Geotechnical
Investigation
Albany Municipal Airport
Runway Extension & Apron Rehabilitation
Albany, Oregon
Prepared for:
Precision Approach Engineering, Inc.
Corvallis, Oregon
January 16, 2017
Foundation Engineering, Inc.
Professional Geotechnical Services
Albany Municipal Airport – Runway Extension & Apron Rehabilitation January 16, 2017
Geotechnical Investigation 1 Project 2161117
Albany, Oregon Precision Approach Engineering, Inc.
GEOTECHNICAL INVESTIGATION ALBANY MUNICIPAL AIRPORT
RUNWAY EXTENSION & APRON REHABILITATION
ALBANY, OREGON
BACKGROUND
The Albany Municipal Airport is planning improvements that will include extending
Runway 16-34 and rehabilitating the main apron west of the runway. We understand
the runway extension will incorporate the existing blast pad/overrun pavements on both
ends of the runway and will also include the construction of new connector taxiways
at both ends. The project location is shown on Figure 1A (Appendix). A layout of the
improvement areas is shown on Figures 2A through 4A (Appendix A).
Precision Approach Engineering, Inc. (PAE) is the prime engineering consultant and will
provide pavement and civil design services. PAE indicated the design for both the
runway extension and apron rehabilitation will be completed in 2017. Construction for
the apron rehabilitation is currently planned for 2017, while construction for the runway
extension is planned for 2018.
Foundation Engineering, Inc. was retained by PAE to perform the subsurface
investigation, conduct laboratory testing, and provide recommendations for subgrade
preparation and design parameters associated with the pavement improvements. We
have completed multiple investigations for different projects at the airport, which
include the Runway 16-34 rehabilitation project (circa 2010) and the access road
(i.e., Aviation Way SE) rehabilitation and north taxiways project (circa 2000).
Information from those investigations has been used to supplement the current work,
where applicable. The following sections summarize our work.
SITE CONDITIONS AND LOCAL GEOLOGY
The airport is located on a relatively flat alluvial plain, ±¾ mile east of the Willamette
River. Topographic relief is typically limited within the airport and the surrounding
area. A small drainage provides the southern boundary to the site and connects
Timber-Linn and Swan Lakes on the east and west sides of the airport. Vegetation
within the airport is primarily limited to short grass and scattered weeds.
Local geologic mapping (e.g., Wiley 2006) indicates the airport is underlain by
Willamette Silt and Linn Gravels. The Willamette Silt may contain mixtures of silt,
sandy silt, and silty clay. Our previous and current explorations at the airport
encountered mixtures of silt, clay, and sand at shallow depths, consistent with the
Willamette Silt. We have also completed deeper borings immediately north and west
of the airport for a previous project. Those borings encountered medium dense to
very dense gravel at depths ranging from ±0 to 15.5 feet.
Albany Municipal Airport – Runway Extension & Apron Rehabilitation January 16, 2017
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FIELD EXPLORATION
Pavement Cores
Twelve pavement cores (C-1 through C-12) were completed at the site on
December 21, 2016, using a 5-inch diameter core drill and trailer-mounted drill rig.
C-1 was cored at the north end of Taxiway A, near the planned north taxiway and
runway extension. C-2 through C-10 were cored within the main apron and its
connecting taxilanes. C-11 was cored within the overrun pavement at the south end
of Runway 16-34 and C-12 was cored near the south end of Taxiway A (west of
C-11). The approximate core locations are shown on Figures 2A through 4A.
The exploration at C-10 was limited to the depth of the asphaltic concrete (AC) core
only. At the other explorations, the AC cores were removed and the base rock and
underlying subgrade was excavated using a solid-stem auger or hollow-barrel drilling
attachment. Drilling extended to maximum depths ranging from ±2 to 5 feet below
the paved surface. The core holes were logged to delineate the thickness of the AC
and the base rock, and to identify the subgrade conditions. The core hole logs are
included in Appendix B. Dynamic Cone Penetrometer (DCP) testing was performed
on the base rock and subgrade in each core hole. The DCP testing is described in a
subsequent section of this report.
Following the completion of the explorations, the core holes were backfilled with the
excavated materials, placed and compacted in thin lifts, and capped with granular fill
and AC cold patch.
Test Pits
Three test pits (TP-1 through TP-3) were excavated on December 21, 2016, using a
CASE 580 Super N backhoe. The test pits were dug to help document the soil
conditions across the site and to obtain bulk subgrade samples. TP-1 was dug north
of Taxiway A, near the planned connector for the north runway extension. TP-2 was
dug in a grass area adjacent to the main apron. TP-3 was dug where a connector
taxiway is planned near the south end or the runway. The approximate test pit
locations are shown on Figures 2A through 4A.
Each of the test pits extended to a depth of ±5 feet. The soil profiles were logged
and disturbed soil samples were retained for possible laboratory testing. Upon
completion, the excavated materials were placed back into the test pits and the
ground surface at each location was graded relatively smooth. The test pit logs are
included in Appendix B.
Albany Municipal Airport – Runway Extension & Apron Rehabilitation January 16, 2017
Geotechnical Investigation 3 Project 2161117
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DISCUSSION OF SUBSURFACE CONDITIONS
The following sections provide a summary of the subsurface conditions encountered
in the explorations. More specific details are provided on the logs (Appendix B).
Photos of the pavement cores are also provided in Appendix B.
Pavement Cores
Pavement Section
The pavement cores encountered ±3 to 6 inches of AC. Consistent with the available
pavement inventory (e.g., Pavement Consultants, Inc. 2015), several of the cores
showed at least one previous overlay. The observed overlay thickness varied between
cores and typically included a non-woven paving fabric between the overlay and the
original wearing course. Additional details are provided in the logs and the pavement
core photos (Appendix B).
The AC is underlain by base rock that varies with location. At most of the explorations,
the base material consists of ±1.5 or 2-inch minus crushed gravel with varying sand
and silt content. Some of the cores (C-2, C-5, C-9, and C-12) encountered base
material consisting of unprocessed (i.e., uncrushed) gravel or sandy gravel. The
exploration at C-11 (completed in the south blast pad/overrun pavement) encountered
base material that included ±4 inches of AC millings and crushed gravel over an
additional ±4 inches of crushed gravel. Unified Soil Classification System (USCS)
Classifications for the base materials include GW, GP, and GP-GM.
The base rock thickness ranged from ±4 to 16 inches in the explorations. The total
thickness of the pavement sections (including the AC and base rock) ranged from
±9 to 20 inches. Pavement section thicknesses are summarized on Table 1B
(Appendix B).
Subgrade
The subgrade underlying the pavement section varies with location. Consistent with
previous investigations at the airport, most of the explorations encountered brown to
dark brown, low plasticity silty clay to silt with some clay, sand and gravel. These
soils were encountered in C-1, C-2, C-3, C-7, C-9, and C-11. Silty to sandy gravel was
encountered beneath the fine-grained subgrade in most of the above-noted locations at
depths ranging from ±2 to 3.5 feet. The gravel stratum was encountered directly
below the pavement section in C-12 and within a few inches below the pavement
section in C-8. The gravel stratum appears to be shallower towards the south end of
the airport.
Grey, medium to high plasticity clay or silty clay was encountered towards the middle
of the apron in C-4, C-5, and C-6. At these locations, the clay extended to the
maximum depth of the explorations (±5 feet). Similar soil was also encountered in C-8,
but to only a few inches below the pavement section. We also encountered grey, high
plasticity clay in one exploration (TP-2) completed for the north taxiways project in
2000. That test pit was located near the hangars at the northwest corner of the airport.
Albany Municipal Airport – Runway Extension & Apron Rehabilitation January 16, 2017
Geotechnical Investigation 4 Project 2161117
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We interpreted the approximate limits of clay within the apron based on where it was
encountered in the recent explorations. The limits are represented as yellow dashed
lines in Figure 3A. However, the extent of the clay may be more variable than what is
shown in Figure 3A since it was also encountered further north during a previous
investigation.
Test Pits
The test pits encountered varying subgrade conditions, similar to the pavement
cores. TP-1 and TP-2 encountered dark brown, low plasticity silty clay or silt with
some clay, sand and gravel extending below the ground surface. This stratum was
encountered to ±3 feet in TP-1 and to ±1.5 feet in TP-2. The fine-grained soil is
followed by medium dense silty or sandy gravel that extended to the bottom of the
test pits (±5 feet). The fine-grained soil was not encountered in TP-3. Instead, the
exploration encountered silty to sandy gravel for the full depth of the exploration
(±5 feet). Medium to high plasticity clay, similar to that observed in C-4, C-5, and
C-6, was not encountered in the test pits.
