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SCSI, Inc.
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San Diego, CA 92120
N P619kit
877.215.4321
.280.4321
c 619.280.4717
-• W www.scst.com
SDVOSB.DVBE :
January 30, 2016 SCSI No. 150448P3.5
Report No. I
Mr. Scott Fisher
City of Carlsbad
1635 Faraday Avenue
Carlsbad, California 92008
Subject: PAVEMENT INVESTIGATION REPORT
PIRGOS WAY REHABILITATION
OCEANSIDE, CALIFORNIA
Dear Mr. Fisher:
This report presents the results of our pavement investigation for Pirgos Way pipeline improvement
project located in the city of Oceanside, California; The purpose of our pavement investigation was
to evaluate the existing pavement condition and subsurface conditions at the site and provide
geotechnical conclusions as to the existing conditions of the pavement and recommendations for
pavement rehabilitation alternatives. This investigation was performed in general accordance with
our Proposal Number 16-0669 dated November 9, 2016.
I SITE AND PROJECT DESCRIPTION
Pirgos Way is a residential street approximately 1,080 linear feet in length, located within a gated
homeowners' association (HOA) community in the City of Oceanside, California. It is our
understanding that subsurface water utility improv'ments were recently constructed along the
length of -Pirgos Way by the City of Carlsbad. The improvement consisted of trench excavation,
water main abandonment and replacement, and trench backfill.
The project will consist of the rehabilitation of Pirgos Way. The general project location is shown on
the Site Vicinity Map (Figure 1).
2 SCOPE OF WORK
Our scope of work performed consisted of:
• Visited the site to observe and document the existing site conditions
• Reviewed historic aerial photographs
• Notified Underground Service Alert (USA) DigAlert prior to field activities
• Provided traffic control during fieldwork
Advanced five borings below the existing pavement using a truck mounted drill rig equipped
with a hollow stem auger. An SCST engineer logged the borings and obtain subgrade soil
samples for examination and laboratory testing
City of Carlsbad January 30, 2016
Pirgos Way Rehabilitation SCST No. 150448P3.5-1
Oceanside, California Page 2
.. Backfilled borings with soil cuttings and patched surface with asphalt cold patch after
obtaining soil samples
Performed laboratory testing on selected samples obtained from the borings to evaluate
pertinent classification and engineering properties and enable development of geotechnical
conclusions
.Calculated pavement structural sections and assessed appropriate rehabilitation
recommendations to extend pavement life
Prepared this illustrated report complete with field and laboratory data, summarizing our
conclusions and recommendations for the appropriate pavement rehabilitation
3 FIELD EXPLORATION
Our pavement investigation was conducted on December 27, 2016 and consisted of advancing five
geotechnical borings to depths of between approximately 3 and 5 feet below the existing pavement
surface. The borings were advanced using a truck mounted drill rig equipped with a 6 inch diameter
hollow stem auger. An SCST engineer logged and sampled the borings: Bulk and Modified
California drive samples were obtained from the borings in general conformance with current
applicable ASTM standards. The samples were then transported to our in-house geotechnical
laboratory for testing. Borings were bäckfilled with soil cuttings and patched with asphalt cold patch
material.
Logs of the borings are presented in Appendix I. Soils are classified in accordance with the Unified
Soil Classification System (USCS) present on Figure I-I. The approximate locations of the
geotechnical borings are presented on the Subsurface Investigation Map (Figure 2).
4 LABORATORY TESTING
Selected samples obtained from the borings were tested to evaluate pertinent classification and
engineering properties and enable development of geotechnical conclusions. Laboratory testing of
representative soil samples included an evaluation of moisture content and density, sieve analysis
(ASTM 0422), Atterberg Limits (ASTM 04318) and resistance (R) value (California Test 301). Brief
descriptions of the laboratory test procedures and the test results are presented in Appendix II.
5 FINDINGS
Since construction operations by the City of Carlsbad, Pirgos Way has reportedly displayed distress
in the form of severe fatigue (alligator) cracking and pot holes. Based on our pavement distress
evaluation, pavement distress along Pirgos Way is isolated to where construction was performed.
Photographs documenting the pavement distress are presenting in Appendix Ill.
