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HomeMy WebLinkAboutLetter; Report of Preliminary Geotechnical Services - Existing Structure3866 PROSPECT AVENUE o SUITE 9 ©`dVEST PALM BEACH, FLORIDA 33404 a (561) 881-1939 6 August 2021 Winchipp-Construction 7502 S.W. Sandpiper Street Hobe Sound, FL 33455 1 Subject: Report of Preliminary Geotechnical Services — Existing Structure 804 N.E. Winters Creek Road — St. Lucie County, Florida Allterra Engineering & Testing respectfully submits this report of preliminary geotechnical services for the subject project. This report is Aliterra's instrument -of -service provided for sole reliance and use by its client. Third parties may read this report for information purposes only. PROJECT AND SCOPE Project Information. The project is an investigation around an existing structure on the subject property. Scope and Constraints. Allterra was tasked with performing exploratory borings and providing preliminary characterization subsurface conditions. Access to boring locations was constrained by existing site improvements and landscaping. PRELIMINARY CONCLUSIONS The presence of construction debris, as encountered for this site, can be problematic for shallow foundations such as conventionalor monolithic -slab footings.. Such soils are subject to excess settlement under applied. structural load. This material was encountered in the area of boring B-3. PRELIMINARY FIELD WORK Allterra mobilized personnel and equipment to the project site on August 2, 2021.. Allterra performed a series of soil -test borings. Copies of the boring logs are attached for the reader's reference. ,.Otto � Preliminary Geotechnical Services — Existing Structure 1 804 N.E. Winters Creek RoayrsRucie County, FL August 6, 2021 21 - 456 BORING LOCATION PLAN. PRELIMINARY FINDINGS Subsurface Profile. The subsurface profile can be described as: • Topsoil sampled as dark -gray, fine sand with occasional roots from surface grade to approximately 6 inches below grade. • Loose to firm, tan to brown fine sand to approximately 15 feet below grade. Groundwater. Groundwater was encountered approximately 9 feet below surface grade at the time of boring. The depth to groundwater may vary at other times due to changes in hydrological conditions; including tidal changes. RECOMMENDATIONS For new construction, Allterra recommends performing a design -specific subsurface exploration to prepare final recommendations for foundation systems. The number and depth of borings will depend upon the footprint geometry and design -loads for new buildings, walls and other structural and civil features. When this information is provided, Allterra will prepare a scope and budget for additional borings and recommendations. It is Allterra's opinion that the construction debris would need to be removed in order for the site to be buildable. Due to the shallow depth (1 foot) and the absence of the water table, it can be removed when normal clearing and grubbing takes place. Additional borings at time of construction will provide further recommendations. Preliminary Geotechnical Services — Existing Structure 2 804 N. E. Winters Creek Road, St Lucie County, FL August 6, 2021 21 - 456 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 appropriate. Yours truly, Allterra Enginee�i Certificate of AutlZoriz Ikon 9139 [WN 1271 Matthew watts' -A'.... STATE OF �((44/� Senior Engineer%�� ' • CORVD.N GN\�� FL Lic No. 81271 ,S&70 * ' " ENAIL Attachments Preliminary Geotechnical Services — Existing Structure 3 804 N. E Winters Creek Road, St. Lucie County, FL August 6, 2021 21- 456 3866 PROSPECT AVENUE'• SUITE 9 • .WEST PALM BEACH, FLORIDA 33404'e..(561) 881-1939 PROJECT Harbour Ridge - PLAT#21 -LOT "K" - 804 N.E. WINTERS CREEK ROAD - St. Lucie County, FI LOCATION B-1. (Approximate) BORING NO. 1 PRELIMINARY AROUND EXISTING STRUCTURE DEPTH DESCRIPTION OF MATERIAL SaNple m o Blows Per Foot DEPTH Dark Grey Fine Sand, trace of roots (topsoil) 6"-3' Tan Fine Sand, some rock 3'-10' Light Grey Fine Sand — - 1 2 4 2 3 5 3 4 5 4 5 7 5 6 6 6 7 5 7 8 6 8 9 7 10 8 1 11 10 11 12 12 13 13 14 1 15 15 16 16 17 17 18 18 19 19 20 20 21 21 22 22 23 23 24 , 24 25 2 26 2 27 27 28 28 29 29 30 30 31 3 32 32 3 33 34 3 35 35 36 36 37 37 38 38 39 39 40 40 1 41 42 43 43 44 44 45 5 40 46 47 47 48 4 49 49 50 50 CLIENT Winchip Construction JOB NO. 21-456 DRILLER DD/MSS WATER TABLE N/A DATE 8/2/21 TEST DATA Dynamic Cone Penetrometer (ASTM Publication #399) These Sol[ 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, 3 86 6 PROSPECT AVENUE • SUITE 9 • WEST PALM UhAUH, rLUMIUM oaYuy. - %­ -1 PROJECT Harbour Ridge PLAT #21 LOT "K" 804 N E WINTERS CREEK ROAD - St Lucie County; FI LOCATION B-2 (Approximate) BORING NO. 2 nooi mniniAOV ADnI IAIM PYICTIMr; RTRUCTURE CLIENT Winchip Construction JOB NO. 21-456 DRILLER -DD/MSS ' WATER TABLE N/A DATE 8/2/21 TEST DATA Dynamic Cone Penetrometer (ASTM Publication #399) These Soll 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. i 3866 PROSPECT AVENUE . SUITE 9 • WEST PALM BEACH, FLORIDA 33404 a (561) 881-19sa PROJECT Harbour Ridge-PLAT#21 -LOT "K" - 804 N E WINTERS CREEK ROAD -St. Lucie County, FI LOCATION B-3 (Approximate) BORING NO. 3 o MCI 1KAIMADV ADnI Mir) GYICTIAIC, CTRI Ir.TI Ipr- DEPTH ..__..-..... - - DESCRIPTION OF MATERIAL Sam ple Ne Blows Per Foot DEPTH 1 0'-1' Dark Grey Fine Sand, slight trace of roots and concrete debris 1'-5' Light Grey Fine Sand 1-1 1 2 3-5 2 3 6-7 3 4 9-9 4 5 9-9 5 3-3 6 6 5'-7' Tan Fine Sand ' 7'-12' Brown Fine Sand, trace of marl 12'-18' Grey Fine Sand, some marl 18'-20' Brown Fine Sand 7 3-4 8 4-4 8 9 4-5 10 5-6 10 11 4-8 11 12 8-9 12 13 10-10 13 14 10-9 14 15 10-11 15 16 2-5 16 17 5-6 17 18 7-7 18 19 8-7 19 20 7-8 20 21 21 22 22 23 23 24 24 25 2 26 2 27 27 28 28 29 29 30 30 31 3 32 32 33 •33 34 34 35 35 36 36 37 37 38 38 39 39 40 40 41 41 42 2 43 43 44 44 45 45 46 46 47 47 48 48 49 49 50 50 CLIENT Winchip Construction JOB No. 21-456 DRILLER DD/MSS WATER TABLE 11' DATE 812/21 TEST DATA In genera( accordance with ASTM D-1586 These Sol] 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.