HomeMy WebLinkAboutSDP 00-06C; DAYBREAK COMMUNITY CHURCH PHASE IV; FINAL SOILS REPORT; 2016-10-31Project No. FC-4-15-13
October 31, 2016
SMS GEOTECHNICAL SOLUTIONS, INC.
Consulting Geotechnical Engineers & Geologists
5931 Sea Lion Place, Suite 109
Carlsbad, California 92010
Office: 760-602-7815
smsgeosol.inc@gmail.com
Daybreak Community Church of Carlsbad North County
Attention: Pastor Gary Webb
6515 Ambrosia Lane
Carlsbad, California 92011
Final Report Of Geotechnical Engineering Observations And Compaction Testing, Phase IV
Worship Center Building Pad And Retaining Wall Backfill, Daybreak Community Church,
6515 Ambrosia Lane, Carlsbad
I. INTRODUCTION
Submitted herewith please find the following summary of geotechnical engineering observations and
compaction testing recently completed by our firm in connection with the project Phase IV worship
center building final phase retaining wall backfill and upper building pad development at the above-
referenced church property. Wall backfill and grading limits (inclusive of initial phase lower pad
partial development) at the property are delineated on the enclosed Approximate Compaction Tests
Location Map reproduced from the project grading plan.
The project consisted of pad development completed in two phases. Partial pad development was
carried out for the lower building areas in the initial phase grading operations. At the completion
of the initial phase partial pad development, a report of geotechnical engineering observations and
compaction testing, dated June 20, 2016, was prepared and issued by this office (see References
below). This report summarizes retaining wall backfill and upper pad rough grading operations and
compaction test results performed during second (final) phase development, supplemented with test
results complied during the first phase partial development oflower building pad areas. First phase
compaction test locations are also shown on the attached Approximate Compaction Tests Location
Map.
Overall, upper elevated portions of the building pad development consisted of backfilling the
perimeter retaining walls and remedial grading work to provide uniform bearing and subgrade soil
conditions throughout. Backfills behind the western building retaining wall was compacted to higher
Final Report Of Geotechnical Engineering Observations and Compaction
Testing, Daybreak Community Church, 6515 Ambrosia Lane, Carlsbad
Page2
Oct. 31, 2016
(minimum 93%) compaction levels in order to create a more uniform bearing soil condition
throughout the building areas. Elsewhere, remedial pad grading chiefly consisted of stripping and
recompaction of the native Terrace Deposits (or existing well-compacted fills, where they were
encountered) a minimum of 12 inches below the bottom of finish subgrade surfaces. Upper level
building foundations were stepped down and deepened to near the bottom of the transition wall
foundation level, with the elevating and stepping up foundations supported on minimum 93%
compacted fills/backfills or dense native Terrace Deposits, as required by the project soils report(s).
Final phase perimeter retaining wall backfill and upper building pad development and remedial,
sub grade preparations, compaction and testing were mostly carried out periodically from August 23
to September 28, 2016 under engineering observations and testing services provided by this office.
Intermittent trench testing was also carried between the initial and final phase pad development as
requested.
II. REFERENCES
The following plans and documents were used by this office in support of our field work and
preparation of this report:
1. "Report of Geotechnical Engineering Observations and Compaction Testing, Phase IV
Worship Center Building Pad, Daybreak Community Church, 6515 Ambrosia Lane,
Carlsbad," prepared by SMS Geotechnical Solutions, Inc., Project No. FC-4-15-13, dated
June 20, 2016.
2. "Report of Geo technical Engineering Observations and Compaction Testing, Phase IV Upper
Pad Parking and Drainage Improvements, Daybreak Community Church, 6515 Ambrosia
Lane, Carlsbad," prepared by SMS Geotechnical Solutions, Inc., Project No. FC-4-15-13,
dated August 31, 2015.
