HomeMy WebLinkAboutCT 02-03; VILLAGES OF LA COSTA OAKS SOUTH; PAVEMENT RECOMMENDATIONS; 2004-01-20c-rc 2--O
GEOCON 0 I N C OR P 0 R A T E D
GEOTECHNICAL CONSULTANTS
Project No. 06105-52-15
January 20, 2004
Centex Homes
1815 Aston Street, Suite 101
Carlsbad, California 92008
Attention: Mr. Kurt Hubbell
Subject: VILLAGES OF LA COSTA - THE OAKS SOUTH
NEIGHBORHOODS 3.12 AND 3.13
SITIO LIMA STATION 10+60 TO 25+55
SITIO ESPINO STATION 10+00 TO 11+60
CORTE DELFINTO STATION 11+75 TO 17+50
CIRCULO SEQUOIA STATION 55+15 TO 76+50
CARLSBAD, CALIFORNIA
PAVEMENT RECOMMENDATIONS
Gentlemen:
In accordance with your request, we have performed supplemental geotechnical services for the
subject streets within Villages of La Costa - The Oaks South development. The scope of our services
included obtaining representative subgrade soil samples within the street areas and performing
Resistance Value (R-Value) tests. The purpose of our work was to provide pavement design
recommendations. To aid in preparing this letter, we have reviewed the improvement plans entitled
Improvement and Utility Plans for. Villages of La Costa - Neighborhoods 3.12 and 3.13, prepared
by Hunsaker & Associates, City of Carlsbad approval dated May 1, 2003 and our report entitled
Update Geotechnical Report, Villages of La Costa-The, Oaks South, Neighborhood 3.12 and 3.13,
Carlsbad, California, dated November 12, 2003 (Project No. 06105-52-15).
Subgrade soils in the area are predominately sandy to clayey gravels and typically exhibit relatively
low R-Value characteristics. Based on field observations and previous laboratory tests, subgrade
materials possess an expansion potential of "low" to "medium" (Expansion Index of 90 or less) as
defined by the Uniform Building Code (UBC) Table 18-I-B. R-Value laboratory tests were
performed in accordance with ASTM D 2844-99 (California Test Method 301) and the laboratory
test results are presented in Table I.
It is our understanding that a Traffic Index (TI) of 5.0 has been assigned to the subject streets, with
the exception of Sitio Espino, which has been assigned a TI of 4.5. Based on the above information
and laboratory testing, we recommend the pavement sections indicated in Table If. Pavement section
calculations were performed in accordance with California Department of Transportation Highway
Design Manual; Section 608.4 and the City of Carlsbad Mininum Structural Standard GS-] 7.
Pavement section calculations are presented in Figure 1. These recommended sections should be
considered preliminary with final sections to be determined and approved by the City of Carlsbad.
6960 Flanders Drive U San Diego, California 92121-2974 0 Telephone (858) 558-6900 0 Fax (858) 558-6159
Furthermore, 'we understand that the City of Carlsbad requires lime treatment of subgrade soils when
the R-Value is less than 12 However, it is the opinion of Geocon Incorporated that the lime
treatment of subgrade soils along the subject roadway alignments is not feasible due to the amount of
rock present near finish subgrade elevation. Therefore,. a waiver of the lime treatment policy is
requested. -
Prior to placing base material for roadways, as well as curb and gutter, we recommend the upper
12 inches of subgrade be scarified, moisture conditioned as necessary, and compacted to a dry
density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum
moisture content in accordance with ASTM D 1557-00. In addition, the Class 2 aggregate base
should be compacted to a dry density of at least 95 percent of the laboratory maximum dry density
near to slightly above optimum moisture content Asphalt concrete should be compacted to a density
of at least 95 percent of the laboratory Hveem density in accordance with ASTM D 2726-96a The
upper 12 inches- of subgrade soils beneath areas to receive concrete sidewalks should be compacted
to a dry density of at least 90 percent of the laboratory maximum dry density 'near to slightly above
optimum moisture content. Fill soil and base lift thickness should not exceed 6 inches. Class 2
aggregate base and asphalt concrete should conform'to the City. of Carlsbad specifications.
