HomeMy WebLinkAboutCDP 2019-0023; HERNANDEZ RESIDENCE; REVIEW OF GEOTECHNICAL REPORT; 2020-03-02, .
City of Carlsbad
1635,Faraday Avenue
Carlsbad, California 92008
Attention: Ms. Kyrenne Chua
Subject: Review of Geotechnical Report
Project: Proposed Hernandez Residence
3677 Garfield Street
Carlsbad, California
Project ID: CDP2019-0023
City GR No: GR2020-0004
NVS
March 2, 2020
Project No.: 226816-00101.70
References: 1) "Preliminary Geotechnical Evaluation, Proposed Residential Development,
3677 Garfield Street, Carlsbad, California", prepared by GeoTek, Inc., Project No. 3592-
SD, dated October 18, 2019.
2) "Technical Guidelines for Geotechnical Reports ", issued by the City of Carlsbad, dated
January 1993.
3)"CGS Note 41, Guidelines for Reviewing Geologic Reports", prepared by the State of
California, Department of Conservation, California Geological Survey, dated 2017.
Dear Ms. Chua:
As requested, NV5, West Inc. (NV5) has conducted a geotechnical review of the referenced geotechnical report
for the proposed project in Carlsbad, California. The purpose of the review was to provide an opinion on
whether the geotechnical aspects of the project have been identified and appropriately addressed in the report.
NV5's geotechnical review is based on geotechnical information presented in the referenced report, guidelines
provided in the referenced City of Carlsbad and CGS documents, and experience with the geotechnical
conditions in the general site area. NV5 has not performed an independent geotechnical studies at the project
site and therefore does not offer or imply any guarantee or warranty as to future site performance. The opinions
presented below are limited. Other consultants could arrive at different conclusions. This report presents a
summary of the review.
Review Summary
Based on the review, it is NV5's opinion that the referenced update geotechnical report for the proposed
project has generally identified and addressed the significant geotechnical factors affecting the site
development, and the report is approved. Note that acceptance or approval of the report does not guarantee
or constitute approval for grading or building permits
It is recommended that the project geotechnical consultant review and approve the grading and building
foundation plans prior to construction.
OFFICES NATIONWIDE
I 5092 AVENUE OF SCIENCE, SUITE 200 SAN DIEGO, CA 92 I 28 WWW.NV5.COM OFFICE 858.385.0 500 FAX 858 385 0 40 0
CONSTRUCTION OUAl..liY ASSURANCE INFRASTAUC. T\JRt. ENERGY PROGRAM MANAOEMEfl\l'T -Et-tVJRONMENTAi..
, '
Review of Geo technical Report
Proposed Hernandez Residence
3677 Garfield Street
Carlsbad, California
Project No.: 226816-00101.70
NV5 appreciates the opportunity to be of service to you on this project. If you have any questions regarding
this report, please do not hesitate to contact our office.
Respectfully submitted,
NVS West, Inc.
Attachment: City of Carlsbad Geotechnical Report Review Checklist
Distribution: ( 1) Addressee, via email
NIVIS
OFFlCES N,ATIQNWIOE
Carl Henderson, PhD, GE 2886
CQA Group Director (San Diego)
CONSTRUCTION QUALITY ASSUR.6.NCE INF'RASTRUCTURE ENCINEERINC -MUNICIPAL OUTSOURCING -ASSET MANAGEMENT ENVIRONMENTAL SERVICES
GEOTECHNICAL REPORT REVIEW CHECKLIST
Plan Check Number: CDP2019-0023/GR2020 -0004
Location / Address: 3677 Garfield Street
City Plan Checker: Date: March 2, 2 02 o
GEOTECHNICAL REPORT -GENERAL
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Signed by RCE/GE ~ □ □
Signed by CEG (Required for Hillside Area) ~ □ □
Project Address ~ □ □
Location Index Map with reference north, scale, etc. ~ □ □
Site Description (topography, vegetation, existing structures/improvements, drainage) □ □ Ill
Description of Proposed Development (grading, structures/improvements, drainage, use, foundation z □ □ type, estimated structural loads)
GEOTECHNICAL REPORT -FIELD INVESTIGATION
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Site Specific Subsurface Investigation ~ □ □
Description of Investigative and Sampling Methods ~ □ □
Boring/Test Pit Logs (Soil/Bedrock descriptions with depth, type and depth indicated for sampling, ¥J □ □ real or assumed elevation indicated, qroundwater conditions)
Sampling performed to anticipated depth of foundations and/or deepest excavation CJ □ □
Boring/Test Pits located on Geotechnical Map/Plot Plan ~ □ □
Revised 5/10/2018 Page 1 of 7
GEOTECHNICAL REPORT -LAB TESTING
Description of lab test performed with referenced test method (ASTM, EPA, etc)
Soil Strength (Shear)
Expansion
Sulfate
Gradation
Classification of soil in accordance with ASTM D 2487 (when using California Building Code values
for lateral load)
Moisture/Density
Consolidation
Atterberg Limits
Maximum Dry Density/Optimum Moisture Content
GEOTECHNICAL REPORT -EARTH MATERIALS
Description and designation of geologic units (surficial soils and bedrock, including depth, thickness)
Geologic structure (bedding , fracturing, faulting of bedrock material)
Description of regional geologic conditions (including reported regional trends of bedding and
faultinq)
GEOTECHNICAL REPORT -SEISMICITY
General description of regional and local faulting
Site Class
Mapped Spectral Acceleration Parameters (Ss, S1)
Site Coefficients (Fa, Fv)
Design Spectral Acceleration Parameters (Sos, So1)
Geotechni cal Report Checklist
Revised 5/10/2018 Page 2 of 7
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Seismic Design Category
GEOTECHNICAL REPORT -GEOLOGIC HAZARDS
Landslide
Expansive Soils
Surficial Slope Instability
Slope Creep
Groundwater
Total and Differential Settlement
Sulfate
Liquefaction
Affect of liquefiable soils on utilities and lifeline services outside of structural mitigation
Seismic Induced Landsliding
Tsunami Potential
GEOTECHNICAL REPORT -ILLUSTRATIONS
Geotechnical Map / Plot Plan
Existing topography / improvements
Proposed topography/ improvements
Location of subsurface exploration (borings, test pits, etc.)