3. "R-Value Test Results and Pavement Structural Section Design Conformation, Phase IV
Upper Pad Parking Improvements, Daybreak Community Church, 6515 Ambrosia Lane,
Carlsbad," prepared by SMS Geotechnical Solutions, Inc., Project No. FC-4-15-13, dated
June 1, 2015.
4. "Final Grading Plan and Bioswales/Bioretention BMP Design Review, Daybreak
Community Church, 6515 Ambrosia Lane, Carlsbad," prepared by SMS Geotechnical
Solutions, Inc., Project No. GI-7-14-7, dated February 26, 2015.
5. "Phase IV Grading Plan Review and Recommendations, Daybreak Community Church, 6515
Ambrosia Lane, Carlsbad, California,"prepared by SMSGeotechnical Solutions, Inc., Project
No. GI-7-14-7, dated November 24, 2014.
Final Report Of Geotechnical Engineering Observations and Compaction
Testing, Daybreak Community Church, 6515 Ambrosia Lane, Carlsbad
Page3
Oct. 31, 2016
6. "Geotechnical Update Letter and Additional Field Testing for the Proposed Bioswales, Phase
N Development, Daybreak Community Church, 6515 Ambrosia Lane, Carlsbad, California,"
prepared by SMS Geotechnical Solutions, Inc., Project No. GI-7-14-7, dated August 8, 2014.
7. Final Report of Geotechnical Engineering Observations and Compaction Testing, Remedial
Pad Grading, Daybreak Community Church, Phase III, Building C, 6515 Ambrosia Lane,
Carlsbad, California," prepared by Vinje & Middleton Engineering, Inc., Job #12-252-F,
dated August 15; 2013.
8. "Geotechnical Update Report, Proposed Phase III and Phase N, Daybreak Community
Church, 6515 Ambrosia Lane, Carlsbad, California," prepared by Vinje & Middleton
Engineering, Inc., Job #11-259-P, dated November30, 2011.
9. "Geotechnical Final Report for the Grading Operations and Field Documentation Conducted
During Grading and Construction of Daybreak Community Church Phase II, City of Carlsbad
Drawing #3 92-6B," prepared by Vinj e & Middleton Engineering, Inc., Job #09-159-F, report
dated November 30, 2010.
10. "Update R-Value Test Result, Pavement/Base Thickness and Sub/Basegrade
Recommendations for On-Site hnprovements," prepared by Vinje & Middleton Engineering,
Inc., Job #09-159-F, letter dated October 28, 2010.
11. "As-Graded Compaction Report and Foundation Recommendations for Proposed 2-Story
Building Addition," prepared by Vinj e & Middleton Engineering, Inc., Job #09-159-F, report
dated June 18, 2010.
12. "Update of Compaction Report, Proposed 2-Story Building Addition," prepared by Vinje &
Middleton Engineering, Inc., Job #09-159-F, report dated April 8, 2010.
13. "Grading and Foundation Plan Review, Proposed 2-Story Building Addition," prepared by
Vinje & Middleton Engineering, Inc., Job #09-159-F, letter dated January 12, 2010.
14. Precise Grading Plan, Sheet 4 of 22, prepared by Hofman Planning & Engineering, dated
December 08 2015. Pertinent portions of the grading plan are reproduced herein as
Compaction Tests Location Map.
III. GEOTECHNICAL CONDITIONS AND FILL/BACKFILL OPERATIONS
Geotechnical conditions at the project building pad areas substantially remained unchanged from
those described in the referenced reports. Upper building pad was chiefly established by backfilling
of the westerly transition retaining wall benched into wall backcut exposing dense sandstone
formational units, and remedial grading of the remainder pad grade surfaces.
Final Report Of Geotechnical Engineering Observations and Compaction
Testing, Daybreak Community Church, 6515 Ambrosia Lane, Carlsbad
Page4
Oct. 31, 2016
Prior to the backfilling and remedial grading operations, all vegetation, roots and other surface
improvements were removed and cleared for the site as appropriate. Site excavations and wall
backcut exposures developed undisturbed natural dense formational units (or existing well-
compacted fills, where they were encountered). Exposed backcutwas subsequently benched to allow
horizontal lift backfill placement and compaction. The bottoms of over-excavations were also
ripped, reworked, moisture conditioned to near optimum moisture levels and recompacted within
the upper 6 inches.
