HomeMy WebLinkAboutPD 2019-0007; MADISON STREET APARTMENTS; FINAL COMPACTION 1; 2019-09-06Project No. FC-19-08-145
September 6, 2019
Prophet solutions, Inc.
Mr. George Stoutenburg
814 South El Camino Real
San Clemente, California 92672
SJIS GEOTECHNICAL SOLUTIONS. INC.
Consulting Geotechnical Engineers
5931 Sea Lion Place, Suite 109
Carlsbad, California 92010
760-602-7815
smsgeosol.inc@gmail.com
Final Geotechnical Certification Letter, Madison Street Apartments, 3130 Madison Street,
Carlsbad, California (Project No. PD 2019-0007, Drawing No. 516-SA)
~'11~• Geotechnical Solutions, Inc. has provided construction-phase geotechnical services during
grading, earthworks and construction of the subject project. ~'11~• Geotechnical Solutions, Inc.
services have included geotechnical observations, field compaction testing, and appropriate
laboratory testing during the construction phase.
Based on s.11~• Geotechnical Solutions, Inc. observations and compaction testing, it is our
professional opinion that the geotechnical engineering aspects of the construction have been
completed in compliance with the approved geotechnical report(s), and grading plans. It is also our
professional opinion that the site is suitable for its intended use.
~'ll~'Geotechnical Solutions, Inc., has performed engineering observations and compaction testing
for the project with the degree of skill and care ordinarily exercised by geotechnical engineers
practicing for similar projects and in this localities. No other warranty, expressed or implied is
given regarding the conclusions or professional opinions given in this report. ~'11~• Geotechnical
Solutions, Inc. assumes no responsibility for any work or fill materials placed without our
knowledge and/or inspection and testing.
Distribution: Address ( e-mail)
§Jl§GEOTECHNICAL SOLUTIONS, INC.
Project No. FC-19-08-145
September 5, 2019
Prophet Solutions, Inc.
Mr. Rod Boone
5845 Avenida Encinas, Suite 138
Carlsbad, California 92008
§M§ GEOTECHNICAL SOLUTIONS, INC.
Consulting Geotechnical Engineers & Geologists
5931 Sea Lion Place, Suite 109
Carlsbad, California 92010
760-602-7815
smsgeosol.inc@gmail.com
Report of Geotechnical Engineering Observations And Compaction Testing, Remedial Pad
Grading, Proposed Madison Street Apartments, 3130 Madison Street, Carlsbad, California
(Project No. PD 2019-0007, Drawing No. 516-SA)
Submitted herewith please find the following summary report of our geotechnical engineering
observations and compaction testing completed by our firm in connection with the remedial building
pad grading at the above-referenced property. Approximate limits of the remedial grading works
and compacted fill areas at the property are delineated on the enclosed Approximate Compaction
Tests Location Map (Figure 1), reproduced from the project Grading Plans (Sheet 2 of 4).
Overall, associated operations at the project site chiefly consisted of demolition works of pre-
existing structures and site improvements, and remedial building pad grading for reestablishing final
design grades. Earthworks and remedial building pad grading operations within the designated
limits were performed under engineering observations and compaction testing services provided by
this office from August 21 , 2019 through August 29, 2019.
I. REFERENCES
The following pertinent reports and documents were used as a basis of our engineering observations
and compaction testing services.
1. "Grading Plans For Madison Street Apartments (4-Unit Apartment Complex)," Sheet 2 of
4, Prepared by bHA, Inc., dated July 22, 2019.
2. "Geotechnical Grading Plan Review And Response to Third-Party Review Comments,
Proposed Madison Street Apartments, 3130 Madison Street, Carlsbad, California 92008
(GR2019-0004, PD2019-0007, DWG516-5A)," prepared by SMSGeotechnical Solutions,
Inc., Project No. GI-18-03-119, dated April 26, 2019.
