactive.
Rockfall: Site is not located within rockfall hazard zone. Rockfall hazard atthe site is minimal
under normal site, topographic, geologic, and weather conditions.
Landsf ides: Our review of available geologic maps and landslide hazard maps did not indicate
that recent landslides or recent debris flow had occurred at the site or in the immediate proposed
building area. During our site reconnaissance, we did not notice scarps, crevices, depressions,
tension cracks in the ground surface, irregular slope toes, exposed surfaces of ruptures without
vegetation, presence of distinct fast-growing vegetation, undrained depressions, etc., that are
generally indicative of local active and/or inactive landslides or slope instability that would
adversely impact the on-site structure at this time, however, a detailed landslide evaluation of any
kind or slope stability evaluation under seismic conditions was beyond our scope of services.
However, the site is located within the mapped landslide hazard areas surrounding the site (Figure
6). There are potentially mapped landslides and/or ancient landslide deposits close to the site
boundaries or within the site boundaries. There is also moderate to high potential for the presence
of ciormani ancjior unknown hisioric iancisiicies, deep-seated ancient iandsiides, oi'geologically"-
recently developed dormant landslides in the site vicinity close to the site.
The site itself is mapped as being situated within the possibly existing active or ancient active
landslide mass or an ancient active global landslide. Considering these findings, the site
topography, and site geologic conditions, it is our opinion that the site area have 'site-specific
Project No: 0125-WS24
February 12,2024
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landslide hazards' and has some 'inherent' risk associated with slope instability and structural
impact from the movement of any global/ancient landslide and local slope movements. Moreover,
historically, with construction in such areas, there is always an inherent risk associated with
ground movement and/or settlements and related structural damage. The owner should
understand these inherent risks related to site vicinity. lf the owner wants to better understand the
risks and to eliminate the site-specific landslide hazard risks, then a detailed and comprehensive
geotechnical evaluation including deep drilling, detailed slope stability modeling, and a detailed
geologic hazards assessment (including global landslide hazards evaluation) should be
performed in the site vicinity area to quantify the abovementioned risks and to provide detailed
geotechnical design recommendations for comprehensive mitigation measures. Unless these
recommended studies are performed, the owner is completely responsible for taking any and all
risks associated with any future potential for instability at the site occurring due to landslide
hazards in the site vicinity.
Evaporite Formations: The site and/or the immediate vicinity area are underlain by Evaporite
Formations which consist of significant volumes of relatively highly water-soluble minerals
including gypsum, anhydrite and halite (rock salt) interbedded with siltstones and sandstones.
These formations are highly susceptible to forming sinkholes due to dissolution of soluble
minerals in the bedrock. At the time of our site visit, we did not notice any sinkholes or small
depressions in the proposed construction area. lt should be noted that detailed evaluation of this
geologic hazard was beyond our scope of services.
Historically, with construction in such areas, there is always an inherent risk associated with
settlements and related structural damage. The owner should understand these inherent risks
related to the site and site vicinity. lf the owner wants to better understand the risks and to
eliminate the site-specific sinkhole hazard risks, then a detailed and comprehensive geotechnical
evaluation including deep drilling, detailed modeling, and a detailed evaporite hazard assessment
should be performed to quantify the abovementioned risks and to provide detailed geotechnical
design recommendations for comprehensive mitigation measures. Unless these recommended
studies are performed, the owner is completely responsible for taking any and all risks associated
with any future potential for instability at the site occurring due to this geologic hazard.
Earthquakes: Based on site geology, topography, and our preliminary evaluation, in our opinion,
the site is generally not considered to be located within a highly active seismic area. Therefore,
anticipated ground motions in the region due to seismic activity are relatively low and do not pose
a significanthazard. Ground accelerations in excess of 0.19 to -0.29 are not anticipated to occur
at the site.
Project No: 0125-WS24
February 12,2024
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Based on the results of our subsurface explorations and review of available literature (Gurrent
lnternational Building Code), in our opinion, a site classification "C" may be used for this project.
However, this site classification may be revised by performing a site-specific shear wave velocity
study.
Subsurface soil conditions at the site are not susceptible to liquefaction. Seismically induced slope
instability may occur on a global scale impacting not just the site but also the surrounding area,
however, such an evaluation was beyond our scope of services. A detailed seismic hazards
evaluation of the site was beyond the scope of services.
CONCLUSIONS AND RECOMMENDATIONS
Based on the results of our geotechnical evaluation, in our opinion, the site is suitable for the
proposed construction provided the following recommendations are strictly followed. lt should be
noted that our conclusions and recommendations are intended as design guidance. They are
based on our interpretation of the geotechnical data obtained during our evaluation and following
assumptions:
. ProposediFinal site grades will not differ significantly from the current site grades;
. Proposed foundations will be constructed on level ground; and
o Structural loads will be static in nature.
Construction recommendations are provided to highlight aspects of construction that could affect
the design of the project. Entities requiring information on various aspects of construction must
make their own interpretation of the subsurface conditions to determine construction methods,
cost, equipment, and work schedule.
Pool Retaining Walls and Subgrades: Considering the presence of medium to high expansive
soils near the surface. Moreover, the site is located within a swell hazard zone (Figure 5).
Considering these site conditions, we recommend that the proposed pool retaining wall footings
and pool subgrades should be designed and constructed in accordance with following criteria:
Excavate the subgrade and call us for the inspection and approval of the prepared subgrade
prior to the placement of concrete.
Foundations bearing upon properly prepared and approved subgrade should be designed for
a maximum allowable bearing pressure of 2,000 pounds per square foot (psf).
Project No: 0125-WS24
February 12,2024
Page No: 5 of 1 B
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a Estimated final structural loads will dictate the final form and size of foundations to be
constructed. However, as a minimum, we recommend bearing walls be supported by
continuous footings of at least 16 inches in width.
Continuous foundation walls should be reinforced in the top and bottom to span an
unsupported length of at least 8 feet to further aid in resisting differential movement.
Exterior footings should extend below design frost depth of 36 inches.
We understand the retaining walls will be designed to be rigid (unyielding), and not free to
rotate. Retaining walls for at-rest conditions can be designed to resist an equivalent fluid
density of 55 pcf for on-site fill materials if needed only imported granular backfill meeting
CDOT Class 1 structural backfill should be used. Retaining walls for unrestrained conditions
(free lateral movement) can be designed to resistan equivalentfluid densityof 35 pcf foron-
site fill materials and 35 pcf for imported granular backfill or CDOT Class 1 structural backfill.
For passive resistance of unrestrained walls, we recommend passive resistance of 300 psf
per foot of wall height. A coefficient of friction value of 0.35 may be used for contact between
the prepared soil surface and concrete base. The above recommended values do not include
a factor of safety or allowances for surcharge loads such as adjacent foundations, sloping
backfill, vehicle traffic, or hydrostatic pressure. We should be contacted to provide additional
recommendations for any specific site retaining conditions.
Retaining wall backfill should be placed in strict accordance with our earthwork
recommendations given below. Backfill should not be over-compacted in order to minimize
excessive lateral pressures on the walls.
Retaining walls should be adequately designed as retaining walls with adequate drainage
measures implemented. As a precautionary measure, a drainage collection system (drains
or geosynthetic drains) should be included in the wall design in order to minimize hydrostatic
pressures. A prefabricated drainage composite or drain board such as the MiraDrain 2000 or
an engineer-approved equivalent may be installed along the backfilled side of the retaining
walls.
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We estimate total settlement for footings designed and constructed as discussed in this section
will be one inch or less, with differential settlements on the order of one-half to three-fourths of
the total settlement, not considering landslide hazards and evaporite hazards.
Project No: 0125-WS24
February 12,2024
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Pool Deck: We provide following recommendations for Pool deck areas:
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Pool deck should be designed and constructed to move independently of pool structure and
reinforced to function as an independent unit. Provide slip joints around adjacent structures
to allow free vertical movement of the deck.
Deck should be designed as 'square' reinforced panels instead of 'rectangular' reinforced
panels.
Frequent control joints should be provided to reduce problems with shrinkage and cracking
according to ACI specifications. Controljoint spacing is a function of slab thickness, aggregate
size, slump and curing conditions. The requirements for concrete deck thickness, joint
spacing, and reinforcement should be established by the designer, based on experience,
recognized design guidelines and the intended slab use. Placement and curing conditions
will have a strong impact on the final concrete slab integrity. Deck slabs should be adequately
reinforced with welded wire mesh and steel rebar. Structural engineer should include steel
rebar in addition to welded wire mesh in order to reduce the risk of differential movement due
to bending over 8 feet of unsupported length.
Plumbing passing through deck areas should be isolated from the deck slabs and provided
with flexible connections to allow for movement. Under deck plumbing should be avoided if
possible and should be brought above the deck as soon as possible.
Where mechanical/plumbing equipment is supported on deck slabs, we recommend provision
of flexible connections with a minimum of 2 inches of allowance for vertical movement.
Above recommendations should significantly reduce the potential for cracking pool
deck/slabs. However, pool deck cracking cannot be eliminated. Therefore, whenever cracking
occurs, immediate measures should be taken to seal the cracks. On a regular basis, all cracks
and controljoints should be sealed to minimize water seepage into the subgrades. Pool deck
will require maintenance throughout design life.