The performance of asphalt concrete pavement is highly dependent on providing, positive surface
drainage away from the edge of the pavement Ponding of water on or adjacent to the pavement will
likely result in pavement distress and subgrade failure. To reduce the occurrence for such situations,
we recommend that a minimum drainage gradient of 1 percent be maintained for pavement surfaces
Drainage from landscaped areas should be directed to controlled drainage structure
Should you have any.questions regarding this correspondence, or if we may be of further service,
please contact the undersigned at your 1.convenience
Very truly, yours, -
GEOCON INCORPORATED
(2) Addressee
(3/del) Centex Homes (Job Site)
Attention: Mr. Larry Galant
(I) Hunsaker & Associates
Attention: Mr. David Blalock
Project No. 06105-52-15 1 -2- January 20, 2004
TABLE I
SUMMARY OF R-VALUE TEST RESULTS
ASTM D 2844-99 (CALIFORNIA TEST METHOD 301)
Sample No. Location R-Value
R-1 Sitio Lima Station 22+40 to 25+55 31
R-2 Sitio Lima Station 19+20 to 22+40 28
R-3 Sitio Lima Station 16+00 to 19+20 18
R-4 Sitio Espino Station 10+00 to 11+60 16
R-5 Sitio Lima Station 13+00 to 16+00 11
R-6 Sitio Lima Station 10+60 to 13+00 22
R-7 Corte Delfinio Station 14+80 to 17+50 33
R-8 Corte Delfinio Station 11+75 to 14+80 26
R-9 Circulo Sequoia Station 55+15 to 58+15 12
R-10 Circulo Sequoia Station 58+15 to 61+15 13
R-11 Circulo Sequoia Station 61+15 to 64+15 29
R-12 Circulo Sequoia Station 64+15 t&67+15 21
R-13 Circulo Sequoia Station 67+15 to 70+15 9
R-14 • Circulo Sequoia Station 70+15 to 73+15 27
R-15 • CirculoSequoia Station 734115 to 76+50 19
Project No. 06105-52-15 January 20, 2004
* TABLE. 11
PAVEMENT SECTION RECOMMENDATIONS
7
- •
Location Traffic Index
(TI)
Asphalt
Concrete
(inches)
Class 2
Aggregate
Base
(inches)
Sitio Lima Station 22+40 to 25+55 5.0 . 4 4
Sitio Lima Station 19+20 to 22+40 5.0 4 4
Sitio Lima Station 16+00 to 19+20 5.0 4 6
Sitio Espino Station 10+00 to 11+60 4.5 4 5
Sitio Lima Station 13+00 to 16+00 5.0 4 7
Sitio Lima Station 10+60 to 13+00 5.0 4 5
Corte Delfmio Station 14+80 to 17+50 5.0 4 4
Corte Delfinio Station 11+75 to 14+80 5.0 4 4
Circulo Sequoia Station 55+15 to 58+15 5.0 4 7
Circulo Sequoia Station 58+15 to 61+15 5.0 4 7
Circulo Sequoia Station 61+15 to 64+15 5.0 4 4
Circulo Sequoia Station 64+15 to 67+15 5.0 4 5
Circulo Sequoia Station 67+15 to 70+15 5.0 4 7
Circulo Sequoia Station 70+15 to 73+15 5.0 4 4
Circulo Sequoia Station 73+15 to 76+50 5.0 4 6
4 * •
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Project No. 06105-52-15 January 20, 2004
FIGURE 1
PAVEMENT SECTION CALCULATIONS
VILLAGES OF LA COSTA - THE OAKS SOUTH
Sitio Lima - Station 22+40 to 25+55
Use subgrade R-Value = 31.0
Traffic Index (TI) = 5.0
Methodology = CALTRANS Highway Design Manual Section 608.4
Safety Factor = 0.2 - Applied to Asphalt Concrete (AC)
GE for AC = (0.0032)(5.0)(100-78.0)+0.2 =.55 feet
from Table 608.4B Highway Design Manual
GE = .55 feet for AC yields actual thickness = 2.65 inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC =.83 feet
GE for base = (0.0032)(5.0)(100-31.0) -.83= .27 feet
from Table 608.413 Highway Design Manual with GF for Class 2 base =
Base thickness = 2.95 inches
Use base thickness = 4.0 inches
Design Street Structural Section
Asphalt Concrete Thickness = 4.0 inches.
Class 2 Aggregate Base Thickness =4.0 inches.