Site fills and backfills were adequately processed, moisture conditioned to near or slightly above the
optimum moisture levels, as appropriate, manufactured into a uniform mixture, placed in thin
( approximately 8 inches thick) horizontal lifts and mechanically compacted with heavy construction
equipments consisting of a hand-held whacker, walk-behind sheepsfoot vibratory roller (Wacker
Neuson RTSC2 remote control trench roller), and a loader (Komatsu WA500) to at least 90% of the
corresponding laboratory maximum density per ASTM D-15 57. Water was added with a water hose.
Remedial subgrade preparation and recompaction were extended a minimum of 3 horizontal feet
outside the building envelop.
Earth deposits exposed at finish pad grade surfaces predominantly consisted of sandy to silty sand
(SM/SP) deposits with very low to low expansion potential ( expansion index less than 50) based on
visual observations.
Periodic engineering observation of the wall backfill and remedial subgrade operations and
compaction testing within the limits of the project grading were provided by this office from August
23 to September 28, 2016. Approximate limits of wall backfill and remedial sub grade grading works
and test locations, as established by a hand level and pacing/tape measure relative to identifiable
features located at the site and noted on the grading plan, are shown on the enclosed Compacted
Tests Location Map. Pertaining maximum dry density and optimum moisture content tests (ASTM
D1557) were obtained from prior site geotechnical investigations reports (see references) and are
summarized in the enclosed Maximum Dry Density & Optimum Moisture Content sheet.
Site preparations and remedial subgrade grading were conducted in substantial conformance with
Chapter 18 (Soils and Foundations) and Appendix "J" (Grading) of the 2013 California Building
Code (CBC), the Grading Ordinance for the City of Carlsbad, the requirements of the project soil
report( s) referenced herein and our field recommendations, where applicable and as appropriate. All
observations and testing were conducted by a representative from this office under direct supervision
of the project geotechnical engineering ..
Field density tests establishing both the in-place dry densities and moisture contents were performed
in accordance with the ASTM DI 556 sand cone test method. 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. Engineering observations and compaction test results indicated that the site fills/wall
Final Report Of Geotechnical Engineering Observations and Compaction
Testing, Daybreak Community Church, 6515 Ambrosia Lane, Carlsbad
PageS
Oct. 31, 2016
backfill soils within the project building pad areas were properly placed and compacted to at least
90% ( or 93% where specified) of the corresponding maximum dry density at the tested locations and
are suitable for their intended use.
IV. CONCLUSIONS AND RECOMMENDATIONS
In our opinion, site excavations, wall backfill operations, and building pad remedial grading works
and recompaction procedures were completed in substantial conformance with the project approved
plans, project pertinent geotechnical reports, and applicable codes, and are acceptable for their
intended use.
Substantially the same or better site conditions, earth materials and engineering properties of the
compacted fills, compared to those outlined in the referenced reports, were indicated. All
conclusions and recommendations including soil design parameters, geotechnical foundation/slab
designs and improvement sections provided in the referenced reports will stay unchanged, as
specified therein and should be considered in the final designs and implemented during the
construction phase.
V. 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. Utility Trenches: Engineering observations or testing will 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 90% 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 slabs for minimum compaction requirements prior
to sand 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:
0 Building pad contour grading.
Final Report Of Geotechnical Engineering Observations and Compaction
Testing, Daybreak Community Church, 6515 Ambrosia Lane, Carlsbad
Page6
Oct. 31, 2016
• Driveways, street and yard improvements, sidewalks, curbs and gutters.
• Utility trench backfills.
