HomeMy WebLinkAboutCT 02-17; BLACKSTONE RANCH; PAVEMENT RECOMMENDATIONS; 2014-08-07GEO QN
INCORP0RATED
G E 0 1 E C H N I C A • ENVIRONMENTAL• M A T ER I A;S
Project No. G15i7-11-03
1' August 7, 2014
pLb
California West Communities
5927 Priestly Drive,.Site 10
Carlsbad, California 92008
Attention: Mr. Jack Hepworth
Subject: PAVEMENT RECOMMENDATIONS •
BLA'CKSTONERANCH PHASE 3
PASEO ENCINO STATION 7+20 TO 9+60
CAMINO MINERO STATION 1+00 TO 6+50
.CARLSBAD, CALIFORNIA
Reference Report of Testing and Observation Services Performed During Grading Operations
Blackstone Ranch Lots 37 Through 42 Carlsbad California prepared by Geocon
Tncoi-porated, dated April-2, 2014 (Project No.G15 17-1103):.
Dear Mr. Hepworth:
We prepared letter to provide pavement recommendations for Phase 3 paving of Paseo Encino
Station 7+20 to 9+60and Carnino Miñero Station 1+00 to 6+50 within thepthpbsed development.
We understand that the traffic index (TI) of the subject roadways has been classified as a local street
having a TI of 5.0 as provided by PLSA and the City of Carlsbad We prepared this letter to provide
recommendations for asphalt concrete (flexible) and Portland cement concrete (rigid) pavement
structural sect!ons for the planned roadways.
-.
The recommendations provided herein are based on laboratory test results obtained from subgrade
soil samples We performed laboratory resistance value (R-Value) testing on the subgrade soil in
_accordance with AJTM_D 2844 (California Test Method No 301). The' subgr cLconsist
predominately of sandy clay with gravel and cobble size rock and exhibit very low R Value strength
characteristics. Table I pieeiits the laboratory R-Value test results.
(
TABLE • SUMMARY OF LABORATORY R-VALUE TEST RESULTS
ASTMD2814 •
Sample No Location R-Value
R-13 • Paseo Encino Station 8+00 (7±20 to 9+60) • >5
R-14 Camino Minero Station 2+50 (1+00 to 4+00) • . >5
R-15 Camino Minero Station 5+50(4+066+50) >5
6960 Flanders Drive U San Diego, California 92121-2974 u Telephone 858.558690O • Fax 858.558.6159
-
As indicated on Table 1, the laboratory R-Value tests results are less than 12. We understand the City of
Carlsbad typically requires lime treatment of subgrade soil when the R-Value is less than 12. It has been
our experience that lime treatment is most effective when used in situations where clays of "high" to
"very high" expansion potential (Expansion Index greater than 90) are present with little' to no rock.
Due to the presence of significant cobble size material within the subgrade soil of up to 60 percent rock,
ventioTlpaiernent section along the subject ro,a4ways
uldbegreappthriate 1The'efore, vereomrnend the implementation of the corenttonal
pavement section recommendations provided on Table 2
FLEXIBLE PAVEMENT RECOMMENDATIONS
We calculated the flexible pavement sections in general conformance with the Caltrans' Method of
Flexible Pavement Design (Highway Design Manual, Section 608.4). Table 2 presents the calculated
pavement sections using the City of Carlsbad minimum design sections in accordance with
Supplemental Standard No. GS-17 dated June 2004. Figure 1 presents the calculations for the planned
sections.
TABLE 2
FLEXIBLE PAVEMENT SECTION
Traffic Subgrade Calculated Calculated Class 2
Location Ind R-Value Asphalt Concrete Aggregate Base
Thickness (inches) Thickness (inches)
Paseo Encino 7+20 to 9+60 , 5.0 1 '4* '
Camino Minero 1+00 to 6+50 5.0 2 4* 8
* Minimum thickness required by the City of Carlsbad.
Prior to placing the base materials, the upper 12 inches of pavement subgrade soil should be scarified,
moisture conditioned as necessary, and compacted to a dry density of at least of 95 percent of the
laboratory maximum dry density near to slightly above optimum moisture content as determined by
ASTM D 1557. Base materials should be moisture conditioned near to slightly above opt.imum
moisture content and compacted to a dry density of at least 95 percent of the laboratory maximum dry
--- to.adensityoLat.Jeast..95. .percenLoLthe.,.laboratory.,
Hveem density in accordance with ASTM D 2726.