Drainage and Moisture Control: Considering the presence of evaporite hazard at the site and
in the site vicinity area, we recommend following drainage and moisture control measures, as a
minimum. Any evaporite related hazards and damage caused by that is owner's full responsibility:
The entire pool shell and the drainage envelope around the pool should be underlain by an
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A perimeter underdrain/dewatering system and a base underdrain system should be installed
above the Hypalon Liner at the base of the pool and behind the retaining walls to reduce the
potential for water seepage into the underlying bedrock strata. The perimeter and base
underdrain/dewatering system should be properly designed and connected to the area
Project No: 0125-WS24
February 12,2024
Page No: 7 of 18
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underdrain system (if present) or a sump-pump system for suitable discharge from the pool
area. As a minimum, the subsurface drainage system should consist typically of 4-inch
minimum diameter perforated rigid PVC or flexible pipes (rigid preferred due to depth of
placement) surrounded by at least one pipe diameter of free draining gravel. The pipe should
be wrapped in a geosynthetic to prevent fine soils from clogging the system in the future. The
pipe should drain by gravity to a suitable all-weather outlet or a sump-pit. Surface cleanouts
of the perimeter drain should be installed at minimum serviceability distances around the
structure. A properly constructed drain system can result in a reduction of moisture infiltration
of the subsurface soils.
The entire design and construction team should evaluate, within their respective field of
expertise, the current and potential sources of water throughout the life of the structure and
provide any design/construction criteria to alleviate the potential for moisture changes. lf
recommended drain systems are used, the actual design/layout, outlets, locations, and
construction means and methods should be observed by a representative of AGS.
Proper surface drainage should be maintained at this site during and after completion of
construction operations. The ground surface adjacent to pool areas should be sloped to
promote rapid run-off of surface water. We recommend a minimum slope of six inches in the
first five horizontal feet for landscaped or graveled areas. These slopes should be maintained
during the service life of pool structures. Landscaping should be limited around building areas
to either xeri-scaping, landscaping gravel, or plants with low moisture requirements. lrrigation
should be minimal and limited to maintain plants. Roof downspouts of adjacent residential
structures should discharge on splash-blocks or other impervious surfaces and directed away
from the pool areas. Ponding of water should not be allowed immediately adjacent to pool
areas.
It is important to follow these recommendations to minimize wetting or drying of the foundation
and subgrade elements throughout the life of the facility. Construction means and methods
should also be utilized which minimize improper increases/decreases in the moisture contents
of the soils during construction.
Again, positive drainage away from the new structures is essential to their successful long-
term performance and should be provided during the life of the structure. Deck areas, paved
areas, or landscape areas within 10 feet of structures should slope at a minimum grade of
10H:1V away from pool structure. Once again, downspouts from all roof drains of adjacent
residential structures, if any, should discharge all water away from the pool areas. Drainage
should be created such that surface and subsurface water is diverted away from the pool
areas.
Project No: 0125-WS24
February 12,2024
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SHALLOW FOUNDATIONS
a Foundations bearing upon properly prepared and approved subgrade should be designed for
a maximum allowable bearing pressure of 2,000 pounds per square foot (psf).
o Estimated final structural loads will dictate the final form and size of foundations to be
constructed. However, as a minimum, we recommend bearing walls be supported by
continuous footings of at least 18 inches in width. lsolated columns should be supported on
pads with minimum dimensions of 24 inches square.
r Exterior footings and footings in unheated areas should extend below design/preferred frost
depth of 36 inches.
. Continuous foundation walls should be reinforced in the top and bottom to span an
unsupported length of at least 8 feet to further aid in resisting differential movement. As a
minimum, additional reinforcement as shown in Figure 7 should be placed.
r Foundation/stem walls should be adequately designed as retaining walls and adequate
drainage measures should be implemented as shown in Figure L
We estimate total seftlement for foundations designed and constructed as discussed in this
section will he one inch or less, with differential settlements on the order of one-half to three-
fourths of the total settlement, not considering landslide hazards and evaporite hazards.
STRUCTURAL FLOOR & CRAWL SPACE (lF REQUIRED)
We understand a structural/framed floor with crawl space may be used for this project. The grade
beams (if used) and floor system should be physically isolated from the underlying soil materials
with crawl-space type construction. The void or crawl space of minimum of 6 inches or whatever
minimum current Uniform Building Code (UBC) requirement is.
For crawl-space construction, various items should be considered in the design and construction
that are beyond the scope of geotechnical scope of work for this project and require specialized
expertise. Some of these include design considerations associated with clearance, ventilation,
insulation, standard construction practice, and local building codes. lf not properly drained and
constructed, there is the potential for moisture to develop in crawlspaces through transpiration of
the moisture/groundwater within native soils underlying the structure, water intrusion from
snowmeit anci precipiiation, anci suriace runoii or infiitration of waier through ii-i-igation of iawr-rs
and landscaping. ln crawl space, excessive moisture or sustained elevated humidity can increase
the potential for mold to develop on organic building materials. A qualified professional engineer
in building systems should address moisture and humidity issues.
Pro.ject No: 0125-WS24
February 12,2024
Page No: 9 of 1 8
GRAWL SPACE PERIMETER/UNDERDRAIN SYSTEM (lF REQUIRED)
ln order for the crawl space to remain free of moisture, it is important that drainage
recommendations are properly implemented, and adequate inspections are performed priorto the
placement of concrete
As a minimum, subgrade beneath a structural floor system should be graded so that water
does not pond. Perimeter drains and under-slab drains should be installed in conjunction with
a sump pump system to eliminate the potential for ponding and any subsequent damage to
foundation and slab elements. The lot-specific perimeter dewatering, and underdrain systems
should be properly designed and connected to the area underdrain system or a sump-pump
system for suitable discharge from the lot.
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SLAB-ON-GRADE AND PERTMETER/UNDERDRAIN SYSTEM (lF REQUIRED)
Groundwater is not expected to be at depths below the proposed foundation levels if excavation
is performed during dry seasons. ln order to assure proper slab-on-grade construction (if used),
following recommendations should be strictly followed:
A perimeter dewatering system should be installed to reduce the potential for groundwater
entering slab-on-grade areas. The lotspecific perimeter dewatering should be properly
Drainage recommendations illustrated in Figure 8 should be implemented. The subsurface
drainage system should consist typically of 4-inch minimum diameter perforated rigid PVC or
flexible pipe (rigid preferred due to depth of placement) surrounded by at least one pipe
diameter of free draining gravel. The pipe should be wrapped in a geosynthetic to prevent fine
soils from clogging the system in the future. The pipe should drain by gravity to a suitable all-
weather outlet or a sump-pit. Surface cleanouts of the perimeter drain should be installed at
minimum serviceability distances around the structure. A properly constructed drain system
can result in a reduction of moisture infiltration of the subsurface soils. Drains which are
improperly installed can introduce settlement or heave of the subsurface soils and could result
in improper surface grading only compounding the potential issues.
The underdrain system should consist of adequate lateral drains and a main drain, regular
clean out and inspection locations, and proper connections to the sump-pump system for
discharge into suitable receptacles located away from the site.
The entire design and construction team should evaluate, within their respective field of
expertise, the current and potential sources of water throughout the life of the structure and
provide any design/construction criteria to alleviate the potential for moisture changes. lf
recommended drain systems are used, the actual design/layout, outlets, locations, and
construction means, and methods should be observed by a representative of AGS.
Project No: 0125-WS24
February 12,2024
Page No: 10 of 18
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designed and connected to the area underdrain system or a sump-pump system for suitable
discharge from the lot.
As a minimum, drainage recommendations illustrated in Figure 8 should be implemented. The
subsurface drainage system should consist typically of 4-inch minimum diameter perforated
rigid PVC or flexible pipe (rigid preferred due to depth of placement) surrounded by at least
one pipe diameter of free draining gravel. The pipe should be wrapped in a geosynthetic to
prevent fine soils from clogging the system in the future. The pipe should drain by gravity to
a suitable all-weather outlet or a sump-pit. Surface cleanouts of the perimeter drain should
be installed at minimum serviceability distances around the structure. A properly constructed
drain system can result in a reduction of moisture infiltration of the subsurface soils. Drains
which are improperly installed can introduce settlement or heave of the subsurface soils and
could result in improper surface grading only compounding the potential issues.
The entire design and construction team should evaluate, within their respective field of
expertise, the current and potential sources of water throughout the life of the structure and
provide any design/construction criteria to alleviate the potential for moisture changes. lf
recommended drain systems are used, the actual design/layout, outlets, locations, and
construction means, and methods should be observed by a representative of AGS.
The "Slab Performance Risk" associated with native soils is "Low". Therefore, the slab can be
constructed as a slab-on-grade provided the owner is aware that there is still potential risk of
some slab movement due to presence of possibly collapsible soils.
The actual slab movements that will occur on a particular project site are very difficult, if not
impossible, to predict accurately because these movements depend on loads, evapo-
transpiration cycles, surface and subsurface drainage, consolidation characteristics, swell index,
swell pressures and soil suction values. The actual time of year during which the slab-on-grade
is constructed has been found to have a large influence on future slab-on-grade movements.
Slab heaves or settlements are normally defined in terms of "total" and "differential" movement.
"Total" movement refers to the maximum amount of heave or settlement that the slab may
experience as a whole. "Differential" movement refers to unequal heave or settlement that
different points of the same slab may experience, sometimes over relatively short horizontal
distances. Differential movements are arbitrarily determined to be one-half of the total movement
in soils exhibiting Low Slab Performance Risk. Greater differential movements can occur in areas
where expansive soils have been encountered and where the natural soils abruptly transition to
fill material.