Ground Water
Ground water infiltration was observed in the explorations completed near the north
and south ends of the runway. At the north end, moderate to rapid seepage was
observed in TP-1 at a depth of ±2.5 to 3 feet. Moderate seepage was also observed
in C-1 at ±3 feet. At the south end, moderate seepage was observed at ±3 feet in
TP-3 and C-11. Ground water was not observed in the other explorations. However,
the subgrade was typically moist at shallow depths across the site. Similar
conditions were observed during our previous explorations at the airport.
Given the close proximity of the airport to the surrounding Timber-Linn and Swan
Lakes, and the Willamette River further west, we anticipate the local ground water
remains relatively shallow throughout the year and closely corresponds to the water
level in the lakes. During periods of prolonged rainfall, perched ground water
conditions are also likely to develop at shallower depths where the low permeability
fine-grained soils (i.e., silts and clays) are present.
FIELD AND LABORATORY TESTING
DCP Testing
Dynamic Cone Penetrometer (DCP) testing was completed on the base rock and
subgrade within each of the core holes (except C-10). The DCP test consists of
driving the cone of the DCP apparatus into the soil and recording the penetration
versus blow count (mm/blow) as the DCP value. The Oregon Department of
Transportation (ODOT) Pavement Design Guide (2011) provides a correlation for
estimating the in-situ resilient modulus from results of the DCP testing. A summary
of the DCP test results and the correlated in-situ subgrade and base rock modulus
values are summarized in Table 1C (Appendix C).
Albany Municipal Airport – Runway Extension & Apron Rehabilitation January 16, 2017
Geotechnical Investigation 5 Project 2161117
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In-situ modulus values ranging from ±7,739 to 22,565 psi were calculated for the
base rock, with an average value of ±16,674 psi. The relatively low modulus values
are likely due, in part, to thin base rock sections being influenced by the underlying
subgrade.
In-situ modulus values ranging from ±3,219 to 12,435 psi were calculated for the
subgrade, with an average value of ±5,131 psi. The FAA Airport Pavement Design
and Evaluation Circular (2016) recommends estimating the subgrade modulus based
on the following correlation with laboratory California Bearing Ratio (CBR) tests:
E = 1,500 x CBR
Based on the above equation, we back-calculated in-situ CBR values ranging from
±2.1 to 8.3 for the subgrade, with an average value of 3.4.
Significantly higher subgrade modulus values were observed where gravel was
encountered (C-8 and C-12). At those locations, the calculated modulus value
ranged from ±6,309 to 12,435 psi, with back-calculated CBR values ranging from
4.6 to 8.3. The remaining explorations with predominantly silt or clay subgrade had
calculated modulus values ranging from ±3,219 to 6,309 psi, and back-calculated
CBR values ranging from 2.1 to 4.2 (with an average value of 2.7).
Laboratory Testing
Index Tests
The laboratory work included natural water content determinations, Atterberg limits
tests, and mechanical sieve and hydrometer analyses to classify the soils and
estimate their overall engineering properties. The test results are summarized on
Table 2C and Figures 1C through 6C (Appendix C).
The Atterberg limits tests were completed on two bulk samples from TP-1 and TP-2
(S-1-1 and S-2-1) and four samples from the pavement cores (C-3-2, C-5-2, C-6-2,
and C-11-2). The samples were selected to represent the range in plasticity observed
in the subgrade soils. Most of the test results fall on or near the dividing line between
USCS classifications CL and ML (i.e., low plasticity clay or silt). Therefore, we used
a dual classification to characterize most of the subgrade. Sample C-6-2 (from core
hole C-6) was an outlier, with USCS classification CH (i.e., high plasticity clay).
The Atterberg limits results are generally consistent with the range of values from
previous projects at the airport. Figure 1C provides a summary of the Atterberg
limits test results from the current project and previous projects. As noted in
Figure 1C, most of the test samples fall close to the dividing line between CL and
ML soils. Two samples, C-6-2 from the current study and S-2-2 from the Access
Road & Taxiways project (2000), have significantly higher plasticity and are classified
as CH soils.
Sieve and hydrometer gradation curves were completed on the bulk samples from
TP-1 and TP-2 (Figures 2C and 3C). The results are consistent with the Atterberg
limits, indicating primarily silt and clay-sized particle with some sand and gravel. A
Albany Municipal Airport – Runway Extension & Apron Rehabilitation January 16, 2017
Geotechnical Investigation 6 Project 2161117
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sieve analysis on the bulk sample from TP-3 (S-3-1) indicated the subgrade at that
location consists of primarily gravel with some sand and silt, and a USCS
classification of GM.
Sieve analyses were also completed on two samples of the base rock from the apron
at C-4 and C-5 (samples C-4-1 and C-5-1). Both samples contain primarily
gravel-sized particles with fines contents ranging from ±5.8 to 7 percent, and
resulting USCS classification of GW-GM.
Moisture-Density and CBR Testing
Moisture-density curves (ASTM D698) were developed for bulk samples obtained
from TP-1 (S-1-1) and TP-2 (S-2-1). The individual test results are summarized in
Figures 7C and 9C (Appendix C). The results are also summarized in Table 3C
(Appendix C). The test results indicate a maximum dry density of 107.7 pcf at an
optimum moisture content of 16.2% for S-1-1, and a maximum dry density of
106.0 pcf at an optimum moisture content of 14.2% for S-2-1. Both
moisture-density test curves were modified using an oversize correction factor since
the samples included greater than 5% gravel content.
California Bearing Ratio (CBR, ASTM D1883) tests were completed on samples S-1-1
and S-2-1 using the results from the compaction tests. The individual CBR results
are summarized in Figures 8C and 10C (Appendix C). The results are also
summarized in Table 3C. At 95% relative compaction (with oversize correction), the
test results indicate a CBR value of 8.9 for sample S-1-1 and a CBR value of 4.3 for
S-2-1.
The test results indicate a wide range in CBR values for similar soils. The CBR value
of 8.9 for S-1-1 is high for predominantly silt and clay soils. Therefore, we believe
the gravel in sample S-1-1 (±23.7% gravel; see Figure 2C) likely skewed the results.
A CBR value of 4.3 for sample S-2-1 is more typical for these soils.
Moisture-density and CBR test results for the current project and previous projects
at the airport are summarized in Table 3C. Additional scattered in the CBR values is
apparent from Table 3C. Some of this additional scatter can be attributed to the
varying soil conditions. For example, the lowest CBR value of 1.4 was from a test
complete on a sample of high plasticity clay (USCS classification CH). We note
consistent CBR values of 4.3 for two samples of silty clay or clayey silt (USCS
classification CL). Additional discussion and recommendations for design CBR values
are provided in the following section.
DISCUSSION OF GEOTECHNICAL CONSIDERATIONS AND DESIGN REQUIREMENTS
The following sections discuss geotechnical considerations and recommendations for
the proposed runway extension and apron rehabilitation. We anticipate PAE will
evaluate options that include full depth reconstruction or overlay of the existing apron
and the overrun pavements where the runway will be extended. New pavement
sections will be required to provide connector taxiways between the lengthened
runway ends and Taxiway A.
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Geotechnical Investigation 7 Project 2161117
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Discussion of Subgrade Conditions
The pavement subgrade varies across the site, but typically consists of silty clay
and/or silt with some clay, sand and gravel. Corresponding USCS classifications
range from CL to ML. Appendix A of the 2016 FAA Airport Pavement Design and
Evaluation Advisory Circular (AC 150/5320-6F) indicates that soils designated as CL
or ML are “fair to good” as a foundation material when not subject to frost action.
Frost-susceptibility is discussed in a subsequent section of this report.
A portion of the apron is underlain by high plasticity clay with corresponding USCS
classification CH. The FAA Pavement Advisory (2016) characterizes this soil as
“poor to very poor”. The estimated limits of the high plasticity clay are shown in
Figure 3A.
Silty gravel (with corresponding USCS classification GM) was encountered at shallow
depths in some of the explorations. The FAA Pavement Advisory (2016)
characterizes these soils as “good” as a foundation material. The gravel may be
shallowest towards the south end of the airport. However, the depth to gravel
appears to vary across the site. Therefore, we do not recommend predicating any
portion of the pavement design on the gravel subgrade.
Parameters for Pavement Overlay
If rehabilitation of the apron includes pavement overlay (or mill and inlay), we
recommend the following design parameters:
Subgrade
If pavement overlay is planned, the subgrade will remain in its present condition.
Therefore, the results of the DCP testing are most suitable for evaluating the
subgrade. Excluding the DCP test on gravel subgrade, which was only encountered
at two locations, the tests indicated a mean resilient modulus of 4,116 psi (CBR
value of 2.7) with a standard deviation of 900 psi. The mean minus one standard
deviation is 3,216 psi, which correlates to a CBR value of ±2.1. Therefore, we
recommend assuming a CBR value of 2.1 for design. This value is recommended
across the site, regardless if the subgrade is classified as CL/ML or CH.