Geologic Contacts
Geologic Structure
Location of fill key / buttress
Geologic Cross-Section
Existing topography/ improvements
Geotechnical Report Checklist
Revi sed 5/10/2018 Page 3 of 7
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Proposed topography/ improvements
Location of subsurface exploration {borings, test pits, etc.)
Geologic Contacts
Geologic Structure
Slope setbacks
Temporary cuts / shoring
Fill Key/ buttress
Slope benching
GEOTECHNICAL REPORT -CONCLUSIONS/ RECOMMENDATIONS
Statement as to feasibility of project
Statement as to impact on adjacent properties
Statement of the condition of slopes with respect to stability
Slope stability analysis provided to support conclusion/recommendations
Statement regarding liquefaction potential
Liquefaction analysis provided to support conclusion/recommedations
Grading Recommendations
Remedial grading
Compaction standards
Groundwater Mitigation
Temporary excavation {backcuts, slopes) with time limit recommendations
Shoring
Benching
Keys / buttresses
Canyon/Key Subdrains
Foundation Recommendations
Geotechnical Report Checklist
Revised 5/1 0/2018 Page 4 of 7
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Expansive soil mitigation (CBC 1805) □
Description of approved embedment material (i.e. compacted fill, terrace deposits, etc) ~
Minimum depth of embedment (into approved material) for foundations ,i
Minimum width of footings ~
Minimum diameter of caissons □
Bearing capacity (end bearing for caissons) ~
Coefficient of friction (caisson skin friction) □
Lateral bearing r:,
Down drag forces (liquefiable soils,) □
Lateral Spread forces (liquefiable soils) □
Foundation slope/trench setback li
Minimum reinforcement requirements ~
Minimum slab thickness and reinforcement □
Slab underlayment ~
Soluable Sulfate exposure mitigation (typically cement type) z
Conventional Retaining Wall Recommendations ~
Active pressures (level, sloping) ~
Retaining wall backdrain or recommendation of additional hydrostatic pressure ~
Backfill ~
Surcharges r/J
MSE Wall Recommendations (facing material, grid, backfill, stability analysis) □
Flatwork / Hardscape recommendations including driveways (subgrade preparation, minimum slab □ thickness, reinforcement and joint spacing)
Roadway Pavement recommendations (section design, subgrade preparation) □
Swimming Pool recommendations □
GEOTECHNICAL REPORT -OBSERVATION/TESTING DURING CONSTRUCTION
Geotechnical Report Checkli st
Revised 5/10/2018 Page 5 of 7
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Footing Excavations
Subdrains
Caisson/ Drilled Pier excavations (CBC Table 1704.9)
Pool Excavations
Benching
Keyways
Temporary excavations
Geologic mapping of bedrock excavations
Retaining wall backfill
Utility trench backfill
Engineered fill
Hardscape subgrade (driveways, patios, walkways, etc.)
Import soils
GEOTECHNICAL REPORT -REFERENCES
Current/ City adopted Building Code
Grading Code
Geotechnical reports I publications/ geologic maps
Ariel photographs
Websites
GEOTECHNICAL REPORT -COASTAL BLUFF
Top of bluff designation (presented on geologic map and cross-sections)
Geotechnical Report Checklist
Revised 5/10/2018 Page 6 of 7
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Arial photograph of site showing top of bluff
Bluff retreat rate and total estimated retreat for a 50 year period
Codified Bluff top setback (presented on geologic map and cross-sections)
Slope stability analysis
References for bluff retreat rate
Slope Stability Setback presented on geologic map (surface expression of 1.5 FS)
Total Setback presented on geologic map (greater of A: Slope Stability Setback + 50 yr bluff retreat
or B: 10-feet buffer+ 50 yr bluff retreat)
Explanation and justification of 40-feet setback deviation
Geotechni cal Report Checklist
Revi sed 5 /10/2018 Page 7 of 7
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