The placement of base materials should conform to Section 26-1.02A of the Standard Specifications
for The State of California Department of Transportation (Caltrans) with a %-inch maximum size
aggregate and the City of Carlsbad specifications. The placement of asphalt concrete should conform
to Section 203-6 of the Standard Specifications for Public Works Construction (Greenbook). The
asphalt concrete should be placed in two lifts with the base course lift having a thickness of
2.5 inches and the surface course placed after construction is completed.
Project No. G1517-1 1-03 -2- , August 7, 2014
RIGID PAVEMENT RECOMMENDATIONS
A rigid Portland cement concrete (PCC) pavement section should be placed in roadway cross gutters
and lot driveway ramps. We calculated the rigid pavement section in general conformance with the
procedure recommended by the American Concrete Institute report ACI 330R-08 Guide for Design
and Construction of Concrete Parking Lots using the paratheters presented in Table 3
TABLE 3
RIGID PAVEMENT DESIGN PARAMETERS
Design Parameter Design Value
Modulus of Subgrade Reaction, k 50 pci
Modulus of Rupture for Concrete, MR 506 psi
Traffic Category, TC A and C
Average Daily Truck Traffic, ADTT 77 I and 100
Based on the criteria presented herein, the PCC pavement sections should have a minimum thickness
as presented in Table 4
TABLE 4
RIGID PAVEMENT RECOMMENDATIONS
Location Portland Cement Concrete (inches)
Lot Driveway Ramps (TCA)' 6.0
Roadway Cross-Gutters (TC=C) 7.5
Prior to the placement of PCC pavement, subgrade soil 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. Base materials should be moisture conditioned to near optimum moisture content and
compacted to a dry density of at least 95 percent of the laboratory maximum dry density with a
thickness in accordance with 'the specifications of the City of Carlsbad. This pavement section is
based on a minimum concrete compressive strength of 3,000 psi (pounds per square inch).
A thickened edge or integral curb should be constructed on the outside of concrete slabs subjected to
wheel loads. The thickened edge should be 1.2 times the slab thickness or a minimum thickness of
2 inches, whichever results in a thicker edge, and taper back to the recommended slab thickness 4 feet
behind the face of the slab (e.g., a 7.5-inch-thick slab would have a 9.5-inch-thick edge). Reinforcing
steel will not be necessary within the concrete for geotechnical purposes with the possible exception
of dowels at construction joints as discussed herein.
Project No. G1517-1 1-03 -'3- August 7, 2014
To control the location and spread of concrete shrinkage cracks, crack-control joints (weakened plane
joints) should be included in the design of the concrete pavement slab. Crack-control joints should have
a maximum spacing of 15 feet for the 6- to 7.5-inch-thick slabs and should be sealed with an
appropriate sealant to prevent the migration of waterthrough the control joint to the base and subgrade
materials. The depth of the crack-control joints should be determined by the referenced ACI report.
To provide load transfer between adjacent pavement slab sections, a butt-type construction
joint should be constructed. The butt-type joint should be thickened by at least 20 percent at the edge
and taper back at least 4 feet from the face of the slab. As an alternative to the butt-type construction
joint, dowelling can be used between construction joints for pavements of 7 inches or thicker. As
discussed in the referenced ACI guide, dowels should consist of smooth, i-inch-diameter reinforcing
steel 14 inches long embedded a minimum of 6 inches into the slab on either side of the construction
joint. Dowels should be located at .the midpoint of the slab, spaced at 12 inches on center and
lubricated to allow joint movement while still transferring loads. In addition, tie bars should be
installed at the as recommended in Section 3.8.3 of the referenced ACI guide. The structural engineer
should provide other àlteinãtive recommendations for load transfer as necessary.
