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HomeMy WebLinkAboutsoil bearingHeadquarters 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 6 Mark Montalto Sr. March 4, 2022 c/o R & E Loader Service, Inc. 375 SW Dalton Circle Port St. Lucie, Florida 34953 Re: 11850 Twin Creeks Drive Port St. Lucie, Florida KSM Project #: 2201666-b Dear Mr. Montalto: 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 canal front site was fairly flat with a few oak and palm trees. The site appeared to be approximately 2 feet above existing road elevation, and there appeared to be approximately 3 feet of existing fill on the center of the property. Project Description: It is our understanding that a one-story, single-family residence is planned to be constructed on the site. Although our office has not been furnished with structural loading conditions or a foundation plan, for our geotechnical analysis we have assumed that loads from the structure will be transferred to the ground by conventional shallow footings and we estimate the maximum loads will be less than 2,000 pounds per linear foot along the wall foundations. We assume approximately 0 to 2 feet of additional fill may be installed to reach the finished building pad elevation. The Structural engineer of record should notify our office if more fill is needed to achieve finished grade for this project. 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 groundwater level at each boring. 3. Evaluated the discovered subsurface conditions with respect to the proposed construction and provided recommendations for site preparation and foundation design. 4. Prepared this report to document our findings. 11850 Twin Creeks Drive Port St. Lucie, Florida KSM Project #: 2201666-b Page 2 of 6 Site Investigation: The site investigation program consisted of performing four (4) Standard Penetration Test (SPT) borings, in the proposed construction area. The SPT borings were terminated at approximate depths of 10 to 25 feet below existing grade. Please note, borings 1, 3, and 4 were performed on the existing pad, and boring 2 was performed North of the existing pad. The locations of the borings are indicated on the attached location plan. The SPT borings were completed in general accordance with procedures described in ASTM D-1586. Also, the groundwater table was allowed to stabilize, and the depth of the groundwater elevation recorded from existing grade. 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: Subsurface Conditions Summary - The boring logs indicate the subsurface soils discovered and the SPT “N” values recorded during the boring process in the proposed project area consist mostly of the following: • Deposits of very loose to medium-dense fine-grained clayed sand, fine-grained sand with traces of clay and rock, and fine-grained sand with traces of roots were discovered from the surface to an approximate depth of 13 feet below existing grade. • Deposits of very loose to loose fine-grained silty sand with traces of shell fragments were encountered from an approximate depth of 13 feet to about 23 feet below existing grade. • Deposits of medium-dense fine-grained sand with shell fragments were found approximately 23 feet to about 25 feet below existing grade. Please refer to the attached soil boring logs for specific information relative to the soil description and the SPT resistance record. Observed Groundwater Table - The observed water table was encountered at approximate depths ranging from 90 to 98 inches below existing grade. Foundation Evaluation – Based on the site plan provided to us by the client, it is our understanding that the proposed structure will extend into portions of the site that are not at the current elevation of the existing building pad. Therefore we expect that fill material will be placed on, what we assumed to be the historically undeveloped land surface. Based on the discovered subsurface conditions we anticipate that the fill 11850 Twin Creeks Drive Port St. Lucie, Florida KSM Project #: 2201666-b Page 3 of 6 material placed in the areas that are not within the existing building pad will settle due to the assumption that the land has not experienced loading in the past. In order for shallow foundations to perform satisfactorily, they must be able to support the dead weight and live loads applied