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HomeMy WebLinkAboutSoil Testing Report done 3.4.20213866 PROSPECT AVENUE • SUITE 9 - WEST PALM BEACH, FLORIDA 33404 - (561) 881-1939 1 March 2021 Phoenix Custom Homes 1760 Jog Road, Suite 120 West Palm Beach, FL 33411 Subject: Report of Geotechnical Services - 3-Level Custom Home 8208 South Ocean Drive, Diamond Sands Lot 31, Jensen Beach, Florida Allterra Engineering & Testing respectfully submits this report of geotechnical services for the subject project. Allterra's services have been performed to meet certain requirements of chapter 18 of the 2020 Florida Building Code and local amendments. This report is Allterra's instrument -of - service provided for sole reliance and use by Phoenix Custom Homes. Third parties may read this report for information purposes only. Project and Scope Reference Documents. Digital copies of drawings A200, A201, A202, A301, and A302 dated 12/29/2020 by Randall Stofft Architects (their job number 1702030) were provided for Allterra's reference in performing its services. Project Information. The project is a 3-level custom home and its associated swimming pool proposed for construction upon the subject property. The property is bounded on the west by South Ocean Drive, on the east by the Atlantic Ocean, and on the north and south by other residential properties. The project is designed for supported upon a foundation of grade beams and piles. According to elevations presented on drawing A302, surface -grade elevation is +7.0 feet NAVD and bottom of 2nd-level beam is +16.5 feet. Scope and Constraints. Allterra was tasked with performing soil -test borings to characterize subsurface conditions and providing recommendations for foundation design (pile length, diameter, and capacity). Specific information on design storm parameters has not been provided at this time. These parameters are provided by the project coastal engineer and typically include information such as breaking wave -crest elevations, eroded -grad elevation, wave impact force and elevation of force resultant, debris impact force and elevation of force resultant, etc. For purposes of this report, Allterra assumed: head -of -pile at 9.5 feet above existing surface grade and fixed against rotation, and eroded grade plus scour loss at 8 feet below existing surface grade. /f these assumptions are erroneous, the conclusions and recommendations of this report may warrant change. Field Work Allterra mobilized personnel and equipment to the project site on 24 February 2021. At that time access paths had been cleared across the site by the Client. Alterra performed three soil -test borings approximately as represented on the Boring Location Plan of this report. Penetration Geotechnical Services — 3-Level Custom Home t 8208 South Ocean Drive, Jensen Beach, FL 1 March 2021 21 - 179 testing was performed in the soil -test borings by driving a 2-inch diameter steel sampler with blows of a 140-pound hammer free -falling 30 inches. Copies of the boring logs are attached to this report for the reader's reference. BORING LOCATION PLAN I� �iiieni�nie • � • iiiic•/cr/tt•/c/■ nr/•r/•c/N"UN■ WHOWENNUUMENEERE nr/•c/r•/•/Rc■ nr/rr/c•/u•/r/Rc/■ '�RGut..r�ru•■ ' 1. All• ■■■R•1S■ • L,� Liii ��. ,onR�c 6 ■R!PRI�■ ruuu■ in �. no II 1N�� - 1/c• -- tiocu■ I��11■ � rnn 1/uucL� �n�u���ut.uuuuumu Findings Subsurface Profile. Allterra encountered similar conditions at each boring location. The conceptual subsurface profile is described as: • Topsoil sampled as dark -gray fine sand with occasional roots from surface grade to approximately 6 inches below grade underlain by • Stratum 1 - very -firm to dense, brown to tan, sand -and -shell to approximately 24 feet below grade underlain by • Stratum 2a - dense, gray, fine sand with trace of shell to approximately 32 feet below grade, underlain by' • Stratum 2b - soft