The perfoi'mance of pavement is highly dependent on providing positive surface drainage away from
the edge Of the pavement. Ponding of surface water on or adjacent to roadway pavement will likely
result in pavement distress and subgrade failure. Drainage from landscaped areas should be directed
to controlled drainage structures. Landscape areas adjacent to the edge of asphalt pavements are not
recommended due to the potential for surface or irrigation water to infiltrate the underlying
permeable aggregate base and cause distress Where such a condition cannot be avoided,
consideration should be given to incorporating measures that will significantly reduce the potential
for subsurface water migration into the aggregate base.
Should you have any questions regarding this letter, or if we may be of further service, please contact
the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
J obs
G 1524
JH:SFW:dmc
Attachment: Figure 1
(2/del) Addressee
JOHN o HOOBS ir No. —1
CERTIFIED *. * ENGINEERING
p GEOLOGIST
N9F cit-9'
Shawn Foy Weedon
GE 2714
Project No. G1517-I 1-03 -4- August 7, 2014
<i),~GEOCON
PAVEMENT DESIGN
Reference: Highway Design Manual, July 1 1990; PP. 600-3210 600-40' .
Project Name J'7BIickst6i Rarcch]
Project Number G1517:11-03!.';
Date . 817/2014
Sample Roadway: . . " - Pèö ; - athiñoMineró .
Sample Staions ,- 7+20109+60 _'I , 1-i-00466+50 1.
Sample Number . A 13 -- , .+ - R-_1 4 & R 15 ' , •
Subgrade R Value i__ 2 2 'T I
Minimum City of Carlsbad Asphalt thickness (in) - 4 0 40
Minimum Base Thickness tB(in) 40
Gravel Equiv (G1) for Base 1 1 -.j .' L " 1 1
Base Material A Value 78 - -, 78
Use Equivalent Asphalt Thickness (Y/N) N . I iN ._-
EquivalentAsphalt Thickness (in) 0 .
ic Index, TI
Gravel Equivalent, GE (ft) = 0.0032(Tl)(100-R) 1.57 1.57 -
FULL ASPHALT SECTION -
4
lAsphalt Design Thickness, (in.) -. ' ' I - 748 ' , I ' - 7.48
ASPHALTAND'BASESECTION
Traff
t
Asphalt Thickness if <0.5ft(ft)=((GE+0.1)*TlO5)/5.67 0.66 0.66
Check if Asphalt Thickness if> 0.5 ft ( ) = (((GE+0.1)*TIOS)17)O75, 0.62 0.62
Figure 1,
f
01
GEA =TG1 =0.0032(Tl)(100-78)+0.2,(ft)0.55 ..., ,0.55 ,-
Asphalt Thickness; Iif <0.5ff(It)=GEA/GI =GEA Tl°5/567 0.22 ., ,0.22
Asphalt Thickness, Tif>0.5ft (ft)=(GEA*TlO5/7)O75 0.22 -0.22
DesignAsphalt Thickness, tAc (ft).-'- 0.33 -,.. .0.33
GEAC of Design Asphalt Thickness =tAC 5.671r1°'5_[tAO.5]OR(7*tAc4O)/TIO5 0.85 0.85
Required GE6 for Base Section =GE-GEAC --0.72
Thickness of Aggregate Base, tAB (It)=GE5/G1 0.66 0.66
Design Aggregate Base Thickness, 'AB (ft)0.66 0.66
Minimum Asphalt Design Thickness, tAc (in.) 4.00 , - 4.00
Minimum Aggregate Base Design Thickness, tAB (in.) 8.00 8.00 -
er'ol
ENVIRONMENTAL. MATE'RIAlS '
GEOC.ON
: INCORPORATED
G E 0 1 E C H N I C Al
Project No. G1517-11-03
July 18, 2014
California West Communities
5927 Priestly Drive, Suite 110
Carlsbad, California 92008
Attention: Mr. Jack Hepworth
Subject:. PAVEMENT RECOMMENDATIONS
BLACKSTONE RANCH PHASE 2
çAMINO JUNIPEROSTATION48+75 TO 53+32r
PASEO ENCINO STATION 0+80 TO 7+20
PASEO CRISTAL STATION 9+60 TO 12+86
CORTE CLARO'STATIQN 1+20 TO 4±35
SITIOCONEJO STATION 1±40 TO 2+75
CARLSBAD, CALIFORNIA
Reference: Report of Testing and 'Observation Services Performed During Grading Operations,
Blackstone Ranch Lots 37 Through 42 Carlsbad California prepared by Geocon
Incorporated, dated April 2, 2014 (ProjectNo; G1517-11-03). :
Dear Mr. HèpwOrth:
. We prepared letter to provide pavement recommendations for the second phase of paving of Camino
Junipero Station 48+75 to 53+32, Paseo Encino Station 0+80 to 7+20, Paseo Cristal Station 9+60
to 12+86, Corte'Claro Station 1±20 to 4+35 (full length), and Sitio Conejo'Station 1+40 to.2+75 (full
length) within the proposed development. We understand that the City of Carlsbad has evaluated the
Traffic Index (TI) of Camino Juhipero at 6.0. The remainder of the roadways have been classified as
a local street having a TI of 5.0 as provided by PLSA and the City of Carlsbad We prepared this
letter to provide recommendations for asphalt concrete (flexible) and Portland cement concrete (rigid).
