HomeMy WebLinkAboutCT 07-03; ROBERTSON RANCH PA 14; SUPPLEMENTAL PAVEMENT DESIGN REPORT; 2011-07-075741 Palmer Way ' Carlsbad, California 92010 • (760) 438-3155 FAX (760) 931-0915 www.geosoilsinc.com
July 7, 2011
W.O. 5949-E-SC
Brookfield.San Diego Builders, Inc.
12865 Pointe Del Mar, Suite 200
Del Mar, California 92014 tl
Attention: Mr. Greg McDonnell
Subject: Supplemental Pavement Design Report, Glen Avenue (Approximate
Stations 5+00 to 9-), Planning Area 14 of Robertson Ranch, Carlsbad,
San Diego County, California
Dear Mr. McDonnell:
In accordance with your request, GeoSoils, Inc. (GSI) has prepared this pavement design
report for asphalt concrete (AC) pavement at the subject site, to include recommendations
for the use of subgrade enhancement geotextiles (SEG's) and subgrade lime treatment,
as well as a modified, conventional asphaltic concrete over aggregate base section. The
scope of services provided in preparation of this report include a review of the referenced
reports and documents (see the Appendix), an evaluation of the pavement section for the
subject area, and preparation of this report.
PAVEMENT DESIGN
Pavement section evaluation was based on traffic index (TI) values provided by O'Day
Consultants (personal communication). Pavement sections were evaluated in general
accordance with the California Department of Transportation (Caltrans) Highway Design
Manual of Instructions and the City of Carlsbad Standard Drawings (see the Appendix).
Pavement sections presented are based on the aforementioned criteria and resistance
value (R-value) data (seethe attached Figures 1 and 2), evaluated from soils exposed at,
or near, final subgrade elevations within the subject area. R-value testing was performed
in general accordance with the latest revisions to the Department of Transportation, State
of California, Material & Research Test Method No. 301.
ASPHALT CONCRETE PAVEMENT
Structural Section
A Traffic Index (TI) was provided by the project civil engineer (O'Day Consultants) as 5.0 for
the subject traffic area. H-values (see attached Figures 1 and 2) of <10 were obtained
from representative samples of subgrade soil and used in pavement design. Where
"un-treated" H-values are less than 12, alternative pavement design is recommended by
the City (Carlsbad, 1993). The alternative methods included in our evaluation consisted
of the following:
Increase the minimum untreated aggregate base section to exceed the minimum
criteria for both Carlsbad (1993) and State of California (2008) for pavements on
subgrades with H-values less than 12. See Table 1 herein.
Design pavement sections using SEG's per Section 614.5 of the Highway Design
Manual (State of California, 2008), the State of California (2009), and Mirafi (2005).
See Table 2 herein.
Design pavement sections using a lime treated subgrade per Carlsbad (1993),
Section 614.4 of the Highway Design Manual (State of California, 2008). See
Table 3 herein.
In consideration of cost, and environmental concerns regarding the use of lime, as well as
other aspects of lime use discussed in Mirafi (2005), increasing the overall base section
thickness, or using SEG's are preferred as an alternative to lime treatment, and have been
evaluated and approved by Caltrans, as well as the City of Carlsbad, in similar applications.
GSI has used a similar approach (i.e., with SEG), for a major roadway with low strength
subgrades in the City of Oceanside, and with the City's review and approval. The
recommended pavement sections, provided in general accordance with the City guidelines
(Carlsbad, 1993), and the State of California (2008, 2009), are presented as follows:
Brookfield San Diego Builders, Inc.
PA 14 of Robertson Ranch
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W.O. 5949-E-SC
July 7, 2011
Page 2
Pavement with Thickened Aggregate Base, Option A.
mBLE:1 -ASPHALTIC CONCRETE/AGGREGATE BASE
TIE" SUBORADE THICKNESS BASE IHKNESS TRAFFIC AREA RNALUE (inches)
Glen A 5 venue. .+00 LO +
-
0
50 7 40 100>
(Sample obtained from Sta. 5
Glen Avenue. 6to 9 50 8 40 100(2) (Sample obtained from Sta. 8)
'> Per O'Day Consultants (Improvement plans)
Exceeds design per State of California (2008)
Per Carlsbad (1993)
Denotes Class 2 Aggregate Base R >78, SE >25)
This alternative includes increasing the minimum aggregate base section to exceed the
minimum criteria for both Carlsbad (1993) and State of California (2008). The aggregate
base thickness presented in Table 1 is approximately 125 percent of the minimum design
per State of California (2008).
Pavement with Subgrade Enhancement Geotextile (SEG), Option B.