Sitio Lima - Station 19+20 to 22+40
Use subgrade R-Value = 28.0
Traffic Index (TI) = 5.0
Methodology = CALTRANS Highway Design Manual Section 608.4
Safety Factor = 0.2 - Applied to Asphalt Concrete (AC)
GE for AC = (0.0032)(5.0)(100-78.0)+0.2 = .55 feet
from Table 608.4B Highway Design Manual
GE = .55 feet for AC yields actual thickness = 2.65 inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC = .83 feet
GE for base = (0.0032)(5.0)(100-28.0) -.83 = .32 feet
from Table 608.4B Highway Design Manual with GF for Class 2 base = 1
Base thickness = 3.48 inches
Use base thickness = 4.0 inches
Design Street Structural Section
Asphalt Concrete Thickness = 4.0 inches.
Class 2 Aggregate Base Thickness = 4.0 inches.
Project No. 06105-52-15 January 20, 2004
FIGURE 1 (Continued)
PAVEMENT: SECTION CALcULATIONS
VILLAGES OF LA COSTA - THE OAKS SOUTH
Sitió Lima Station 16+00 to 19+20
Use subgrade R-Value= 18.0Traffic Index (TI) = 50
Methodology = CALTRANS Highway Design Manual Section 608 4
Safety Factor = 0.2 - Applied to Asphalt Concrete (AC)
GE for AC = (0.0032)(5.0)(100-78.0)+0.2 =.55 feet
from Table 608.4B Highway Design Manual
GE = .55 feet for AC yields actual thickness =.2.65. inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC = .83 feet
GE for báse,= (0.0032)(5.0)(100-18.0) -.83 = .48 feet
from Table 608.413 Highway Design Manual with'GF for Class 2base = 1.1
Base thickness 5.22 inches
Use base thickness = 6.0 inches
Design Street Structural Section
Asphalt Concrete Thickness = 4.0 inches.
Class 2 Aggregate Base-Thickness = 6.0 inches.
'S
Sitio Espino - Station 10+00 to 11+60
Use subgrade R-Value 16:0
Traffic Index (TI) = 4.5
Methodology = CALTRANS Highway Design Manual Section 608.4
Safety Factor = 0.2 - Applied to Asphalt Concrete (AC)
GE for AC = (00032)(4.5)(100-78.0)+0.2 = .52 feet.
froth Table 608.4B Highway Design Manual
GE = .52 feet for AC yields actual thickness = 2.48 inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC =.83 feet
GE for base = (0.0032)(4.5)(100-16.0) -.83 = .38 feet
from Table 6084B Highway Design Manualwith GF for Class 2 base = 1.1
Base thickness= 4.10 inches
Use base thickness = 5.0 inches
Design Street Structural Section
Asphalt Concrete Thickness = 4.0 inches.
Class 2 Aggregate Base Thickness 5.0 inches.
Project No. 06105-52-15 ' Jiiiii 20, 2004
FIGURE 1 (Continued)
PAVEMENT SECTION CALCULATIONS
VILLAGES OF LA COSTA - THE OAKS SOUTH
Sitio Lima - Station 13+00 to 16+00
Use subgrade R-Value = 11.0
Traffic Index (TI) = 5.0
Methodology = CALTRANS Highway Design Manual Section 608.4
Safety Factor = 0.2 - Applied to Asphalt Concrete (AC)
GE for AC = (0.0032)(5.0)(100-78.0)+0.2 =.55 feet
from Table 608.413 Highway Design Manual
GE = .55 feet for AC yields actual thickness = 2.65 inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC = .83 feet
GE for base = (0.0032)(5.0)(100-11.0) -.83 = .59 feet
from Table 608.4B Highway Design Manual with GF for Class 2 base =1.1
Base thickness = 6.44 inches
Use base thickness = 7.0 inches
Design Street Structural Section
Asphalt Concrete Thickness = 4.0 inches.
Class 2 Aggregate Base Thickness = 7.0 inches.
Sitió Lima - Station 10+60 to 13+00
Use subgrade R-Value = 22.0
Traffic Index (TI) = 5.0
Methodology = CALTRANS Highway Design Manual Section 608.4
Safety Factor = 0.2 - Applied to Asphalt Concrete (AC)
GE for AC = (0.0032)(5.0)(100-78.0)+0.2 = .55 feet
from Table 608.4B Highway Design Manual
GE = .55 feet for AC yields actual thickness = 2.65 inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC = .83 feet
GE for base = (0.0032)(5.0)(100-22.0) -.83 =.41 feet
from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1
Base thickness = 4.52 inches
Use base thickness = 5.0 inches
Design Street Structural Section ***
Asphalt Concrete Thickness = 4.0 inches.
Class 2 Aggregate Base Thickness= 5.0 inches.