pavement structural sections for'the planned roadways at the subject project.
The recommendations provided herein are based on laboratory test results obtained from subgrade
soils. We performed laboratory resistance value (R-Value) testing on the subgrade soil in accordance
with ASTM.D 2844 (California Test Method No. 301). The subgrade soil consists predominately of
sandy clays with gravel and cobble, size rock and exhibit low R-Value strength, characteristics.
Table I presents the laboratory R-Value test resuljs.
6960 Flanders Drive. 'U San Diego, CaliForni 92121.2974 0 Telephone 858.558.6900 • Fax 858.558.6159
TABLE I
SUMMARY OF LABORATORY R-VALUE TEST RESULTS
ASTMD2844
Sample No. Location R-Value
R-6 Camino Junipero Station 50+00 (48+75 to 51+50) 11
R-7 Camino Junipero Station 52+06 (51+50 to 53+32) . 6
R-8 Corte Claro Station 2+75 (1+20 to 4+35) 34
R-9 Sitio Conejo Station 2+00 (1+40 to 2+75). 20
R-10 Paseo Cristal Station 11+00(9±60 to 12+86) 18
R-1 1 Paseo Encino Station 2+50 (0+80 to.4±00) .' 4
R-12 Paseo Encino Station 5+50 (4+00 to 7+20) 6
As indicated on Table 1, the laboratory R-Value tests results for Sample Nos. R-6, R-7, R-1 1, and R-12
are less than 12. We understand the City of Carlsbad typically requires lime treatment of subgrade soils
when the R-Value is less than 12. It has been our experience that lime treatment is most effective when
used in situations where clays of "high" to "very high" expansion potential (Expansion 'Index greater
than 90) are present with little to no rock. Doe to the presence-of significant cobble size material within
the subgrade soils up to 60 percent rock, it is our opinion that the construction of a conventional
pavement section along the subject roadways would be more appropriate. Therefore, we récomhiend the
implementation of the conventional pavement. section recommendations provided on Table 2.
FLEXIBLE PAVEMENT RECOMMENDATIONS
We calculated the flexible pavement sections in general conformance with the Caltrans Method of
Flexible Pavement Desi'gn (Highway Design Manual, Section 608.4). Table 2 presents the calculated
pavement sections using the City of Carlsbad minimum design sections • in accordance with
Supplemental Standard No. GS-1 7 dated June 2004. Figure 1 presents the calculations for the planned
sections.
TABLE2'
FLEXIBLE PAVEMENT SECTION
.affic d S e
Calculated Calculated Class 2 Location Tr
in Yiie Asphalt Concrete Aggregate Base
Thickness (inches) Thickness (inches)
Camino Junipero 48+75 to 53+32 6.0 ,6 4* 12
Paseo Encino 0+80 to 7+20 5.0 4 4* . 8
Paseo Cristal 9+60 to 12+86 5.0 18 4* . 6
Corte Claro 1+20to4+35 50 34 4* 4*
Sitio Conejo 1+40 to 2+75 5.0 20 4* 5
* Minimum thickness required by the City of Carlsbad.