Base Rock
The existing base rock consists of crushed and uncrushed gravel with varying silt
and sand content. The DCP tests indicated an average base rock modulus of
±16,674 psi. Default modulus values for unreinforced base material in FAARFIELD
are significantly greater, ranging from 40,000 psi (P-154) to 70,000 psi (P-209). We
anticipate the relatively low modulus values correlated from the DCP testing are due
to the quality of the existing base rock and the relatively thin base rock section over
weak subgrade. We recommend assuming a base rock modulus of 15,000 psi to
evaluate a pavement overlay.
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Existing AC
We recommend assuming a modulus value of 200,000 psi to represent the existing
AC to evaluate the pavement overlay. A modulus value of 200,000 psi is consistent
with the FAARFIELD default for existing surface AC that will be overlain.
If all or portions of the existing pavements remain in place, methods should be
evaluated to mitigate the risk of existing cracks propagating through the new AC.
Mitigation techniques typically include milling the existing AC, placing fabric and
sealants over the existing AC prior to paving, and/or providing a relatively thick
overlay. When milling to repair existing pavement damage, FAA requires leaving at
least 2 inches of AC in place unless the entire section is removed.
Subgrade Preparation and Parameters for New Pavement Design
For new pavements and/or full-depth reconstruction, the appropriate subgrade
parameters and preparation will depend, in part, on location since the subgrade varies
across the airport. As discussed above, three general soil types were identified at
the subgrade elevation, which include: low plasticity silty clay or silt with some clay
(CL or ML soils), medium to high plasticity clay (CH soil), and silty gravel (GM soil).
The extent of the silty gravel at the subgrade elevation is variable and appears to be
limited. Therefore, we recommend the pavement design be predicated on either the
CL/ML soil or the CH soil. Recommendations for these two soil types is provided
below.
Low Plasticity Silty Clay to Silt, some Clay (CL/ML Soil)
Low plasticity silty clay to silt, some clay (CL/ML soil) was encountered in most of
the explorations within the improvement area, except the mid-section of the apron
(see Figure 3A). Therefore, the recommended soil parameters and preparation
described below should be suitable for most of the planned pavement improvements.
The laboratory testing indicated a range of CBR values for the CL/ML soil that varied
for reasons discussed above. A CBR value of 4.3 (indicated by two test results) is
within the typical range for these soils. Therefore, we recommend assuming a design
CBR value of 4 for the CL/ML subgrade soils where new pavements and/or full-depth
reconstruction is planned. This is consistent with the recommended CBR value for
the Runway 16-34 Rehabilitation project completed in 2010.
The recommended CBR value assumes the subgrade will be moisture-conditioned, as
required, and compacted to a minimum of 95% relative compaction (based on the
maximum dry density of ASTM D698) prior to placing subbase and base rock.
Multiple moisture-density curves and careful inspection of the soils will be required
to evaluate the relative compaction of the subgrade because of the varying
moisture-density test results that have been observed. This includes allowing for an
over-size correction where the subgrade has greater than 5% gravel content.
Albany Municipal Airport – Runway Extension & Apron Rehabilitation January 16, 2017
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The subgrade is moisture-sensitive. Therefore, we recommend compacting it at or
slightly dry of optimum moisture to reduce the risks of pumping. The prepared
subgrade should be backfilled with base rock or subbase as soon as practical to limit
moisture fluctuations (i.e., wetting or drying).
Medium to High Plasticity Clay (CH Soil)
Medium to high plasticity clay (CH soil) was encountered near the mid-section of the
apron (see Figure 3A). Laboratory test results from a previous project indicated a
CBR value of 1.4 for this soil (see Table 3C). In-situ DCP tests during the current
investigation indicated subgrade modulus values ranging from ±3,564 to 4,441 psi
(i.e., CBR values ranging from ±2.4 to 3.0). Based on these results, we recommend
assuming a design CBR value no greater than 2 for this material for designing new
pavements.
The FAA Pavement Advisory (AC 150/5320-6E) indicates a CBR of 3 (i.e., subgrade
modulus of 4,500 psi) is the lowest value recommended for design of new
pavements. For subgrade with a CBR below 3, subgrade stabilization or other means
to improve the CBR value is recommended. FAA also requires stabilization for
subgrade with swell greater than 3% and high potential for moisture fluctuation. The
previous CBR test on CH soil from the airport indicated a swell of at least 3.4%.
Options available for subgrade improvement include mechanical and chemical
stabilization. Given the relatively limited treatment area, which includes only a
portion of the apron, we anticipate the most cost-effective solution will be partial
overexcavation and replacement where the clay is present. For completeness,
additional options are also discussed briefly below.
Mechanical Stabilization. Mechanical stabilization typically includes overexcavating
and replacing soft soils, and bridging the soft areas with a thick lift of large,
open-graded aggregate. The clay subgrade encountered in the explorations was
typically medium stiff to stiff. Therefore, we do not anticipate needing an
overly-thick layer of stabilization material to facilitate construction. Rather, the
stabilization layer would be used to mitigate the long-term pavement performance
due to low CBR value and swell potential and the clay.
If overexcavation and replacement is selected, we believe it would be reasonable to
assume a nominal overexcavation and replacement depth 1 foot below the planned
subgrade elevation. This will provide a suitable treatment depth to mitigate swelling
soils per FAA requirements and provide a working platform for placing new base rock
and subbase. The excavation should extend to medium stiff to stiff, relatively
undisturbed subgrade and the overexcavated material should be replaced with
granular material (e.g., additional base rock or subbase) underlain by a separation
geotextile. If these two requirements are met, it is our opinion a CBR of 3 may be
used for flexible pavement design to represent the combination of imported fill within
the overexcavated zone and the underlying native soils.
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Geogrid reinforcement could also be used to improve the strength of the pavement
section to compensate for the low subgrade strength. The relative improvement is
highly dependent on the selected geogrid and may be proprietary to particular geogrid
manufacturers. Therefore, the design of a geogrid-reinforced pavement section
would require consultation and analysis from selected geogrid manufacturer(s).
Chemical Stabilization. Chemical stabilization includes mixing cement, lime, or other
additives into the subgrade to improve its strength. Cement stabilization would
provide an additional, stabilized layer within the pavement section. It also would
provide a working surface to facilitate placement of the granular base course. If this
option is desirable, additional testing would be required to evaluate the required
application rate to meet durability requirements, as well as a design CBR value for
the treated layer. For preliminary evaluation of costs, we recommend assuming a
nominal treatment depth of 12 inches and a cement application rate of ±12% by
weight based on the subgrade soils at the site. The underlying subgrade (below the
treatment depth) should remain relatively undisturbed.
FAA’s recommends selecting the design CBR value for chemically-treated subgrade
as one standard deviation below the mean CBR value from the laboratory testing.
For the underlying, untreated and uncompacted subgrade, we recommend assuming
a CBR of 2.
Frost Considerations
Most of the subgrade consists of silty clay or silt with some clay (CL to ML soil) with
plasticity index (PI) values typically less than 12. This material corresponds to a FAA
frost group classification of FG-4, suggesting most of the subgrade is highly
frost-susceptible. The high plasticity clay (CH soil) that was encountered in the
mid-section of the apron has a corresponding frost group classification of FG-3.
Complete mitigation of the risk of detrimental frost heave requires overexcavation and
replacement of the soils below the depth of frost penetration. The local building code
for Linn County indicates a frost penetration depth of ±12 inches in the vicinity of the
airport. Given the limited frost depth, we expect frost mitigation will not be an issue
in the design of new pavements.
Site Drainage
The 2016 FAA Pavement Advisory (AC 150/5320 6E), Appendix A, indicates soil
classified as CL or ML can have drainage characteristics ranging from fair to
practically impervious. Soil classified as CH generally has very low permeability.
The 2013 FAA Surface Drainage Design Advisory Circular (AC 150/5320-5D),
Figure G-3, suggests a coefficient of permeability, k, for these soils in the range of
10-7 cm/sec to 10-10 cm/sec, which corresponds to practically impermeable soil.
Given the high clay content of the subgrade, we recommend assuming a k value no
higher than 10-8 cm/sec for evaluating drainage alternatives.
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Construction Considerations
Site Stripping
Where new pavements are planned (i.e., connector taxiways), we recommend
assuming a nominal stripping depth of 4 inches to remove sod, roots, and/or other
organics.
Construction Timing
The airport site is relatively flat and underlain by low permeability soils. As such,
rainfall perches on the site in the wet winter and spring months. The perched water
typically disappears in the summer months, where the soil is exposed to dry weather
(i.e., outside existing paved areas). However, it has been our experience that
subgrade covered by existing pavements can remain wet of optimum year-round.
Therefore, where complete reconstruction is planned, wet subgrade should be
anticipated beneath the existing pavements regardless of the construction season.
As such, the construction schedule should include ample time to aerate and
moisture-condition the soils prior to compaction. We anticipate
moisture-conditioning will require ripping and aerating the soils to a depth of
±12 inches.