Project No. 06105-52-15 January 20, 2004
FIGURE 1 (Continued)
PAVEMENT SECTION CALCULATIONS
VILLAGES OF LA COSTA - THE OAKS SOUTH
Corte Delfinio - Station 14+80 to 17+50
Use subgrade R-Value = 33.0
Traffic Index (TI) = 5.0
Methodology CALTRANS Highway Design Manual Section 608.4
Safety Factor = 0.2 - Applied to Asphalt Concrete (AC)
GE for AC = (0.O032)(5.0)(100-78.0)+0.2= .55 feet
from Table 608.4B Highway Design Manual
GE = .55 feet for AC yields actual thickness 2.65 inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC = .83 feet
GE for base = (0.0032)(5.0)(100-33.0) .83 = .24 feet
from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1
Base thickness = 2.60 inches
Use base thickness = 4.0 inches
Design Street Structural Section
Asphalt Concrete Thickness = 4.0 inches.
Class 2 Aggregate Base Thickness = 4.0 inches.
C'
Corte Delfinio - Station 11+75 to 14+80
Use subgrade R-Value = 26.0
Traffic Index (TI) = 5.0
Methodology = CALTRANS Highway Design Manual Section 608.4
Safety Factor = 0.2 - Applied to Asphalt Concrete (AC)
GE for AC =(00032)(5.0)(100-78.0)+0.2 = .55 feet
from Table 608.413 Highway Design Manual
GE = .55 feet for AC yields actual thickness = 2.65 inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC = .83 feet
GE for base= (0.0032)(5.0)(100-26.0) -.83 = .35 feet
from Table 608.4B Highway Design Manual with GF for Class, 2 base = 1.1
Base thickness = 3.83 inches
Use base thickness = 4.0 inches
Design Street Structural Section
Asphalt Concrete Thickness = 4.0 inches.
Class 2 Aggregate Base Thickness = 4.0 inches.
Project No. 06105-52-15 January 20, 2004
FIGURE 1 (Continued)
PAVEMENT SECTION CALCULATIONS
VILLAGES OF LA COSTA - THE OAKS SOUTH
Circulo Sequoia - Station 55+15 to 58+15
Use subgrade R-Value = 12.0
Traffic Index (TI) = 5.0
Methodology = CALTRANS Highway Design Manual Section 608.4
Safety Factor = 0.2 - Applied to Asphalt Concrete (AC)
GE for AC = (0.0032)(5.0)(100-78.0)+0.2 =.55 feet
from Table 608.4B Highway Design Manual
GE = .55 feet for AC yields actual thickness = 2.65 inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC =.83 feet
GE for base = (0.0032)( 5.0)(100-12.0) -.83 =.57 feet
from Table 608.4B Highway Design Manual with GE for Class 2 base = 1
Base thickness = 6.27 inches
Use base thickness = 7.0 inches
Design Street Structural Section
Asphalt Concrete Thickness = 4.0 inches.
Class 2 Aggregate Base Thickness = 7.0 inches.
Circulo Sequoia - Station 58+15 to 61+15
Use subgrade R-Value = 13.0
Traffic Index (TI) = 5.0
Methodology = CALTRANS Highway Design Manual Section 608.4
Safety Factor = 0.2 - Applied to Asphalt Concrete (AC)
GE for AC = (0.0032)(5.0)(100-78.0)+0.2 =.55 feet
from Table 608.4B Highway Design Manual
GE = .55 feet for AC yields actual thickness = 2.65 inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC =.83 feet
GE for base = (0.0032)(5.0)(100-13.0) -.83 = .56 feet
from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1
Base thickness = 6.09 inches
Use base thickness = 7.0 inches
Design Street Structural Section
Asphalt Concre6 Thickness = 4.0 inches.
Class 2 Aggregate Base Thickness = 7.0 inches.
Project No. 06105-52-15 January 20, 2004
FIGURE t(Cohtihued)
PAVEMENT SECTION CALCULATIONS
VILLAGES OF LA-COSTA - THE OAKS SOUTH
Circulo Sequoia - Station 61+15 to 64+15
Use subgradeR-Value = 29.0
Traffic Index (Ti) = 5.0
Methodology = CALTRANS Highway Design Manual Section 608.4
Safety Factor = 0.2 - Applied to Asphalt Concrete (AC)
GE for AC = (0.0032)(5.0)(100-78.0)+0.2 =.55 feet
from Table 608.4B Highway Design Manual
GE = .55 feet for AC yields actual thickness = 2.65 inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC =.83 feet
GE for base = (0.0032)(5.0)(100-29.0) -.83 = .30 feet
from Table 608.4B Highway Design Manual withGF for Class 2 base = 1.1
Base thikness =3.30 inches
Use base thickness =4.0 inches
Design Street Structural Section
Asphalt Concrete Thickness = 4.0 inches.