0 Additional retaining wall backfills.
0 Spreading or placement of soil obtained from any excavation ( spoils from footings,
underground utilities, swimming pools, etc.).
b) Observation and testing of base and subgrade beneath the perimeter yards, driveways,
patios, sidewalks, etc., prior to placement of pavement or concrete.
c) Moisture testing prior to concrete pour, if required and as specified.
d) Any operation not included herein which requires our testing, observation, or
conformation for submittal to the appropriate agencies.
VI. DRAINAGE
The owner/ developer is responsible for insuring adequate measures are taken to proper I y 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 and top of slope.
A minimum of2% gradient should be maintained away from all foundations and top of slopes. 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 surlace water.
Planter areas adjacent to foundations should be provided with damp/water proofing, using an
impermeable liner against the footings, and a sub-drainage system, if appropriate. Site and building
type retaining walls should be provided a well-constructed back drain as specified in the project soil
report(s). Planting large trees near the building foundations and behind site retaining walls 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 and infiltration bio-retention facilities
which was not present prior to the site redevelopment. Proposed storm water BMP infiltration
facilities shall not be allowed to result in saturation of building foundation bearing and sub grade
soils, wall backfills or cause soil piping or daylight water seepage conditions. Concrete slurry cutoff
walls shall be provided along the edge of infiltration bio-retention facilities, where necessary and as
Final Report Of Geotechnical Engineering Observations and Compaction
Testing, Daybreak Community Church, 6515 Ambrosia Lane, Carlsbad
Page?
Oct. 31, 2016
appropriate, for protection of nearby building foundation, pavings, improvements, graded slopes,
utilities and wall backfills per the recommendations of the referenced reports.
It is almost impossible to absolutely prevent the possibility of shallow water conditions developed
from excessive landscape irrigation over the entire site and storm water BMP infiltration facilities.
Therefore, we recommend that shallow water conditions, if developed, be immediately remedied.
The property owner should be made aware that altering drainage patterns, landscaping, altering or
removals of protective cutoff walls, planters, and other improvements, as well as over-irrigation and
variations in seasonal rainfall, all effect subsurface moisture conditions, which in tum effect
structural and overall slope performance.
VII. LIMITATIONS
Our description of project parking improvements, including engineering observations and
compaction testing services provided, has been limited to those work performed periodically from
August 23 through September 28, 2016. The recommendations provided by this office during the
course of project wall backfill and building pad development were based on our field observations
and testing, as noted or brought to our attention. No representations are made as to the quality,
extent or performance of materials, fills/backfills, pavings and construction works not observed and
tested. All geotechnical information, test location and mapping on the enclosed Approximate
Compaction Tests Location Map are based on approximate field measurements for the purpose of
geotechnical presentations only.
Surface run-off and captured water from the bioretentions/bioswales should be directed into the
storm drain facilities in a continuously uninterrupted controlled manner. Periodic maintenance and
repairs of the project bioretentions/bioswales and storm drain system should be carried out, as
necessary, to assure proper functioning as intended. Poor bioretentions/bioswales and storm drain
system performance or failure during a major rainfall event can potentially result in large
consequential slope, improvements and structural failures and shall not be allowed.
Storm and surface run off water should not be allowed to impact or saturate graded surfaces, natural
and graded embankment faces, wall backfills, and bearing and sub grade soils. Concentrated run off,
which could cause erosion or scouring, should not be allowed to develop over the graded areas.
Over-watering of site vegetation should also not be allowed. Only the amount of water to sustain
vegetation should be provided.
If you have any questions or need clarification, please contact this office at your convenience.
Reference to our Project No. FC-4-15 -13 will help to expedite our response to your inquiries.