For design of floor slabs, a modulus of subgrade reaction of 200 pounds per cubic inch (pci) may
be used. Based on the results of our analyses, we believe that interior floor slabs designed as
Project No: 0125-WS24
February 12,2024
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recommended above and constructed as recommended in following paragraphs could result in
"total" movement of approximately up to 1-inch with "differential" movement on the order of half
the total movement.
We recommend that the construction measures outlined in the following paragraphs be followed
to reduce potential damage to floor slabs, should excessive wetting of the subsurface soils occur:
r Design and construct the floor slab to move independently of bearing members (floating slab
construction). Provide slip joints around exterior walls and interior columns to allow free
vertical movement of the slabs.
Frequent controljoints should be provided at about 10 feet spacing in the floor slab to reduce
problems with shrinkage and cracking according to ACI specifications. Controljoint spacing
is a function of slab thickness, aggregate size, slump and curing conditions. The requirements
for concrete slab thickness, joint spacing, and reinforcement should be established by the
designer, based on experience, recognized design guidelines and the intended slab use.
Placement and curing conditions will have a strong impact on the final concrete slab integrity.
Floor slabs should be adequately reinforced with welded wire mesh and steel rebar. Structural
engineer should include steel rebar in addition to welded wire mesh in order to reduce the risk
of differential movement due to bending over I feet of unsupported length.
The need for a vapor barrier will depend on the sensitivity of floor coverings to moisture. lf
moisture sensitive floor coverings are proposed for portions of the proposed structure, a
capillary break material, typically consisting of "clean" gravel, should be considered. We can
provide additional recommendations if this is the case.
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Provided gravel is desired below the slab, a layer of 4 to 6 inches can be used. Plumbing
passing through slabs should be isolated from the slabs and provided with flexible connections
to allow for movement. Under slab plumbing should be avoided if possible and should be
brought above the slab as soon as possible.
lf slab-bearing partitions are used, they should be designed and constructed to allow for
movement. A minimum of 2 inches of void space (as illustrated in Figure 3) should be
maintained below or above partitions. lf the void is provided at the top of partitions, the
connections between the interior, slab-supported partitions and exterior foundation supported
walls should allow for differential movement.
Where mechanical equipment and HVAC equipment are supported on slabs, we recommend
provision of a flexible connection between the furnace and ductwork with a minimum of 2
inches of vertical movement.
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February 12,2024
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RETA|NTNG WALL (tF REQUIRED)
Retaining walls for at-rest conditions can be designed to resist an equivalent fluid density of 55
pcf for on-site fill materials if needed only imported granular backfill meeting CDOT Class 1
structural backfill should be used. Retaining walls for unrestrained conditions (free lateral
movement) can be designed to resist an equivalent fluid density of 35 pcf for on-site fill materials
and 35 pcf for imported granular backfill or GDOT Class 1 structural backfill. For passive
resistance of unrestrained walls, we recommend passive resistance of 300 psf per foot of wall
height. A coefficient of friction value of 0.35 may be used for contact between the prepared soil
surface and concrete base.
The above recommended values do not include a factor of safety or allowances for surcharge
loads such as adjacent foundations, sloping backfill, vehicle traffic, or hydrostatic pressure. We
should be contacted to provide additional recommendations for any specific site retaining
conditions.
Retaining wall backfillshould be placed in strict accordance with our earthwork recommendations
given below and as illustrated in Figure 8. Backfill should not be over-compacted in order to
minimize excessive lateral pressures on the walls. As a precautionary measure, a drainage
collection system (drains or geosynthetic drains) should be included in the wall design in order to
minimize hydrostatic pressures. A prefabricated drainage composite or drain board such as the
MiraDrain 2000 or an engineer-approved equivalent may be installed along the backfilled side of
the basement foundation wall.
EARTHWORK CONSTRUCTION
Site grading should be carefully planned so that positive drainage away from all structures is
achieved. The following earthwork recommendations should be followed for all aspects of the
project.
Fill material should be placed in uniform horizontal layers (lifts) not exceeding 8 inches before
compacting to the required density and before successive layers are placed. lf the contractor's
equipment is not capable of properly moisture conditioning and compacting 8-inch lifts, then the
lift thickness shall be reduced until satisfactory results are achieved.
Clays or weathered sandstone/claystone bedrock (if encountered) should not be re-used onsite
except in landscaped areas. lmported soils should be approved by AGS prior to placement. Frl/
placement observations and fill compacfion fesfs should be performed by AGS Engineering in
order to minimize the potential for future problems. Fill material should not be placed on frozen
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February 12,2024
Page No: 13 of 18
ground. Vegetation, roots, topsoil, the existing fill materials, and other deleterious material to
depth of approximately 6 inches should be removed before new fill material is placed.
On-site fill to be placed should be moisture treated to within 2 percent of optimum moisture content
(OMC) for sand fill and from OMC to 3-4 percent above OMC for clay and weathered bedrock.
Fill to be placed in wall backfill areas and driveway areas and all other structural areas should be
compacted to 95% of Standard Proctor (ASTM D 698) dry density or greater. Compaction in
landscape areas should be 85% or greater.
lmported structural fill should consist of sand or gravel material with a maximum particle size of 3
inches or less. ln addition, this material shall have a liquid limit of less than 30 and a plasticity
index of 15 or less. Structural fill should also have a percent fine between 15 to 30 percent
passing the No. 200 sieve. Structural fill should be moisture conditioned to within 2 percent of
OMC and compacted to at least 95 percent of Standard Proctor (ASTM D698) dry density.
ln our opinion, the materials encountered at this site may be excavated with conventional
mechanical excavating equipment. For deeper excavations, heavier equipment with toothed
bucket may be required. Although our soil explorations did not reveal "buried" foundation elements
or other structures or debris within the building footprint, these materials may be encountered
during excavation activities. Debris materials such as brick, wood, concrete, and abandoned
utility lines, if encountered, should be removed from structural areas when encountered in
excavations and either wasted from the site or placed in landscaped areas.
Temporary excavations should comply with OSHA and other applicable federal, state, and local
safety regulations. ln our opinion, OSHA Type A/B soils should be encountered at this site during
excavation. OSHA recommends maximum allowable unbraced temporary excavation slopes of
1 : 1 (H:V) for Type A/B soils for excavations up to 1 0 feet deep. Permanent cut and fill slopes are
anticipated to be stable at slope ratios as steep as 2H:1V (horizontal to vertical) under dry
conditions. New slopes should be revegetated as soon as possible after completion to minimize
erosion.
We recommend a minimum of 12feet of clearance between the top of excavation slopes and soil
stockpiles or heavy equipment or adjacent structures. This setback recommendation may be
revised by AGS once the project plans are available for review. lf braced excavations or shoring
systems are to be used or needed, they should be reviewed and designed by AGS. lt should be
noted that near-surface soils encountered at the site will be susceptible to some sloughing and
excavations should be periodically monitored by AGS's representative.
Project No: 0125-W524
February 12,2024
Page No: 14 of 18
The proposed excavation should not adversely impact any existing structures. Proper shoring
and/or underpinning should be used to maintain the stability of the existing structure as well as
the excavated faces of the new construction area.
It should be noted that the above excavation recommendations are commonly provided by local
consultants. The evaluation of site safety during construction, stability of excavated slopes and
cuts, and overall stability of the adjacent areas during and after construction is beyond our scope
of services. At your request, we can provide these services at an additional cost.
During construction in wet or cold weather, grade the site such that surface water can drain readily
away from the building areas. Promptly pump out or otherwise remove any water that may
accumulate in excavations or on subgrade surfaces and allow these areas to dry before resuming
construction. Berms, ditches and similar means may be used to prevent storm water from
entering the work area and to convey any water off-site efficiently.
lf earthwork is performed during the winter months when freezing is a factor, no grading fill,
structural fill or other fill should be placed on frosted or frozen ground, nor should frozen material
be placed as fill. Frozen ground should be allowed to thaw or be completely removed prior to
placement of fill. A good practice is to cover the compacted fill with a "blanket" of loose fill to help
prevent the compacted fill from freezing overnight. The "blanket" of loose fill should be removed
the next morning prior to resuming fill placement.
During cold weather, foundations, concrete slabs-on-grade, or other concrete elements should
not be constructed on frozen soil. Frozen soil should be completely removed from beneath the
concrete elements, or thawed, scarified and re-compacted. The amount of time passing between
excavation or subgrade preparation and placing concrete should be minimized during freezing
conditions to prevent the prepared soils from freezing. Blankets, soil cover or heating as required
may be utilized to prevent the subgrade from freezing.
GENERAL DRAINAGE
Proper drainage is criticalfor achieving long-term stability and overall success. ln general, where
interior floor elevations are situated at an elevation below proposed exterior grades, we
recommend installation of perimeter drains around the exterior grade beam and foundations as
illustrated in Figure 8. ln addition, drain laterals that span the crawl space are recommended to
prevent ponding of water within the crawlspace (if used). lf necessary, AGS can provide further
recommendations for the exterior drain system and a typical drain detail.
Project No: 0125-WS24
February 12,2024
Page No: 15 of 18
Groundwater was encountered at depth at the time of our explorations. However, based on the
weather and surface water run-off conditions in the site vicinity area during construction, site may
require pumping and other dewatering methods during construction.
Proper surface drainage should be maintained at this site during and after completion of
construction operations. The ground surface adjacent to buildings should be sloped to promote
rapid run-off of surface water. We recommend a minimum slope of six inches in the first five
horizontal feet for landscaped or graveled areas. These slopes should be maintained during the
service life of buildings. lf necessary, adequate interceptor drains should be installed on uphill
sides to intercept any surface water run-off towards the site.
