HomeMy WebLinkAboutCT 09-01; ROBERTSON RANCH PA22; PAVEMENT DESIGN REPORT; 2010-05-24C1O1Ol
Geotechnical . Geologic. Coastal • Environmental
5741 Palmer Way • Carlsbad, California 92010 • (760) 438-3155 • FAX (760)931-0915 . www.geosoilsinc.com
Brookfield San Diego Builders, Inc.
12865 Pointe Del Mar, Suite 200
Del Mar, California 92014
Attention: Mr. Greg McDonnell
RECEIVED -
JUN -4 2010
CITY OF CARLSBAD ENGINEERING DEPARTMENT DIVISION
W.O. 5949-E-SC
Subject: Pavement Design Report, RV Parking Area, Planning Area 22
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 geotetiIes (SEG's) and subgrade time 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. ThisTeporti for tF parking)
temporary d rivewannetI RigTo
aroBoa d. Subgradior temporary pavement should be prepared in accordance
with the recommendations presented herein.
PAVEMENT DESIGN
Pavement section evaluation was based on traffic index (TI) values provided by O'Day
Consultants ([O'Day], 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 (see the attached Figure 1), 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 Plans
(O'Day, 2010) indicate a temporary driveway pavement of 2 inches asphaltic concrete over
prepared subgrade. It is our understanding that this pavement will be removed at a later
date. These temporary driveways are not under the purview of this report. Subgrades for
temporary pavement should be prepared in accordance with the recommendations
presented herein.
ASPHALT CONCRETE PAVEMENT
Structural Section
A traffic index (TI) of 5.0 was used is in accordance with recommendations presented in
Carlsbad (1993). An R-value (see attached Figure 1) of 10 was obtained for representative
subgrade soils onsite and used in pavement design. Where "un-treated" R-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:
o 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 R-values less than 12. See Table 1 below.
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 following.
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 in similar applications. GSl 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. W.O. 5949-E-SC
RV Parking Lot, PA 22 of Robertson Ranch • May 24, 2010
Fite:e:\wpl2\5900\5949e.pdr3PA22 • • Page 2
GeoSoils, Inc.
Pavement with Thickened Aggregate Base, Option A.
TABLE 1 - ASPHALTIC CONCRETE/AGGREGATE BASE
A.C. AGGREGATE
APPROXIMATE TI SUBGRADE THICKNESS BASE THICKNESS"')
TRAFFIC AREA R-VALUE (inches)"' -(inches)
RV Lot Parking Area, PA 22
[
5.0
[
10 4.0 8.5(2)
Per the City (1993)
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 CaliforniOf 8Jhgrgate
ihickhs been increased by e minimum desigjj
rtate of Californ(2O08/
Pavement with Subgrade Enhancement Geotextile (SEG), Option B.
TABLE 2 -ASPHALTIC CONCRETE/AGGREGATE BASE/SEG
A.C. AGGREGATE SEG CLASS
APPROXIMATE TI(1)SUBGRADE THICKNESS BASE THICKNESS(3)(Caltrans,
TRAFFIC AREA R-VALUE (2) (Inches) (inches) 2009)
RV Parking Lot, PA 22 [50 20 j 4.0 5.0 [ B1
Per the City (1993).
Effective R-value when using SEG HP 570, or equivalent (State of California, 2008, 2009)
Denotes Class 2 Aggregate Base R >78, SE >25)
Class Bi, Mirafi HP 570, or equivalent
This alternative includes 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). Subgrade enhancement geotextile (SEG).used shall be Mirafi HP 570
(Class Bi), or equivalent. All SEG's shall be placed per the manufacturers guidelines.
Pavement with Lime Treated Subgrade, Option C.
TABLE 3 PRELIMINARY ASPHALTIC CONCRETE/AGGREGATE BASE/LIME TREATED SUBGRADE
UNTREATED TREATED A.C. AGGREGATE
APPROXIMATE Tl 1 SUBGRADE SUBGRADE THICKNESS BASE
THICKNESS (3) TRAFFIC AREA R-VALUE R-VALUE (Inches) (inches)
RV Parking Lot, PA 22 50 10 >60(2) 4.0 4.0
Per the City (1993)
Estimated R-value using 3 to 4 percent Quicklime by weight.
Denotes Class 2 Aggregate Base R >78, SE >2511
This alternative includes design pavement sections using a lime treated subgrade
per Carlsbad (1993), and Section 614.4, of the Highway Design Manual
(State of California, 2008). Treated R-values shown are estimates based on previous
testing performed on similar subgrades within adjacent "Planning Areas" of Robertson
Ranch (GSl; 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, shall 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
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.
