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Home My WebLink AboutKSM Engineering & TestingHeadquarters Mailing 11345 U.S. Highway 1 P.O. Box 78-1377 Sebastian, FL. 32958 Sebastian, FL. 32978 Orlando Phone: 772-589-0712 723 Progress Way C.A. # 5693 Sanford, FL. 32771 KSMengineering.net Page 1 of 4 May 1, 2021 Christopher Carter Carter's Concrete Construction 5610 Smith Lane Ft. Pierce, FL 34982 Re: 1812 Wildcat Cove Drive Lot 52, Riverpointe at the Sands Fort Pierce, Florida KSM Project #: 213141-b Dear Mr. Carter: As requested, KSM Engineering & Testing has performed a subsurface investigation at the referenced site. Presentation of the data gathered during the investigation, together with our geotechnical related opinions, are included in this report. Site Description: At the time of drilling, the river front site was fairly flat with light surface vegetation (grass). Project Description: A one-story single-family residence, approximately 3,500 sq ft is planned to be constructed on the site. Loads from the one-story structure will be transferred to the ground by conventional shallow footings. We anticipate maximum wall loads for the structure will be less than 2,500 pounds per linear foot along the wall foundation. We estimate several feet of site fill will be required to reach the desired grades. The scope of our study consisted of the following: 1. Performed Standard Penetration Test Borings in the proposed construction area to estimate the subsoil relative density. 2. Measured the observed groundwater level at each boring. 3. Evaluated the existing soil conditions with respect to the proposed construction and provided recommendations for site preparation and foundation design. 4. Prepared this report to document our findings. 1812 Wildcat Cove Drive Fort Pierce, Florida KSM Project #: 213141-b Page 2 of 4 Site Investigation: The site investigation program consisted of performing three (3) Standard Penetration Test borings in the proposed construction area. The borings were terminated at depths of 10 to 14 feet below grade. The locations of the borings are indicated on the attached boring logs. The SPT borings were completed in accordance with procedures described in ASTM D-1586. A standard 1.5 inch I.D., 2 inch O.D. split-spoon sampler is driven into the soil by successive blows of a 140 pound hammer freely falling 30 inches. The number of blows required to drive the sampler 1 foot, after seating 6 in., is designated the Penetration Resistance, or "N" value. At regular intervals the sampler is extracted from the ground and opened to allow visual examination and classification of the retained soil sample. The records of the soils encountered, the penetration resistances and groundwater level are shown on the attached logs. Engineering Evaluation and Conclusions: Based on the information obtained from this site investigation we are pleased to offer the following evaluation: The boring logs indicate the subsurface soils consist mostly of fine-grained sand however a layer of very loose clayed silt was encountered in all the boring locations. In the location of B-2 and B-3 the layer was encountered at 3.5 to 5 feet below grade and in B-1 the layer was encountered at 5 to 9 feet below grade. Please refer to the soil boring logs for specific information relative to the soil description. "N" values recorded during the boring operation indicate the existing soil density is generally medium-dense excluding the very loose clayed silt. Please refer to the soil boring logs for specific information relative to the soil description. In order for a shallow foundation to perform satisfactorily, it must be able to support the structural loads with an acceptable factor of safety against excessive settlements; both total and differential. Due to the settlement potential of the very loose sandy clay/silt layers found on the site, we do not recommend supporting the proposed residence on conventional shallow footings. The anticipated settlement, in our opinion, would be too excessive and beyond the general accepted safe limits for the structure. In order to avoid any damaging structural distress due to settlements, a more appropriate foundation system would be an engineered concrete steel reinforced “waffle type” structural