Report of Geotechnical Engineering Observations And Compaction Testing Page 2
Proposed Madison Street Apartments, Carlsbad September 5, 2019
3. "Geotechnical Foundation Plan Review, Proposed Madison Street Apartments, 3130
Madison Street, Carlsbad, California," prepared by SMS Geotechnical Solutions, Inc.,
Project No. GI-18-03-119, dated March 11, 2019.
4. "Geotechnical Investigation, Proposed Madison Street Apartments, 3130 Madison Street,
Carlsbad, California," prepared by SMSGeotechnical Solutions, Inc., Project No. GI-18-03-
119, dated May 1, 2018.
II. GEOTECHNICAL CONDITIONS
Geotechnical conditions at the project site were found to be substantially the same as described in
the referenced Geotechnical Investigation report (Referenced 4). All demolition works and site
grubbing and clearing were completed prior to our first site on August 21, 2019.
In general, the project property consists of a relatively level pad underlain by a thin section ofloose
and compressible undifferentiated fill/topsoil deposits mantle, on the order of 12 inches, atop
Quaternary age Old Paralic Deposits and Santiago Formation (buried). The upper near surface
exposures of the underlying Old Paralic Deposits were found in a weathered loose to medium dense
conditions becoming dense and tight with depth.
III. LABORATORY TESTING
Pertaining maximum dry densities and optimum moisture contents (ASTM D1557) for the onsite
representative soil types were obtained from the project Geotechnical Investigation report, dated
May 1, 2018 (Reference 4). Pertinent test results are summarized on the attached Compaction Test
Results, Figure 2.
IV. GROUND PREPARATION AND REMEDIAL GRADING OPERATIONS
Prior to the remedial grading operations, any surface vegetation, roots and tree stumps, old
foundation, surface improvements and buried structures were removed and cleared for the project
areas, as appropriate. Surficial loose and compressible soil mantle and upper weathered section of
the underlying Old Paralic Deposits within the Approximate Limits of Remedial Grading areas (see
attached Approximate Compaction Tests Location Map, Figure 1) encompassing the building
envelop plus a minimum of3 feet outside the perimeter were then stripped and removed. Removals
were extended to a minimum depth of 4 feet below rough finish pad grade, or 2 feet below the
bottom of deepest footing, whichever is more, exposing the underlying dense natural Old Paralic
Deposits throughout. All exposed bottom of removals and over-excavations were visually
examined, and probed to assure competent Old Paralic Deposits exposures suitable for receiving
new fills.
Report of Geotechnical Engineering Observations And Compaction Testing Page 3
Proposed Madison Street Apartments, Carlsbad September 5, 2019
Earth deposits generated from the onsite removals and over-excavations were reused as new fills
and backfills and predominantly consisted of sandy to silty sand (SM/SP) deposits, ranging to very
low expansion potential ( expansion index less than 20, based on ASTM D4829 classification). Site
new fills and backfills were properly processed, moisture conditioned to near optimum moisture
levels, manufactured into a uniform mixture, placed in thin ( approximately 8 inches thick) horizontal
lifts and mechanically compacted with a Tracked Loader (CAT 963B), a Bobcat (259D) and a water
truck to at least 95 percent of the corresponding laboratory maximum density per ASTM D1557, as
required and where specified in the project soils report. Bottom of stripping, removals and over-
excavations were additionally ripped, processed and recompacted to a minimum depth of 6 inches
as a part of initial fill lift placement. Water was provided with a water truck.
Engineering observation and compaction testing of the remedial pad grading operations carried out
within the designated areas of the property were provided by this office from August 21 through
August 29, 2019. Approximate limits of the remedial pad grading works, and field compaction test
locations, as roughly established in the field by a hand level and pacing/tap measure form staking
provided by others, or relative to identifiable features located at the site and noted on the project
plans are shown on the enclosed Approximate Compaction Tests Location Map, Figure 1.