We recommend completing the earthwork during the dry summer months (typically
July through September), when it should be practical to adjust the moisture content
of the soil to near optimum and compact the subgrade. The contractor may still
experience pumping problems and have difficulty achieving adequate compaction in
the summer if the soils have not adequately dried.
If the construction schedule does not allow enough time for soil aeration,
overexcavation and replacement of wet soils should be anticipated. Where wet soils
are overexcavated, a thickened subbase and/or base rock section over a separation
geotextile is typically required to protect the moisture-sensitive soils and limit the risk
of subgrade pumping from repeated construction traffic. A fill thickness of ±18 to
24 inches is typical required. The actual fill thickness will depend on the stiffness
and moisture content of the exposed subgrade.
Reclamation of Existing Materials
The existing base materials are variable and likely will not meet the requirements for
re-use as P-209 (base course). However, it may be possible to re-use the base
material as P-154 (subbase course) for reconstructed pavement sections if it is mixed
with reclaimed AC (ground to 3-inch minus particle size) or combined with cleaner
imported granular fill. AC millings and reclaimed base rock could also be used in
areas where overexcavation of poor subgrade is required (e.g., CH soil in the apron).
Fill Materials and Compaction
The base rock for new pavements should consist of 1 or ¾-inch minus, clean
(i.e., less than 5% passing the No. 200 sieve), well-graded, crushed gravel or rock
conforming to FAA P-209 requirements. Subbase material should consist of
Albany Municipal Airport – Runway Extension & Apron Rehabilitation January 16, 2017
Geotechnical Investigation 12 Project 2161117
Albany, Oregon Precision Approach Engineering, Inc.
free-draining sand, gravel, rock, asphalt grindings, or mixtures of the above that
conform to FAA P-154 requirements and are free of plastic clay and organic matter.
All fill should be placed in level lifts not exceeding 12 inches and compacted to a
minimum of 95% relative compaction. The maximum dry density of ASTM D698
should be used as the standard for estimating relative compaction of the fill. The
moisture content of the fill and subgrade should be adjusted to within ±2% of its
optimum value prior to compaction.
Imported granular fill will compact most efficiently with a smooth-drum, vibratory
roller. Efficient compaction of fine-grained subgrade (where practical) will typically
require the use of a tamping foot or kneading roller. Field density tests should be
run frequently to confirm adequate compaction of the base rock, subbase, and
subgrade. Adequate compaction of fill materials, which are too coarse or variable
for density testing, should be evaluated by observation of the compaction method
and proof-rolling with a loaded dump truck or other approved heavy construction
vehicle.
DESIGN REVIEW/CONSTRUCTION OBSERVATION/TESTING
We should be provided the opportunity to review all drawings and specifications that
pertain to site preparation and fill placement. Site preparation for new pavements
will require field confirmation of the subgrade conditions. Mitigation of pumping
subgrade and fill will also require engineering review and judgment. That judgment
should be provided by one of our representatives. We recommend we be retained
to provide the necessary construction observations.
VARIATION OF SUBSURFACE CONDITIONS, USE OF THIS REPORT AND WARRANTY
The analysis, conclusions, and recommendations contained herein assume the soil
profiles encountered in the pavement cores and test pits are representative of the
site conditions. The above recommendations assume we will have the opportunity
to review final drawings and be present during construction to confirm the assumed
subgrade conditions. No changes in the enclosed recommendations should be made
without our approval. We will assume no responsibility or liability for any engineering
judgment, inspection, or testing performed by others.
This report was prepared for the exclusive use of Precision Approach
Engineering, Inc. and their design consultants for the Albany Municipal Airport –
Runway Extension and Apron Rehabilitation project in Albany, Oregon. Information
contained herein should not be used for other sites or for unanticipated construction
without our written consent. This report is intended for planning and design
purposes. Contractors using this information to estimate construction quantities or
costs do so at their own risk. Our services do not include any survey or assessment
of potential surface contamination or contamination of the soil or ground water by
hazardous or toxic materials. We assume those services, if needed, have been
completed by others.
Our work was done in accordance with generally accepted soil and foundation
engineering practices. No other warranty, expressed or implied, is made.
Albany Municipal Airport – Runway Extension & Apron Rehabilitation January 16, 2017
Geotechnical Investigation 13 Project 2161117
Albany, Oregon Precision Approach Engineering, Inc.
REFERENCES
ASTM, 2014, Standard Test Methods for CBR (California Bearing Ratio) of Laboratory-Compacted Soil: American Society for Testing and Materials (ASTM), Standard D1883, vol. 04.08.
ASTM, 2012, Standard Tests Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort (12,400ft-lbf/ft3 (600kN-m/m3)): American Society for Testing and Materials (ASTM), Standard D698, vol. 04.08.
FAA, 2016, Airport Pavement Design and Evaluation Advisory Circular: AC No. 150/5320-6F, Federal Aviation Administration.
FAA, 2013, Subsurface Drainage Design Advisory Circular: AC No. 150/5320-5D, Federal Aviation Administration.
FAA, 2014, Standards for Specifying Construction of Airports Advisory Circular:
AC No. 150/5370-10G, Federal Aviation Administration.
ODOT, 2011, ODOT Pavement Design Guide, Oregon Department of Transportation
(ODOT), Pavement Services Unit.
Wiley, T.J., 2006, Preliminary Geologic Map of the Albany Quadrangle, Linn, Marion
and Benton Counties, Oregon: Oregon Department of Geology and Mineral
Industries, Open-File Report O-06-26.
Appendix A
Figures
Professional Geotechnical Services
Foundation Engineering, Inc.
2161117
Source: ODOT City Maps Database
SITE
Albany
North Albany
2161117
No Scale
2161117
No Scale
Approximate
limits of CH Clay
2161117
No Scale
Appendix B Test Pit and Core Hole Logs and Core Photos
ProfessionalGeotechnicalServices
Foundation Engineering, Inc.
S-1-1
S-1-2
SILT, some clay, sand, and gravel (ML); dark brown, lowplasticity, moist to wet, medium stiff, fine to coarse sand, fine tocoarse subrounded gravel, (alluvium).
Silty GRAVEL, some sand (GM); grey to brown, low plasticity silt,wet, medium dense, fine to coarse sand, fine to coarsesubrounded gravel, (alluvium).
BOTTOM OF EXPLORATION
Surface: Short grass.
Fine roots extend to ±9 inches.
Moderate seepage at ±2.5 feet.
Rapid seepage at ±3 feet.
Albany, Oregon
N/A (Approx.)
Project No.:
Surface Elevation:
Date of Test Pit:
2161117 Test Pit Log: TP-1
Albany Municipal Airport
Runway Extension & Apron Rehabilitation
December 21, 2016
1
2
3
4
5
Soil and Rock Description
Dep
th,
Fee
t
Sam
ple
#
Lo
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Cla
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ymb
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SF
Sym
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Comments
S-2-1
S-2-2
Silty CLAY, some sand and gravel (CL); dark brown, lowplasticity, moist, medium stiff, fine to coarse sand, fine to coarsesubrounded gravel, (alluvium).
Sandy GRAVEL, trace to some silt (GP-GM); brown to grey,damp, medium dense, fine to coarse sand, fine to coarsesubrounded gravel, (alluvium).
BOTTOM OF EXPLORATION
Surface: Short grass.
Fine roots extend to ±4 inches.
No seepage or ground waterencountered to the limit of excavation.
Albany, Oregon
N/A (Approx.)
Project No.:
Surface Elevation:
Date of Test Pit:
2161117 Test Pit Log: TP-2
Albany Municipal Airport
Runway Extension & Apron Rehabilitation
December 21, 2016
1
2
3
4
5
Soil and Rock Description
Dep
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Fee
t
Sam
ple
#
Lo
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on
Cla
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ymb
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SF
Sym
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Comments
S-3-1
S-3-2
Silty, sandy GRAVEL (GM); grey to brown, low plasticity silt,moist, medium dense, fine to coarse sand, fine to coarsesubrounded gravel, (alluvium).
Sandy GRAVEL, scattered cobbles (GP); grey, wet, mediumdense, fine to coarse sand, fine to coarse subrounded gravel,subrounded cobbles up to ±6 inch diameter, (alluvium).
BOTTOM OF EXPLORATION
Surface: Short grass and weeds.
Fine roots extend to ±3 inches.
Moderate seepage at ±3 feet.
Albany, Oregon
N/A (Approx.)
Project No.:
Surface Elevation:
Date of Test Pit:
2161117 Test Pit Log: TP-3
Albany Municipal Airport
Runway Extension & Apron Rehabilitation
December 21, 2016
1
2
3
4
5
Soil and Rock Description
Dep
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t
Sam
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#
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Comments
C-1-1
C-1-2
ASPHALTIC CONCRETE (±4 inches).
CRUSHED GRAVEL (GW) (±16 inches); grey, damp, dense,±1½-inch minus, angular to subrounded gravel, (base rock).
