HomeMy WebLinkAboutCD 13-18; FLORAL TRADE CENTER; PAVEMENT STUDY; 2014-01-24RECORD COPY
Initial Date.
PAVEMENT STUDY
5600 AVENIDA ENCINAS
CARLSBAD, CALIFORNIA
PREPARED FOR
THE MART - CARLSBAD LLC
DEL MAR, CALIFORNIA
Cs'
JANUARY 24, 2014
PROJECT NO. G1076-32-02
GEOCON
INCORPORATED
GEOTECHNICAL a ENVIRONMENTAL • MATERIALS
Project No. G1076-32-02
January 24, 2014
The Mart - Carlsbad LLC
221 Fifteenth Street
Del Mar, California 92014
Attention: Mr. Peter Spencer
Subject: PAVEMENT STUDY
5600 AVENTDA ENCINAS
CARLSBAD, CALIFORNIA
Dear Mr. Spencer:
In accordance with your authorization, we are submitting the results of our pavement study for the
parking lot surrounding the existing building at the subject site. The accompanying report presents
the findings and conclusions from our study.
If you have any questions regarding this study, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
14~'4mv v My'e'rs
RCE 63773 /7
TEM:DBE:tmj :dmc
(4) Addressee
(e-mail) K+S Engineering, Inc.
Attention: Mr. Manuel Salcido
(e-mail) Smith Consulting Architects
Attention: Mr. Scott Cairns
David B. Evans
CEG 1860
EVANS
CEFMRMi -4
6960 Flanders Drive S Son Diego, CaliFornia 92121-2974 a Telephone 858.55&6900 S Fax 88.5584159
TABLE OF CONTENTS
PURPOSE AND SCOPE ..................................................... . ................................................................. 1
EXISTING PAVEMENT CONDITION ................................................................................................ I
CONCLUSIONS AND RECOMMENDATIONS ................................................................................ 2
3.1 General ........................................................................................................................................ 2
3.2 Recommendations for Existing Parking Lot Areas ..................................................................... 2
3.3 Recommended Pavement Section for New Parking Lot Areas ................................................... 3
3.4 Drainage and Maintenance..........................................................................................................4
LIMITATIONS AND UNIFORMITY OF CONDITIONS
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Site Plan
APPENDIX A
FIELD INVESTIGATION
Table A-I, Summary of Asphalt Concrete Pavement Coring Test Results
APPENDIX B
LABORATORY TESTING
Table B-I, Summary of Laboratory Resistance Value Test Results
5
PAVEMENT STUDY
1. PURPOSE AND SCOPE
This report presents the results of a pavement study for the parking lot surrounding the existing
building at the subject site in the City of Carlsbad, California (see Vicinity Map, Figure 1). The
purpose of the study was to measure the thickness of the existing pavement section, evaluate the
underlying soil support characteristics, and to provide recommendations relative to the adequacy of
the section to be reused following planned building modifications.
The scope of our study included a site reconnaissance, field investigation, laboratory testing,
engineering analyses and preparation of this report. The field investigation was performed on
December 27, 2013, and consisted of coring through the existing pavement at 5 locations and
obtaining samples of the subgrade soils. A table presenting the existing thickness of asphalt concrete
and aggregate base along with the subgrade soil type and other details of the field investigation are
presented in Appendix A. The location of the pavement cores are presented on the Site Plan (Figure
2). A discussion pertaining to the laboratory testing and results is presented in Appendix B.
The conclusions and recommendations presented herein are based on analysis of the data obtained
from the field investigation, laboratory tests, engineering analyses, and our experience with similar
soil conditions.
2. EXISTING PAVEMENT CONDITION
The existing parking lot pavement was examined and cores were drilled through the asphalt at five
locations surrounding the existing building. Table 2 presents the existing pavement sections.
TABLE 2
EXISTING PAVEMENT SECTION
Roadway Core No.
Asphalt
Concrete Th1CkfleSS Aggregate Base
(inches) Thickness (inches)
Parking Lot (NE Corner) it-i 2.75 5
Parking Lot (NW Corner) R-2 2.875 3.5
Parking Lot (Rear Loading Dock Area) R-3 4.5 0
Parking Lot (SW Corner) R4 2.75 4
Parking Lot (SE Corner) it-S 3.25 6
A
Project No. G1076-32-02 - 1- January 24, 2014
3. CONCLUSIONS AND RECOMMENDATIONS
3.1 General
3.1.1 Based on observations during the field exploration, the existing pavement sections
generally consist of approximately 3-inches of asphalt concrete over approximately 4 to
6 inches of aggregate base supported on subgrade soils.