slab designed for a net soil contact pressure not exceeding 1,500 psf designed for differential settlement. The structural slab foundation shall have a footing below all load bearing walls, reinforced with both top and bottom steel and poured monolithically with the concrete slab. The slab should be reinforced with rebars and have interior deepened reinforced sections so that the maximum slab span does not exceed 20 feet in any direction. We also recommend, to limit settlement, the very loose soils nearest to the surface should be densified through cement grouting under pressure. We recommend a representative from our firm be present to observe, document, and certify that the weak soil layer was properly stabilized. The following sections provide our recommendations for site preparation and pressure grouting. 1812 Wildcat Cove Drive Fort Pierce, Florida KSM Project #: 213141-b Page 3 of 4 Site Preparation: The proposed building area and areas to be paved, plus a minimum margin of five feet beyond the proposed construction shall be stripped and grubbed of surface debris, including vegetation, roots and organic matter. The building area should be graded level and proofrolled. Any soft yielding areas shall be excavated and replaced with clean compacted fill. Sufficient passes should be made during the compaction operations to produce a density no less than 95 percent of its modified dry Proctor value (ASTM D 1557) to a depth of two feet. No large vibratory equipment should be utilized due to neighboring structures. After the exposed surface has been proofrolled, the building and pavement areas may be filled to the desired grades. Additional fill material shall consist of clean granular sand containing less than 10% material passing the U.S. Standard No. 200 mesh sieve. Structural fill should be placed in uniform loose layers of 12 inches in thickness and compacted to at least 95 percent of its modified dry Proctor value (ASTM D 1557). We recommend field density tests be performed at appropriate times during the earth work operations in order to verify that the site has been properly constructed. Pressure Grouting: Prior to beginning the pressure grout stage, the site preparation stage must be concluded which includes the placement and compaction of fill to subgrade. This is especially important on this site due to the depth at which we encountered the very loose soil layer. The injection points of the pressure grouting shall not exceed 5 feet on center below load bearing walls (interior and exterior locations) and at least 1 per column pad which is less than 3 x 3. Column pads greater than 3 x 3 and less than 6 x 6 shall have 2 points. The contractor shall offset the bearing wall injection points to ensure proper densification under the foundations. KSM recommends providing an injection point plan for our review prior to the installation of pressure grouting. The tip of the injection point should penetrate the soft soils so that the injection points create a lift of at least 1/8 of an inch of ground heave. We recommend the design grout mix per batch should be proportioned as to prevent excessive travel which would prevent compactive effort or an admixture used to facilitate the gelling time of the grout to allow for the seal of the grout hole to set. The licensed contractor should be experienced in soil pressure grouting, and the mix utilized in the field can be modified under their direct supervision. The mix may also need to be modified based on the thickness layer. The decision of the mixture is the responsibility of the licensed grout contractor. Upon completion of the recommended pressure grouting by a licensed contractor in a workmanlike manner following industry standards, KSM requires the densification of the soils be verified with additional soil borings to ensure that the specified soil densification is achieved prior to any additional foundation work starting. The total number of required borings is determined by the size of the project along with judgement of the Lead Driller during the drilling process. 