Field density tests establishing both the in-place dry densities and moisture contents were performed
in accordance with the ASTM D6938 (Nuclear Gauge) test methods, as the fill placement
progressed. Test locations were placed to provide the best possible coverage. Areas of low
compaction, as indicated by the field density tests, were brought to the attention of the project
contractor. These areas were reworked by the contractor and retested. Field compaction test results
including pertinent bottom of over-excavation and test elevations are tabulated on the enclosed
Compaction Test Results, Figure 2. Engineering observations and compaction test results indicated
that the new fills and backfills within the approved areas (see Approximate Limits of Remedial
Grading on the enclosed Approximate Compaction Tests Location Map, Figure 1) were properly
placed and compacted to at least 95 percent of the corresponding maximum dry density at the tested
locations.
Site preparations and remedial pad grading were conducted in substantial conformance with Chapter
18 (Soils and Foundations) and Appendix "J" (Grading) of the 2016 California Building Code
(CBC), applicable codes, the Grading Ordinances for the city of Carlsbad and current engineering
standards, as appropriate. All observations and testing were conducted by a representative from this
office under direct supervision of the project geotechnical engineering.
V. CONCLUSIONS AND RECOMMENDATIONS
In our opinion, all site excavations and remedial building pad grading operations, fill/backfill
placement and compaction procedures were completed in substantial conformance with the project
soils reports (see References), approved plans, city of Carlsbad grading ordinances, applicable codes
and current engineering standards, and are acceptable for their intended use.
Report of Geotechnical Engineering Observations And Compaction Testing Page 4
Proposed Madison Street Apartments, Carlsbad September 5, 2019
All conclusions and recommendations including soil design parameters, geotechnical
foundation/slab designs and improvement sections provided in the referenced reports (see
References) stay unchanged, as specified therein and should be considered in the final designs and
implemented during the construction phase, where applicable and as appropriate.
VI. ADDITIONAL GEOTECHNICAL OBSERVATIONS AND TESTING
This office should be notified before any of the following operations begin in order to schedule
appropriate testing and/or field observations for confirmation and approval of the completed work:
1. Foundations and Utility Trenches: Engineering observations or testing will also be
required for the following work prior to foundation and slab concrete pours:
a) Observe the plumbing and utility trenches after the pipes are laid and prior to backfilling.
Backfill soils within trenches 12 inches or more in depth shall be compacted by
mechanical means to a minimum of 95 percent of the corresponding maximum dry
density, unless otherwise specified. Jetting or flooding of the backfill is not allowed.
Care should be taken not to crush the utilities or pipes during the compaction of the
trench backfill.
b) Test the plumbing trenches beneath the floor slabs for mm1mum compaction
requirements prior to sand and moisture barrier placement.
c) Confirm minimum foundation embedment requirements and observe bottom of the
footing trenches for proper compaction levels, including design foundation widths and
embedment depths. Building foundations adjacent to the PICP pavements should be
extended a minimum of24 inches below the bottom of the paver section (see referenced
plans and reports).
d) Confirm footing reinforcement size and placement, slab thickness and reinforcing, sand
thickness and moisture barrier placement.
2. Fine Grading and Improvements:
a) Observe placement and perform compaction testing for fills placed under any conditions
12 inches or more in depth, to include:
• Pad perimeter contour grading for establishing positive (minimum 5 percent)
drainage away from the building.
• Utility and storm trench backfills.
• Spreading or placement of soil obtained from any excavation (spoils from footings,
underground utilities, etc.).
Report of Geotechnical Engineering Observations And Compaction Testing Page 5
Proposed Madison Street Apartments, Carlsbad September 5, 2019
b) Any operation not included herein which requires our testing, observation, or
conformation for submittal to the appropriate agencies.
VII. DRAINAGE
The owner/developer is responsible for insuring adequate measures are taken to properly finish
grade the building pad after the structures and other improvements are in-place so that the drainage
waters from the graded pad and improved sites as well as adjacent properties are directed away from
the new building foundations. Stormwater and surface run off water should not be allowed to
impact or saturate natural and graded ground surfaces, fills and backfills, foundation bearing and
subgrade soils. Only the amount of water to sustain vegetation should be provided.