The structural pavement section and subsurface conditions encountered are presented in Table 1
below. Based on the geotechnical borings, Pirgos Way is paved with approximately 4 inches of
asphalt concrete (AC) and underlain with approximately 5 inches of aggregate base (AB), except in
one location where no AB was encountered. The subgrade material encountered consists of stiff,
sandy lean clay. The result of the representative R-Value test was 5, and is presented in Table 1
below.
'City of Carlsbad ' •' January 30, 2016
Pirgos Way Rehabilitation ' SCST No: 150448P3.5-1
Oceanside, California ' Page 3
Table I ,
Summary of Existing Structural Pavement Sections and
Subgrade Support Characteristics
AC Thickness AB Thickness Subgrade
Location (inches) (inches) Classification Tested R-Value
(USCS)
B-I 4 Not Encountered Sandy Clay 5 (CL)
B-2 4 5 ' Sandy Clay
(CL).
B-3 4 5 ,
Sandy Clay
-
(CL)
B-4 ' 4 5 , Sandy Clay
-
(CL)
B-S ' 4 ' 5 ,
'Sandy Clay
-
(CL)
USUS = Unified Soil Classitication System
6 CONCLUSION AND PAVEMENT REPAIR RECOMMENDATIONS
The observed pavement distress along Pirgos Way is most likely due to age, poor surface and
subsurface drainage, and to a greater degree, overloaded subgrade (e.g., inferior pavement section
thickness during heavy traffic loading). ,
Based on historical aerial photographs, Pirgos way was constructed between 1990 and 1997.
Therefore, the pavement is greater than 20 years old which is the typical design life of pavements is.
It is our opinion that Pirgos Way has reached its design life and is due for reconstruction.
The original design Traffic Index (TI) of Pirgos Way was calculated from the existing pavement
section and tested R-Value to be approximately 4.5. Based on current design standards, a
minimum TI of 5 to 5.5 is recommended for residential streets, especially those anticipated to
receive regular trash service (heavy truck loading). It is our opinion that the existing structural
pavement section design is NOT adequate for the anticipated residential traffic loading. However, no
major distress was observed in adjacent pavements which did not receive heavy construction traffic
within the HOA, e.g. Milissi Way, Patra Way and Tolo Way.
Based on the results of our pavement investigation, it is considered feasible to rehabilitate Pirgos
Way with a street wide cold mill and AC overlay to extend the life, of the pavement. However,
localized areas should be removed and reconstructed full depth, i.e. "dig outs", due to the severity of
the pavement distress. The city's representative should evaluate these areas with the contractor
prior to construction. The main geotechnical consideration affecting the proposed rehabilitation is
the presence of saturated subgrade below Pirgos Way. Accordingly, subgrade stabilization may be
necessary to create a stable working platform for full depth reconstruction operations.
City of Carlsbad January 30, 2016
Pirgos Way Rehabilitation SCST No. 150448P3.5-1
Oceanside, California Page 4
6.1 PAVEMENT SECTION RECOMENDATIONS
SCST used the Caltrans Highway Design Manual pavement design procedures and methods to
assist us in determining the appropriate structural pavement section. The preliminary AC overlay
and pavement section recommendations to extend the life of the pavement are presented in
Tables 2 and 3, respectively.
6.1.1 Cold Milling and Placement of a New Asphalt Overlay
As discussed in our conclusions, localized areas of pavement removal and replacement
should be planned as a part of construction, and reflective cracking and premature
deterioration should be expected after the design life.
Table 2
Cold Mill and Asphalt Concrete Overlay
Grind Thickness Overlay Thickness Repair Method
(inches) (inches)
Cold Mill and AC Overlay 3 3
Subsequent to cold milling and cleaning the surface, observable cracks should be filled prior
to placement of the new AC overlay. However, cracking is anticipated to be substantial.
Alternatively, a leveling course may be applied to the milled surface. The removed AC
material should then be replaced with AC overlay as recommended.
To reduce the extent of reflective cracking and extend the life of the pavement rehabilitation,
a paving reinforcement may be considered as part of the overlay construction alternative.
6.1.2 Structural Pavement Section for Digouts
The structural pavement section for localized pavement removal and replacement is
summarized in Table 3 below. Asphalt grindings produced from construction operations may
be reused as base in lieu of importing material. Additionally, a reinforcing geogrid such as
Tensar TX-5, should be placed at the bottom of the removal to provide a stable working
platform to place and compact the asphalt grindings.