TABLE 2- ASPHI\L. nc CONCRETE'AGGREGATE BASE/SEG -
APPROXIMATE
TRAFFjC R-VALUE
RADE UBG A C
THICKNESS BASE THICKESc3)EA
AGGREGATE SEG CLASS
(Gallrans,.
.2009)
Glen Avenue. 5+00 to 6 +50
(Sample obtained from 5.0 20 4.0 '5.0 B14>
Sta. 52)
Glen Avenue, Sta. 6+L" to 9
(Sample obtained from 5.0 20 4.0 5.0 • B1 4
Sta. 8)
Per O'Day Consultants (Improvement plans)
Effective R-value when using SEG HP 570, or equivalent (State of California, 2008, 2009)
)3) Denotes Class 2 Aggregate Base R >78, SE >25)
Class Bi, Mirafi HP 570, or equivalent
Brookfield San Diego Builders, Inc.
PA 14 of Robertson Ranch
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W.O. 5949-E-SC
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This alternative includes a design pavement section using SEG's per Section 614.5 of the
Highway Design Manual (State of California, 2008), the State of California (2009), and Mirafi
(2005). Subgrade enhancement geotextile (SEG) used shall be Mirafi HP 570 (Class Bi),
or equivalent. All SEG's shalt be placed per the manufacturers guidelines.
Pavement with Lime Treated Subgrade, Option C.
UNTREATED TREATED . AGGREGATE
APPROXIMATE TIM SUBGRADE SUBGRADE THICKNESS
AC BASE
TRAFFIC AREA A-VALUE R-VALUE (Inches) T'-cKNESS3
(inches
A -I-OD 5O Glen ,-venue. - Lto +
-
50 7 >60(2) 40 40 (Sample obtained from Sta. 5)
Glen Avenue, Sta. 6 to 9 8 >60(2) 4.0 4.0 (Sample obtained from Sta. 8) 5
-
Per O'Day Consultants (Improvement plans)
Estimated R-value using 3 to 4 percent Quicklime by weight.
Denotes Class 2 Aggregate Base R >78, SE >25)
This alternative includes a design pavement section using a lime treated subgradë per
Carlsbad (1993), and Section 614.4 of the Highway Design Manual (State of California,
2008). The treated R-values shown are an estimate based on previous testing performed
on similar subgrades within adjacent "Planning Areas" of Robertson Ranch (GSI; 2010a,
2010b, and 2010c). The minimum treated subgrade thickness shall be 8 inches. per
Carlsbad (1993). Lime treatment shall be per the standard of practice, and the National
Research Council (1987).
General Installation Considerations
All pavement installation, including preparation and compaction of subgrade, compaction
of base material, and placement and rolling of asphaltic concrete, shalt be done in
accordance with the City guidelines, and under the observation and testing of the project
geotechnical engineer and/or the City.
The recommended pavement sections provided above are intended as a minimum
guideline. if thinner or highly variable pavement sections are constructed, increased
maintenance and repair should .be expected. If the ADT (average daily traffic) or ADTT
(average daily truck traffic) increases beyond that intended, as reflected by the TI used for
design, increased maintenance and repair could be required for the pavement section.
Consideration should be given to the increased potential for distress from overuse of
Brookfield San Diego Builders, Inc. W.O. 5949E-SC
Planning Area 14, Robertson Ranch July 7, 2011
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oSoL, Inc.
paved street areas by heavy equipment and/or construction related heavy traffic
(e.g., concrete trucks, loaded supply trucks, etc.), particularly when the final section is not
in place (i.e., topcoat). Best management construction practices should be followed at all
times, especially during inclement weather.
PAVEMENT GRADING RECOMMENDATIONS
General
All section changes shall be properly transitioned. If adverse conditions are encountered
during the preparation of subgrade materials, special construction methods may need to
be employed. A GSI representative shall be present for the preparation of subgrade, base
rock, and asphalt concrete.
Subgrade
Within street and parking areas, all surficial deposits of loose soil material shall be removed
and recompacted as recommended. After the loose soils are removed, the bottom is to
be scarified to a depth of at least 12 inches, moisture conditioned as necessary, and
compacted to 95 percent of the maximum laboratory density, as determined by ASTM test
designation D 1557.
Deleterious material, excessively wet or dry pockets, concentrated zones of oversized rock
fragments, and any other unsuitable materials encountered during grading shall be
removed. The compacted fill material shall then be brought to the elevation of the
proposed subgrade for the pavement. The subgrade shall be pro6f-rolled in order to
ensure a uniform firm and unyielding surface. All grading and fill placement shall be
observed by the project soil engineer and/or his representative.
