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HomeMy WebLinkAboutADDITIONAL SUBSURFACE SOIL EXPLORATIONel f SCANNED BY ST LUOIE 09YNTY Additional Subsurface Soil Exploration New Single -Family Residence 4905 River Place St. Lucie County, Florida 7=011AWN OFFICES RECEIVED WAY 0 7 MR Permitting Department St. Lucie County Orlando — 8008 S. Orange Avenue, Orlando Florida 32809 — Phone (407) 8553860 Alexandria — 3609 Mac Lee Drive, Alexandria, Louisiana 71302 — Phone (318) 443-2888 Bartow —1525 Centennial Drive, Bartow, Florida 33830 — Phone (863) 533-0858 Baton Rouge — 316 Highlandia Drive, Baton Rouge, Louisiana 70884 — Phone (225) 752-4790 Cocoa —1300 N. Cocoa Blvd., Cocoa, Florida 32922 — Phone (321) 632-2503 Fort Myers — 9970 Bavaria Road, Fort Myers, Florida 33913 — Phone (239) 768-6600 Miami — 2608 W. 84th Street, Hialeah, Florida 33016 — Phone (305) 825-2683 Monroe —1122 Hayes Street, West Monroe, Louisiana 71292 — Phone (318) 387-4103 New Orleans —1305 Distributors Row, Suite I, Jefferson, Louisiana 70123 — Phone (504) 835-2593 Port St Lucie — 460 Concourse Place NW, Unit 1, Port St Lucie, Florida 34986 — Phone (772) 878-0072 Sarasota — 78 Sarasota Center Blvd., Sarasota, Florida 34240 — Phone (941) 922 3526 Shreveport— 7222 Greenwood Road, Shreveport, Louisiana 71119 — Phone (318) 6363673 Tallahassee — 3175 West Tharpe Street, Tallahassee, Florida 32303 — Phone (850) 576-6131 Tampa — 3925 Coconut Palm Drive, Suite 115, Tampa, Florida 33619 — Phone (813) 620-3389 West Palm Beach — 2200 North Florida Mango Road, Suite 101, West Palm Beach, Florida 33409 — Phone (561) 687-8200 MEMBERS: A-S F_E American Concrete insti:u­ ASTM International Florida Institute of Consulting Engi r P K R®V E® r � Ardarnan & Associates, Inc. Geotechnical, Environmental and Materials Consultants March 27, 2018 Mr. Steve LiCausi 2907 SW Boxwood Circle Port St. Lucie, Florida 34953-6966 Subject: Additional Subsurface Soil Exploration New Single -Family Residence 4905 River Place St. Lucie County, Florida Mr. LiCausi: As requested and authorized by you, we have completed an additional subsurface soil exploration for the subject project. The purposes of performing this exploration were to evaluate the general subsurface conditions within the proposed building area following the reported demucking operation conducted without notifying Ardaman & Associates, Inc. (Andaman). This report documents our findings and presents our engineering conclusions. SITE LOCATION AND SITE DESCRIPTION The subject site is located at 4905 River Place (Lot 4) in White City, St. Lucie County, Florida. The subject site is situated in Section 4, Township 36 South, Range 40 East. At the time of our field explorations were performed, the subject residential lot was cleared of vegetation and recently backfilled following a reported demucking operation. PROPOSED CONSTRUCTION AND GRADING It is our understanding that the proposed construction consists of a one-story, approximate 3,000- square foot (or less) residence. We anticipate that the proposed building will consist of load bearing masonry walls and interior columns with a slab -on -grade floor. Maximum anticipated loading conditions for the building are assumed to be on the order of 2 to 3 kips per linear foot for wall foundations, 30 to 40 kips for individual column foundations, and 100 pounds per square foot (psf) for the floor slab. Grading plans are not completed at this time; therefore, we have assumed that less than 2 feet of fill is required to raise the building area to final elevation. If actual building loads or fill height exceed our assumptions, then the recommendations in this report may not be valid. BACKGROUND Ardaman previously performed a geotechnical exploration of the site in 2015, consisting of two auger borings and two Standard Penetration Test (SPT) borings to a depth of 15 feet below the existing ground surface. The soil borings from the 2015 exploration generally encountered very loose to medium dense fine sand with silt (Unified Soil Classification SP-SM), silty fine sand (SM) and clayey fine sand (SC) with varying amounts of roots, organics and vegetative debris at depths 460 NW Concourse Place, Unit 1, Port St. Lucie, FL 32986 Phone (772) 878-0072 Louisiana: Alexandria, Baton