Maximum Dry Density & Optimum Moisture Content
(ASTM D-1557)
PROJECT NO:
PROJECT NAME:
LOCATION:
TEST RESULTS:
Soil Type 1:
Soil Type 2:
Soil Type 3:
FC-04-15-13
Daybreak Community Church of Carlsbad
Phase IV Worship Center Building
6515 Ambrosia Lane, Carlsbad, California
Yellowish Tan Silty Fine Sand
Maximum Dry Density: 122.6 pcf
Optimum Moisture: 13 %
Tan to Gray Medium to Coarse Sand
Maximum Dry Density: 121.9 pcf
Optimum Moisture: 12 %
Well-Graded Class II Base Material (Import)
Maximum Dry Density: 142.0 pcf
Optimum Moisture: 7 %
COMPACTION TEST RESULTS
PROJECT NO: FC-04-15-13
PROJECT NAME:
PROJECT LOCATION:
Daybreak Community Church of Carlsbad, Phase IV Worship Center Building
6515 Ambrosia Lane, Carlsbad, California
FIELD COMPACTION TEST RESULTS (ASTM D1556):
Appr.oximate Fielii 11 Max Approximate Fielii Relative
Date Test Test Test Moisture Dry Dr-y Compaction No. Location Elentioli (MSL) (%) Density Densicy (%) (ft) (ocf) (pcf)
6/16/16 1 Westerly, Pad Finish Grade 10 110.3 122.6 90
6/16/16 2 Central, Pad Finish Grade 10 110.6 122.6 90
6/16/16 3 Easterly, Pad Finish Grade 14 112.8 122.6 92
6/22/16 4 Central, Sunken Pad Area Finish Grade 11 110.9 122.6 90
6/22/16 5 Easterly, Pad Area Finish Grade 10 112.7 122.6 92
6/28/16 6 Outside The Work Area Finish Grade 5 134.3 142 95
6/30/16 7 Southerly, Street 306± 11 109.8 121.9 90
6/30/16 8 Southerly, Street 308± 13 115.2 121.9 95
6/30/16 9 Southerly, Street Finish Grade 5 135.9 142 96
7/8/16 10 Easterly, Pad Area Finish Grade 11 109.7 121.9 90
7/8/16 11 Southerly, Pad Area Finish Grade 11 110 121.9 90
8/12/16 12 Westerly, Raised Pad Area 308± 11 112.5 121.9 92
8/12/16 13 Westerly, Raised Pad Area Finish Grade 9 109.6 121.9 90
Comments
Trench Backfill
Not Shown On The Map
Sewer Trench Backfill
Sewer Trench Backfill
Sewer Trench Backfill
Sewer Trench Backfill
Sewer Trench Backfill
Appr.oximate Approximate Field, M:ax Relative
Date Test test 'F,est Field Dry Dr.y ComP,action Comments No. Elevation, ~SL) Moistllle Densify Density Location fft) ,(%) (pcf) (pcf,) (%)
8/23/16 14 Northerly End 309± 15 112.2 122.6 92 Wall Backfill
8/23/16 15 Northerly End Finish Grade 12 112.1 122.6 91 Wall Backfill
8/24/16 16 Northerly End Finish Grade 12 113.5 122.6 93 Wall Backfill
8/24/16 17 Westerly, Upper Pad 312± 9 113.2 121.9 93 Wall Backfill
8/25/16 18 Westerly, Upper Pad 314± 12 114.7 121.9 94 Wall Backfill
8/25/16 19 Westerly, Upper Pad 314± 11 112.9 121.9 93 Wall Backfill
8/25/16 20 Westerly, Upper Pad 315.5± 10 113.5 121.9 93 Wall Backfill
8/26/16 21 Westerly, Upper Pad 317.5± 12 115.4 121.9 95 Wall Backfill
8/26/16 22 Westerly, Upper Pad 317.5± 12 112.9 121.9 93 Wall Backfill
8/29/16 23 Westerly, Upper Pad 319.5± 12 113.4 121.9 93 Wall Backfill
8/29/16 24 Westerly, Upper Pad Finish Grade 11 112.8 121.9 93 Wall Backfill
8/29/16 25 N. E., Lower Pad Area Finish Grade 11 109.6 121.9 90 Trench Backfill
9/28/16 26 Southerly, Lower Pad Area 307.5± 12 110.5 121.9 91 Sewer Trench Backfill