Sandy SILT, some clay (ML); dark brown, low plasticity, moist towet, soft to medium stiff, fine to coarse sand, (alluvium).
BOTTOM OF EXPLORATION
Core includes ±2-inch overlay overoriginal wearing course.
Moderate seepage at ±3 feet.
N/A (Approx.)
Project No.:
Surface Elevation:
Date:
2161117 Core Hole Log: C- 1
Albany Municipal Airport
Runway Extension & Apron Rehabilitation Albany, OregonDecember 21, 2016
1
2
3
4
5
Soil and Rock Description
Dep
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Sym
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Comments
C-2-1
C-2-2
C-2-3
ASPHALTIC CONCRETE (±6 inches).
GRAVEL (GP) (±4 inches); grey, damp, medium dense, coarsesubrounded gravel, (base rock).Silty CLAY to SILT, some clay, sand, and gravel (CL to ML); darkbrown, low plasticity, moist, medium stiff, fine sand, (alluvium).
Silty GRAVEL, some sand (GM); grey to brown, low plasticity silt,moist, medium dense, fine to coarse sand, fine to coarsesubrounded gravel, (alluvium).
Sandy GRAVEL, trace silt (GP); grey, damp to moist, dense, fineto coarse sand, fine to coarse subrounded gravel, (alluvium).
BOTTOM OF EXPLORATION
Core includes 3 lifts: 2.25-inch withgeotextile fabric/1.75-inch/2-inch
No seepage or ground waterencountered to the limit of excavation.
N/A (Approx.)
Project No.:
Surface Elevation:
Date:
2161117 Core Hole Log: C- 2
Albany Municipal Airport
Runway Extension & Apron Rehabilitation Albany, OregonDecember 21, 2016
1
2
3
4
5
Soil and Rock Description
Dep
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t
Sam
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#
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Comments
C-3-1
C-3-2
C-3-3
ASPHALTIC CONCRETE (±4 inches).
CRUSHED GRAVEL, some sand and silt (GW-GM) (±11 inches);grey to brown, damp, ±1½-inch minus, (base rock).
Silty CLAY to SILT, some clay, sand, and gravel (CL to ML); darkbrown, low plasticity, moist, medium stiff, fine to coarse sand,fine subrounded gravel, (alluvium).
Silty GRAVEL, some sand (GM); grey to brown, low plasticity silt,moist, medium dense to dense, fine to coarse sand, fine tocoarse subrounded gravel, (alluvium).
BOTTOM OF EXPLORATION
Cored on surface crack that extendedthrough the core. ±1.75-inch overlaywith geotextile fabric over originalwearing course.
Base rock is minimally processed withfew fractured faces.
No seepage or ground waterencountered to the limit of excavation.
N/A (Approx.)
Project No.:
Surface Elevation:
Date:
2161117 Core Hole Log: C- 3
Albany Municipal Airport
Runway Extension & Apron Rehabilitation Albany, OregonDecember 21, 2016
1
2
3
4
5
Soil and Rock Description
Dep
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t
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#
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Comments
C-4-1
C-4-2
ASPHALTIC CONCRETE (±5 inches).
CRUSHED GRAVEL, some sand and silt (GW-GM) (±9 inches);grey, damp, dense, ±1½-inch minus, angular to subroundedgravel, (base rock).CLAY (CH); grey, high plasticity, moist, medium stiff, (alluvium).
BOTTOM OF EXPLORATION
Irregular surface on the bottom of thecore. Reported AC thickness of5 inches is the thickest portion of thecore.
No seepage or ground waterencountered to the limit of excavation.
N/A (Approx.)
Project No.:
Surface Elevation:
Date:
2161117 Core Hole Log: C- 4
Albany Municipal Airport
Runway Extension & Apron Rehabilitation Albany, OregonDecember 21, 2016
1
2
3
4
5
Soil and Rock Description
Dep
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Sam
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#
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Comments
C-5-1
C-5-2
ASPHALTIC CONCRETE (±5 inches).
Sandy GRAVEL, some silt (GW-GM) (±6 inches); grey to brown,moist, medium dense, fine to coarse sand, fine to coarsesubangular to subrounded gravel, (base rock).Silty CLAY (CL to ML); grey, medium plasticity, moist, mediumstiff to stiff, (alluvium).
BOTTOM OF EXPLORATION
Core includes ±1.75-inch overlay withgeotextile fabric over original wearingcourse.
No seepage or ground waterencountered to the limit of excavation.
N/A (Approx.)
Project No.:
Surface Elevation:
Date:
2161117 Core Hole Log: C- 5
Albany Municipal Airport
Runway Extension & Apron Rehabilitation Albany, OregonDecember 21, 2016
1
2
3
4
5
Soil and Rock Description
Dep
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Sam
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Comments
C-6-1
C-6-2
ASPHALTIC CONCRETE (±4 inches).
CRUSHED GRAVEL (GW) (±8 inches); grey, damp to moist,dense, ±1½-inch minus, angular to subrounded gravel, (baserock).CLAY (CH); grey, high plasticity, moist, stiff, (alluvium).
BOTTOM OF EXPLORATION
Core includes ±2.5-inch overlay withgeotextile fabric over original wearingcourse. Lower AC lift is fractured.
No seepage or ground waterencountered to the limit of excavation.
N/A (Approx.)
Project No.:
Surface Elevation:
Date:
2161117 Core Hole Log: C- 6
Albany Municipal Airport
Runway Extension & Apron Rehabilitation Albany, OregonDecember 21, 2016
1
2
3
4
5
Soil and Rock Description
Dep
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Sam
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#
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Comments
C-7-1
C-7-2
ASPHALTIC CONCRETE (±3.75 inches).CRUSHED GRAVEL, some sand (GW) (±13.25 inches); grey,damp, dense, ±1-inch minus, angular to subrounded gravel,(base rock).
Gravelly SILT, some clay (ML); brown, low plasticity, moist,medium stiff, fine subrounded gravel, (alluvium).
Silty GRAVEL, some sand (GM); grey to brown, low plasticity silt,moist, medium dense, fine to coarse sand, fine to coarsesubrounded gravel, (alluvium).
BOTTOM OF EXPLORATIONNo seepage or ground waterencountered to the limit of excavation.
N/A (Approx.)
Project No.:
Surface Elevation:
Date:
2161117 Core Hole Log: C- 7
Albany Municipal Airport
Runway Extension & Apron Rehabilitation Albany, OregonDecember 21, 2016
1
2
3
4
5
Soil and Rock Description
Dep
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C-8-1
C-8-2C-8-3
ASPHALTIC CONCRETE (±4.5 inches).
CRUSHED GRAVEL, some sand (GW) (±4.5 inches); grey, damp,medium dense, ±2-inch minus, angular to subrounded gravel,(base rock).CLAY, trace gravel (CH); grey, high plasticity, moist, stiff,(alluvium).Silty GRAVEL, some sand (GM); grey to brown, low plasticity silt,moist, dense, fine to coarse sand, fine to coarse subroundedgravel, (alluvium).
BOTTOM OF EXPLORATION
Core includes ±½-inch overlay withgeotextile fabric. Irregular surface onthe bottom of the core. Reported ACthickness of ±4.5 inches is the thickestportion of the core.
Practical drilling refusal at ±2.5 feet oncoarse gravel or cobble.
No seepage or ground waterencountered to the limit of excavation.
N/A (Approx.)
Project No.:
Surface Elevation:
Date:
2161117 Core Hole Log: C- 8
Albany Municipal Airport
Runway Extension & Apron Rehabilitation Albany, OregonDecember 21, 2016
1
2
3
4
5
Soil and Rock Description
Dep
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C-9-1
C-9-2
ASPHALTIC CONCRETE (±6 inches).
Sandy GRAVEL (GP) (±7.5 inches); grey, damp, dense, fine tocoarse sand, fine to coarse subrounded gravel, (base rock).
SILT, some clay, trace gravel (ML); dark brown, low plasticity,moist, medium stiff, fine subrounded gravel, (alluvium).
Silty GRAVEL, some sand (GM); grey to brown, low plasticity silt,moist, medium dense, fine to coarse sand, fine to coarsesubrounded gravel, (alluvium).BOTTOM OF EXPLORATION
Core includes ±2.5-inch overlay withgeotextile fabric over original wearingcourse.
Practical drilling refusal at ±3 feet oncoarse gravel or cobble.No seepage or ground waterencountered to the limit of excavation.
N/A (Approx.)
Project No.:
Surface Elevation:
Date:
2161117 Core Hole Log: C- 9
Albany Municipal Airport
Runway Extension & Apron Rehabilitation Albany, OregonDecember 21, 2016
1
2
3
4
5
Soil and Rock Description
Dep
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ASPHALTIC CONCRETE (±3 inches).BOTTOM OF EXPLORATION
Limited to AC core only.