City of Carlsbad January 30, 2016
Pirgos Way Rehabilitation SCST No. 150448P3.5-1
Oceanside, California Page 5
Table 3
Structural Pavement Section
Subgrade Asphalt Hot Mix Asphalt
Repair Method Stabilization Grindings . Concrete
(inches) (inches)
12-inch Removal TensarTX-5
New AC over Asphalt (or equivalent) 8 4
Grindings
New fill soils and base courses for pavements, if any, should be placed in 6-inch to 8-inch loose
lifts, moisture conditioned to near optimum moisture content and compacted to at least 95
percent relative compaction. Materials and methods of construction should conform to good
engineering practices and the minimum standards of the local agency having jurisdiction.
7 GEOTECHNICAL ENGINEERING DURING CONSTRUCTION
We recommend SCST observe pavement repair construction and perform appropriate field and
laboratory teststo evaluate the degree of compaction achieved and material qualities. In the event
unusual or unanticipated conditions are encountered, the presence of the geotechnical engineer
during construction will enable modification of the recommendations in this report or the
development of additional recommendations on a timely basis.
8 LIMITATIONS
SCST should be advised of changes in the project scope so that the recommendations contained in
this report can be evaluated with respect to the revised plans. The findings in this report
are valid as of the date of this report. Changes in the condition of the streets or traffic expectations
can, however, occur with the passage of time, whether they are due to natural processes or work in
this or adjacent areas. In addition, changes in the standards of practice and government regulations
can occur. Thus, the findings in this report could be invalidated wholly or in part by changes beyond
our control. This report should not be relied upon after a period of two years without a review by us
verifying the suitability of the conclusions and recommendations to site conditions at that time.
In the performance of our professional services, we comply with that level of care and skill ordinarily
exercised by members of our profession currently practicing under similar conditions and in the
same locality. The client recognizes that subsurface conditions may vary from those encountered at
the boring locations, and that our data, interpretations, and recommendations are based solely on
the information obtained by us. We will be responsible for those data, interpretations, and
recommendations, but will not be responsible for interpretations by others of the information
developed. Our services consist of professional consultation and observation only, and no warranty
of any kind whatsoever, express or implied, is made or intended in connection with the work
performed or to be performed by us, or by our proposal for consulting or other services, or by our
furnishing of oral or written reports or findings.
City of Carlsbad January 30, 2016
Pirgos Way Rehabilitation SCST No. 150448P3.5-1
Oceanside, California Page 6
If you have any questions, please call our office at 619-280-4321.
Respectfully submitted,
SCST, INC.
/fVincent A. Uhde, EIT 151458 Emil Rudolph E", GE 27
Project Manager/ Staff Engineer Principal Engineer
VAU:ER:rt
Attachments
Figure 1 - Site Vicinity Map
Figure 2 - Subsurface Exploration Map
Appendix I - Field Investigation
Appendix II - Laboratory Testing
Appendix Ill - Site Photographs
(1) Addressee via e-mail: Scott.Fisher@CarlsbadCA.gov S
(1) J Fretwell via e-mail: JFretwell@lECorporation.com
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2 Oceanside, California Job No.: 150448P3.5
APPENDIX
APPENDIX I
FIELD INVESTIGATION
Our subsurface exploration was condUcted on December 27, 2016 and consisted of advancing five
geotechnical borings to depths of between approximately 3 and 5 feet below the existing pavement.
The borings were advanced using a truck mounted drill rig equipped with a 6 inch diameter hollow
stem auger. An SCST engineer logged the borings in accordance with the Unified Soil Classification
System (USCS) and sampled the borings in general conformance with current applicable ASTM
standards.
Relatively undisturbed, drive samples were obtained using a Modified California sampler (CAL),
which is a ring-lined split tube sampler with a 3-inch outer diameter and 21,4-inch inner diameter.
The CAL samplers were driven with a 140-pound weight dropping 30 inches. The number of blows
needed to drive the samplers the final 12 inches of an 18-inch drive is noted on the boring logs as
"Driving Resistance (blows/ft of drive)." CAL sampler refusal was encountered when 50 blows were
applied during any one of the three 6-inch intervals, a total of 100 blows was applied, or there was
no discernible sampler advancement during the application of 10 successive blows. Disturbed bulk
samples were obtained from the drill cuttings.