Landscaping should be limited around building areas to either xeri-scaping, landscaping gravel,
or plants with low moisture requirements. No trees should be planted or present within 15 feet of
the foundations. lrrigation should be minimal and limited to maintain plants. Roof downspouts
should discharge on splash-blocks or other impervious surfaces and directed away from the
building. Ponding of water should not be allowed immediately adjacent to the building.
It is important to follow these recommendations to minimize wetting or drying of the foundation
elements throughout the life of the facility. Construction means and methods should also be
utilized which minimize improper increases/decreases in the moisture contents of the soils during
construction.
Again, positive drainage away from the new structures is essential to the successful performance
of foundations and flatwork and should be provided during the life of the structure. Paved areas
and landscape areas within 10 feet of structures should slope at a minimum grade of 10H:1V
away from foundations. Downspouts from all roof drains, if any, should cross all backfilled areas
such that they discharge all water away from the backfill zones and structures. Drainage should
be created such that water is diverted away from building sites and away from backfill areas of
adjacent buildings.
CONCRETE CONSTRUCTION
Concrete sidewalks and any other exterior concrete flatwork around the proposed structure may
experience some differential movement and cracking. While it is not likely that the exterior
flatworks can be economically protected from distress, we recommend following techniques to
reduce the potential long-term movement:
Scarify and re-compact at least 12 inches of subgrade material located immediately beneath
structures.
Project No: 0125-WS24
February 12,2024
Page No: 16 of 18
a
. Avoid landscape irrigation and moisture holding plants adjacent to structures. No trees should
be planted or present within 15 feet of the foundations.
. Thicken or structurally reinforce the structures.
We recommend Type l-ll cement for all concrete in contact with the soil on this site. Calcium
chloride should not be added. Concrete should not be placed on frost or frozen soil. Concrete
must be protected from low temperatures and properly cured.
LIMITATIONS
Detailed geologic hazards evaluation of any kind was beyond our scope of services, therefore, no
warranty of any kind is made regarding geologic hazards present at the site. Evaluation of any
kind of existing structures on the site was beyond the scope of services.
Recommendations contained in this report are based on our field observations and subsurface
explorations, limited laboratory evaluation, and our present knowledge of the proposed
construction. lt is possible that soil conditions could vary between or beyond the points explored.
lf soil conditions are encountered during construction that differ from those described herein, we
should be notified so that we can review and make any supplemental recommendations
necessary. lf the scope of the proposed construction, including the proposed loads or structural
locations, changes from that described in this report, our recommendations should also be
reviewed and revised by AGS.
Our Scope of Work for this project did not include research, testing, or assessment relative to past
or present contamination of the site by any source. lf such contamination were present, it is very
likely that the exploration and testing conducted for this report would not reveal its existence. lf
the Owner is concerned about the potential for such contamination, additional studies should be
undertaken. We are available to discuss the scope of such studies with you. No tests were
performed to detect the existence of mold or other environmental hazards as it was beyond Scope
of Work.
Local regulations regarding land or facility use, on and off-site conditions, or other factors may
change over time, and additional work may be required with the passage of time. Based on the
infanr{ar{ r rca nf fho rannrf rrrifhin ^na rraar frnm fha r{afa nf rannr} nranarafinn AllQ marrrrrv rvyvrr Yrrrrrrrr vrr9 Jvsr rrvrrr rrrv vqlv vr rvyvrr lJrvPsrsrrvrrr nvv rrrsJ
recommend additionalwork and report updates. Non'compliance with any of these requirements
by the client or anyone else will release AGS from any liability resulting from the use of this report
by any unauthorized party. Client agrees to defend, indemnify, and hold harmless AGS from any
claim or liability associated with such unauthorized use or non-compliance.
Project No: 0125-WS24
February 12,2024
Page No: 17 of 18
ln this report, we have presented judgments based partly on our understanding of the proposed
construction and partly on the data we have obtained. This report meets professional standards
expected for reports of this type in this area. Our company is not responsible for the conclusions,
opinions or recommendations made by others based on the data we have presented. Refer to
American Society of Foundation Engineers (ASFE) general conditions included in an appendix.
This report has been prepared exclusively for the client, its' engineers and subcontractors for the
purpose of design and construction of the proposed structure. No other engineer, consultant, or
contractor shall be entitled to rely on information, conclusions or recommendations presented in
this document without the prior written approval of AGS.
We appreciate the opportunity to be of service to you on this project. lf we can provide additional
assistance or observation and testing services during design and construction phases, please call
us at 1 8882764027.
Sincerely,
Sam Adettiwar, MS, PE, GE
Senior Engineer
Attachments
Project No: 0125-W524
February 12,2024
Page No: 18 of 18
FIGURES
FIGURE 1: SITE LOCATION MAP
AMERICAN CEOSERVICES
tft ,!Urt0li . rfi !ri*tsgda*{a*(nn+
E
m
I
:@
SITE F
1
1-,-.. .H_I:g-;
tiEr]
iAspea lree $Cfrtce
'P'"
---"jh;
..1a-
7
i
SITE
t
TION gLOCA
I
*Q't
!!r'
ir*
*$
LY
j
.1
otcAEo ?o aRoAooi
' {d.3,Zoorr; 16
Scale:9O28+
I ooort I--r - ----:TI.- -dfg!r
REFERENCE:
GOOGLE MAPS N
USGS TOPOGRAPHIC MAPS
AMERICAN CEOSERVICES
r{fl J?dJ{!t. @f arw4ri l*l\e**-
NOTE:
SCHEMATIC PLAN TO SHOWAPPROXIMATE SUBSURFACE EXPLORATION LOCATION ONLY; NOT SURVEYED
N
LEGEND:
9o=r,cNATES suBSURFAcE EXpLoMTToN LocATroN, By AMERT.AN GEosERVrcES, LLc. , FEBRUAR' 2024 sEE
EXPLORATION LOG IN APPENDIX FOR FURTHER DETAILS.
REFERENCE:
GARFIELD COUNTY
COLORADO GIS FIGURE 2: SCHEMATIC SITE PLAN
r\.tull:R tLr\t! C 1 .05LRv !L L-5
li"li ?:6..il1:: . r.a N rn:(n9..ri it{r {,tFrV FIGURE 3: GEOLOGIC MAP
wvc. ,
-r
.i,
': fi!3: J
.i
wd',
I
i
I
'A
itl
I I lrtrl
l-)'ii
LEGEND
tlvl
Str*am-channel, floot'l-plain, and low-terruce depositri
(Hclocene and late Pleistocene)-Mustlv prxrrlv surted.
clast-srrpparterl g:avel in.r srrnt{v or silty nratrix.
lnclutJes terrar-ss rtp ln atrortt l2 fl nbove modern rir"er
level
Sheetwrsh deposits llfol{reene and lrte Plelstocen*}-
lfrrhl:lv silty F,rnd, snrdy silt, *ru<l clnvr.v :iill !{i:pr'$it{\'l
irr ephrmcral .ilrd itt('rnlitteilt str'irarJr r'.rllc1,s, rrrr g$rtth.r
lrillshrpus, ancl in basinal .rreas
Young,er terrace alluviunr (late Pleistocenel-futortly
fl corly sortcr{, clasl-supptrrted, lrrcallv I'oulds,rv pelrhlu
and robbk' gravr'l rn ir $ttfld tttld sill matlir. I)e1:r*siterl
ar llhrcial (rutwash. tJnd*rlrcs t('rrnc('s l"l-{5 ft alrovc
moricrn strcam ltvcl. Ivla1,' incluilt' finr*graincd
overbank clcposit:
Marool Fo:malion (Lower Permian? and Upper
Perrnsvlvanianl-ll*d hods rrl riiln(l:itcnu,
c(rnglomt.ralu, nrrrtl'tonr'. sillston(, .rIil sh.'h,rrrd
milror, tlrin bcds il[.g,rJy lir]rc$toiru. lr)p r)f lor[rntidn n(tt
elinol(5rl ir quird 1.1 rtg,kl
Eagle Valley Formation (Middle
PennsylvaIien)-Rudilirh-brolvn, gral', reddish-gray,
.rn!i lan siltstrrrq.. slt.llt'. t;rndstortc, livPsum, dnd
cnrhon.rte rock: u'hirh ale grad,tdonill belrveel atrd
irrtcrtrlrguulg rvitJr llru [ti]rlron li.lflnAlioI lrrd li.rgie
V,rlley Evaporit*
Collapse dcposits {}leisloer.nr and lete Tertiary}-
Hokifi)grnsouji clt'prr*iF of :lightll' trr highly rlrkrm*d
bcdr$tk anrl overlling unctr,hrrutetl trt nrorleralely
dcfornrerl surfici.rl dcposiis. I-.ncallr, inclurl{s largr
int.rct blocks of basalt (Tb) th.rt.rrr. lorvertl lrv roll.rpric.