by and on the structure with an acceptable factor of safety against both a shear failure in the subgrade soil and settlements, both total and differential, must lie within acceptable limits. The exploration revealed that a very loose, potentially compressible, layer of silty sand was discovered that extended between approximately 13 to 20 feet below existing grade in borings 1 and 2. KSM has concluded that adding significant stress to this soil layer could trigger compression (consolidation) of the soil, leading to excessive settlement, both total and differential. It is KSM’s opinion that excessive settlements can be mitigated by densifying the soil below the base of the foundations, to stiffen the discovered very loose and loose clayed sand and slightly clayed sand deposits, and by limiting the width of the foundations, to avoid transferring stress to the very loose silty sand deposits. It is also important on this site to limit the amount of fill that will be used to reach the finished building pad elevation. The following sections provide recommendations for the site preparation and foundation design. Site Preparation: Site Subgrade Preparation – Due to the near surface weak soils, KSM recommends that the building site subgrade be prepared for construction of the foundations and floor slabs- on-grade by improving the in-place density of the soil that will support the structure within the zone where the stress from the structure will be primarily distributed. KSM has assumed that the proposed finished floors of the structure lies above the discovered land surface level. The following earthwork procedure is recommended. 1. The proposed construction area, plus a minimum margin of five feet beyond the proposed limit of construction, should initially be prepared by removing any organic materials including roots and surface vegetation. 2. The exposed surface, created in step 1 above, should be graded level and proofrolled to compact the subgrade. Sufficient passes of the roller should be made to produce an in-place dry density that equals or exceeds 95 percent of the Modified Proctor (ASTM D-1557) maximum dry density to a depth of 2 feet below the proofrolled surface. 3. Upon completion of the proofrolling operation, the exposed surface should be filled to produce the desired line and grades of the building pad. Fill should consist of sandy soil containing less than 10% material that passing through the U.S. Standard no. 200 sieve and is free of debris and organic material. The fill should be placed in level lifts not more than 12-inches thick, moisture conditioned, and compacted to attain an in- place dry density that equals or exceeds 95 percent of the Modified Proctor (ASTM D- 1557) maximum dry density. 11850 Twin Creeks Drive Port St. Lucie, Florida KSM Project #: 2201666-b Page 4 of 6 4. Excavate the compacted pad to the proposed foundation subgrade elevation. The exposed footing subgrade should then be compacted to attain an in-place dry density that equals or exceeds 95 percent of the Modified Proctor (ASTM D- 1557) maximum dry density, to depth of 24 inches below the footing subgrade surface. This can be achieved by making several passes with a “Jumping Jack” impact type compactor. Testing should be done to confirm that the specified level of compaction has been achieved. 5. Following the successful completion of the preparation of the foundation subgrade, foundation forms (if used) and steel reinforcement should be placed, and the foundation concrete should be cast, as necessary. Any backfill that is placed adjacent to the foundations, as well as backfill placed in utility trench excavations within the building pad, should be likewise compacted to attain or exceed 95 percent of the Modified Proctor (ASTM D-1557) maximum dry density. Compaction Equipment - KSM does not recommend using heavy vibratory equipment on this site, due to the proximity of the neighboring structures and the potential that ground vibrations created by the compaction machinery might be transmitted and cause damage to the nearby structures. Accordingly, non-vibratory compaction methods are preferred to perform the recommended earthwork delineated above. Compaction Testing - In-place density of the compacted soil can be verified using a nuclear density gauge or any other ASTM approved method