3.1.2 Laboratory R-Value testing was performed on five samples of the subgrade soils obtained
from the field investigation. The R-values ranged from 16 to 60, with an average R-value
of approximately 49. The laboratory test results are presented in Appendix B.
3.1.3 The existing parking lot is currently being used to support a warehouse distribution facility.
Although some signs of minor distress were observed to the parking lot surface, the overall
parking lot has performed adequately to support the heavy truck traffic associated with the
existing usage.
3.1.4 A 1-inch asphalt concrete overlay is proposed to the existing structural section. We
understand that it is desired to utilize the existing parking lot structural section and 1-inch
overlay for the new development, where possible.
3.1.5 Based on the above, it is our opinion that the existing parking lot structural section, plus 1-
inch overlay, will perform adequately and may be used for light to heavy truck traffic and
fire truck loading.
3.2 Recommendations for Existing Parking Lot Areas
3.2.1 Cracks greater than approximately 1/8-inch wide should be filled with a rubberized asphalt
emulsion in accordance with the manufacturer's guidelines. The cracks should be cleaned
and/or pressure washed prior to installing the sealant.
3.2.2 Any isolated areas exhibiting pavement distress due to subgrade failure, i.e. potholes,
depressions, etc., should be remediated prior to placing the 1-inch overlay. The subgrade
soil should be exposed and evaluated. The subgrade soil should be relatively firm and
unyielding prior to placing aggregate base. The subgrade should be compacted to at least
95 percent of the applicable maximum dry density at or slightly above optimum moisture
content.
Project No. 01076-32-02 -2- January 24, 2014
3.3 Recommended Pavement Section for New Parking Lot Areas
3.3.1 Based on a design R.-Value of 25 and Traffic Index (Ti) of 5.0, we recommend a structural
section for the parking lot stalls, drive aisles and fire lanes consisting of 4-inches asphalt
concrete over 4-inches of Class 2 aggregate base. In accordance with City of Carlsbad
guidelines, all routes leading to trash enclosures shall be designed with at least 4-inches of
asphalt concrete over 6-inches of Class 2 aggregate base. In addition, the minimum asphalt
concrete thickness is 44nches for all pavement areas.
3.3.2 Asphalt concrete should conform to Section 203-6 of the Standard Specifications for
Public Works Construction (Greenbook). Class 2 aggregate base materials should conform
to Section 26-1.02B of the Standard Specifications of the State of California, Department
of Transportation (Caltrans) or approved equivalent. Additionally, all materials should
conform to City of Carlsbad-specifications.
3.3.3 Prior to placing base materials, the subgrade should be scarified, moisture conditioned and
recompacted to a minimum of 95 percent relative compaction. The depth of compaction
should be at least 12 inches. The base material and asphalt concrete pavement should be
compacted to at least 95 percent relative compaction.
3.3.4 A rigid Portland Cement concrete (PCC) pavement section should be placed in driveway
entrance aprons, trash bin loading/storage areas and loading dock areas. The concrete pad
for trash truck areas should be large enough such that the truck wheels will be positioned
on the concrete during loading.
3.3.5 Based on City of Carlsbad requirements, the minimum PCC pavement thickness is 7-1/2
inches.
3.3.6 The PCC pavement should be placed over subgrade soil that is compacted to a dry density
of at least 95 percent of the laboratory maximum dry density near to slightly above
optimum moisture content. This pavement section is based on a minimum concrete
compressive strength of approximately 3,250 psi (pounds per square inch).
3.3.7 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, at the slab edge and
taper back to the recommended slab thickness 3 feet behind the face of the slab (e.g., a
7Y2-inch-thick slab would have a 9-inch-thick edge). Reinforcing steel will not be necessary
within the concrete for geotechnical purposes.
Project No. 01076-32-02 -3- January 24, 2014
3.3.8 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 not exceed 30 times the slab thickness with a maximum
spacing of 15 feet and should be sealed with an appropriate sealant to prevent the migration
of water through the control joint to the subgrade materials. The depth of the crack-control
joints should be determined by the referenced ACI report.
3.3.9 The performance of 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. 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. If planter islands are planned, the perimeter curb should extend at least 6 inches
below the level of the base materials.
