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Home My WebLink AboutReport Of Geotechnical ExplorationGF FI k INTERNATIONAL )RIDA'S LEADING ENGINEERING SOURCE port of Geotechnical Exploration Proposed Residence 10701 S Ocean Dr. (Lot B-7 Venture 3) St. Lucie County, Florida April 8, 2013 GFA Project No.: 13-0616.00 For: Mr. Donald L. Snodgrass �saaa ouna., .• aaCCa9�!:`t:. a npaa CY `. 1 Proposed Residence. j Geotechnical Report 10701 S Ocean Dr. (Lot 8-7 Venture 3) April 8, 2013 GFA Project No. 13-0616100 Page 2 of 10 The very organic soils (muck) encountered in the subsurface exploration will likely cause excessive settlement and poor foundation performance if shallow foundations are used for support of the residence. Excavation of the organic soils (demucking) was considered, but due to the depth of muck and water table and water inflow during excavation, muck removal verification would not be accurate. Also, demucking was considered but due to site constraints could not likely be accomplished safely without affecting the adjacent properties. GFA recommends that the proposed residence including the floor slab be supported using a deep foundation system consisting of augered cast -in -place (ACIP) piles. Based on our analysis, GFA has estimated that a 14-inch-diameter ACIP pile installed to a depth of 36 feet below existing grade (grade 1/2feet above the adjacent roadway) can provide a maximum allowable axial complressive capacity of 30 tons and a maximum tension capacity of 10 tons. We appreciate the opportunity to be of service to you on this project and look forward to a continued association. Please do not hesitate to contact us if you have any questions or comments, or if we may further assist you as your plans proceed. Respectfully Submitted, GFA International Inc. Florida Certificate of Authorization Number 4930 Donald W. Moler, P.E. Senior Geotechnical Engineer Florida Registration No. 60675 Copies: 2, Add f t David Alker Project Manager I I I Proposed Residence j Geotechnical Report 10701 S Ocean Dr. (Lot B 7 Venture 3) April 8, 2013 GFA Project No. 13-0616.00 Page 4 of 10 I 1.0 INTRODUCTION i 1.1 Scope of Services The objective of our geotechnical services was to collect subsurface data for the subject project, summarize the test I results, and discuss any apparent site conditions that may have geotechnical significance for building construction. The following scope of services are provided within this report: j 1. Prepare records of the soil boring logs depicting the subsurface soil conditions encountered during our field exploration. i 2. Conduct a review of each soil sample obtained during our field exploration for classification and additional t Isting if necessary. 3. Analyze the existing soil conditions found during our exploration with respect to foundation support for the proposed structure. 4. Provide recommendations with respect to foundation support of the structure, including allowable soil -fearing capacity, bearing elevations, and foundation design parameters. 5. Provide criteria and site preparation procedures to prepare the site for the' proposed construction. I 1.2 Project Description Based on conversations with the client, the project consists of constructing a two-story residence with al ground level footprint on the order of 1575 sf. We have not received any information regarding structural loads. For the foundation recommendations presented in this report we assumed the maximum column load will be 75 kips and the maximum wall loading will be 4 kips per linear foot. We estimate that 1 foot of fill will be required to bring the foundation pad to design glade. The recommendations provided herein are based upon the above considerations. If the project description has been revised, please inform GFA International so that we may review our recommendations -with respect to any modifications. 2.0 OBSERVATIONS 2.1 Site Inspection The project site was generally flat and grassy but cleared. The grade at the site was estimated to be '/2 feeti above the adjacent road at the time of drilling. Two-story residential structures (mobile homes and CBS residences) were adjacent to the property. The site is located on an extension into the Intracoastal Waterway (Indian River) which bordered the east side of the property. Proposed Residence I Geotechnical Report 10701 S Ocean Dr. (Lot B-7 Venture 3) April 8, 2013 GFA Project No. 13-061I .00 Page 6 of 10 The subsurface soil conditions encountered at this site generally consist of very loose sand (SP) to a depth of 5 feet, Ivery soft sand with organic silt (muck) (PT) from 5 to 8%2 feet, medium dense sand (SP) frorp 8'/2 to 26 feet, stiff sand/silt/clay mix (CL,CH) from 26 to 30 feet, and then loose to medium dense sand to the boring termination depths. Of note was hard drilling from about 30 to 33'/2 feel which was indicative of hard cemented sand or rocky layers. Please refer to Appendix D - Record of Test Borings for a detailed account of each boring. 