Scveral fllrvr in lhrsc blocks rtere gr-trlrenrically
.rnalvzcd. Formeel in rfsf()nsr to difft'n:ntiol r:trllapse
resulting from dissr:lutirn uI rurdcrlving rvaprrr:ite
PFm
Pc
OTcd
Qtv
REFERENCE:
U.S. GEOLOGICAL MAPS
N
OTcd
.ts
AMERICAN CET)SERYICES
tEl,l?r',{nI| " rmdrtrndrr+'ir*rrm FIGURE 4: SOIL SURVEY MAP
LEGEND
Aspen-Gypsum Area, Colorado, Parts cf Eagle,
Garfield, and Fitkin Counties (COGSSI
Aspen-Gypsurn Area, Colorado, Parts @
of Eagle, Garfleld, and Pitkin Countlee
(co6ss)
106 Brownsto 7,9 15.0VoF{ap
Unit llap Unit Hame
Acres
in
AOI
4.9
Percent , stonY sandy
loams, 12 to 50
, percent slopes,
extrcmely stony
Totals for Area of
Interest
Symbol of AOI
35
35
4Z
55
Ernpedrado
loam, 5 to 12
percent slopes
Ernpedrado
9 4a/a
7Bla
Zo/a
5Va
52,5 ltll}.Oqb
4
rloam, 12 to 25
lpercent slopes
,Fluvaquents,0
,to 10 percent
,slopes
Gypsum land-
Gypsiorthlds
'complex, 12 to
'65 percent
slopes
6.9 1 3.
5.5 10
N
REFERENCE:
WEB SOIL SURVEY
Showalter-
Morval complex,
15 to 25 percent
lslopes
2r+"8. 47
A,\'TERICAN CLSSIRYICES
iq{ z:fj q4i . .Fi*{itr.t{riF{Oiealrfr-"':v FIGURE 5: COLLAPSIBLE SOILS MAP
$
- l-
gtlloo
I
!
t..
I)
I
'i *
strd,locnrroru
*l
II
.t
I
I
I
I
I I
I
Legend
Co [l a psa b l e_5 o i ls-ut/ itl'r Me e ke n
EG-1 4 Eslian {uiind-blown) deposits
EG-14 Dune and she,ec sand deposits
EG-14 Cretacesus and Tertiary F*rmatinns
::l:,,
EG- 1 4 E*,iapor{te ForrFrati ons
N
REFERENCE
COLORADO GEOLOGICAL
SURVEY
I F
Colorado-la ndsli de-inventory-new
/.1,i-i -
,i conrFiled landslides-fronr LiDAR-and-.other-mapsI
compiled-landslid es-from-24K-maps
&a5.J CrsGf,
compiled-landelldes-from-48- 1 00K-maps,I
compiled-landslid es-from-H8 l 04 li-maps
I
compiled-l ancislicl esJrom-250K-mapsI
6eologicQ'uddslndex
tr
*
:\
o
r-)
-{L
,t ;1;t irl,!tr
:.
:
...1:
11 $gr lna L:" rsl
't.'!
a
' : f il
-*
REFERENCE:
COLORADO LANDSLIDES
INVENTORY
j\\L-egend
N
A,UT[IT, ICA N CIC-TilIV ICLS
dta t'r, + 4'r -.r-'{riirE('d(arlilqd'nV FIGURE 6: LANDSLIDES HMARD
FIGURE 7: TYPICAL DETAILSAMERICAN CEOSERVICES
888.276.4027 - rmcrichgslen iKcom
NOTESI
A. ADDITIONAL REINFORCEMENT, #4 CONTINUOUS BAR,
BOTTOM OF FOOTING.
B. ADDITIONAL REINFORCEMENT, #4 A1 48" C/C, TOP OF
FOOTING.RETAINING WALL DIMENSIONS AND
REINFORCEMENT TO BE DONE BY
PROJECT STRUCTURAL ENGINEER BASED
ON GEOTECHNICAL RECOMMENDATIONS.
C, REINFORCEMENT AS PER STRUCTURAL ENGINEER'S
DESIGN. AS A MINIMUM, USE #4 NT 48" CIC.
CONCRETE FOOTING TO BE
DIMENSIONED BY PROJECT
STRUCTURAL ENGINEER BASED ON
GEOTECHNICAL RECOMMENDATIONS.
ADDITIONAL FOOTING REINFORCEMENT DETAIL
NEW INTERIOR
PART WALL
NOTES:
D. 4Od NAILS EVERY 24" THROUGH BOTTOM PLATE
INTO PRE.DRILLED HOLES OF THE FLOOR PLATE.
WALL FINISH
WALL BASE BOARD
NAILED ONLY TO BASE
PRESSURE TREATED 2'X4" BASE
PLATE SECURED WITH 3"
CONCRETE NAILS OR EQUIVALENT
PLATE;TOP IS FREE
3'MIN VOID SPACE
SPACER-SAME THICKNESS AS
WALL FINISH MATERIAL
CONCRETE BASEMENT SLAB
"FLOAT' (FLOATING WALL DETAIL)
,k *y"f"l::*H5:tERV rcFs FIGURE 8: DRAINAGE DETAILS
FLEXIBLE ADHESIVE EQUIVALENT,
4" ABOVE GROUND;
MAINTAIN LEAK-FREE
COMPACTED EARTH BACKFILUSOIL CAP
(DO NOT USE rF STEM WALL rS
DESIGNED AS A RETAINING WALL. IN
CASE OF RETAINING WALL, USE
FREE-DRAINING CRUSHED ROCK FILL TO
AVOID HYSROSTATIC PRESSURE.
OVER.EXCAVATION
(sEE NOTE B)
LEAK-FREE AND ADEQUATE
CAPACIry DOWNSPOUTS
MINIMUM 3" THICK
DECORATIVE GRAVEL,
RocK oR ennr uYei
AT LEAST 4 FT LONG
20 MIL THICK POLY
SHEET LINER AT LEAST
4FT LONG; EXTEND 4'
ABOVE GROUND & 36"
BELOW GROUND
DOWNSPOUT & MOISTURE BARRIER DETAIL
EXTEND DOWNSPOUT
BEYOND
DECORATIVE LAYER,
10H:1V GMDE;
WITHOUT CAUSING
ADVERSE IMPACT
ON ADJACENT
PROPERTIES; DISCHARGE
ONTO SPLASH BLOCKS.
4
6'MlN l-
OFFSET FOR ANY
SPRINKLER
HEADS; PART CIRCLE
SPRAYING
AWAY FROM BUILDING
SLOPE TO DRAIN AWAY
FROM STRUCTURE, 10H:1V
(sEE DOWNSPOUT DETATL)
FOUNDATION/STEM WALL
-
POLYETHYLENE FILM GLUED TO
FOUNDATION WALL AND EXTENDED
BELOWTHE DRAIN AS SHOWN
MIRAFI 140 N FILTER
FABRIC OR EQUIVALENT
f-
IzSI-AB-ON-GRADE WITH
EXPANSION JOTNTS OR CRAWL€PACE-)
12" MINI
6'MIN
FREE.DRAINING
CLEAN CRUSHED
ROCI(GRAVEL
EXCAVATED TRENCH,
NEARVERTICALTO
0.5H:1V
\-,SUBGRADE, IN-SITU SOIN
,AFF TIA-F A\(oEEr\\,,rErr,
PERIMETER OR FOUNDATION DRAIN DETAIL
NOTES: A.4-INCH DIAMETER PERFORATED PIPE PLACED 2" ABOVE DRAIN SUBGRADE EMBEDDED IN FREE-DRAINING GMVEL OR
CRUSHED ROCK ENVELOPE WITH 2% GRADE TO SUMP PIT OR DISCHARGED TO A SUITABLE RECEPTACLE SUCH THAT ON.SITE AS
WELL AS OFF.SITE STABILITY IS NOT ADVERSELY IMPACTED. B. DEPTH BASED ON OPEN HOLE INSPECTION, FOR SHALLOW
FOUNDATION OPTION. C. ALL FOUNDATION OR OVER-EXCAVATED SUBGRADES MUST BE INSPECTED AND APPROVED BY A
GEOTECHNICAL ENGINEER.
APPENDIX
B1
Project Number 012s-ws24 Soil Auger and Dynamic Cone Penetrometer (DCP)
Ground Elevation See FiguresGeologisVEngineer SMA
Date Drilled 02-12-2024 Total Depth of Borehole 5 Feet
Borehole Diameter 4 OD lnches Depth to Water Not Encountered
cDoJ
.9
CL
(E
Lo
Description / Lithology
oo
CLoo
g
CL
E
Go
c
oo
=-9E
Fo-o
E
ao
oootr
s
o
.9o
=
(,
CL
oo
s
J
o-
s
JJ
s
o;o
tr
.9{.4g
CL
Eoo
t: , d. !-::
,:, l'.j:',,
'. J t- ':,^
SM/
ML
SANDY SILT to SILTY SAND, with
GRAVEL/COBBLES, medium to fine grain,
tan,dry to damp, medium stiff
(ALLUVTUM)
Completely to partially weathered
BEDROCK
(POSSTBLY SANDSTONEiMUDSTONE/
STLTSTONE)
-2.5-
-5.0-
50+
t GM
End of Exploration.
Groundwater was not encountered
during or at the completion of drilling
At completion, borehole was
backfilled with soil cuttings.
Soil/bedrock descriptions are based
on subsurface explorations and
observation of on-site exposed cuts.
