HomeMy WebLinkAboutAddendum To Report Of Geothecnical Services3866 PROSPECT AVENUE SMITE 9 a WEST PALM BEACH, s p, FLORID 94 1�
FEB 17 Z022
20 October 2021
LST. Lucie Countv, P erizitting
Phoenix Custom Homes
1760 Jog Road, Suite 120
West Palm Beach, FL 33411
Subject: Addendum to Report of Geotechnical Services — 3-Level Custom
8204 South Ocean Drive, Diamond Sands Lot 30, Jensen Beach, Florida
Allterra respectfully submits this correspondence on pile depth and capacity. A letter dated 13
October 2021 from the coastal engineer for the above referenced project was provided to Allterra
to aid its in recommendations for pile design. The parameters for eroded grade and scour depths in
this letter confirm the conclusions and recommendations in the 3-March-2021 report by Allterra.
The recommendations are repeated below for completeness.
Conclusions
Pile Capacity. Considering the conceptual subsurface profile and estimates of eroded grade
Allterra estimated allowable axial -load capacity of 60 Kips (30 tons) and 72 Kips (36 tons),
respectively, for 14- and 16-inch-diameter auger -cast piles installed to elevation -15 feet NAVD (to
achieve fixed -toe condition against lateral wave load) about 22 feet below existing surface grade.
Pile Lateral Displacement. Considering the conceptual subsurface profile and estimates of eroded
grade and wave -force loads, Allterra calculated lateral displacement of 1.4 inches and 0.9 inch,
respectively, for 14-inch and 16-inch auger -cast piles. The estimates assume a fixed -toe pile with
head restrained against rotation in a rigid beam.
Recommendations
Pile Installation and Materials. Piles shall be formed with minimum 4000 PSI grout placed under
pressure as the auger is progressively withdrawn from the borehole. Piles shall be reinforced with
five and seven full -depth number-5 steel bars, respectively, for 14- and 16-inch-diameter auger -
cast piles. Ties shall be formed with number-3 bars spaced 16 inches. The structural engineer
shall determine the number and distribution of piles considering structural loads and geometry.
Piles shall be spaced at -least 3 diameters center -to -center to avoid group effect on stress
distribution in the bearing stratum.
Pile -Installation Monitoring. Engage Allterra to monitor installation of piles. For auger -cast piles,
monitoring shall include:
1. Check pile layout for conformance to design foundation plan.
Geotechnica/ Services — 3-Level Custom Home
20 October 2021
8204 South Ocean Drive, Jensen Beach, FL
21-179
2. Observe field trial and calculate gout -pump factor.
3. Observe drilling of pile to verify target depths are achieved.
4. Observe grouting of pile bore to verify acceptable grout return.
5. Sample grout for compressive -strength testing.
6. Observe installation of reinforcing steel to verify full -depth penetration.
7. Test grout specimens to verify design compressive strength is achieved.
8. Calculate grout factors and summarize installation data for each pile.
9. Prepare report of work acceptance signed and sealed by Professional Engineer.
Qualification
Allterra has based its conclusions and recommendations upon certain client -provided information
and interpretation of data obtained at discrete points within the limits of exploration. It is possible
that conditions may vary between boring locations or beyond the limits of the boring array. Project
designs may also change. If additional information about the project or site is discovered that does
not appear to conform to the conditions presented in this report, Allterra reserves the right to
review the new information and modify its conclusions and/or recommendations where warranted.
........
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Yours truly, Q�.• '\oEN�.
Allterra Engingring & Testing".. ;
Re ist uMber.41 9 No. 81271
Matthew W' ,PE STATE OF •' �/��
Senior Engirfe` '.,PcoRIDP``/'G�=;
FL Lic. No. 8�—' `SIONAI- \`"
Geotechnica/ Services — 3-Level Custom Home 2 8204 South Ocean Drive, Jensen Beach, FL
20 October 2021 21 - 179