3.4 Drainage and Maintenance
3.4.1 Establishing proper drainage is critical to reduce the potential for differential soil
movement, erosion and subsurface seepage. Positive measures should be taken to properly
finish grade the improvements, so that drainage water from the building pads and adjacent
properties is directed to controlled drainage devices. Under no circumstances should water
be allowed to pond adjacent to improvements. Experience has shown that even with these
provisions, a shallow groundwater or subsurface condition can develop in areas where no
such condition existed prior to site development. This is particularly true where a
substantial increase in surface water infiltration results from an increase in landscape
irrigation.
Project No. (31076-32-02 -4- January 24, 2014
LIMITATIONS AND UNIFORMITY OF CONDITIONS
The firm that performed the geotechnical investigation for the project should be retained to
provide testing and observation services during construction to provide continuity of
geotechnical interpretation and to check that the recommendations presented for geotechnical
aspects of site development are incorporated during site grading, construction of
improvements, and excavation of foundations. If another geotechnical firm is selected to
perform the testing and observation services during construction operations, that finn should
prepare a letter indicating their intent to assume the responsibilities of project geotechnical
engineer of record. A copy of the letter should be provided to the regulatory agency for their
records. In addition, that firm should provide revised recommendations concerning the
geotechnical aspects of the proposed development, or a written acknowledgement of their
concurrence with the recommendations presented in our report. They should also perform
additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record.
The recommendations of this report pertain only to the site investigated and are based upon
the assumption that the soil conditions do not deviate from those disclosed in the
investigation. If any variations or undesirable conditions are encountered during construction,
or if the proposed construction will differ from that anticipated herein, Geocon Incorporated
should be notified so that supplemental recommendations can be given. The evaluation or
identification of the potential presence of hazardous or corrosive materials was not part of the
scope of services provided by Geocon Incorporated.
This report is issued with the understanding that it is the responsibility of the owner or his
representative to ensure that the information and recommendations contained herein are
brought to the attention of the architect and engineer for the project and incorporated into the
plans, and the necessary steps are taken to see that the contractor and subcontractors carry Out
such recommendations in the field.
The findings of this report are valid as of the present. date. However, changes in the
conditions of a property can occur with the passage of time, whether they be due to natural
processes or the works of man on this or adjacent properties. In addition, changes in
applicable or appropriate standards may occur, whether they result from legislation or the
broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly
or partially by changes outside our control. Therefore, this report is subject to review and
should not be relied upon after a period of three years.
Project No. 01076-32-02 .. January 24, 2014
FIG.1
APPENDIX
APPENDIX A
FIELD INVESTIGATION
The field exploration was performed on December 27, 2013, and consisted of coring the asphalt
concrete pavement section at 5 locations. Hand augers were used to excavate through the core hole
and into the subgrade soil. Eight-inch-diameter cores were drilled to aid in obtaining a significant
amount of subgrade soils for laboratory testing. The approximate locations of the cores are shown on
Figure 2.
The soils encountered beneath the asphalt were visually examined and classified in general
conformance with the American Society for Testing and Materials (ASTM) Practice for Description
and Identification of Soils (Visual-Manual Procedure D2844).
TABLE A-I
SUMMARY OF ASPHALT CONCRETE PAVEMENT CORING TEST RESULTS
Coring No. Asphalt Concrete
Thickness (inches)
Aggregate Base
Thickness (inches) Subgrade Soil
R-1 2.75 5 SP-SM
R-2 2.875 3.5 SM
R.3 4.5 0 SC
R4 2.75 4 SP-SM
R-5 3.25 6 SM
Project No. G1076-32-02 January 24, 2014
FA,A kl W N FAR
APPENDIX B
LABORATORY TESTING
Laboratory tests were performed in accordance with generally accepted test methods of the American
Society for Testing and Materials (ASTM) or other suggested procedures. Selected soil samples were
analyzed for Resistance Value (R-value) characteristics. The results of the laboratory tests are
presented in Table B-i.
TABLE B-I
SUMMARY OF LABORATORY RESISTANCE VALUE TEST RESULTS
Sample No. Soil Description Resistance Value
R-1 Dark brown SAND with Silt 58
R-2 Grayish-brown Silty, fine to coarse SAND 64
R-3 Brown Clayey SAND 16
R4 Dark brown SAND with Silt 45
R-5 Reddish-brown Silty, fine to medium SAND 60
Project No. 01076-32.02 January 24, 2014
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