HomeMy WebLinkAbout3151; Palomar Airport Road Widening; Supplementary Geotechnical Consulting Palomar Airport Road; 1987-05-22Testing Engineers^San Diego
A Division of United States Testing Company. Inc
3467 Kurtz St.. P.O. Box 80985. SanDiego, Ca. 92138(619) 225-9641
2956 Industry Street. Oceanside. California 92054 (619) 757-0248
City of Carlsbad
Community Development
2075 Las Palmas Drive
Carlsbad, California 92008
Attention: Mr. Al Virgilio
May 22, 1987
Job No. 7092-1
RECEIVii^D
MUNICIPAL PROJECTS
DIVISION
Subject: Supplementary Geotechnical Consulting Services
Palomar Airport Road
East of Paseo Del Norte
Carlsbad, California
Gentlemen:
This report presents results of our additional soil
investigation and pavement section design of the subject site.
The purpose of the soil investigation was to retain bulk soil
samples to be used in the laboratory for "R"-value tests. These
actual "R'*-value test results were then used to estimate the
various pavement sections presented herewith.
Subsurface conditions were explored by drilling ten 8-inch
diameter test borings with a Mobile B-61 drill rig, to 4 to 20
feet depths. A staff geologist from our office was present
during the drilling of the test borings. The sample locations
and soil types with the respective "R"-value results are
presented in Table I.
Palomar Airport Road
East of Paseo Del Norte
Carlsbad, California
Page No, 2
May 22, 1987
Job No, 7092-1
TABLE I
Bore
Hole No
Bore
Hole
Location
Sample
Depth
Feet
Soil
Type R-Value
1 30+00 8 Sandy clay 12
2 32+50 13 Sandy clay 13
3 36+00 12-15 Sandy clay 9
4 36+00 18-20 Sandy clay 8
5 40+00 7 Gravelly
Refusal @ 7 ft.
6 42+00 7 Sandy clay 6
7 50+00 2-4 Silty sand 47
8 53+00 4-6 Clayey sand 21
9 72+50 5 Silty sand 57
10 85+00 6-8 Silty clay 27
Palomar Airport Road Page No, 3
East of Paseo Del Norte May 22, 1987
Carlsbad, California Job No, 7092-1
ASPHALTIC CONCRETE DESIGN
Based on the R-value results and a T.I. value of 9 for primary
arterial, as required by the City of Carlsbad, alternate
structural sections are computed. For purposes of section
design, "R"-value results have been separated to represent three
zones of the alignment. The results are summarized and
presented on Table II,
The design assumes a minimum asphaltic concrete thickness of 6
inches and processed Class II aggregate base course. If the
three layer conventional system is preferred, we recommend
disintegrated granite (D.G.) with minimum "R"-value of 50 to be
used as select import for a subbase course.