Rouge, Monroe, New Orleans, Shreveport Florida: Bartow, Cocoa, Fort Myers, Miami, Orlando, Port Charlotte, Port St. Lucie, Sarasota, Tallahassee, Tampa, West Palm Beach { LiCausi Residence -2- ranging from 1.5 to 9 feet. These soils were underlain by loose to medium dense fine sand (SP) to the boring termination depth of 15 feet. Recommendations were provided to excavate (demuck) the unsuitable organic soils beneath the building footprint and replace them with suitable sandy soils. We note that it was also recommended to have an Ardaman representative present to monitor the demucking operation and to test the compaction of the backfilled soils. Ardaman representative, Dan Zrallack, P.E. and the owner met at the site to perform test pits within the general area of the proposed residence to observe the consistency and vertical extent of the unsuitable organic soils. The test pits indicated unsuitable organic soils and soils mixed with varying amounts of concrete rubble and various types of other discarded items to depths ranging from about 7 to 10 feet. Ardaman informed the owner that the concrete rubble and discarded items identified in the test pits would also need to be removed along with the organic soils during the demucking operation. After further discussions and considerations of costs to remove the unsuitable materials, the client requested Ardaman to provide recommendations for a deep foundation alternative. In 2016, Ardaman performed an additional SPT boring to a depth of 40 feet below the existing ground surface and provided recommendations for an augered and cast -in -place (augercast) foundation alternative to demucking. Ardaman was recently informed that a contractor was hired to remove the unsuitable soils (demucking) from beneath the proposed building footprint. We note that Ardaman recommended in the 2015 report that the demucking operation should be continuously monitored by a representative of Ardaman. Ardaman was not notified of the demucking operation, and therefore, did not monitor the demucking operation. The owner however was reportedly present during the demucking operation and believes that most of the unsuitable soils were removed and that the contractor compacted the backfilled soils. The owner has since asked Ardaman to perform an additional exploration to evaluate the subsurface conditions at the site following the reported demucking operation. FIELD EXPLORATION PROGRAM SPT Borings The field exploration program described in this report included performing two additional SPT borings (B-4 and B-5) within the proposed footprint of the new residence. The borings were advanced to a depth of 20 feet below the ground surface using the methodology outlined in ASTM D-1586. Split -spoon soil samples recovered during performance of the borings were visually classified in the field and representative portions of the samples were transported to our laboratory in sealed sample jars. The groundwater level at the boring locations was measured during drilling. Upon completion, the borings were backfilled with soil cuttings. Test Locations The approximate locations of the borings are schematically illustrated on a site plan shown on Figure 1. These locations were determined in the field by wheel measuring/estimating distances from existing site features and should be considered accurate only to the degree implied by the method of measurement used. LiCausi Residence -2- LABORATORY PROGRAM Representative soil samples obtained during our field sampling operation were packaged and transferred to our laboratory for further visual examination and classification. The soil samples were visually classified in general accordance with the Unified Soil Classification System (ASTM D-2488). The resulting soil descriptions are shown on the soil boring profiles presented on Figure 2. GENERAL SUBSURFACE CONDITIONS General Soil Profile The results of the field exploration and laboratory programs are graphically summarized on the soil boring profiles presented on Figure 2. The stratification of the boring profiles represents our interpretation of the field boring logs and the results of laboratory examinations of the recovered samples. The stratification lines represent the approximate boundary between soil types. The actual transitions