The soils are classified in accordance with the Unified Soil Classification System as illustrated on
Figure I-I. Logs of the borings are presented on Figures 1-2 through 1-6.
(
SUBSURFACE EXPLORATION LEGEND
UNIFIED SOIL CLASSIFICATION CHART
GROUP SOIL DESCRIPTION TYPICAL NAMES SYMBOL
COARSE GRAINED, more than 50% of material is larger than No. 200 sieve size.
GRAVELS CLEAN GRAVELS GW Well graded gravels, gravel-sand mixtures, little or no fines More than half of
coarse fraction is GP Poorly graded gravels, gravel sand mixtures, little or no fines. larger than No. 4
sieve size but GRAVELS WITH FINES GM Silty gravels, poorly graded gravel-sand-silt mixtures. smaller than 3
. (Appreciable amount of
fines) GC Clayey gravels, poorly graded gravel-sand, clay mixtures.
SANDS CLEAN SANDS SW Well graded sand, gravelly sands, little or no fines. More than half of
coarse fraction is SP . Poorly graded sands, gravelly sands, little or no-fines. smaller than No.
4 sieve size. SM Silty sands, poorly graded sand and silty mixtures.
SC Clayey sands, poorly graded sand and clay mixtures.
FINE GRAINED, more than 50% of material is smaller than No. 200 sieve size.
SILTS AND CLAYS ML Inorganic silts and very fine sands, rock flour, sandy silt or clayey-silt-
(Liquid Limit less sand mixtures with slight plasticity.
than 50) CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays,
silty clays, lean clays.
OL Organic silts and organic silty clays or low plasticity.
SILTS AND CLAYS MH Inorganic silts, micaceous or diatomaceous,fine sandy or silty soils,
(Liquid Limit elastic silts.
greater than 50) CH Inorganic clays of high plasticity, fat clays.
OH Organic clays of medium to high plasticity.
HIGHLY ORGANIC SOILS PT Peat and other highly organic soils.
SAMPLE SYMBOLS LABORATORY TEST SYMBOLS
- Bulk Sample AL - Atterberg Limits.
CAL - Modified California sampler CON - Consolidation
CK - Undisturbed Chunk sample COR - Corrosivity Tests
MS - Maximum Size of Particle (Resistivity, pH, Chloride, Sulfate)
ST - Shelby Tube OS - Direct Shear
SPT - Standard Penetration Test sampler El - Expansion Index
MAX - Maximum Density
GROUNDWATER SYMBOLS RV - R-Value
- Water level at time of excavation or as indicated i SA - Sieve Analysis
- UC - Unconfined Compression
- Water seepage at time of excavation or as indicated .
Pirgos Way
I nc. Oceanside, California
By: CLF Date: January, 2017
Job Number: 150448P3.5 Figure: I-i
LOG OF BORING B-I
Date Drilled 12/27/2016 Logged by VAU
Equipment: Truck-Mounted CME-45, 6-inch Hollow-Stem Auger Project Manager: TH
Elevation (ft): 378 Depth to Groundwater (ft): Not Encountered
SAMPLES _-
0
0 CL
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4 inches of asphalt concrete.
CL SANDY CLAY, olive green, fine grained, moist, very stiff. /
- i
- . CAL 27
-3
-4
BORING TERMINATED AT 5 FEET.
-6
-7
-8
-9
-10
- 11
-12
- 13
-14 ..
-15
-16
-17
-18
- 19
-20— — — - — — - —
Pirgos Way
Z Oceanside, California I nc.
IN UZ By: CLF Date: January, 2017
Job Number: 150448P3.5. Figure: 1-2
LOG OF BORING B-2
Date Drilled: 12/27/2016 Logged by: VAU
Equipment: Truck-Mounted CME-45, 6-inch Hollow-Stem Auger Project Manager: TH
Elevation (ft): 384 Depth to Groundwater (It): Not Encountered
SAMPLES o (I) --w
z I- w W I
c2 H
>- i H z W y LU o c o ij Of 0 SUMMARY OF SUBSURFACE CONDITIONS > ix
O 0 z 0 Z Df >e. I- D 0
0 SQ 0
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— 4 inches of asphalt concrete! 5 inches of aggregate base. —
CL SANDY CLAY, olive green, fine grained, moist, stiff to very stiff. - i —
- 2 CAL 19 15 18.4 109.9
:
BORING TERMINATED AT 5 FEET.