A minimum of 5 percent gradient should be maintained away from all foundations, unless otherwise
noted. Roof gutters and downspouts should be installed and all discharge from downspouts should
be led away from the foundations and slab to a suitable location. Install area drains in the yards for
collection and disposal of surface water.
Planter areas adjacent to foundations should not to allowed. Site retaining walls should be provided
a well-constructed back drainage. Planting large trees behind site retaining walls and near the
building foundations should be avoided.
It should be noted that shallow groundwater conditions may develop in areas where no such
conditions existed prior to site development. This can be contributed to by substantial increases of
surface water infiltration resulting from landscape irrigation which was not present prior to the site
redevelopment. It is almost impossible to absolutely prevent the possibility of shallow water
conditions developed from excessive landscape irrigation over the entire site, onsite drainage
facilities and site flooding due to a major storm event. Street runoff flow shall be diverted from
entering the property. We also recommend that shallow water conditions, if developed, be
immediately remedied by implementing appropriate measure, which may include the installation
of sub-drain( s) consisting of a 4-inch diameter perforated pipe (SD R 3 5) surrounded in ¾-inch rocks
all wrapped in filter fabric.
The property owner( s) should be made aware that altering drainage patterns, landscaping, the
addition of patios, planters, and other improvements, as well as over-irrigation and variations in
seasonal rainfall, all affect subsurface moisture conditions, which in tum affect structural and overall
building pad performance.
Report of Geotechnical Engineering Observations And Compaction Testing Page 6
Proposed Madison Street Apartments, Carlsbad September 5, 2019
Project development includes the installation ofPervious (Permeable) Interlocking Concrete Pavers
(PICP) with an adequate storage capacity for retaining the majority of the onsite storm waters, as part
of the storm water BMP designs (see project plans). The PICP pavers requires periodic monitoring
and some maintenance that is the responsibility of the current and future property owner(s), in order
prevent any potential for failures or impacts on the nearby structures and improvements. Prolonged
excessive accumulation of water collected in the storage zone ofPICP, if it is allowed to occur, can
have a major adverse impact on the stability of on and off site adjacent structures and improvements,
and shall not be permitted. To reduce potential problems associated with project PICP driveway,
the following recommendations are presented:
1. Establish and carry out a periodic maintenance/monitoring of the PICP pavements and
associated drainage facilities by a qualified personnel. For this purpose, a regular
maintenance, upkeep, and repair program should be considered and implemented, as
necessary and appropriate. As a minimum, monitoring, and maintenance if needed, on a
semi-annual basis (before and after the rainy season) and immediately after a major storm
event should be considered.
2. Provide landscaping consisting of drought resistant plants and monitor the amount of
irrigation that is suggested. Irrigation should be limited to the amount of water necessary
to sustain plant life. A landscape architect may be consulted in this regard.
3. Should any saturated surfaces or seepage conditions occur, the project design consultant
should be immediately notified. Additional recommendations and mitigation measures may
be necessary and should be provided at that time which may be expected to include the
installation of a subsurface or pavement underdrain(s) consisting of a 4-inch diameter (Sch
40) perforated pipe with a filter sock to allow relief from excessive accumulation of
collected water in the PICP pavement storage zone.
VIII. LIMITATIONS
Our description of the remedial grading operations, as well as observations and testing services
described herein, are limited to the work performed by this office during the period from August 21
through August 29, 2019. The recommendations provided herein have been based on our field
observations and testing, as noted. No representations are made as to the quality or extent of
materials not observed and tested.
All geotechnical information, test location and mapping on the enclosed Approximate Compaction
Tests Location Map are based on rough field measurements for the purpose of geotechnical
presentations only.
Report of Geotechnical Engineering Observations And Compaction Testing Page 7
Proposed Madison Street Apartments, Carlsbad September 5, 2019
This report is issued with the understanding that the owner or his representative is responsible for
ensuring that the information and recommendations are provided to the project architect/structural
engineer and respective contractors so that they can be incorporated into the plans and implemented
at the site. Necessary steps shall be taken to ensure that the project general contractor and
subcontractors carry out such recommendations during construction.