may be more gradual than implied. The results of the borings indicate the following general soil profile: Depth Below Ground Surface Description (Unified Soil Classification) (feet) 0 to 4.5 Loose to medium dense, fine sand (SP) and fine sand with clay (SP-SC) Very loose to medium dense fine sand with 4.5 to 8 clay (SP-SC) and varying amounts of small concrete rubble to mostly small concrete rubble pieces Very loose to medium dense silty fine sand 8 to 11 (SM) with varying amounts for roots and organics 11 to 15 Very loose to medium dense fine sand (SP) and silty fine sand (SM) The above soil profile is outlined in general terms only. Please refer to Figure 2 for soil profile details. Groundwater Level The groundwater level was measured in the boreholes on the day drilled. As shown on Figure 2, groundwater was encountered in the boings at depths of 4.9 and 5.1 feet below the existing ground surface on the date indicated. Fluctuations in groundwater levels should be anticipated throughout the year primarily due to seasonal variations in rainfall and other factors that may vary from the time the borings were conducted. UCausi Residence ENGINEERING EVALUATION ARID CONCLUSION -3- The results of our exploration indicate that the organic soils beneath the building had mostly been removed in the demucking operation, except for some roots and organics mixed with silty fine sand soils at depths ranging from about 8 to 11 feet below the existing ground surface. Additionally, it is apparent that pieces of concrete were used as backfill material between depths of about 4.5 and 8 feet below existing grade. Based on the results of our explorations, it is our opinion that the one-story residence can be supported on conventional shallow foundations provided that the client understands some settlement of the structure may occur over time as the remaining organic soils decompose. We note that the remaining organic soils encountered in the borings were not compressible in nature and were at depths well below the groundwater table. Therefore, the remaining organic soils should not decompose rapidly since they are not exposed to air. In other words, any long-term settlement associated with the decomposition of the remaining organic soils should be negligible and could be remediated as necessary with foundation enhancements such as helical piles. Recommendations for shallow foundations and site preparation and testing procedures were provided in our 2015 report. We strongly recommend that the foundation excavations be inspected by Ardaman to determine if overexcavation of unsuitable soils beneath the foundations is necessary and/or feasible. CLOSURE The analyses and recommendations submitted herein are based on the data obtained from the soil borings presented on Figures 1 and 2, and on the assumed loading conditions and fill heights. This report does not reflect any variations which may occur adjacent to or between the boring locations. The nature and extent of the variations between the boring locations may not become evident until during construction. If variations then appear evident, it will be necessary to re- evaluate the recommendations presented in this report after performing on -site observations during the construction period and noting the characteristics of the variations. This report has been prepared for the exclusive use of the Mr. Steve LiCausi in accordance with generally accepted geotechnical engineering practices. In the event any changes occur in the design, nature, or location of the proposed facility, we should review the applicability of conclusions and recommendations in this report. We recommend a general review of final design and specifications by our office to verify that earthwork and foundation recommendations are properly interpreted and implemented in the design specifications. We are pleased to be of assistance to you on this project. When we may be of further service to you or should you have any questions, please contact us. ARDAMAN & ASSOCIATES, INC. Certificate of Authorization No. 5950 g pan J ^ Zrallac �x T� ' k �� 'r ke Digitally signed by: Dan J Zrallack fanJ. allaek, F.E. r v D[V CN Dan J Zrallack email = dzrallack@ardaman.com C = US OU = Ardaman and a' Associates, Inc. Branc Manager r! t oo, Cj�S k q 'pate ?p�lg .2814:56:52-WW' Florida License No. 63917 r.