to determine percent compaction. It is our recommendation that compaction tests in the excavated footings should be conducted prior to placement of any steel or concrete and conducted at every column footing and once for every 100 linear feet of footing trench. Subgrade and each lift (12” max) of fill should be tested for compaction at a frequency of no less than one test per 2,500 sf of building area, per lift and one test per 10,000 sf of pavement area, per lift with a minimum of 4 tests in each area prepared. The placement and frequency of testing can be modified at the discretion of the site contractor and the onsite soils technician based on the requirements of the project as stated by the Engineer of Record. Foundation: Provided that our recommendations for site preparation are followed, the proposed structure may be supported on conventional concrete, steel reinforced footings designed for an allowable soil bearing pressure of 2,000 pounds per square foot, or less. KSM recommends that concrete slabs-on-grade be steel reinforced structures that feature integrally-cast strip footings beneath the load bearing walls that are reinforced with both top and bottom steel. In order to avoid any major cracks in the interior slabs-on-grade, due to differential settlement, the floor slab should also be reinforced. KSM recommends installing, at the minimum, 6 x 6 - W4.0 X W4.0 Welded Wire Mesh (W.W.M.) in place of the 6 x 6 - W1.4 X W1.4 W.W.M. that is commonly specified to withstand internal temperature related tensile stresses in the concrete. The W.W.M. should be supported on concrete bricks at 11850 Twin Creeks Drive Port St. Lucie, Florida KSM Project #: 2201666-b Page 5 of 6 a maximum spacing of 3 feet on center. Alternatively, #3 steel reinforcing bars, placed at 16" O.C. (each way) may be used in place of the 6 X 6 - W4.0 X W4.0 W.W.M. With the foundation properly designed and the site properly prepared, we anticipate total settlements less than ¾ of an inch and differential settlement of less than ¼ of an inch. The majority of the settlement should occur during construction. This is based on the assumed loading conditions stated in the “project description” section of this report and a minimum continuous footer width of 16 inches with a minimum embedment of 16 inches. Please note that the continuous footer width should not exceed 24 inches. The Structural engineer of record should notify our office if the design loading or foundations differ from our assumptions so that we may provide additional settlement calculations. Floor Slabs: A conventional slab-on-grade can be used in the “at grade” portion of the buildings. We recommend the disturbed subgrade below the floor slab be re-compacted to 95 percent of the modified Proctor maximum dry density (ASTM D 1557) prior to placement of the concrete. We recommend that control joints be incorporated in the slab at frequent intervals to control shrinkage cracks. A moisture barrier is recommended beneath the floor slab to prevent moisture migration from the underlying soil resulting in dampness of the slab. Closure: Based upon our subsurface investigation at the above-mentioned project location, the reliance of the recommendations presented within this signed and sealed report is predicated on KSM representation to verify that not only have the soils been prepared following the indicated recommendations, but the foundations are installed in compliance within the parameters indicated. The Structural Engineer of Record is responsible for confirming the estimated loading and that the foundation parameters indicated are structurally adequate. If the indicated assumed loads are found to be less than actual loads, KSM is to be notified so that our recommendations can be amended as required. This report has been prepared in accordance with generally accepted soil and foundation engineering practice based on the results of the test borings and 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. Environmental conditions, wetland delineation, karst activity, water quality, and municipal requirements are not a part of this report. 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 the office. 