N/A (Approx.)
Project No.:
Surface Elevation:
Date:
2161117 Core Hole Log: C-10
Albany Municipal Airport
Runway Extension & Apron Rehabilitation Albany, OregonDecember 21, 2016
1
2
3
4
5
Soil and Rock Description
Dep
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C-11-1
C-11-2
C-11-3
ASPHALTIC CONCRETE (±4 inches).
CRUSHED GRAVEL and ASPHALTIC CONCRETEGRINDINGS, trace sand and silt (GW) (±4 inches); grey to black,damp, dense, ±2-inch minus, angular to subangular gravel, (baserock).CRUSHED GRAVEL, trace silt and sand (GP) (±4 inches); grey,damp, dense, ±1½-inch minus, angular to subrounded gravel,(subbase).Silty CLAY to SILT, some clay and gravel (CL to ML); darkbrown, low to medium plasticity, moist to wet, medium stiff tostiff, fine subrounded gravel, (alluvium).
Clayey GRAVEL, some silt and sand (GC); brown, mediumplasticity clay, wet, medium dense, fine to coarse sand, fine tocoarse subrounded gravel, (alluvium).
BOTTOM OF EXPLORATION
Moderate seepage at ±3 feet.
N/A (Approx.)
Project No.:
Surface Elevation:
Date:
2161117 Core Hole Log: C-11
Albany Municipal Airport
Runway Extension & Apron Rehabilitation Albany, OregonDecember 21, 2016
1
2
3
4
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C-12-1
C-12-2
ASPHALTIC CONCRETE (±5 inches).
Sandy GRAVEL, trace silt (GP) (±5 inches); grey to brown, dampto moist, dense, fine to coarse sand, fine to coarse angular tosubrounded gravel, (base rock).Sandy GRAVEL, some silt (GW-GM); grey to brown, lowplasticity silt, moist, dense, fine to coarse sand, fine to coarsesubangular to subrounded gravel, (possible fill).
BOTTOM OF EXPLORATION
Core includes ±2.25-inch overlay withgeotextile fabric over original wearingcourse.
Practical drilling refusal at ±2 feet oncoarse gravel or cobble.No seepage or ground waterencountered to the limit of excavation.
N/A (Approx.)
Project No.:
Surface Elevation:
Date:
2161117 Core Hole Log: C-12
Albany Municipal Airport
Runway Extension & Apron Rehabilitation Albany, OregonDecember 21, 2016
1
2
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Foundation Engineering, Inc. Albany Municipal Airport Runway Extension & Apron Rehabilitation Project 2161117
Photo 1. Pavement Core C-1
Photo 2. Pavement Core C-2
Foundation Engineering, Inc. Albany Municipal Airport Runway Extension & Apron Rehabilitation Project 2161117
Photo 3. Pavement Core C-3
Photo 4. Pavement Core C-4
Foundation Engineering, Inc. Albany Municipal Airport Runway Extension & Apron Rehabilitation Project 2161117
Photo 5. Pavement Core C-5
Photo 6. Pavement Core C-6
Foundation Engineering, Inc. Albany Municipal Airport Runway Extension & Apron Rehabilitation Project 2161117
Photo 7. Pavement Core C-7
Photo 8. Pavement Core C-8
Foundation Engineering, Inc. Albany Municipal Airport Runway Extension & Apron Rehabilitation Project 2161117
Photo 9. Pavement Core C-9
Photo 10. Pavement Core C-10
Foundation Engineering, Inc. Albany Municipal Airport Runway Extension & Apron Rehabilitation Project 2161117
Photo 11. Pavement Core C-11
Photo 12. Pavement Core C-12
Foundation Engineering, Inc.
Albany Municipal Airport
Runway Extension & Apron Rehabilitation
Project 2161117
Table 1B. Summary of Pavement Thicknesses
1Exploration 1Location 2Asphaltic Concrete
Thickness
(in.)
3,4,5Base Rock
Thickness
(in.)
Total
Pavement Section
(in.)
C-1 Taxiway A (north) 4 16 20
C-2 Apron at north
Taxiway A access 6 4 10
C-3 Apron 4 11 15
C-4 Apron 5 9 14
C-5 Apron 5 6 11
C-6 Apron 4 8 12
C-7 Apron 3.75 13.25 17
C-8 Apron at A3 4.5 4.5 9
C-9 Apron 6 7.5 13.5
4C-10 Taxilane south of
apron 3 - -
5C-11 South blast pad/
overrun pavement 4 4/4 12
C-12 Taxiway A (south) 5 5 10
Notes: 1. See Figure 2A for approximate pavement core locations.
2. Pavement core photos are included in Appendix B.
3. Base rock varied in the explorations, typically consisting of either 1.5 to 2-inch minus
CRUSHED GRAVEL or sandy GRAVEL. USCS Classifications include GW, GP and
GP-GM.
4. Exploration C-10 was limited to the asphaltic concrete (AC) core only and did not
measure the entire pavement section.
5. Exploration C-11 encountered ±8 inches of base material that appeared to include
±4 inches of AC millings and gravel over ±4 inches of sandy gravel. See pavement
core log for additional details.
Appendix C
Field and Laboratory Test Results
Professional Geotechnical Services
Foundation Engineering, Inc.
Foundation Engineering, Inc. Albany Municipal Airport Runway Extension & Apron Rehabilitation Project 2161117
Table 1C. Summary of DCP Test Results
Exploration Initial Test
Depth (inches)
Soil Description 1Average DCP
(mm/blow)
2Average Mr
(psi)
3Corrected Mr
(psi)
4Correlated CBR Value
C-1 4 CRUSHED GRAVEL (GW) 4.6 27,046 16,769 -
21 Sandy SILT, some clay (ML) 73.0 9,198 3,219 2.1
C-2
6 GRAVEL (GP) 33.4 12,482 7,739 -
12 Silty CLAY to SILT, some
clay, sand and gravel (CL to ML)
54.5 10,311 3,609 2.4
C-3
4 CRUSHED GRAVEL, some sand and silt (GW-GM)
4.8 26,650 16,523 -
15 Silty CLAY to SILT, some
clay, sand and gravel (CL to ML)
42.3 11,377 3,982 2.7
C-4 5 CRUSHED GRAVEL,
some sand and silt (GW-GM) 3.9 28,846 17,885 -
14 CLAY (CH) 56.2 10,183 3,564 2.4
C-5 5 Sandy GRAVEL, some silt
(GW-GM) 7.5 22,344 13,853 -
11.5 Silty CLAY (CL to ML) 32.0 12,688 4,441 3.0
C-6 4 CRUSHED GRAVEL (GW) 2.5 34,103 21,144 -
12 CLAY (CH) 36.3 12,081 4,228 2.8
C-7
4 CRUSHED GRAVEL, some sand (GW)
5.3 25,615 15,881 -
12.5 Gravelly SILT, some clay (ML) 43.6 11,249 3,937 2.6
C-8
4.5 CRUSHED GRAVEL, some sand (GW) 8.7 21,110 13,088 -
12.5 Silty GRAVEL, some sand (GM) 10.1 19,911 6,969 4.6
Notes: 1. DCP (mm/blow) based on the average readings from the initial test depth. 2. Mr value based on average DCP value at the test depth and the ODOT recommended correlation:
Mr = 49,023 (DCP)-0.39. Values may vary slightly due to rounding. 3. Corrected Mr value is based on the ODOT recommended correction factors of 0.62 for base rock
and 0.35 for subgrade. 4. Correlated CBR value for subgrade is based on the FAA recommended correlation of
MR = 1,500*CBR.
Foundation Engineering, Inc. Albany Municipal Airport Runway Extension & Apron Rehabilitation Project 2161117
Table 1C. Summary of DCP Test Results (continued)
Exploration Initial Test
Depth (inches)
Soil Description 1Average DCP
(mm/blow)
2Average Mr
(psi)
3Corrected Mr
(psi)
4Correlated CBR Value
C-9
6 Sandy GRAVEL (GP) 2.1 36,395 22,565 -
15.5 SILT, some clay, trace gravel (ML)
49.3 10,718 3,751 2.5
C-10 Exploration limited to AC core only. No DCP testing.
C-11
5 CRUSHED GRAVEL and AC Grindings (GW)
4.5 27,335 16,948 -
15 Silty CLAY to SILT, some
clay, sand and gravel (CL to ML)
13.0 18,026 6,309 4.2
C-12
5 Sandy GRAVEL, trace silt (GP) 2.6 33,897 21,016 -
14 Sandy GRAVEL, some silt (GM) 2.3 35,527 12,435 8.3
Notes: 1. DCP (mm/blow) based on the average readings from the initial test depth. 2. Mr value based on average DCP value at the test depth and the ODOT recommended correlation:
Mr = 49,023 (DCP)-0.39. Values may vary slightly due to rounding. 3. Corrected Mr value is based on the ODOT recommended correction factors of 0.62 for base rock
and 0.35 for subgrade. 4. Correlated CBR value for subgrade is based on the FAA recommended correlation of
MR = 1,500*CBR.