-6
-7
-8
-9
-10
-11
-12
-13
-14
-15 .
-16
-17
- 18
-19
-20 — -- — ------ — — —
z
IN
Pirgos Way
Inc. Oceanside, California
By: CLF Date: January, 2017 MW SCST,
Job Number: 150448P3.5 Figure: 1-3
LOG OF BORING B-3
Date Drilled 12/27/2016 Logged by VAU
Equipment: Truck-Mounted CME-45, 6-inch Hollow-Stem Auger Project Manager: TH
Elevation (ft): 384 Depth to Groundwater (It): Not Encountered
SAMPLES
Z l- z
a-
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w o 0 SUMMARY OF SUBSURFACE CONDITIONS w
0 0 .2 D Z Q
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—.4 inches of asphalt concrete! 5 inches of aggregate base. -,
CL SANDY CLAY, olive green, fine grained, moist, very stiff.
- i
- 2 CAL 25 20 16.9 110.1
BORING TERMINATED AT 3 FEET.
-4 -
-5 -
-6
-7
-8
-9
-10
-11
-12
-13
-14
-15
-16
-17
-18
-19
-20 1
Pirgos Way
Oceanside, California SCST, I nc.B CLF Date: January, 2017 MHz Job Number: 150448P3.5 Figure: 1-4
____
DEPTH (ft)
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DRY UNIT WEIGHT (pcf) 8
LABORATORY TESTS
N)
—1 a- 1
LOG OF BORING B-5
Date Drilled 12/27/2016 Logged by VAU
Equipment: Truck-Mounted CME-45, 6-inch Hollow-Stem Auger Project Manager: TH
Elevation (ft): 399 Depth to Groundwater(ft): Not Encountered
SAMPLES _. C.) (I) --w
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- 4 inches of asphalt concrete! 5 inches of aggregate base.
CL CLAY, coyote tan, fine grained, moist, hard.
-
- 2 CAL 56 45 143 1104
BORING TERMINATED AT 3 FEET.
-4
-.5
-6
-7
-8
-9
-10
-11
- 12
-13
-14
-15
-16
- 17
-18 . .
-19 . .
-20 -
IN .
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. Pirgos Way
SCST, Inc. Oceanside, California
By: CLF Date: January, 2017 HIN Job Number: 150448P3.5 Figure: - 1-6
APPENDIX II
APPENDIX II
LABORATORY TESTING
Laboratory tests were performed to provide geotechnical parameters for engineering analyses. The
following tests were performed:
CLASSIFICATION: Field classifications were'verified in the laboratory by visual examination.
The final soil classifications are in accordance with the Unified Soil Classification System.
IN SITU MOISTURE AND DENSITY: The in situ moisture content and dry unit weight were
determined on samples collected from the borings. The test results are presented on the
boring logs in Appendix I.
GRAIN SIZE DISTRIBUTION: The grain size distribution was determined on one soil
sample in accordance with ASTM D422. Figure lI-I presents the test results.
ATTERBERG LIMITS: The Atterberg limits were determined on one soil sample in
accordance with ASTM D4318. Figure Il-I presents the test results.
RESISTANCE (R) VALUE: R-values were determined at one representative subgrade
samples in accordance with California Test 301. The results are summarized on Figure 11-4.
U.S. Standard Sieve Sizes
1-W 3/4 3/8 #4 #8#10 #16 #30 #40#50 #100 #200
1000 100 10 1 0.1 0.01
Grain Size in Millimeters
Cobbles Gravel I Sand Silt or Clay
Coarse I Fine I Coarse I Medium I Fine
SAMPLE LOCATION UNIFIED SOIL CLASSIFICATION: I CL
B-i at 1/2 to 5 feet DESCRIPTION SANDY LEAN CLAY
ATTERBERG LIMITS
LIQUID LIMIT 44
PLASTIC LIMIT 19
PLASTICITY INDEX 25
Pirgos Way
Elmo Oceanside California
is flC• By: JD Date: January, 2017
Job Number: 150448P3.5 Figure: Il-i
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