,l- *|:5,}:."$SHtERVT.ES Page 1
82
Project Number 0125-WS24 Soil Auger and Dynamic Cone Penetrometer (DCP)
GeologisVEngineer SMA Ground Elevation See Figures
Date Drilled 02-12-2024 Total Depth of Borehole 5 Feet
Borehole Diameter 4 OD lnches Depth to Water Not Encountered
u,oJ
o
CL(E
(9
Description / Lithology
oo
CLoo
g
CL
E(so
tr
oo
=-9o
F
o-o
s
o
oootr
s
o
.2o
=
o
CL
oo
s
J
o-
s
JJ
s
o!
at
o
g
CL
Eoo
sM/
ML
SANDY SILT to SILTY SAND, with
GRAVEL/COBBLES, medium to fine grain,
tan,dry to damp, medium stiff
(ALLUVTUM)
Completely to partially weathered
BEDROCK
(POSST BLY SANDSTONE/MU DSTONE/
STLTSTONE)
-2.5-
trn
50+
l
GM
End of Exploration.
Groundwater was not encountered during
or at the completion of drilling.
At completion, borehole was backfilled with
soil cuttings.
Soil/bedrock descriptions are based on
subsurface explorations and observation of
onsite exposed cuts.
AMERICAN GEOSERVICES-tt-*'?8S,U 6,@7 - redtug@re^ic6oB Page 1
V NMTRICNN
CEOSERVICES
DESCRIPTIVE TERMINOLOGY & SOIL CLASSIFICATION
UNIFIED SOIL CLASSIFICATION SYSTEM
UNIFIED SOIL CLASSIFIGATION AND SYMBOL CHART LABORATORY CLASSIFICATION CRITERIA
COARSE-GRAINED SOILS
(more than 50% of material is larger than No. 200 sieve size.)
GW Well-graded gravels, gravel-sand
mixtures, little or no fines "" = +f sreater than 4; c" = D10 " D6-!!9-0
between 1 and 3GW
GP Poorly-graded g ravels, gravel-sand
mixtures, little or no fines GP Not meeting all gradation requirements for GW
GM Silty g ravels, gravel-sand-silt mixtures GM Atterberg limits below'4"
line or P.l. less than 4
GC
Clean Gravels than 5%
Gravels with fines lhan 12%
GRAVELS
More than 50%
of coarse
fraction larger
than No. 4
sieve size
Clayey gravels, gravel-sand-clay
mixtures GC Atterberg limits above "A"
line with P.l. greater than 7
Above "A" line with Pl. between
4 and 7 are borderline cases
requlring use of dual symbols
SW Well-graded sands, gravelly sands
little or no fines ", = + sreater than o, "" = -l!LO, ** between I and 3
SW
SP Poorly graded sands, gravelly sands,
little or no fines SP Not meeting all gradation requirements for GW
SM Silty sands, sand-silt mixtures Atterberg
line or Pl.SM limits below "A"
less than 4
sc
Clean Sands than 5%
Sands with fines than 1
SANDS
50% or more
of coarse
fraction smaller
than No. 4
sieve size
Clayey sands, sand-clay mixtures sc Atterberg limits above "A"
line with P.l. greater than 7
Limits plotting in shaded zone
with P.l. between 4 andT are
borderline cases requiring use
of dual symbols.
(50% or more of material is smaller than No. 200 sieve size.)
FINE-GRAINED SOILS
ML
Determine percentages of sand and gravel from grain-size curve. Depending
on percentage of fines (fraction smaller than No. 200 sieve size),
coarse-grained soils are classilied as follows:
Less than 5 percent ..
More than 12 percent .
5to12percent.......
GW Gq SW, SP....,... cM, GC,SM,SC
Borderllne cases requiring dual Symbols
CL
lnorganic silts and very fine sands, rock
flour, silty of clayey fine sands or clayey
silts with slight plasticity
lnorganic clays of low to medium
plasticity, gravelly clays, sandy clays,
silty clays, lean clays PLASTICIry CHART
SILTS
AND
CLAYS
Liquid limit
less than
50%
OL Organic silts and organlc silty clays of
low plasticity
MH
lnorganic silts, micaceous or
dialomaceous fine sandy or silty soils,
elastic silts
CH lnorganic clays of high plasticity, fat
clays
SILTS
ANN
CLAYS
Liquid limit
50%
or greater
OH Organic clays of medium to high
plasticity, organic silts
HIGHLY
ORGANIC
sorLs :1-2
PT Peat and other highly organic soils
60
sx50
o-fao
u.lctZa^
E20F6J10
o-
CH
A
=u
NE:
CL MH (OH
ML8 )L;L+llt .!
0 10 20 30 40 50 60 70 80 90 100
LTQUlD LrMlr (LL) (%)
0
DESCRIPTIVE TERMINOLOGY & SOIL CLASSIFICATION
IELD TESTING DEFINITIONS FOR CONSISTENCY OF COHESIVE sorLs
NCY STP (BPF)
VERY SOFT
EXPLORATION LOGS
0-1
t-4
PP (TSF)
LESS THAN 0.25
o.rb - o.sSOFT
MEDIUM STIFF
STI
VERY STIFF
HARD
DD
WD
MC
PL
LL
PI
oc
DRY DENSITY (PCF)
WET DENSITY (PCF)
MOISTURE CONTENT (%)
PLASTTC LrMrT (%)
LTQUtD LtMtT (%)
PLASTICIry INDEX
oRGANtC CONTENT (%)
SATU RATION PERCENT (7o)
SPECIFIC GRAMry
COHESION
ANGLE OF INTERNAL FRICTION
UNCONFINED COMPRESSION
STRENGTH
PERCENT PASSING THE #2OO SIEVE
CALIFORNIA BEARING RATIO
VANE SHEAR
POCKET PENETROMETER
DRIVE PROBE
STANDARD PENETMTION TEST
BLOWS PER FOOT (N VALUE)
SHELBY TUBE SAMPLE
GROUND WATER
ROCK QUALIry DESIDNATION
TEST PIT
BORING
HAND AUGER
5-B
9-15
16-30
0.5 - 1.0
1.0 - 2.0
2.0 - 4.0
30+
DIAMETER
0NcHES)
>120
12-120
3-12
314-3
1t4 - 3t4
4.75 MM
OVER 4,0
RELATIVE DENSIry OF COHESIONLESS SOILS
DENSITY s PT (BPF)
VERY 0-4
LOOSE 5-10
MEDIUM DENSE 11-30
c
o
SG
QU
DENSE
VERY DENSE
PARTICLE SIZE IDENTIFICATION
31 -50
50+
SIEVE NO.#200 =
CBR =
VS=
PP
DP=
SPT =
BPF =
SH=
GW
RQD =
TP=
l|=
HA=
NO.4
10
MEDIUM
FINE
SILT
CLAY
.075 MM ,
2,OMM
:
NO.40
.425 MM NO- 200
<0.005 MM
FEW GRAINS ARE
DISTINGUISHABLE IN THE
FIELD OR WITH HAND LENS.
GRAINS ARE
DISTINGUISHABLE WITH THE
AID OF A HAND LENS.
MOST GRAINS ARE
DISTINGUISHABLE WITH THE
NAKED EYE.
V'- GRoUNDWATERLEVEUSEEPAGE
ENCOUNTERED DURING EXPLOMTION
Y
-
sTATtc 6RSUNDWATER LEVEL WITH
DATE MEASURED
GRAIN SIZE
GRAINED
MEDIUM
GRAINED
COARSE
GRAINED
<0.04 tNcH
0 tttCH
0.04-0.2 tNcH
NAME
BOULDER
COBBLE
GRAVEL
COURSE
COARSE
FINE
SAND
DESCRIPTIVE TERMINOLOGY & SOIL CLASSIFICATION
SPT EXPLORATIONS:
STANDARD PENETRATION TESTING IS
PERFORMED BY DRIVING A 2 - INCH O.D. SPLIT-
SPOON INTO THE UNDISTURBED FORMATION AT
THE BOTTOM OF THE BORING WITH REPEATED
BLOWS OF A 140 - POUND PIN GUIDED HAMMER
FALLTNG 30 tNCHES. NUMBER OF BLOWS (N
VALUE) REQUIRED TO DRIVE THE SAMPLER A
GIVEN DISTANCE WAS CONSIDERED A MEASURE
OF SOIL CONSISTENCY.
SH SAMPLING:
SHELBY TUBE SAMPLING IS PERFORMED WITH A
THIN WALLED SAMPLER PUSHED INTO THE
UNDISTURBED SOIL TO SAMPLE 2.0 FEET OF
solL.
AIR TRACK EXPLORATION:
TESTING IS PERFORMED BY MEASURING RATE
OF ADVANCEMENT AND SAMPLES ARE
RETRIEVED FROM CUTTINGS.
HAND AUGUR EXPLORATION
TESTING IS PREFORMED USING A 3.25'
DIAMETER AUGUR TO ADVANCE INTO THE EARTH
AND RETRIEVE SAMPLES.
DRIVE PROBE EXPLORATIONS:
THIS'RELATIVE DENSIry" EXPLORATION DEVICE
IS USED TO DETERMINE THE DISTRIBUTION AND
ESTIMATE STRENGTH OF THE SUBSURFACE SOIL
AND DECOMPRESSED ROCK UNITS. THE
RESISTANCE TO PENETRATION IS MEASURED IN
BLOWS-PER-1/2 FOOT OF AN 11-POUND HAMMER
WHICH FREE FALLS ROUGHLY 3.5 FEET DRIVING
THE 0.5 INCH DIAMETER PIPE INTO THE GROUND.
FOR A MORE DETAILED DESCRIPTION OF THIS
GEOTECHNICAL EXPLORATION METHOD, THE
SLOPE STABILIry REFERENCE GUIDE FOR
NATIONAL FORESTS IN THE UNITED STATES,
VOLUME I, UNITED STATES DEPARTMENT OF
AGRICULTURE, EM-7170-13, AUGUST 1994, P. 317-
321.