Class '2 Aggregate Base Thickness = 4.0 inches.
Circulo Sequoia - Station 64+15 to 67+15
Use subgrade R-Value = 21.0
Traffic Index (Ti) = 5.0
Methodology = CALTRANS Highway Design Manual Section 608.4
Safety Factor= 0.2 - Applied to Asphalt Concrete (AC)';
GE for AC = (0.0032)(5.0)(100-78.0)+0.2 =.55 feet
from Table 608.4B Highway Design Manual
GE = .55 feet for AC yields actual thickness = 2.65inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC = .83 feet
GE for base = (0.0032)(5.0)(100-21.0) -.83 = .43 feet
from Table 6084B Highway Design Manual with GF for Class 2 base = 1.. 1
Base thickness = 4.70 inches
Use base thickness = 5.0 inches
*** Design Street Structural Section
Asphalt Concrete Thicknès = 4.0 inches.
Class 2 Aggregate Base Thickness = 5.0 inches
Project No. 06105-52-15 January 20, 2004
FIGURE 1 (Continued)
PAVEMENT SECTION CALCULATIONS
VILLAGES OF LA COSTA - THE OAKS SOUTH
Circulo Sequoia - Station 67+15 to 70+15
Use subgrade R-Value = 9.0
Traffic Index (TI) = 5.0
Methodology = CALTRANS Highway Design Manual Section 608.4
Safety Factor = 0.2 - Applied to Asphalt Concrete (AC)
GE for AC = (0.0032)(5.0)(100-78.0)+0.2 =.55 feet
from Table 608.4B Highway Design Manual
GE = .55 feet for AC yields actual thickness = 2.65 inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC = .83 feet
GE for base = (0.0032)(5.0)(100- 9.0) -.83 = .62 feet
from Table 608.4B Highway Design Manual with GF for Class 2 base = 1
Base thickness = 6.79 inches
Use base thickness = 7.0 inches
Design Street Structural Section
Asphalt Concrete Thickness = 4.0 inches.
Class 2 Aggregate Base Thickness = 7.0 inches.
Circulo Sequoia - Station 70+15 to 73+15
Use subgrade R-Value = 27.0
Traffic Index (TI) = 5.0
Methodology = CALTRANS Highway Design Manual Section 608.4
Safety Factor = 0.2 - Applied to Asphalt Concrete (AC)
GE for AC = (0.0032)(5.0)(100-78.0)+0.2 = .55 feet
from Table 608.4B Highway Design Manual
GE = .55 feet for AC yields actual thickness = 2.65 inches
Use 4.0 inches of AC - City Minimum
GE for 4.0 inches of AC =.83 feet
GE for base = (0.0032)(5.0)(100-27.0) -.83 = .33 feet
from Table 608.4B Highway Design Manual with GF for Class 2 base = 1
Base thickness = 3.65 inches
Use base thickness = 4.0 inches
Design Street Structural Section
Asphalt Concrete Thickness = 4.0 inches.
Class 2 Aggregate Base Thickness = 4.0 inches.
Project No. 06105-52-15 January 20, 2004
FIGURE. (Càñtiued)
PAVEMENT SECTION CALCULATIONS
VILLAGES OF LA COSTA THE OAKS SOUTH
Circulo Sequoia Station 73+15 to 76+50
Use subgade RYalue.= 19.0
Traffic Index (TI)=5M •••
Methodology = CALTRANS Highway Design Manual Section 608.4
Safety Factor = 0.2 - Applied to Asphalt Coñcrête (Ac)
GE for AC = (0.O032)(.0)(100-78.0)+0.2 = .5.5,feet
from Table 60.8.4B Highway Design Manual
GE = .55 feet for AC yields actual thickness. 2.65. inches
Use 4.0 inches- of AC - City Minimum
GE for 4.0inch6s of AC = .83 feet
GE for base = (0.0032)(.5.0)(100-1 9.0) -.83 =.46 feet
from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1
Base thickness 5.05 inches
Use baë thickness = 6.0 inches
Design Street StructuralSection •
Asphalt Concrete Thickness = 4.0 inches. •
• Class 2 Aggregate-Base Thickness = 6.0 inches.
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Project No. 06105-52-15 January 20, 2004