- - - INDICATES SPT BORING LOCATION SECTION: 4 ai TOWNSHIP: 36 SOUTH z RANGE: 40 EAST Image obtained from Google Earth Pro �K 4�n,adtr q 'A BORING LOCATION PLAN Qj Ardarnan & Associates, Inc. Geotechnical, Environmental and Materials Consultants Additional Subsurface Soil Exploration 4905 River Place - Lot 4 White City, St. Lucie County, Florida ME 140 1 APPROVED BY, FIGUREo DJZ 1 BORING: B-1 DATE DRILLED: 03/15/18 N W 0 5F 10F 15F x a W c 20 8 5 1 14 3 16 20 9 9 3 B-2 03/15/18 N -10 5 2A 12 CONCRETE PIECES 10 2A WITH CONCRETE PIECES 10 3C WITH ROOTS AND ORGANICS 2 15 18 19 22 5 3 8 CONCRETE PIECES 4C 3C WITH ROOTS ORGANICS 16 E9 10 15 20 LEGEND SOIL DESCRIPTIONS COLORS ENGINEERING CLASSIFICATION O1 FINE SAND (SP) AO BROWN I COHESIONLESS SOILS DESCRIPTION BLOW COUNT °N° 20 FINE SAND WITH CLAY (SPSC) © GRAY VERY LOOSE <4 LOOSE 4 TO 10 O3 SILTY FINE SAND (SM) OC DARK BROWN MEDIUM DENSE DENSE 10 TO 30 30 TO 50 VERY DENSE >50 O4 CLAYEY FINE SAND (SC) N STANDARD PENETRATION RESISTANCE IN BLOWS PER FOOT -:L7- GROUNDWATER LEVEL MEASURED ON DATE DRILLED SP,SP-SM UNIFIED SOIL CLASSIFICATION SYSTEM (ASTM D-2487) SM,SC,CH NOTE. ALL SPT BORINGS WERE PERFORMED USING A HAND AUGER IN THE UPPER 4 FEET AND AN AUTOMATIC HAMMER BELOW 4 FEET TO THE BORING TERMINATION DEPTH. AUTOMATIC HAMMER N-VALUES MAYBE CONVERTED TO EQUIVALENT SAFETY HAMMER N•VALUES BY MULTIPLYING BY 1.24. WHILE THE BORINGS ARE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT THEIR RESPECTIVE LOCATIONS AND FOR THEIR RESPECTIVE VERTICAL REACHES, LOCAL VARIATIONS CHARACTERISTIC OF THE SUBSURFACE MATERIALS OF THE REGION ARE ANTICIPATED AND MAY BE ENCOUNTERED. THE BORING LOGS AND RELATED INFORMATION ARE BASED ON THE DRILLER'S LOGS AND VISUAL EXAMINATION OF SELECTED SAMPLES IN THE LABORATORY. THE DELINEATION BETWEEN SOIL TYPES SHOWN ON THE LOGS IS APPROXIMATE AND THE DESCRIPTION REPRESENTS OUR INTERPRETATION OF SUBSURFACE CONDITIONS AT THE DESIGNATED BORING LOCATIONS ON THE PARTICULAR DATE DRILLED. GROUNDWATER ELEVATIONS SHOWN ON THE BORING LOGS REPRESENT GROUNDWATER SURFACES ENCOUNTERED ON THE DATES SHOWN. FLUCTUATIONS IN WATER TABLE LEVELS SHOULD BE ANTICIPATED THROUGHOUT THE YEAR. STANDARD PENETRATION TEST The standard penetration test is a widely accepted test method of in situ testing of foundation soils (ASTM D 1586). A 2-foot long, 2-inch O.D. split -barrel sampler attached to the end of a string of drilling rods is driven 18 inches into the ground by successive blows of a 140-pound hammer freely dropping 30 inches. The number of blows needed for each 6 inches of penetration is recorded. The sum of the blows required for penetration of the second and third 6-inch increments of penetration constitutes the test result or N-value. After the test, the sampler is extracted from the ground and opened to allow visual examination and classification of the retained soil sample. The N-value has been empirically correlated with various soil properties allowing a conservative estimate of the behavior of soils under load. The tests are usually performed at 5-foot intervals. However, more frequent or continuous testing is done by our firm through depths where a more accurate definition of the soils is required. The test holes are advanced to the test elevations by rotary drilling with a cutting bit, using circulating fluid to remove the cuttings and hold the fine grains in suspension. The circulating fluid, which is a bentonitic drilling mud, is also used to keep the hole open below the water table by maintaining an excess hydrostatic pressure inside the hole. In some soil deposits, particularly highly pervious ones, NX size flush -coupled casing must be driven to just above the testing depth to keep the hole open and/or prevent the loss of circulating fluid. Representative split -spoon samples from the soils at every 5 feet of drilled depth and from every different stratum are brought to our laboratory in air -tight jars for further evaluation and testing, if necessary. Samples not used in testing are stored for 30 days prior to being discarded. After completion of a test boring, the hole is kept open until a steady state groundwater level is recorded. The hole is then sealed, if necessary, and backfilled.