HomeMy WebLinkAboutMS 2020-0004; ADAMS STREET HOMES; GEOTECHNICAL RESPONSE TO COMMENTS FOR PROPOSED ADAMS STREET HOMES; 2022-03-30Geotechnical Exploration, Inc.
SOIL AND FOUNDATION ENGINEERING • GROUNDWATER • ENGINEERING GEOLOGY
30 March 2022
Rincon Real Estate Group
3005 S. El Camino Real
San Clemente, CA 92672
Attn: Mr. Kevin Dunn
Job No. 20-12852
Subject: Response to City Reviewer Report Redline comments
Rincon Residential Project
3745 Adams Street Homes
Carlsbad, California
Dear Mr. Dunn:
As requested and required by the City of Carlsbad reviewer, Ms. Nicole Fine, we are
responding to redline comments handwritten on a copy of our report dated
September 14, 2020. That copy was transmitted to the project civil engineer, Pasco
Laret Suiter and Associates, which we received by email on March 25, 2022.
REVIEW COMMENTS & RESPONSES
1. Update Site Map and confirm partial infiltration OK for both BMP areas shown
on grading plans.
GEI Response: We updated the Site Map that was included in our September
14, 2020, report (see Appendix A) and included it in our recent response letter
to the city geotechnical reviewer dated March 8, 2022. We have addressed
infiltration test details in another report dated September 14, 2020, as well as
in letters dated February 8, 2021, August 26, 2021, and March 4, 2022.
Herein, we confirm that partial infiltration is ok for the BMP areas shown on
the grading plans.
7420 TRADE STREET• SAN DIEGO, CA. 92121 • (858) 549-7222 • FAX: (858) 549-1604 • EMAIL: geotech@gei-scl.com
Rincon Adams Street Project
Carlsbad, California
Job No. 20-12852
Page 2
2. Structural ca/cs or letter from GEI stating SDRSD C-3 and C-4 can be utilized
on site with influence of structures on footings.
GEI Response: The project grading plans show that some SDRSD retaining
walls will receive some surcharge on their foundations. The influence of the
building structures on the proposed retaining wall foundations is acceptable,
but not if the surcharge is applied on the retaining wall stems. If that is the
case, the retaining walls must be designed by the structural engineer. The
retaining walls on the west side of the ADUs will need to have the ADUs closest
footings deepened to an elevation of 83 feet AMSL, i.e.,4.5 feet below the
building pad elevation, to ensure that the building foundations do not
surcharge the western retaining wall stems.
3. No AC pavement recommendations. Need Adams Street and on-site.
GEI Response: In our geotechnical report dated September 14, 2020, we
provided recommendations for concrete pavement and for concrete
interlocking pavers to be placed inside the property, but we did not include
asphalt concrete (AC) pavement. Herein, we recommend that the AC
pavement cross section inside the project consist of 3 inches of AC on 6 inches
of Class II crushed miscellaneous base material. For public street areas, we
recommend that the pavement cross section consist of the minimum required
by the City of Carlsbad, i.e., 4 inches of AC on 4 inches of Class II crushed
miscellaneous base material.
The Class II base material and the subgrade soils should be compacted to at
least 95 percent relative compaction of the maximum dry density determined
per ASTM D1557. The AC should be compacted to at least 95 percent of the
maximum HVEEM value provided by the AC supplier.
If you have any questions regarding this letter, please contact our office. Reference
to our Job No. 20-12852 will help expedite a response to your inquiry.
Respectfully submitted,
GEOTECHNICAL EXPLORATION, INC.
• I
. . . . . ~=:::::--..... C.E.G. -----1
Senior Geotechnical Engi
al
APPENDIX A
Updated Plot Plan and Site Specific
Geologic Map
INF-2Approximate Location of Infiltration TestApproximate Location of Proposed Biofiltration BasinScale: 1” = 10’(approximate)LEGENDGEOLOGY LEGENDApproximate Locationof Exploratory TrenchT-9Artificial FillOld Paralic Deposits( units 2-4 )INF-2INF-1T-2T-4T-6T-7T-5T-8T-1T-3T-920-12852-24X36-P.aiMarch 2022Adams Street Homes3745 Adams StreetCarlsbad, CA.Figure No. IIJob No. 20-12852PLOT PLAN ANDSITE SPECIFICGEOLOGIC MAPNOTE: This Plot Plan is not to be used for legalpurposes. Locations and dimensions are approximate.Actual property dimensions and locations of utilitiesmay be obtained from the Approved Building Plansor the “As-Built” Grading Plans.REFERENCE: This Plot Plan was prepared from an existing undatedGRADING PLAN by PASCO LARET SUITER & ASSOCIATESand from on-site field reconnaissance performed by GEI.QopQaf2-4QopQaf2-4QopQaf2-4QopQaf2-4QopQaf2-4