CPT EXPLOMTION:
CONE PENETROMETER EXPLORATIONS CONSIST
OF PUSHING A PROBE CONE INTO THE EARTH
USING THE REACTION OF A 2O-TON TRUCK, THE
coNE RESISTANCE (aC) AND SLEEVE FRTCTION
(FS) ARE MEASURED AS THE PROBE WAS
PUSHED INTO THE EARTH. THE VALUES OF QC
AND FS (tN TSF) ARE NOTED AS THE LOCALTZED
INDEX OF SOIL STRENGTH.
SUBROUNDED COARSE GRAINED
ROUNDED
ANGULARTTY OF
SUBANGULNR
SIMILAR TO ANGULAR BUT HAVE
ROUNDED EDGES.
PARTICLES HAVE
NEARLY PLANE SIDES BUT HAVE WELL
ROUNDED CORNERS AND EDGES.
COARSE GRAINED PARTICLES HAVE
SMOOTHLY CURVED SIDES AND NO
EDGES.
MOIST
WET
WEATHERED STATE
SOIL MOISTURE MODIFIER
DRY ABSENCE OF MOISTURE; DUSTY, DRY
TO TOUCH
DAMP BUT NO VISIBLE WATER
VISIBLE FREE WATER
NO VISIBLE SIGN OF ROCK MATERIAL
WEATHERING; PERHAPS SLIGHT
DISCOLORATION IN MAJOR
DISCONTINUIry SURFACES.
INDICATES
WEATHERING OF ROCK MATERIAL AND
DISCONTINUITY SURFACES. ALL THE
ROCK MATERIAL MAY BE DISCOLORED
BY WEATHERING AND MAY BE
SOMEWHAT WEAKER EXTERNALLY
THAN ITS FRESH CONDITION.
rnesH
SLIGHTLY
WEATHERED
MODEMTELY
WEATHERED
HIGHLY
WEATHERED
COMPLETELY
WEATHERED
LESS THAN HALF OF THE ROCK
MATERIAL IS DECOMPOSED AND/OR
DISINTEGRATED TO SOIL. FRESH OR
DISCOLORED ROCK IS PRESENT EITHER
AS A CONTINUOUS FMMEWORK OR NS
CORE STONES.
MORE THAN ANIT OT THE ROCK
MATERIAL IS DECOMPOSED AND/OR
DISINTEGRATED TO SOIL. FRESH OR
DISCOLORED ROCK IS PRESENT EITHER
AS DISCONTINUOUS FMMEWORK OR
AS CORE STONE.
ALL ROCK MATERIAL IS DECOMPOSED
AND/OR DISINTEGRATED TO SOIL. THE
ORIGINAL MASS STRUCTURE IS STILL
LARGELY INTACT.
RESIDUAL SOIL ALL ROCK MATERIAL IS CONVERTED TO
SOIL, THE MASS STRUCTURE AND
MATERIAL FABRIC IS DESTROYED.
THERE IS A LARGE CHANGE IN VOLUME,
BUT THE SOIL HAS NOT BEEN
SIGNIFICANTLY TRANSPORTED.
Map Unit Description: Showalter-Morval complex, 15 to 25 percent slopes*-Aspen-Gypsum
Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties
Aspen-Gypsum Area, Golorado, Parts of Eagle,
Garfield, and Pitkin Gounties
95-Showalter-Morval complex, 15 to 25 percent slopes
Map Unit Setting
National map unit symbol: iqTv
Elevation: 7,000 to 8,500 feet
Mean annual precipitation: 14 to 16 inches
Mean annual air temperature: 42 to 44 degrees F
Frost-free period: 80 to 90 days
Farmland classification: Not prime farmland
Map Unit Composition
Showalter and similar soils: 45 percent
Morual and similar so/s; 35 percent
Minor components: 20 percent
Estimates are based on obseruations, descriptions, and transects of
the mapunit.
Description of Showalter
Setting
Landform: Alluvial fans, terraces, valley sides
Landform position (three-dimensional) : Tread
Down-slope shape : Linear
Across-s/op e sh ape : Li near
Parent material: Alluvium derived from basalt
Typicalprofile
Hl - 0 to 8 inches: very stony loam
H2 - 8 to 39 inches.' very cobbly clay
H3 - 39 to 60 inches.' very cobbly clay loam
Properties and qualities
S/ope; 15 to 25 percent
Depth to restrictive feature: More than 80 inches
Drainage c/ass; Well drained
Runoff class; Very high
Capactty of the most limiting layer to transmit water
(Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calciu m carbonate, maxim um content: 1 0 percent
Available water supply, 0 to 60 inches: Low (about 5.5 inches)
lnterpretive groups
Land capability classification (inigated): None specified
Land capability classification (nonirrigated): 7s
Hydrologic Soil Group: C
Ecologicalslte; R048AY303CO - Loamy Slopes
L[iDA
-
, Natural Resources
:Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2t1312024
Page 1 of 2
Map Unit Description: Showalter-Morval complex, 15 to 25 percent slopes--Aspen-Gypsum
Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties
Other vegetative classificafion: LOAMY SLOPES (null31)
Hydric sol/ ratngj No
Description of Morval
Settlng
Landform: Alluvial fans
Down-slope shape: Linear
Across-s/ope shape : Linear
Parent material: Alluvium derived from basalt
Typical profile
H1 -0to7 inches: loam
H2 - 7 to 19 inches: clay loam
H3 - 19 to 60 inches.' loam
Properties and qualities
S/ope; 15 to 25 percent
Depth to restrictive feature: More than 80 inches
Drainage c/ass; Well drained
Runoff class; Very high
Capacity of the most limiting layer to transmit water
(Ksat): Moderately high (0.20 to 0.60 in/hr)
Depth to water table.' More than 80 inches
Frequency of flooding: None
Freque ncy of pondrng; None
Calciu m carbonate, maximu m content: 25 percent
Maximum salinity: Nonsaline to slightly saline (0.0 to 4.0
mmhos/cm)
Available water supply, 0 to 60 inches: High (about 9.3 inches)
lnterpretive groups
Land capability classification (inigated): None specified
Land capability classification (nonirrigated): 6e
Hydrologic Soil Group: C
Ecologicalslfe; R048AY292CO - Deep Loam
Other vegetative classificaflon; DEEP LOAM (null_11)
Hydric so/ rafing; No
Minor Components
Other soils
Percent of map unit:20 percent
Hydric so/ rafing: No
Data Source lnformation
Soil Survey Area: Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and
Pitkin Counties
Survey Area Data: Version 14, Aug 23,2023
I,[iDA
-
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2t13t2024
Page2 of 2
Map Unit Description: Gypsum land-Gypsiorthids complex, 12 to 65 percent slopes--Aspen-
Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties
Aspen-Gypsum Area, Colorado, Parts of Eagle,
Garfield, and Pitkin Gounties
55-Gypsum land-Gypsiorthids complex, 12 to 65 percent
slopes
Map Unit Sefting
National map unit symbol: jq6f
Elevation: 5,990 to 9,820 feet
Mean annual precipitation: 10 to 15 inches
Mean annual air temperature: 39 to 46 degrees F
Frost-free period: 80 to 105 days
Farmland classification; Not prime farmland
Map Unit Gomposition
Gypsum land:65 percent
Gypsiorthids and similar soils: 2O percent
Minor components: 15 percent
Esfmafes are based on obseruations, descriptions, and transects of
the mapunit.
Description of Gypsum Land
Typicalprofile
Hl - 0 to 60 inches; gypsiferous material
Properties and qualities
S/ope; 12 to 65 percent
Depth to restrictive feature:0 inches to paralithic bedrock
Runoffclass; Very high
Capacity of the most limiting layer to transmit water (Ksat); Very low
(0.00 to 0.00 in/hr)
Maximum salinity: Moderately saline to strongly saline (8.0 to 32.0
mmhos/cm)
Available water supply, 0 to 60 inches: Very low (about 0.0 inches)
Interpretive groups
Land capability classification (irngated) : None specified
Land capability classification (nonirrigated): 8s
Hydric so/ rafing; No
Description of Gypsiorthids
Setting
Landform : Mountains, drainageways, hills
Landform position (two-dimensional) : Shoulder
La ndform position (th ree-di me n si on al) : Mountainfl ank, side slope
Down-slope shape: Linear
Across-s/op e s h ape : Li near
Parent material: Mixed colluvium and/or mixed residuum
I.TiI}A
-
Natural Resources
,Conseryation Service
Web Soil Survey
National Cooperative Soil Survey
2t13t2024
Page 1 of2
Map Unit Description: Gypsum land-Gypsiorthids complex, 12 to 65 percent slopes--Aspen-
Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties
Typical profile
Hl - 0 to I inches: fine sandy loam
H2 - 8 to 23 inches; fine sandy loam
H3 - 23 to 39 inches; fine sandy loam
H4 - 39 to 43 inches.' weathered bedrock
Properties and qualities
S/ope; 12 to 50 percent
Depth to restrictive feature: 10 to 40 inches to paralithic bedrock
Drainage c/ass; Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water
(Ksat): Moderately low to high (0.06 to 2.00 inihr)
Depth to water table: More than 80 inches
Frequency of floodrng; None
Frequency of pondrng: None
Calcium carbonate, maximum content: 1 0 percent
Gypsum, maximum content: 1 2 percent
Maximum salinity: Slightly saline to moderately saline (4.0 to 8.0
mmhos/cm)
Available water supply, 0 to 60 inches: Low (about 5.5 inches)
lnterpretive groups
Land capability classification (irrigated) : None speclfled
Land capability cl assification (noni rrigated) : 8s
Hydrologic Soil Group: B
Hydric so/ rafing; No
Minor Components
Other soils
Percent of map unit: 15 percent
Hydric so/ rafing; No
Data Source Information
Soil Survey Area: Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and
Pitkin Counties
Survey Area Data: Version 14, Aug 23,2023
t,EiDA--Natural Resources
Gonservation Service
Web Soil Survey
National Gooperative Soil Survey
211312024
Page 2 ol 2
IMPORTANT INFORMATION ABOUT YOUR
GEOTECHNICAL ENGINEERING REPORT
As,the client of a consulting geotechnical
engineer, you should know that site subsurface
conditions cause more construction problems than
any other factor. ASFE/the Association of
Engineering Firms Practicing in the Geosciences
offers the following suggestions and observations
to help you manage your risks.