Base Rock
Compaction tests are required for the recommended base section. Minimum relative
compaction required will be 95 percent of the laboratory maximum density as determined
by ASTM test designation D 1557. Base aggregate shall be in accordance with
Section 26 of Caltrans Standard Specifications (California Department of Transportation,
2006), for Caltrans Class 2 aggregate base.
Paving
Prime coat may be omitted if all of the following conditions are met:
The asphalt pavement layer is placed within two weeks of completion of base
and/or subbase course.
Brookfield San Diego Builders, Inc.
Planning Area 14, Robertson Ranch
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Traffic is not routed over completed base before paving.
Construction is completed during the dry season of May through October.
The base is kept free of debris prior to placement of asphaltic concrete.
If construction is performed during the wet season of November through April, prime coat
may be omitted if no rain occurs between completion of base course and paving and the
time between completion of base and paving is reduced to three days, provided the base
is free of loose soil or debris. Where prime coat has been omitted and rain occurs, traffic
is routed over base course, or paving is delayed, measures shall be taken to restore base
course and subgrade to conditions that will meet specifications as directed by the
geotechnical consultant.
Drainage
Positive drainage shall be provided for all surface water to drain toward the curb and
gutter, or to an approved drainage channel. Positive site drainage shall be maintained at
all times. Water shall not be allowed to pond or seep into the ground. Over-watering of
landscape areas should be avoided. Due to the low A-values, wet subgrade conditions
could significantly reduce the life of the pavement. Therefore, it is imperative that subgrade
materials are not allowed to become wet or saturated or allow water to flow into trenches
or behind curbs.
OTHER DESIGN PROFESSIONALS/CONSULTANTS
The design civil engineer shall review the recommendations provided herein, incorporate
those recommendations into their plans, and by explicit reference, make this report part
of their project plans.
LIMITATIONS
The materials encountered on the project site and utilized for our analysis are believed
representative of the area; however, soil and bedrock materials vary in character between
excavations and natural outcrops or conditions exposed during mass grading. Site
conditions may vary due to seasonal changes or other factors.
Inasmuch as our study is based upon our review and engineering analyses and laboratory
data, the conclusions and recommendations are professional opinions. These opinions
have been derived in accordance with current standards of practice, and no warranty is
express or implied. Standards of practice are subject to change with time. GSI assumes
no responsibility or liability for work or testing performed by others, or their inaction, or
Brookfield San Diego Builders, Inc. W.O. 5949-E-SC
Planning Area 14, Robertson Ranch July 7, 2011
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GSils, Inc.
work performed when GSI is not requested to be onsite, to evaluate if our
recommendations have been properly implemented. Use of this report constitutes an
agreement and consent by the user to all the limitations outlined above, notwithstanding
any other agreements that may be in place. In addition, this report may be subject to
review by the controlling authorities.
The opportunity to be of service is greatly appreciated. If you have any questions, please
do not hesitate to call our office.
7 o It GS QN\
C/k? so
if Encirief'20rig
Robert G. Crisman Ojz- c Ck Engineering Geologist, 4
RGC/ATG/JPF/jh
W -4' (~ An d r e /wiT
Geotechnicat Engineer, GE 2320
Respectfully subm
GeoSoils, Inc
Attachments: Figures 1 and 2 - R-value Test Results
Appendix References
Distribution:. (4) Addressee
Brookfield San Diego Builders, Inc. W.O. 5949-E-SC
Planning Area 14, Robertson Ranch July 7, 2011
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GSs, Inc.
TEST SPECIMEN A B C D
Compactor air pressure PSI 230 150 100
Water added % 4.0 5.1 6.1
Moisture at compaction % 14.0 15.1 16.1
Height of sample IN 2.44 2.5 2.56
Dryderisity PCF 118.0 113.5 110.3
R-Value by exudation 19 10 7
R-Value by exudation, corrected 18 10 7
Exudation pressure PSI 566 4021 290
Stability thickness FT 1-04 1.15 1.19
Expansion pressure thickness FT 0.70 0.371 0.00
F I III iIJIiT%Vi SAMPLE INFORMATION
Sample. Location: Glen Av. Cul-De-Sac, PA-14
Sample Description: Pale Brown Sandy Clay
Notes:
0% Retained on 3/4 inch sieve
Test Method: Cal-Trans Test 301
R-Value By Exudation
0.00 l I I I I I I I I I o -
0.00 0.50 1.00 1.50 2.00 800 700 600 500 400 300 200 100 0
Cover Thickness by Expansion Pressure (ft) Exudation Pressure (psi)
Traffic index, assumed 5.0
Gravel equivalent factor, assumed 1.25
Expansion, stability equilibrium 0
R-Value by expansion NA
R-Value by exudation 7
R-Value at equilibrium 7
Expansion, Stability Equilibrium
2.00
V) wtoo
CD 0.50
GeoSofls, Inc.