Project No. Gl5l7-I 1-03 -2- . July 18, 2014
Prior to placing the base materials, the upper 12 inches of pavement subgrade soil should be scarified,
moisture conditioned as necessary, and compacted to a dry density of at least of 95 percent of the
laboratory maximum dry density near to slightly above optimum moisture content as determined by
ASTM D 1557. Base materials should be moisture conditioned near to slightly above optimum
moisture content and compacted to a dry de,nsity of at least 95 percent of the laboratory maximum, dry
density. Asphalt concrete should be compacted to a density -of at least 95 percent of the laboratory
Hveem density in accordance with ASTM D 2726.
The placement of base materials should conform to Section 26-1.02A of the Standard Specifications
for The State of California Department of Transportation (Caltrans) with a 3/4-inch maximum size
aggregate and the City of Carlsbad specifications. The placement of asphalt concrete should conform
to Section 203-6 of the Standard Specifications for Public Works Construction (Greenbook). The
asphalt, concrete should be placed in two, lifts with the base course lift having a thickness of 2.5
inches and the surface course placed after construction is cmpleted.
RIGID PAVEMENT RECOMMENDATIONS
A rigid Portland cement concrete (PCC) pavement section shouldbe placed in roadway cross gutters
and lot driveway ramps We calculated the rigid pavement section in general conformance with the
procedure recommended by the American Concrete Institute report ACI 330R-08 Guide for Design
and Construction of Concrete Parking Lots using the parameters presented in Table 3.
TABLE 3
RIGID PAVEMENT DESIGN PARAMETERS
Design Parameter Design Value'
Modulus of Sübgrade Reaction, k , 50 pci.
Modulus of Rupture for Concrete, MR ' . 5,00 psi
Traffic Category, TC ' 'A and C
Average Daily Truck Traffic, ADTT ' , 1 and 1,00
Based on the criteria presented herein, the PCC pavement sections should have a minimum thickness
as presented in Table 4.
TABLE 4
RIGID PAVEMENT RECOMMENDATIONS
Location Portland Cement Concrete (inches)
Lot Driveway'Ramps (TCA) ' . 5.5
Roadway Cross-Gutters (TC=C) . 7.0
Project No. C 1517-11-03 -3 - July 18, 2014
Prior to the placment of PCC pavement, subgrade soil should be compacted to a dry density of at
least 95 percent of the laboratory maximum dry density near to.slightiy above optimum moisture
content. Base materials should be moisture conditioned to near optimum moisture content and
compacted to a dry density of at Jeast 95 percent of the laboratory maximum dry density with a
thickness in accordance with the specifications of the City of Carlsbad. This pavement section is
based on a minimum concrete compressive strength of 3,000 psi (pounds per square inch).
A thickened edge or integral curb should be constructed on the outside of concrete slabs subjected to
wheel loads. The thickened edge should be 1.2 times the slab thickness or a minimum thickness of
2 inches, whichever results in a thicker edge, and taper back to the recommended slab thickness 4 feet
behind the face of the slab (e.g., a 7-inch-thick slab would have a 9-inch-thick edge). Reinforcing
steel will not be necessary within the concrete for geotechnical purposes with the possible exception
of dowels at construction joints as discussed herein.
To control the location and spread of concrete shrinkage cracks, crack-control joints (weakened plane
.joints) should be included in the design of the concrete pavement slab. Crack-control joints should
have a maximum spacing of 10 feet and 15 feet for the 5- and 7-inch-thick slabs, respectively, and
should be sealed with an appropriate sealant to prevent the migration of water through the cQntrol
joint to the base and subgrade materials: The depth of the crack-control joints should be determined
by the referenced ACI report.
To provide load transfer between adjacent pavement slab sections, a butt-type construction
joint should be constructed. The butt-type joint should be thickened by at least 20 percent at the edge
and taper bak at least 4 feet from the face of the slab. As an alternative to the butt-type construction
joint, dowelling can be used between construction joints for pavements of 7 inches or thicker. As
discussed in the referenced ACI guide, dowels should consist of smooth, 1-inch-diameter reinforcing
steel 14 inches long embedded a minimum of 6 inches intothe slab on either side of the construction
joint. Dowels should be located at the midpoint of the slab, spaced at 12 inches on center and
lubricated to allow joint movement while still transferring loads. In addition, tie bars should be
installed at the as recommended in Section 3.8.3 of the referenced ACT guide. The structural engineer
should provide other alternative recommendations for load transfer as necessary.