Foundation Engineering, Inc. Albany Municipal Airport Runway Extension & Apron Rehabilitation Project 2161117
Table 2C. Natural Water Content, Atterberg Limits and Percent Fines
Sample Number
Sample Depth (feet)
Natural Water
Content (%)
LL
PL
PI
Fines (%)
FAA/USCS Classification
S-1-1 1.0 – 2.0 25.7 36 25 11 55.8 ML
S-2-1 0.5 – 1.5 20.7 33 23 10 58.9 CL
S-3-1 0.5 – 1.5 12.9 GM
C-2-2 1.0 – 2.0 24.3
C-3-2 1.5 – 3.0 17.9 25 20 5 CL-ML
C-4-1 0.4 – 0.7 5.8 GW-GM
C-4-2 1.5 – 3.5 31.5
C-5-1 0.4 – 0.9 7.0 GW-GM
C-5-2 1.5 – 3.5 36.5 45 27 18 CL to ML
C-6-2 1.5 – 3.5 32.8 62 27 35 CH
C-7-2 2.0 – 3.0 20.4
C-9-2 1.5 – 2.5 20.4
C-11-2 2.0 – 3.0 24.2 38 25 13 CL to ML
Note: 1. Percent fines reported herein are based on the results from the sieve and hydrometer gradation tests. See Figures 1C through 5C.
2. Dual USCS classification CL to ML is indicated for samples C-5-2 and C-11-2 because the test results fell on the “A-line” dividing CL and ML soils. Dual USCS classification CL-ML is indicated for sample C-3-2 because the test result indicated a PI between 4 and 7 and LL less than 30. See Figure 1C (Appendix C).
Foundation Engineering, Inc. Albany Municipal Airport Runway Extension & Apron Rehabilitation Project 2161117
Table 3C. Summary of Moisture-Density and CBR Test Results Current and Previous Projects
Project Sample Number
1,2Maximum Dry Density
(pcf)
1,2Optimum Moisture Content
(%)
LL
PI
Fines (%)
USCS 3CBR Value
Runway Extension &
Apron Rehabilitation
(2017)
S-1-1 107.7 16.2 36 11 55.8 ML 8.9
S-2-1 106.0 14.2 33 10 58.9 CL 4.3
Runway 16-34 Rehabilitation
(2010) S-4-1 97.9 21.4 38 7 49.3 ML 6.5
Access Road & Taxiways
(2000)
S-2-2 94.0 23.5 69 49 - CH 1.4
S-6-1 97.0 20.0 41 21 - CL 4.3
Notes: 1. Maximum dry density and optimum moisture content are based on ASTM D698 moisture-density curves.
2. Maximum dry density and optimum moisture for samples S-1-1 and S-2-1 include an oversize correction because the samples included greater than 5% gravel content. See gradation curves (Figures 2C and 3C) and moisture-density curves (Figures 7C and 9C) for additional details.
3. CBR values are for samples compacted to 95% relative compaction based on the maximum dry density of ASTM D698.
Sample No. S-1-1 S-2-1 C-3-2 C-5-2 C-6-2 C-11-2Liquid Limit, LL 36 33 25 45 62 38Plastic Limit, PL 25 23 20 27 27 25Plasticity Index, PI 11 10 5 18 35 13USCS Classification ML CL CL-ML CL to ML CH CL to MLNat. Water% 25.7 22.2 17.9 36.5 32.8 24.2
Sample No. S-4-1 SHC-1-4 SHC-6-4 S-2-2 S-6-1Liquid Limit, LL 38 37 35 69 41Plastic Limit, PL 31 22 25 20 20Plasticity Index, PI 7 15 10 49 21
USCS Classification ML CL ML CH CLNat. Water% 23.5 25.2 23.0 26.2 25.3
Albany, OregonProject No. 2161117
Current and Previous Albany Municipal Airport ProjectsAlbany Municipal Airport - Runway Extension & Apron Rehabilitation
Runway Extension & Apron Rehabilitation (2017)
Runway 16-34 Rehabilitation (2010) Access Road & Taxiways (2000)
FIGURE 1CATTERBERG LIMITS TEST RESULTS
0
10
20
30
40
50
60
0 10 20 30 40 50 60 70 80 90 100
Pla
stic
ity
Ind
ex
Liquid Limit
Runway Ext. & Apron Rehab.
Runway 16-34 Rehab.
Access Road and Taxiways
A-Line
U-Line
OH or MH
CL
ML
CL-ML
CH
OL or ML
(X=NO)PERCENTFINERSIZE
PASS?SPEC.*PERCENTSIEVE
Project No:
Project:Client:
Elev./Depth:Location:Date:Source of Sample:Sample No.:
Remarks
Classification
Coefficients
Atterberg Limits
Material Description
*
AASHTO=USCS=
Cc=Cu=D10=D15=D30=D50=D60=D85=
PI=LL=PL=
Sieve Analysis ASTM D 422
10
20
30
40
50
60
70
80
90
0
100
PE
RC
EN
T F
INE
R
100 10 1 0.1 0.01 0.001500GRAIN SIZE - mm
% COBBLES% GRAVEL
CRS. FINE% SAND
CRS. MEDIUM FINE% FINES
SILT CLAY
6 in
.
3 in
.
2 in
.
1-1/
2 in
.
1 in
.
3/4
in.
1/2
in.
3/8
in.
#4 #10
#20
#30
#40
#60
#100
#140
#200
0.0 7.3 16.4 5.3 8.5 6.7 28.8 27.0
Figure2166001-634
Albany Municipal Airport
Foundation Engineering, Inc.; Project No. 2161117
1.0-2.0'12-23-167108S-1-1
A-4(0)ML
0.00280.01910.26911.2
gravely SILT with sand
(no specification provided)
FEI Testing & Inspection, Inc.
Corvallis, OR
100.095.692.786.779.276.371.062.557.555.8
1.5 in.1 in.
3/4 in.1/2 in.1/4 in.
#4#10#40
#100#200
(X=NO)PERCENTFINERSIZE
PASS?SPEC.*PERCENTSIEVE
Project No:
Project:Client:
Elev./Depth:Location:Date:Source of Sample:Sample No.:
Remarks
Classification
Coefficients
Atterberg Limits
Material Description
*
AASHTO=USCS=
Cc=Cu=D10=D15=D30=D50=D60=D85=
PI=LL=PL=
Sieve Analysis ASTM D 422
10
20
30
40
50
60
70
80
90
0
100
PE
RC
EN
T F
INE
R
100 10 1 0.1 0.01 0.001500GRAIN SIZE - mm
% COBBLES% GRAVEL
CRS. FINE% SAND
CRS. MEDIUM FINE% FINES
SILT CLAY
6 in
.
3 in
.
2 in
.
1-1/
2 in
.
1 in
.
3/4
in.
1/2
in.
3/8
in.
#4 #10
#20
#30
#40
#60
#100
#140
#200
0.0 1.1 14.1 4.5 17.4 4.0 34.3 24.6
Figure2166001-634
Albany Municipal Airport
Foundation Engineering, Inc.; Project No. 2161117
0.5-1.512-23-167108S-2-1
A-4(0)ML
0.00400.02440.09154.90
sandy SILT with sand
(no specification provided)
FEI Testing & Inspection, Inc.
Corvallis, OR
100.098.994.787.184.880.362.961.858.9
1 in.3/4 in.1/2 in.1/4 in.
#4#10#40
#100#200
(X=NO)PERCENTFINERSIZE
PASS?SPEC.*PERCENTSIEVE
Project No:
Project:Client:
Elev./Depth:Location:Date:Source of Sample:Sample No.:
Remarks
Classification
Coefficients
Atterberg Limits
Material Description
*
AASHTO=USCS=
Cc=Cu=D10=D15=D30=D50=D60=D85=
PI=LL=PL=
Sieve Analysis ASTM C 136/C 117
10
20
30
40
50
60
70
80
90
0
100
PE
RC
EN
T F
INE
R
100 10 1 0.1 0.01 0.001500GRAIN SIZE - mm
% COBBLES% GRAVEL
CRS. FINE% SAND
CRS. MEDIUM FINE% FINES
SILT CLAY
6 in
.
3 in
.
2 in
.
1-1/
2 in
.
1 in
.
3/4
in.
1/2
in.
3/8
in.
#4 #10
#20
#30
#40
#60
#100
#140
#200
0.0 13.1 43.0 15.3 14.0 1.7 12.9
Figure2166001-634
Albany Municipal Airport
Foundation Engineering, Inc.; Project No. 2161117
0.5-1.5'12-23-167108S-3-1
A-1-aGM
0.4692.216.118.8017.8
silty gravel with sand
(no specification provided)
FEI Testing & Inspection, Inc.