to firm, silt to approximately 37 feet below grade, underlain by • Stratum 2c - dense, gray, fine sand with trace of shell to approximately 42 feet below grade, underlain by • Stratum 2d - loose, light -tan, fine sand and soft silt to 47 to 49 feet below grade, underlain by • Refusal (presumed sandstone, limestone, or cemented coquina) An exception to the conceptual profile includes the absence of Stratum 2a in B-2 Groundwater. Groundwater was encountered at approximately 5 feet below surface grade at the time of the borings at the time of Allterra's borings. The depth to groundwater may vary at other times due to changes in hydrologic conditions. 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), Geotechnical Services — 3-Level Custom Home 2 8208 South Ocean Drive, Jensen Beach, FL 1 March 2021 21 - 179 respectively, for 14- and 16-inch-diameter auger -cast piles installed to elevation -17 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 auger -cast piles. The estimates assume a fixed -toe pile with head restrained against rotation in a rigid beam. Recommendations Building -Pad Preparation. The building pad is defined as the footprint of construction plus 5 feet in all accessible directions. Allterra recommends: 1. Strip topsoil and vegetation (including roots) from building pad and properly waste. 2. Thoroughly wet the exposed surface and allow it to drain to optimum moisture. 3. Mechanically compact exposed surface to at -least 95 percent of maximum -dry -density as determined by the Modified -Proctor compaction test (ASTM D-1557 / AASHTO T-180). 4. Engage Allterra to perform probe -rod and field density tests on the prepared subgrade to verify compaction standards are achieved. 5. Place fill, where needed to achieve construction -ready grades, in thin lifts and compact (at or near optimum moisture) to at -least 95 percent of maximum -dry -density as determined by the Modified -Proctor compaction test (ASTM D-1557 / AASHTO T-180). Lift thickness will depend upon methods and equipment employed to achieve the target densities. 6. Engage Allterra to perform probe -rod and field density tests on each 2-foot rise in fill height to verify compaction standards are achieved. 7. Once the building pad is prepared, the contractor shall maintain its condition to prevent erosion or other degradation through the placement of subsequent work. 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 sever number-5 full depth steel bars for 14- and 16-inch-diamter auger -cat piles. Ties shall be formed of 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. 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. Geotechnical Services — 3-Level Custom Home 3 8208 South Ocean Drive, Jensen Beach, FL 1 March 2021 21 - 179 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. Closing Thank you for engaging Allterra as your geotechnical consultant. Please call the undersigned if you have questions about this report or need other services. Yours truly, Allterra Engineering & Testing UA Principal Engineer FL Lic. No. 55960 Geotechnical Services — 3-Level Custom Home 4 8208 South Ocean Drive, Jensen Beach, FL 1 March 2021 21 - 179 0000 rKv0rtt;l AVENUE o SUITE 9 • WEST PALM BEACH, FLORIDA 33404 • (561) 881-1939 PROJECT Diamond Sands -Plat No. 2 -LOT #31 - 8208 SOUTH OCEAN DRIVE -Jensen Beach, FI LOCATION B-1 (Approximate) BORING NO. 1 PRf1D(1CC11 TLlccc 1 cvr_i ni in-r�nn r. DEPTH DESCRIPTION OF MATERIAL Sample ( o Blows Per Foot DEPTIi 1 011-611 Dark Grey Fine Sand, trace of roots (topsoil) 611-4' Light Brown Fine Sand, trace of shell (fragmented) 4'-11' Tan Fine Sand, some shell (fragmented) 11'-14' Tan Fine Sand, and shell (fragmented) 18'-20' Tan Fine Sand, and shell (fragmented) to Light Brown Fine Sand, trace of shell (fragmented) 23'-25' Tan Fine Sand, and shell (fragmented) 29'-30' Grey Fine Sand, slight trace of shell (fragmented) 34'-35' Silt 39'-40' Grey Fine Sand, trace of shell (fragmented) 44'-45' Light Tan Fine Sand, and rock (fragmented) 49'- Refusal (rock) 1-3 1 2 3 5-6 2 4 8-10 3 5 15-17 4 6 18-24 5 7 10-10 6 8 10-10 7 9 10-8 8 10 8-8 9 8-10 10 11 12-15 11 12 18-20 12 13 26-32 13 14 50+ 14 15 15 16 1 17 17 18 18 19 12-10 19 20 16-18 20 21 21 22 22 23 23 24 10-10 24 12-16 25 26 2627 27 28 2 8 29 16-18 29 30 20-23 3o 31 31 32 3233 33 34 - 34 35 2-1 35 36 3637 37 38 38 39 16-18 39 40 20-22 40 41 41 42 42 43 43 44 2-3 44 45 4-5 45 46 46 47 47 48 48 49 49 50 50 CLIENT Phoenix Custom Homes JOB No. 21-179 DRILLER TKM/TM/DDD/MS WATER TABLE 5' DATE 2/24/21 TEST DATA In aeneral accordance with ASTM D-1586 These Soil Boring Tests are Representative of and Apply to the Exact Location and Depth of the Boring. AUTHORIZATION FOR PUBLICATION OF STATEMENTS, CONCLUSIONS OR EXTRACTS FROM OR REGARDING OUR REPORTS IS RESERVED PENDING OUR WRITTEN APPROVAL. 3866 PROSPECT AVENUE • SUITE 9 • WEST PALM BEACH, FLORIDA 33404 . (561) 881-1939 PROJECT Diamond Sands - Plat No. 2 - LOT #31 - 8208 SOUTH OCEAN DRIVE - Jensen Beach, FI LOCATION B-2 (Approximate) BORING NO. 2 PRt7Pn..(,Fn THPPP-I F\/Fl r.l ICTnnn rai=clnGnlnr= DEPTH DESCRIPTION OF MATERIAL Sample No 81ows Per Foot DrPTH 1 0"-6" Dark Grey Fine Sand, trace of roots (topsoil) 6"-4' Brown Fine Sand 4'-15' Tan Medium -to -Fine Sand, slight trace of shell 18'-20' Tan Fine Sand, slight trace of shell 23'-25' Tan Fine Sand, trace of shell 28'-30' Tan Fine Sand, and shell 33'-35' Silt 38'-40' Grey Fine Sand 43'-45' Silt 47'- Refusal (rock) 1-1 1 2 3-8 2 3 9-10 3 4 11-13 4 5 18-16 5 6 11-8 6 11-12 7 8 13-11 8 9 15-16 9 10 12-17 10 11 23-28 11 12 33-40 12 13 32-33 13 14 34-46 14 15 15 16 16 17 17 18 18 19 18-21 19 20 25-17 20 21 21 22 22 23 23 24 8-11 24 25 20-20 25 26 26 27 27 28 28 29 25-27 29 30 27-25 30 31 31 32 32 33 33 34 5-4 34 35 3-4 35 36 36 37 37 38 38 39 25-31 39 40 33-38 40 41 41 42 42 43 43 44 1-1 44 45 2-4 45 46 46 47 47 48 48 49 49 50 50 CLIENT Phoenix Custom Homes JOB NO. 21-179 DRILLER TKM/TM/DDD/MS WATER TABLE 5' DATE 2/24/21 TEST DATA In general accordance with ASTM D-1586 These Soil Boring Tests are Representative of and Apply to the Exact Location and Depth of the Boring. AUTHORIZATION FOR PUBLICATION OF STATEMENTS, CONCLUSIONS OR EXTRACTS FROM OR REGARDING OUR REPORTS IS RESERVED PENDING OUR WRITTEN APPROVAL. 3866 PROSPECT AVENUE e SUITE 9 . WEST PALM BEACH, FLORIDA 33404 . (561) 881-1939 PROJECT Diamond Sands - Plat No. 2 - LOT #31 - 8208 SOUTH OCEAN DRIVE - Jensen Beach, FI LOCATION B-3 (Approximate) BORING NO. 3 PROP0SF171 THRFF-I FVFI r,l ICTrIhd RFclnFI\I( G DEPTH DESCRIPTION OF MATERIAL Sample No glows Per Foot DEPTH 1 0"-6" Dark Grey Fine Sand, trace of roots (topsoil) 6"-4' Brown Fine Sand 4'-15' Tan Medium -to -Fine Sand, slight trace of shell 18'-20' Tan Fine Sand, and shell (fragmented) 23'-25' Tan Fine Sand trace of shell (fragmented)16-18 � 28'-30' Grey Fine Sand, trace of shell (fragmented) 33'-35' Silt 38'-40' Grey Fine Sand, trace of shell (fragmented) 43'-45' Silt 47'- Refusal (rock) 1-2 1 2 3-5 2 3 8-10 3 4 12-11 4 5 13-12 5 6 9-10 6 7 12-13 7 8 12-18 8 9 16-18 9 10 15-16 10 11 12-18 11 12 20-23 12 13 25-30 13 14 24-32 14 15 29-30 15 16 16 17 17 18 18 19 16-20 19 20 15-12 20 21 21 22 22 23 23 24 18-16 24 25 25 26 26 27 27 28 28 29 18-18 29 30 20-20 30 31 31 32 32 33 33 34 1-1 34 35 1 1 35 36 36 37 37 38 38 39 12-15 39 40 20-16 40 41 41 42 42 43 43 44 1-1 44 45 1-1 1 45 46 47 47 48 48 49 49 50 50 CLIENT Phoenix Custom Homes JOB No. 21-179 DRILLER TKM/TM/DDD/MS WATER TABLE 5' DATE 2/24/21 TEST DATA In aeneral accordance with ASTM D-1586 These Soil Boring Tests are Representative of and Apply to the Exact Location and Depth of the Boring. AUTHORIZATION FOR PUBLICATION OF STATEMENTS, CONCLUSIONS OR EXTRACTS FROM OR REGARDING OUR REPORTS IS RESERVED PENDING OUR WRITTEN APPROVAL.