Brookfield San Diego Builders, Inc. W.O. 5949-E-SC
RV Parking Lot, PA 22 of Robertson Ranch • May 24, 2010
FiIe:e:\wpl2\5900\5949e.pdr3.PA22 • • Page 4
GeoSoils, Inc. • •
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 proof-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.
Traffic is not routed over completed base before paving.
Construction is completed during the dry season of May through October.
4 The base is kept free of debris prior to placement of asphaltic concrete
Brookfield San Diego Builders, Inc W.0. 5949 -E-SC
RV Parking Lot PA 22 of Robertson Ranch May 24 2010
Fde e \wpl2\5900\5949e pdr3 PA22 Page 5
GeoSoils, Inc.
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 R-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. GSl assumes
no responsibility or liability for work or testing performed by others, or their inaction, or
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.
Brookfield San Diego Builders, Inc W.0. 5949 E SC
RV Parking Lot, PA 22 of Robertson Ranch May 24, 2010
File:e:\wpl 2\5900\5949e.pdr3.PA22 Page 6
GeoSoits, Inc.
The opportunity to be of service is greatly appreciated. If you have any questions, please
do not hesitate to call our office.
Respectfully submitte>._.N
GeoSoils, Inc. 0
- ( 19 3 \LU
Csrz~flod . /7 i.)i.
-
Geologist
/
-2 Robert G Crisman \ / A drew T GuateTli
Engineering Geologist, Q4- Geotechnical Engineer, GE
RGC/ATG/J PF/jh
Attachments: Figure 1 - R-value Test Result
Appendix - References
Distribution: (4) Addressee
Brookfield San Diego Builders, Inc. W.O. 5949-E-SC
RV Parking Lot PA 22 of Robertson Ranch May 24 2010
File e \wpl2\5900\5949e pdr3 PA22 Page 7
GeoSoils, Inc.
TEST SPECIMEN A B C 0
Compactor air pressure PSI 2220 150 70
Water added % 2.7 7.1 9.1
Moisture at compaction % 12.0 16.4 18.4
Height of sample IN 2.47 2.56 2.64
Dry density PCF 122.0 113.2 107.8
R-Valuebyexudation 27 11 7
R-Value by exudation, corrected 27 11 7
Exudation pressure PSI 603 328 193
Stability thickness FT 0.931 1.14 .1.19
Expansion pressure thickness FT 1.771 1.00
DESIGN CALCULATION DATA
Traffic index, assumed 5.0
Gravel equivalent factor, assumed 1.25
Expansion, stability equilibrium 1.11
R-Value by expansion 13
R-Value by exudation 10
R-Value at equilibrium 10
Expansion, Stability Equilibrium
101011
.i.50
.0 ((1
U)
>. .0
U) i,1.0O
CD 0.50
0.00 KI I I I i I I I I
0.00 0.50 1.00 1.50 2.00
Cover Thickness by Expansion Pressure (if)
SAMPLE INFORMATION
Sample Location: RV Parking Lot
Sample Description: Brown Gray Sandy Clay
Notes:
GeoSoils, Inc. R - VALUE TEST RESULTS
5741 Palmer Way Project: BROOKFIELD
Carlsbad, CA 92008
Telephone: (760) 438-3155 Number: 5949.22-E-SC
Fax: (760) 931-0915
Date: May-10 Figure: 1
APPENDIX
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
O'Day Consultants, Inc., 2010, Grading plans for: Robertson ranch PA 22, Sheet 3, Project
No. C.T. 09-01, DWG. No. 466-8A, Job No. 011014, Print dated April 28.
GeoSoils, Inc., 2010a, Pavement design report, Mesa Trail (Stations 10"' to 12), 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+00 to 20), and
Ocala Street (Stations 10+50 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 +21
+40 to 15), portion of Planning Area 16 of Robertson Ranch, Carlsbad, San Diego
County, California, dated January 13.
2009a, Pavement design report, Wind Trail Way (Stations 16 to 18+76 Alander
Court (Stations 12+00 to 19), and Cascade Street (Stations 12+25 to 15), portion
of Planning Area 16 of Robertson Ranch, Carlsbad, San Diego County , California,
W.O. 5949-E-SC, dated December 2
2009b, Report of rough grading, planning area 22 of Robertson Ranch, East Village,
Carlsbad, San Diego County, California, W.O. 5353-B 1 -SC, dated March 9.
Mirafi, 2005, Benefits of subgrade stabilization using geosynthetics versus lime treated soil,
Technical Note TN-LIME-01 05, dated May 1.
National Research Council (U.S.). 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
GeoSoils, 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