A GEOTECHNICAL ENG.NEERING REPORT IS
BASED ON A UNIQUE SET OF PROJECT.
SPECIFIC FACTORS Your geotechnical
engineering report is based on a subsurface
exploration plan designed to consider a unique set
of project-specific factors. These factors typically
include: the general nature of the structure
involved, its size, and conflguration; the location of
the structure on the site; other improvements, such
asi access roads, parking lots, arid underground
utilities; and the additional risk created by scope-
of-service limitations imposed by the client. To
help avoid costly problems, ask your geotechnical
engineer to evaluate how factors that change
subsequent to the date of the report may affect the
report's recommendations.
l
Unless your geotechnical engineer indicates
otherwise, do not use your geotechnical
engineering report:
MOST GEOTECHNICAL FINDINGS ARE
PROFESSIONAL JUDGMENTS
Site exploration identifies actual subsurface
conditions only at those points where samples are
taken. The data were extrapolated by your
geotechnical engineer who then applied judgment
to render an opinion about overall subsurface
conditions. The actual interface between materials
may be far more gradual or abrupt than your
report indicates, Actual conditions in areas not
sampled may differ from those predicted in your
report. While nothing can be done to prevent such
situations. you and your geotechnical engineer
can work together to help minimize their impact.
Retaining your geotechnical engineer to observe
construction can be particularly beneficial in this
respect.
r when the nature of the proposed structure is
changed. for example, if an office building will
be erected instead of a parking garage, or a
refrigerated warehouse will be built instead of
an unrefrigerated one;
o when the size, elevation. or configuration of the
proposed structure is altered;
o when the location or orientation of the proposed
structure is modified;
o when there is a change of ownership; or .for
application to an adjacent site.
Geotechnical enqineers cannot accept
resoonsibilitv for-oroblems that mav occur if thev
are'not condulted after factors considered in their
report's development have changed.
A REPORT'S RECOMMENDATIONS CAN ONLY
BE PRELIMINARY
The construction recommendations included in
your geotechnical engineer's report are
preliminary, because they must be based on the
assumption that conditions revealed through
selective exploratory sampling are indicative of
actual conditions throughout a site.
Because actual subsurface conditions can be
discerned only during earthwork, you should retain
your geo- technical engineer to observe actual
conditions and to finalize recommendations. Only
the geotechnical engineer who prepared the report
is fully familiar with the background information
needed to determine whether or not the report's
recommendations are valid and whether or not the
contractor is abiding by applicable
recommendations. The geotechnical engineer who
developed your report cannot assume
responsibility or liability for the adequacy of the
report's recommendations if another party is
retained to observe construction.
SUBSURFACE CONDITIONS CAN CHANGE A
geotechnical engineering report is based on condi-
tions that existed at the time of subsurface
exploration. Do not base construction decisions on
a geotechnical engineering report whose
adequacy may have been affected by time. Speak
with your geotechnical consult- ant to learn if
additional tests are advisable before construction
starts. Note, too, that additional tests may be
required when subsurface conditions are affected
by construction operations at or adjacent to the
site, or by natural events such as floods,
earthquakes, or ground water fluctuations. Keep
your geotechnical consultant apprised of any such
events.
GEOTECHNICAL SERVICES ARE PERFORMED
FOR SPECIFIC PURPOSES AND PERSONS
Consulting geotechnical engineers prepare reports
to meet the specific needs of specific individuals. A
report prepared for a civil engineer may not be
adequate for a construction contractor or even
another civil engineer. Unless indicated otherwise,
your geotechnical engineer prepared your report
expressly for you and expressly for purposes you
indicated. No one other than you should apply this
report for its intended purpose without first
conferring with the geotechnical engineer. No
party should apply this report for any purpose
other than that originally contemplated without first
conferring with the geotechnical engineer.
GEOENVIRONMENTAL CONCERNS ARE NOT
AT ISSUE
Your geotechnical engineering report is not likely
to relate any findings, conclusions, or
recommendations
about the potential for hazardous materials
existing at the site. The equipment, techniques,
and personnel used to perform a
geoenvironmental exploration differ substantially
from those applied in geotechnical engineering.
Contamination can create major risks. lf you have
no information about the potential for your site
being contaminated. you are advised to speak with
your geotechnical consultant for information
relating to geoenvironmental issues.
A GEOTECHNICAL ENGINEERING REPORT IS
SUBJECT TO MISINTERPRETATION Costly
problems can occur when other design profes-
sionals develop their plans based on
misinterpretations of a geotechnical engineering
report. To help avoid misinterpretations, retain
your geotechnical engineer to work with other
project design professionals who are affected by
the geotechnical report. Have your geotechnical
engineer explain report implications to design
professionals affected by them. and then review
those design professionals' plans and
specifications to see how they have incorporated
geotechnical factors. Although certain other design
professionals may be fam- iliar with geotechnical
concerns, none knows 'as much about them as a
competent geotechnical engineer.
BORING LOGS SHOULD NOT BE SEPARATED
FROM THE REPORT Geotechnical engineers
develop final boring logs based upon their
interpretation of the field logs
(assembled by site personnel) and laboratory
evaluation of field samples. Geotechnical
engineers customarily include only final boring
logs in their reports. Final boring logs should not
under any circumstances be redrawn for inclusion
in architectural or other design drawings. because
drafters may commit errors or omissions in the
transfer process. Although photographic
reproduction eliminates this problem, it does
nothing to minimize the possibility of contractors
misinterpreting the logs during bid preparation.
When this occurs. delays. disputes. and
unanticipated costs ara the alltoo-frequent result.
To minimize the likelihood of boring log
misinterpretation, give contractors ready access to
the complete geotechnical engineering report
prepared or authorized for their use. (lf access is
provided only to the report prepared for you, you
shouicj acivise coniraciors of ihe repori's
limitations. assuming that a contractor was not one
of the specific persons for whom the report was
prepared and that developing
construction cost estimates was not one of the
specific purposes for which it was prepared. ln
other words. while a contractor may gain important
knowledge from a report prepared for another
party, the contractor would be well-advised to
discuss the report with your geotechnical engineer
and to perform the additional or alternative work
that the contractor believes may be needed to
obtain the data specifically appropriate for
construction cost estimating purposes.) Some
clients believe that it is unwise or unnecessary to
give contractors access to their geo- technical
engineering reports because they hold the
mistaken impression that simply disclaiming
responsibility for the accuracy of subsurface
information always insulates them from attendant
liability. Providing the best available information to
contractors helps prevent costly construction
problems. lt also helps reduce the adversarial '
attitudes that can aggravate problems to
disproportionate scale.
READ RESPONSIBILITY CLAUSES CLOSELY
Because geotechnical engineering is based
extensively on judgment and opinion, it is far less
exact than other design disciplines. This situation
has resulted in wholly unwarranted claims being
lodged against geotechnical engineers. To help
preverrt tlris problerrt, geoteclrnical engineers have
developed a number of clauses for use in their l
contracts, reports, and other documents.
Responsibility clauses are not exculpatory clauses
designed to transfer geotechnical engineers'
liabilities to other parties. lnstead, they are
definitive clauses that identify where geotechnioal
engineers' responsibilities begin and end. Their
use helps all parties involved recognize their
individual responsibilities and take appropriate
action. Some of these definitive clauses are likely
to appear in your geotechnical engineering report.
Read them closely. Your geotechnical engineer
will be pleased to give full and frank answers to
any questions.
RELY ON THE GEOTECHNICAL ENGINEER
FOR ADDITIONAL ASSISTANCE
Most ASFE-member consulting geotechnical
engineering firms are familiar with a variety of
techniques and approaches that can be used to
help reduce risks fdr all parties to a constructioh
project, from design through construction. Speak
with your geotechnical engineer not only about
geoiechnicai issues, bui oihers as weii, io iearn
about approaches that may be of genuine benefit.
You may also wish to obtain certain ASFE
publications. Contact a member of ASFE of ASFE
for a complimentary directory of ASFE
publications.
ASFE
8811 Colesville Road/Suite G106/Silver Spring, MD 20910
Telephone: 30 1 I 565-27 33 Facsim i le : 30 1 I 589-20 17
Subsurfqce Explorotions
Soil Tesling
Eorlhwork
nE
.RudGMe
j
' '-+";".e' t
'a; i
l
!
I
i
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t:
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!,:,
-iiiii"'
r0veme nl Design
Droinoge Evoluulions
Groundwoter Sludies
Environmentul Assels
Building Assessmenls
1
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AMERICAN GEOSERYI CES. COM