11850 Twin Creeks Drive Port St. Lucie, Florida KSM Project #: 2201666-b Page 6 of 6 Respectfully, Robert T. Maxwell, E.I. Cody C. Clawson, P.E. Geotechnical Engineer Geotechnical Engineer Florida E.I. No. 1100024249 Florida Lic. No. 91598 CCC/cv/RTM E-mail to: reloaderserviceinc@gmail.com Dark Brown Clayed Sand Gray Clayed Sand Gray/Orange Clayed Sand Light Gray Slightly Clayed Sand Brown Sand with Traces of Clay and Rock Gray Silty Sand with Traces of Shell Fragments Gray Sand, Slightly Silty with Shell Fragments Light Brown Sand with Shell Fragments Bottom of borehole at 25.0 feet. SS SS SS SS SS SS SS SS 1-1-1 (2) 1-2-3 (5) 4-4-4 (8) 5-5-4 (9) 2-2-3 (5) 7-5-1 (6) 1-0-0 (0) 10-12-12 (24) NOTES See Attached Location Plan GROUND ELEVATION LOGGED BY SF/SH/MM DRILLING METHOD Split Spoon Sample DRILLING CONTRACTOR GROUND WATER LEVELS: CHECKED BY CCC DATE STARTED 2/21/22 COMPLETED 2/21/22 AT END OF DRILLING --- AFTER DRILLING --- HOLE SIZE inches AT TIME OF DRILLING 8.17 ft FINES CONTENT (%) 20 40 60 80 20 40 60 80 PL LLMC DEPTH(ft)0 5 10 15 20 25 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 R & E Loader Service, Inc. PROJECT NUMBER 2201666-b PROJECT NAME 11850 Twin Creeks Drive PROJECT LOCATION Port St. Lucie, Florida GEOTECH BH PLOTS - GINT STD US LAB.GDT - 3/4/22 10:29 - K:\KSM FILES\22 DOCS (KSM-SERVER)\2201666\SOIL INVESTIGATION\2201666-B.GPJKSM Engineering & Testing P.O. Box 78-1377 Sebastian, FL 32978 Tel: (772)-589-0712 Fax: (772)-589-6469 KSM Dark Gray Sand with Traces of Root Light Gray Clayed Sand Light Brown Sand Gray Silty Sand with Traces of Shell Bottom of borehole at 15.0 feet. SS SS SS SS SS SS 2-8-7 (15) 5-7-7 (14) 7-7-6 (13) 8-9-9 (18) 5-4-4 (8) 2-0-1 (1) NOTES See Attached Location Plan GROUND ELEVATION LOGGED BY JP/TG/EK DRILLING METHOD Split Spoon Sample DRILLING CONTRACTOR GROUND WATER LEVELS: CHECKED BY CCC DATE STARTED 2/23/22 COMPLETED 2/23/22 AT END OF DRILLING --- AFTER DRILLING --- HOLE SIZE inches AT TIME OF DRILLING 7.50 ft FINES CONTENT (%) 20 40 60 80 20 40 60 80 PL LLMC DEPTH(ft)0 5 10 15 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 R & E Loader Service, Inc. PROJECT NUMBER 2201666-b PROJECT NAME 11850 Twin Creeks Drive PROJECT LOCATION Port St. Lucie, Florida GEOTECH BH PLOTS - GINT STD US LAB.GDT - 3/4/22 10:29 - K:\KSM FILES\22 DOCS (KSM-SERVER)\2201666\SOIL INVESTIGATION\2201666-B.GPJKSM Engineering & Testing P.O. Box 78-1377 Sebastian, FL 32978 Tel: (772)-589-0712 Fax: (772)-589-6469 KSM Light Brown Slightly Clayed Sand Gray Sand Dark Gray Clayed Sand with Traces of Root Light Brown Clayed Sand Bottom of borehole at 10.0 feet. SS SS SS SS SS 1-1-1 (2) 1-1-1 (2) 1-3-3 (6) 6-7-7 (14) 6-7-8 (15) NOTES See Attached Location Plan GROUND ELEVATION LOGGED BY JP/TG/EK DRILLING METHOD Split Spoon Sample DRILLING CONTRACTOR GROUND WATER LEVELS: CHECKED BY CCC DATE STARTED 2/23/22 COMPLETED 2/23/22 AT END OF DRILLING --- AFTER DRILLING --- HOLE SIZE inches AT TIME OF DRILLING 7.67 ft 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 R & E Loader Service, Inc. PROJECT NUMBER 2201666-b PROJECT NAME 11850 Twin Creeks Drive PROJECT LOCATION Port St. Lucie, Florida GEOTECH BH PLOTS - GINT STD US LAB.GDT - 3/4/22 10:29 - K:\KSM FILES\22 DOCS (KSM-SERVER)\2201666\SOIL INVESTIGATION\2201666-B.GPJKSM Engineering & Testing P.O. Box 78-1377 Sebastian, FL 32978 Tel: (772)-589-0712 Fax: (772)-589-6469 KSM Brown Clayed Sand with Root Gray Clayed Sand Light Gray Clayed Sand Bottom of borehole at 10.0 feet. SS SS SS SS SS 1-3-3 (6) 3-4-9 (13) 4-8-7 (15) 6-7-7 (14) 4-4-3 (7) NOTES See Attached Location Plan GROUND ELEVATION LOGGED BY JP/TG/EK DRILLING METHOD Split Spoon Sample DRILLING CONTRACTOR GROUND WATER LEVELS: CHECKED BY CCC DATE STARTED 2/21/22 COMPLETED 2/21/22 AT END OF DRILLING --- AFTER DRILLING --- HOLE SIZE inches AT TIME OF DRILLING 7.75 ft 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-4 CLIENT R & E Loader Service, Inc. PROJECT NUMBER 2201666-b PROJECT NAME 11850 Twin Creeks Drive PROJECT LOCATION Port St. Lucie, Florida GEOTECH BH PLOTS - GINT STD US LAB.GDT - 3/4/22 10:29 - K:\KSM FILES\22 DOCS (KSM-SERVER)\2201666\SOIL INVESTIGATION\2201666-B.GPJKSM Engineering & Testing P.O. Box 78-1377 Sebastian, FL 32978 Tel: (772)-589-0712 Fax: (772)-589-6469 KSM NOT TO SCALE 202202252201666-b PROJECT: DATE: SCALE: SHEET OF DRAWN BY: DESIGNED BY: PROJECT #: C.V. C.C.C.1 11850 Twin Creeks Drive, Port St. Lucie, Florida PERMIT #: 1 LOCATION OF SOIL TESTING B-1 B-2 B-3 B-4