Palomar Airport Road Page No. 4
East of Paseo Del Norte May 22, 1987
Carlsbad, California Job No, 7092-1
TABLE NO. II
RECOMMENDED SECTION DESIGN ALTERNATIVES
Materials are referenced to Cal Trans Standard Specifications
for aggregate subbase, aggregate base, and asphaltic concrete
Zone 1: Station 27+00 to Station 32+50
Basement Soil R-Value 12
Traffic Index (Prime Arterial) 9
Minimum a.c. Thickness, ft, (inch) 0,5' (6'*)
Minimum cover required (GE) ft, (inch) 2.55
Alternative 1: Conventional 3 Layer System:
Actual Gravel
Thickness Equivalent (GE)
Feet Inch Course (Gf) Feet
0.50 6 Asphaltic Concrete 1.80 0,90
0.83 10 Class II Agg. Base 1.10 0.91
0.75 9 Agg. Subbase (R=50) 1.00 0.75
2.08 25 2.56
Alternative 2: Conventional 2 layer System:
0,50 6 Asphaltic Concrete 1.80 0.90
1,50 18 Class II Agg. Base 1.10 1.65
2,00 24 2,55
Palomar Airport Road Page No, 5
East of Paseo Del Norte May 22, 1987
Carlsbad,.California Job No. 7092-1
Zone 2: Station 32+50 to Station 50+00
Basement Soil R-Value 6
Traffic Index (Prime Arterial) 9
Minimum a.c. Thickness, ft. (inch) 0,5' (6")
Minimum cover required (GE) ft. (inch) 2.70
Alternative 1: Conventional 3 Layer System:
Actual Gravel
Thickness Equivalent (GE)
Feet Inch Course (Gf) Feet
0.50 6 Asphaltic Concrete 1.80 0,90
0.83 10 Class II Agg. Base 1,10 0.91
0.92 11 Agg. Subbase (R=50) 1.00 0.92
2.25 27 2.73
Alternative 2: Conventional 2 layer System:
0.50 6 Asphaltic Concrete 1.80 0.90
1.67 20 Class II Agg. Base 1.10 1.83
2.17 24 2.73
Note: Based on the "R"-value results and
uniform soil type at Station 36+00, either of
the above asphaltic pavement sections can be
utilized at 17 feet road level. The "R"-value
shown on Table I should be verified after
grading.
Palomar Airport Road
East of Paseo Del Norte
Carlsbad, California
Page No, 6
May 22, 1987
Job No. 7092-1
Zone 3: Station 50+00 to Station 85+00
Basement Soil R-Value
Traffic Index (Prime Arterial)
21
9
Minimum
Minimum
a.c. Thickness, ft. (inch)
cover required (GE) ft. (inch)
0.5' (6")
2.28
Alternative 1: Conventional 3 Layer System:
Actual
Thickness
Feet Inch Course (Gf)
Gravel
Equivalent
Feet
(GE)
0.50 6 Asphaltic Concrete 1.80 0.90
0.50 6 Class II Agg. Base 1.10 0.55
0.83 10
1.83 22
Agg, Subbase (R=50) 1.00 0.83
2.28
Alternative lA:
Actual
Thickness
Feet Inch Course (Gf)
Gravel
Equivalent
Feet
(GE)
0.50 6 Asphaltic Concrete 1.80 0.90
0,83 10 Class II Agg, Base 1,10 0.91
0.50 6 Agg, Subbase (R=50) 1.00 0.50
1.83 22 2.31
Alternative 2: Conventional 2 layer System:
0,50 6 Asphaltic Concrete 1.80 0.90
1.25 15
1.75 21
Class II Agg, Base 1.10 1.38
2.28
Palomar Airport Road Page No. 7
East of Paseo Del Norte May 22, 1987
Carlsbad, California Job No. 7092-1
The samples taken are assumed to be representatives of the
material which will be immediately under the planned structural
section. The design is based on the lowest "R"-value for that
zone since it represents the lowest quality material
encountered.
The asphaltic pavement sections recommended reflect our best
estimate of the project requirements based on an evaluation of
the subsurface soil conditions encountered at the exploration
locations and the assumption that the soil conditions do not
deviate appreciably from those encountered.
Any unusual conditions, not covered in this report, encountered
during site development, should be brought to the attention of
the soil engineer. The "R"-value results should also be
verified before construction, so that modifications can be made
if necessary.
This office should be advised of any changes in the project
scope or proposed site grading so that it may be determined if
the recommendations contained herein are appropriate.
Palomar Airport Road
East of Paseo Del Norte
Carlsbad, California
Page No. 8
May 22, 1987
Job No. 7092-1
We appreciate the opportunity to be of service to you on this
project and look forward to a continued association on this and
future projects. If you have any questions, please do not
hesitate to contact our office.
Almaz F^seha
Project Engineer
Respectfully submitted,
TESTING ENGINEERS-SAN DIEGO
Thomas H. Chapman, RCE 34228
Vice President
THC/AF/eh
Addressee (2)
cc: Jay F. Olsen