5741 Palmer Way
$. Carlsbad, CA 92008
'- Telephone: (760) 438-3155
Fax: (760) 931-0915
R - VALUE TEST RESULTS
Number: 5949-E-SC
Date: Jul-il Figure:
TEST SPECIMEN A B C D
Compactor air pressure PSI 160 140 100
Water added % 3.7 4.6 5.7
Moisture at compaction % 18.7 19.6 20.7
Height of sample IN 2.46 2.58 2.63
Dry density . PCF 108.8 105.3 103.3
R-Value by exudation 12 10 8
R-Value by exudation, corrected 12 10 8
Exudation pressure PSI 507 403 286
Stability thickness FT 1.13 1.15 1.18
Expansion pressure thickness I FT 1 0.80 0.40 0.17
I DESIGN CALCULATION DATA SAMPLE INFORMATION
Sample Location: Glen Av. Adj. To Lots 14-15
Sample Description: Brown Gray Sandy Clay
Notes:
2% Retained on 3/4 inch sieve
Test Method: Cal-Trans Test 301
R-Valué By Exudation
100 Expansion, Stability Equilibrium
I 90 2.00
80
70
60
50
40
30
'I
I
I
0.00 0.50 1.00 1.50 2.00 300 700 600 500 400 300 200 100 0
Cover Thickness by Expansion Pressure (ft) Exudation Pressure (psi)
Traffic index, assumed 5.0
Gravel equivalent factor, assumed 1.25
Expansion, stability equilibrium 0
R-Value by expansion NA
R-Value by exudation 8
R-Value at equilibrium a
GeoSoils, Inc.
5741 Palmer Way
Q 60, R.
Carlsbad, CA 92008
Telephone: 60) 438-3155
Fax: (760) 931-0915
R - VALUE TEST RESULTS
Project BROOKFIELD
Number. 5949-E-SC
Date: Apr-li Figure:
REFERENCES
California Department of Transportation, 2006, Caltrans, Standard specifications, May
printing.
Carlsbad, City of, 1993, Standards for design and construction of public works
improvements in the City of Carlsbad.
GeoSoils, Inc., 2010a, Pavement design report, Mesa Trail (Stations 10to 121), portion
of Planning Area 21 of Robertson Ranch, Carlsbad, San Diego County, California,
W.O. 5981 -E-SC, dated February 17.
2010b, Revised pavement design report, Arapaho Way (Stations 10"' to 20), and
Ocala Street (Stations 10 to 12), portion of Planning Area 18 of Robertson
Ranch, Carlsbad, San Diego County, California, W.O. 5954-E-SC, dated February 9.
2010c, Supplemental pavement design report, Wind Trail Way (Stations 16 to
18), Alander Court (Stations 12to 19), and Cascade Street (Stations 12
to 15), portion of Planning Area 16 of Robertson Ranch, Carlsbad, San Diego
County, California, dated January 13.
2009, Pavement design report, Wind Trail Way (Stations 16 to 18), Alander
Court (Stations 12+00 to 19), and Cascade Street (Stations 12to 15), portion
of Planning Area 16 of Robertson Ranch, Carlsbad, San Diego County, California,
W.O. 5949-E-SC, dated December 2.
2008, Memo, Clarification of pavement design report, Glen Avenue, Station 26
to the Cut Du Sac, Robertson Ranch East Village, City of Carlsbad, San Diego
County, California, W.O. 5353-B-SC, dated October 31.
2007a, Pavement design report, improvement of "loop" roads, Wind Trait Way, Glen
Avenue, and Hilltop Street, Robertson Ranch East Village, City of Carlsbad, San
Diego County, California, W.O. 5384-E-SC, dated October 31.
Mirafi, 2005, Benefits of subgrade stabilization using geosynthetics versus lime treated soil,
Technical Note TN-LIME-01 05, dated May 1.
National Research Council (US.). Transportation Research Board, 1987, Lime
Stabilization, State of the art Report 5, Committee on Lime and Lime-Fly Ash
Stabilization, last modified September 25, 2009.
NEWCON90, 1991 Computer program for the determination of asphalt pavement sections,
dated April 30.
GeoSofls, Inc.
State of California, Department of Transportation, 2009, Guide for designing subgrade
enhancement geotextiles, dated April 28.
_____ 2008, Highway design manual of instructions, dated July 1
Brookfield San Diego Builders, Inc.
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Appendix
Page 2