Corvallis, OR
100.094.291.686.972.351.043.928.614.613.312.9
1.5 in.1.25 in.
1 in.3/4 in.1/2 in.1/4 in.
#4#10#40
#100#200
(X=NO)PERCENTFINERSIZE
PASS?SPEC.*PERCENTSIEVE
Project No:
Project:Client:
Elev./Depth:Location:Date:Source of Sample:Sample No.:
Remarks
Classification
Coefficients
Atterberg Limits
Material Description
*
AASHTO=USCS=
Cc=Cu=D10=D15=D30=D50=D60=D85=
PI=LL=PL=
Sieve Analysis ASTM C 136/C 117
10
20
30
40
50
60
70
80
90
0
100
PE
RC
EN
T F
INE
R
100 10 1 0.1 0.01 0.001500GRAIN SIZE - mm
% COBBLES% GRAVEL
CRS. FINE% SAND
CRS. MEDIUM FINE% FINES
SILT CLAY
6 in
.
3 in
.
2 in
.
1-1/
2 in
.
1 in
.
3/4
in.
1/2
in.
3/8
in.
#4 #10
#20
#30
#40
#60
#100
#140
#200
0.0 6.1 58.9 13.5 10.9 4.8 5.8
Figure2166001-634
Albany Municipal Airport
Foundation Engineering, Inc.; Project No. 2161117
5-8"12-23-167108C-4-1
A-1-aGW-GM
2.8934.520.3640.9773.6410.512.616.8
well-graded gravel with silt and sand
(no specification provided)
FEI Testing & Inspection, Inc.
Corvallis, OR
100.093.960.740.635.021.510.6
7.35.8
1 in.3/4 in.1/2 in.1/4 in.
#4#10#40
#100#200
(X=NO)PERCENTFINERSIZE
PASS?SPEC.*PERCENTSIEVE
Project No:
Project:Client:
Elev./Depth:Location:Date:Source of Sample:Sample No.:
Remarks
Classification
Coefficients
Atterberg Limits
Material Description
*
AASHTO=USCS=
Cc=Cu=D10=D15=D30=D50=D60=D85=
PI=LL=PL=
Sieve Analysis ASTM C 136/C 117
10
20
30
40
50
60
70
80
90
0
100
PE
RC
EN
T F
INE
R
100 10 1 0.1 0.01 0.001500GRAIN SIZE - mm
% COBBLES% GRAVEL
CRS. FINE% SAND
CRS. MEDIUM FINE% FINES
SILT CLAY
6 in
.
3 in
.
2 in
.
1-1/
2 in
.
1 in
.
3/4
in.
1/2
in.
3/8
in.
#4 #10
#20
#30
#40
#60
#100
#140
#200
0.0 24.7 37.2 12.5 12.9 5.7 7.0
Figure2166001-634
Albany Municipal Airport
Foundation Engineering, Inc.; Project No. 2161117
5-11"12-23-167108C-5-1
A-1-aGW-GM
2.8547.490.2410.6222.818.1511.523.7
well-graded gravel with silt and sand
(no specification provided)
FEI Testing & Inspection, Inc.
Corvallis, OR
100.096.488.275.362.943.638.125.612.7
8.47.0
1.5 in.1.25 in.
1 in.3/4 in.1/2 in.1/4 in.
#4#10#40
#100#200
Test specification:
Date:
Project:Remarks:Client:Project No.
MATERIAL DESCRIPTION
No.200Moist.AASHTOUSCSDepth
% <% >PILLSp.G.
Nat.ClassificationElev/
MOISTURE - DENSITY RELATIONSHIP TEST
Oversize correction applied to each point
Dry
den
sity
, pcf
Water content, %
87
92
97
102
107
112
5 10 15 20 25 30 35
12-23-16
Foundation Engineering, Inc.; Project No.2166001-634
gravely SILT with sand
55.816.8A-4(0)ML1.0-2.0'
ASTM D 698-00a Method B Standard
Albany Municipal Airport
Figure
MOISTURE - DENSITY RELATIONSHIP TEST
FEI Testing & Inspection, Inc.Corvallis, OR
Source: 7108 Sample No.: S-1-1 Elev./Depth: 1.0-2.0'
ROCK CORRECTED TEST RESULTS UNCORRECTED
18.9 % Optimum moisture = 16.2 %
100.5 pcf Maximum dry density = 107.7 pcf
With oversize correction
Without oversize correction
BEARING RATIO TEST REPORTASTM D 1883-05
BEARING RATIO TEST REPORTFEI Testing & Inspection, Inc.
Corvallis, OR
Project No: 2166001-634
Project: Albany Municipal Airport
Source of Sample: 7108 Depth: 1.0-2.0'
Sample Number: S-1-1
Date: 12-23-16
gravely SILT with sand
Test Description/Remarks:
Figure
107.7 16.2ML
Material DescriptionUSCS
Max.Dens.(pcf)
OptimumMoisture
(%)LL PI
MoldedDensity
(pcf)Percent ofMax. Dens.
Moisture(%)
SoakedDensity
(pcf)Percent ofMax. Dens.
Moisture(%)
CBR (%)
0.10 in. 0.20 in.
LinearityCorrection
(in.)
Surcharge(lbs.)
Max.Swell(%)
1 97.0 90.1 16.5 96.1 89.3 26.4 6.0 5.1 0.000 32 0.9
2 102.8 95.5 15.3 102.4 95.1 21.7 9.4 8.3 0.000 32 0.3
3 108.3 100.6 17.3 108.2 100.5 26.2 19.0 18.2 0.000 32 0.1
Pen
etra
tio
n R
esis
tan
ce (
psi
)
0
100
200
300
400
500
Penetration Depth (in.)0 0.1 0.2 0.3 0.4 0.5
Sw
ell (
%)
0
0.2
0.4
0.6
0.8
1
Elapsed Time (hrs)0 24 48 72 96
CB
R (
%)
0
10
20
30
40
Molded Density (pcf)96 99 102 105 108 111
18 blows
34 blows
56 blows
CBR at 95% Max. Density = 8.9%for 0.10 in. Penetration
Test specification:
Date:
Project:Remarks:Client:Project No.
MATERIAL DESCRIPTION
No.200Moist.AASHTOUSCSDepth
% <% >PILLSp.G.
Nat.ClassificationElev/
MOISTURE - DENSITY RELATIONSHIP TEST
Oversize correction applied to each point
Dry
den
sity
, pcf
Water content, %
88
93
98
103
108
113
9 11 13 15 17 19 21
12-23-16
Foundation Engineering, Inc.; Project No.2166001-634
sandy SILT with sand
58.915.2A-4(0)ML0.5-1.5
ASTM D 698-00a Method A Standard
Albany Municipal Airport
Figure
MOISTURE - DENSITY RELATIONSHIP TEST
FEI Testing & Inspection, Inc.Corvallis, OR
Source: 7108 Sample No.: S-2-1 Elev./Depth: 0.5-1.5
ROCK CORRECTED TEST RESULTS UNCORRECTED
No.4
16.3 % Optimum moisture = 14.2 %
100.0 pcf Maximum dry density = 106.0 pcf
With oversize correction
Without oversize correction
BEARING RATIO TEST REPORTASTM D 1883-05
BEARING RATIO TEST REPORTFEI Testing & Inspection, Inc.
Corvallis, OR
Project No: 2166001-634
Project: Albany Municipal Airport
Source of Sample: 7108 Depth: 0.5-1.5
Sample Number: S-2-1
Date: 12-23-16
sandy SILT with sand
Test Description/Remarks:
Figure
106.0 14.2ML
Material DescriptionUSCS
Max.Dens.(pcf)
OptimumMoisture
(%)LL PI
MoldedDensity
(pcf)Percent ofMax. Dens.
Moisture(%)
SoakedDensity
(pcf)Percent ofMax. Dens.
Moisture(%)
CBR (%)
0.10 in. 0.20 in.
LinearityCorrection
(in.)
Surcharge(lbs.)
Max.Swell(%)
1 97.3 91.8 12.3 96.9 91.4 26.6 3.1 2.7 0.000 32 0.4
2 103.2 97.4 11.3 102.0 96.2 23.1 5.3 4.2 0.000 32 1.2
3 107.9 101.8 11.5 106.8 100.8 21.9 7.8 6.3 0.000 32 1
Pen
etra
tio
n R
esis
tan
ce (
psi
)
0
40
80
120
160
200
Penetration Depth (in.)0 0.1 0.2 0.3 0.4 0.5
Sw
ell (
%)
0
0.4
0.8
1.2
1.6
2
Elapsed Time (hrs)0 24 48 72 96
CB
R (
%)
1
3
5
7
9
Molded Density (pcf)92 96 100 104 108 112
18 blows
34 blows
56 blows
CBR at 95% Max. Density = 4.3%for 0.10 in. Penetration