The performance of pavement ishighly dependent on providing positive surface drainage away from
the edge of the pavement. Ponding of surface water on or adjacent to roadway pavement will likely
result in pavement distress and subgrade failure. Drainage from landscaped areas should be directed
to controlled drainage structures. Landscape areas adjacent to the edge of asphalt pavements are not
recommended due to the potential for surface or irrigation water to infiltrate the underlying
permeable aggregate base and cause distress. Where s'uch a condition cannot be avoided,
consideration should be given to incorporating measures that will significantly reduce the potential
for subsurface water migration into the aggregate base.
I
Project No. G1517-ll-03 -4- July 18, 2014
- *.
. , .
Should you have any questions regarding this letter, or if we may be of further service, p lease contact
the undersigned at Your convenience.
Very truly yours, .
GEOCON INCORPORATED
OFES
60 G, -15524
0
Shaw' Foy WeedKn (—D No. 2714 z LU
0. CH
OF CA • Attachment: Figure 1
* (2/del) Addressee S
Project No. G1517-1 1-03 July 18, 2014
GEOCON
PAVEMENT DESIGN .
Reference: Highway Design Manual, July 1, 1990 pp. 600-32 to 600-40
Project Name:.n77 71
Project Number: :G.51,7-11-03 •:: - I
Date 711812014
Sample Roadway: . . . Caindüñiper6. oErino PáieoC.rIstl .. . Cört:CI&.
Sample Staions 48+75 to 53+32 0+80 to 7+20 - 9+6010 12+86 1+20 to 4+35 1+404o 2+75
Sample Number:R
Subgrade R Value 6
Minimum City of Carlsbad Asphalt thickness (in) 40 40 - 40 4 0
Minimum Base Thickness t6 (in) 40 j 40 , 40, 40 40
Gravel Equiv (Gi) for Base 1 i 11 i 1 i 11
Base Material A Value -, 78" 8 - '78 78 - - 78 78.T
Use Equivalent Asphalt Thickness (YIN) N N
Equivalent Asphalt Thickness (in) 00 1 0 'r 2 0 3 Or 4'O
FULL ASPHALT SECTION
Asphalt Design Thickness tAc (in) 885 738 660 547 649
ASPHALT AND BASE SECTION
GEA = TG = 0.0032(Tl)(100-78)+0.2, (ft) 0.62 0.55 .0.55 .' 0.55 0.55
Asphalt Thickness T if <05 ft (ft) = GEA/Gi = GEA TI° 5/5 67 027 022 022 022 022
Asphalt Thickness, I if >0.5 ft (ft) = (GEA*TIO517)075 1 0.27 0.22 .0:22 .'0.22 . 0.22
DesignAsphalt Thickness, tAC (ft) 0.33 0.33 0.33 . 0.33 033
GEAC of Design Asphalt Thickness = tAc5.67/Tl°'5 [tA0.5] OR (7tAc40)/Tl0 0.77 0.85 . 0.85 ' 0.85 ' 0.85
Required GE8 for Base Section = GE-GEAC 1.03 .,.., 0:69,. 0.47 ... 0.21 . . 0.43.
Thickness of Aggregate Base, t.8 (ft) = GEWGi , . .. ' '0.94 0.42 . 0.19 0.40.-
Design Aggregate Base.Thickness, tAB (ft)0.94 . 0.63 : 0.42 . 0.33 0.40
IMinimum Asphalt Design Thickness, tAC (in.) 4.00 4.00 . . 4:00 . 4.00 4.00
Minimum Aggregate Base Design Thickness tAB (in) 1200 800 600 400 500
Traffic Index TI - 6 0' - 50 50 50 7.
. Gravel Equivalent, GE (ft)= 0.0032(Tl)(100-R)
.
1.80- 1.54 1.31 . . 1.06 1.28
= ((GE+O.1)*TIOS)I5.67 . . .S Asphalt Thickness if <0.5 It (ft) . 0.8? ' 0.65 . 0.56 .' 0.46 : .0.54
Check if Asphalt Thickness if> 0.5 ft (ft) = (((GEf0.1)*TlO.5)I7)O?5 ' 0.74 0.61 0.55 0.46 1 0.54
Figure 1