1812 Wildcat Cove Drive Fort Pierce, Florida KSM Project #: 213141-b Page 4 of 4 Closure: This report has been prepared in accordance with generally accepted soil and foundation engineering practices based on the results of the borings and the assumed loading conditions. This report does not reflect any variations which may occur between the borings. If variations appear evident during the course of construction, it would be necessary to re- evaluate the recommendations of this project. We are pleased to be of assistance to you on this phase of your project. When we may be of further service to you or should you have any questions, please feel free to contact us. Respectfully, Julie E. Keller, P.E. President P.E. #68366 JEK/cv E-mail to: cartersconcrete@hotmail.com Gray Sand with Traces of Root Light Brown Sand Gray Sand with Traces of Shell Gray Clayed Silt Light Gray Sand with Traces of Shell Light Gray Sand Bottom of borehole at 14.0 feet. SS SS SS SS SS SS SS 3-5-5 (10) 2-1-2 (3) 3-2-3 (5) 1-1-0 (1) 1-2-4 (6) 8-11-15 (26) 10-13-17 (30) NOTES See Attached Location Plan GROUND ELEVATION LOGGED BY CS/MM DRILLING METHOD Split Spoon Sample DRILLING CONTRACTOR GROUND WATER LEVELS: CHECKED BY JEK DATE STARTED 4/29/21 COMPLETED 4/29/21 AT TIME OF DRILLING 2.25 ft AT END OF DRILLING --- AFTER DRILLING --- HOLE SIZE inches FINES CONTENT (%) 20 40 60 80 20 40 60 80 PL LLMC DEPTH(ft)0 5 10 GRAPHICLOGMATERIAL DESCRIPTION SAMPLE TYPENUMBERRECOVERY %(RQD)BLOWCOUNTS(N VALUE)POCKET PEN.(tsf)DRY UNIT WT.(pcf) SPT N VALUE 20 40 60 80 PAGE 1 OF 1 BORING NUMBER B-1 CLIENT Carter's Concrete Construction PROJECT NUMBER 213141-b PROJECT NAME 1812 Wildcat Cove Drive, Lot 52 PROJECT LOCATION Riverpointe at the Sands, Fort Pierce, FL GEOTECH BH PLOTS - GINT STD US LAB.GDT - 4/30/21 13:55 - K:\KSM FILES\21 DOCS (KSM-SERVER)\213141\SOIL INVESTIGATION\213141-B.GPJKSM Engineering & Testing P.O. Box 78-1377 Sebastian, FL 32978 Tel: (772)-589-0712 Fax: (772)-589-6469 KSM Gray Sand with Traces of Root Light Brown Sand Light Gray Sand with Traces of Shell Gray Clayed Silt Light Gray Sand with Traces of Shell Bottom of borehole at 10.0 feet. SS SS SS SS SS 2-3-3 (6) 2-2-7 (9) 6-6-2 (8) 1-1-0 (1) 1-4-6 (10) NOTES See Attached Location Plan GROUND ELEVATION LOGGED BY CS/MM DRILLING METHOD Split Spoon Sample DRILLING CONTRACTOR GROUND WATER LEVELS: CHECKED BY JEK DATE STARTED 4/29/21 COMPLETED 4/29/21 AT TIME OF DRILLING 2.42 ft AT END OF DRILLING --- AFTER DRILLING --- HOLE SIZE inches FINES CONTENT (%) 20 40 60 80 20 40 60 80 PL LLMC DEPTH(ft)0 5 10 GRAPHICLOGMATERIAL DESCRIPTION SAMPLE TYPENUMBERRECOVERY %(RQD)BLOWCOUNTS(N VALUE)POCKET PEN.(tsf)DRY UNIT WT.(pcf) SPT N VALUE 20 40 60 80 PAGE 1 OF 1 BORING NUMBER B-2 CLIENT Carter's Concrete Construction PROJECT NUMBER 213141-b PROJECT NAME 1812 Wildcat Cove Drive, Lot 52 PROJECT LOCATION Riverpointe at the Sands, Fort Pierce, FL GEOTECH BH PLOTS - GINT STD US LAB.GDT - 4/30/21 13:55 - K:\KSM FILES\21 DOCS (KSM-SERVER)\213141\SOIL INVESTIGATION\213141-B.GPJKSM Engineering & Testing P.O. Box 78-1377 Sebastian, FL 32978 Tel: (772)-589-0712 Fax: (772)-589-6469 KSM Gray Sand with Traces of Root Light Brown Sand with Traces of Shell Gray Clayed Silt Light Gray Sand with Traces of Shell Bottom of borehole at 10.0 feet. SS SS SS SS SS 2-3-3 (6) 3-8-9 (17) 2-2-5 (7) 6-6-8 (14) 6-7-8 (15) NOTES See Attached Location Plan GROUND ELEVATION LOGGED BY CS/MM DRILLING METHOD Split Spoon Sample DRILLING CONTRACTOR GROUND WATER LEVELS: CHECKED BY JEK DATE STARTED 4/29/21 COMPLETED 4/29/21 AT TIME OF DRILLING 2.58 ft AT END OF DRILLING --- AFTER DRILLING --- HOLE SIZE inches FINES CONTENT (%) 20 40 60 80 20 40 60 80 PL LLMC DEPTH(ft)0 5 10 GRAPHICLOGMATERIAL DESCRIPTION SAMPLE TYPENUMBERRECOVERY %(RQD)BLOWCOUNTS(N VALUE)POCKET PEN.(tsf)DRY UNIT WT.(pcf) SPT N VALUE 20 40 60 80 PAGE 1 OF 1 BORING NUMBER B-3 CLIENT Carter's Concrete Construction PROJECT NUMBER 213141-b PROJECT NAME 1812 Wildcat Cove Drive, Lot 52 PROJECT LOCATION Riverpointe at the Sands, Fort Pierce, FL GEOTECH BH PLOTS - GINT STD US LAB.GDT - 4/30/21 13:55 - K:\KSM FILES\21 DOCS (KSM-SERVER)\213141\SOIL INVESTIGATION\213141-B.GPJKSM Engineering & Testing P.O. Box 78-1377 Sebastian, FL 32978 Tel: (772)-589-0712 Fax: (772)-589-6469 KSM NONE 20210430213141-b PROJECT: DATE: SCALE: SHEET OF DRAWN BY: DESIGNED BY: PROJECT #: C.V. J.K. 1 1812 Wildcat Cove Drive, Lot 52, Riverpointe at the Sands, Fort Pierce, Florida PERMIT #: 1 LOCATION OF SOIL BORINGS B-1 B-2 B-3