The project geotechnical engineer should also be provided the opportunity to field verify the
foundation trenching, and foundations/slab steel reinforcement prior to placing concrete. If the
project geotechnical engineer is not provided the opportunity of making these reviews and
observations, he can assume no responsibility for misinterpretation of his recommendations.
This report should be considered valid for permit purposes for a period of six months and is subject
to review by our firm following that time. IF ANY CHANGES ARE MADE IN THE FINAL PAD
SIZE,LINESANDGRADES,BUILDINGLOCATION,ELEVATIONS,ETC.,PRIOR TO THE
CONSTRUCTION, THIS REPORT WILL BECOME INVALID AND FURTHER
ENGINEERING AND RECOMMENDATIONS WILL BECOME NECESSARY.
If you have any questions or need clarification, please contact this office at your convenience.
Reference to our Project No. FC-19-08-145 will help to expedite our response to your inquiries.
We appreciate this opportunity to be of service to you.
SM§ Geotechnical Solutions, Inc.
Attachments: Approximate Compaction Tests Location Map, Figure 1
Compaction Test Results, Figure 2
Distribution: Addressee (3, e-mail)
SM§ GEOTECHNICAL SOLUTIONS, INC.
ATTACHMENTS
PROJECT NO:
PROJECT NAME:
PROJECT LOCATION:
COMPACTION TEST RESULTS
FC-19-08-145
Madison Street Apartments
3130 Madison Street, Carlsbad
LABORATORY MAXIMUM DRY DENSITY/ OPTIMUM MOISTURE CONTENT TEST RESULTS (ASTM D1557):
Soil Type (1):
Maximum Dry Density:
Dark to Tan-Orange Brown Silty Sand
130.0 pcf
Optimum Moisture: 9%
FIELD COMPACTION TEST RESULTS (ASTM D6938):
Test Approximate Approximate Field
Date No. Test Test Moisture
Location Elevation (ft, MSL) (%)
08/23/2019 I Well Area, Westerly 46'± 10.1
08/23/2019 2 Pad Area, Westerly 48'± 7.8
08/23/2019 3 Pad Area, Westerly 48'± 9.5
08/26/2019 4 Pad Area, Central 49.8'± 7.9
08/26/2019 5 Pad Area, Central 49.8'± 8.5
08/26/2019 6 Pad Area, Central 49.8'± 9.6
08/27/2019 7 Pad Area, Easterly 50.9'± 9.8
08/27/2019 8 Pad Area, Easterly 50.9'± 9.4
08/27/2019 9 Pad Area, Easterly 50.9'± 8.7
08/29/2019 lO Pad Area Rough Finish Grade 8.8
08/29/2019 11 Pad Area Rough Finish Grade 8.9
08/29/2019 12 Pad Area Rough Finish Grade 7.8
08/29/2019 13 Pad Area Rough Finish Grade 8.2
08/29/2019 14 Pad Area Rough Finish Grade 9.1
08/29/2019 15 Pad Area Rou_gh Finish Grade IO.I
Field Soil Dry Type Density(pcf)
123.5 I
124.9 I
123.8 I
124.0 I
124.5 I
123.5 I
I 18.6 I
124.0 I
123.5 I
124.2 I
123.7 I
125.2 I
123.5 I
125.3 I
124.4 I
SMSGeotechnical Solutions, Inc.
Max. Relative
Dry Compaction Comments
Density(pcf) (%)
130.0 95 Bottom of Over-Ex. @46'±
130.0 96
130.0 92
130.0 95 Bottom of Over-Ex. @47.5'±
130.0 96
130.0 95
130.0 91 Bottom of Over-Ex. @ 48.5'± / Failure
130.0 95 Retest # 7
130.0 95
130.0 96
130.0 95
130.0 96
130.0 95
130.0 96
130.0 96
Figure 2