2.5 Hydrogeologidal Conditions On the dates of our field exploration, the groundwater table was encountered at depths of approximately 4% and 43/ feet below the existing ground surface. The groundwater table will fluctuate seasonally depending upon local rainfall and other site specific and/or local influences including hurricane and storm events and the water level in the nearby Intracoastal Waterway (Indian River). Brielf ponding of stormwater may occur across the site after heavy rains. No additional investigation was included in our scope of work in relation to the wet seasonal high groundwaterltable or any existing well fields in the vicinity. Well fields may influence water table levels and cause significant fluctuations. If a more comprehensive water table analysis is necessary, please contact our office for additional guidance. ENGINEERING EVALUATION AND RECOMMENDATIONS 3.1 Foundation Recommendations A foundation system for any structure must be designed to resist bearing capacity failures, have settlements that are tolerable, and resist the environmental forces that the foundation may be subjected to over the life of the structure. The soil bearing capacity is the soil's ability to support loads without plunging into the soil profile. Bearing capacity failures are analogous to shear failures in structural design and are usually sudden and catastrophic. The amount Hof settlement that a structure may tolerate is dependent on several factors including: uniformity of settlement, time rate of settlement, structural dimensions and properties of the materials. Generally, total or uniform settlement does not damage a structure but may affect drainage and utility connections. These can generally tolerate movements of several inches for building construction. In contrast, differential settlement affects a structure's frame and is limited by the -structural flexibility. The very organic soils (muck) encountered in the subsurface exploration will likely cause excessive settlement and poor foundation performance if shallow foundations are used for support of the residence. Excavation of the organic soils (demucking) was considered, but due to the depth of muck and water table and water inflow during excavation, muck removal verification would not be accurate. Also, demucking was considered but due to site constraints could not likely be accomplished safely without affecting the adjacent properties. GFA recommends that the proposed residence be supported using a deep foundation to transfer the structural loads from the surface level to an underlying suitable bearing strata. At this time, GFA recommends the deep foundation to consist of augered cast -in -place piles (ACIP). ACIP pile installation procedures should be performed in accordance with the v if Proposed Residence 11 Geotechnical Report 10701 S Ocean Dr. (LotIS-7 Venture 3) April 8, 2013 GFA Project No. 13-0616.00 Page 8 of 10 1. Pile Length: The proposed 14-inch-diameter piles should be installed to a minimum of 5 feet into the dense cemented sand layer as determined by the inspecting Geotechnical Engineer. If during pile construction the aforementioned bearing layer is not encountered where anticipated, the pile shall be further advanced until a hard bearing stratum is reached as determined by the inspecting Geotechnical Engineer. 2. Spacing Pile's installed in groups should be spaced at a center -to -center distance of not less than 3 pile diameters. 3. Plan Location - The center of the top of any pile at cut-off should be displaced laterally no more than 3 inches from the position shown on the plans. This applies to both single piles and piles installed in groups. 4. Vertical All nment - The vertical alignment of the piling should not deviate from the plumb by more than 114 inch per foot of length. 5. Reinforcing Cage Positioning - The top. of the reinforcing cages installed in the piling should not' be more than 6 inches above and no more than 3 inches below the positions shown in the plans. The reinforcing cages should be positioned concentrically within the grouted pile shaft. The grout cover over longitudinal reinforcing bars should not be less than 3 inches. Reinforcing centralizers shall be placed at maximum spacing of 15 feet at the lower portion of.the pile and at 5 feet from the cage's top. 6. Adjacent Piles - A minimum time period of 12. hours should be specified for the installati n of piles located within 5 feet, center -to -center, of each other. 7. Grout Factor - The minimum acceptable grout factor (i.e. actual grout volume divided by theoretical grout volume) should be 1.2. 3.3 Vibration The proposed (construction will be within close proximity to residential structures and roadways that maybe susceptible to damage from vibration generated at the site. We recommend that during all aspects of construction, the bordering landmarks be monitored using a seismograph to determine Ithe extent of vibration absorption that these features will be subject to. The seismograph used to monitor at this site should have the capability to measure ground velocities along vertical, transverse, and longitudinal axes. The project structural engineer should establish allowable ground velocities that the bordering facilities can safely withstand without any damage.. 3.4 Ground Floor Slab The groundlfloor should be structurally integrated with the pile cap foundation. Water vapor is likely to rise through the granular fill and condense beneath the base of the floor slab. If moisture entry into the floor slab is not desirable, an impermeable membrane should be installed atlthe ,slab bottom - subgrade interface. I FILE COP' A I I j I Proposed Residence 1 10701 S Ocean Dr. (Lot 8-7 Venture 3) GFA Project No. 13-0616.00 The analysis and i from the tests perfc report does not ref! representative of tl reaches, local varis may be encountere and the description boring locations on Any third party reli< the expressed writt D-1586), CPT metl used in performini resistance is specif advance other tool: I I I 5.0 BASIS FOR RECOMMENDATIONS Geotechnical Report April 8, 2013 Page 10 of 10 :)mmendations submitted in this report are based on the data obtained ied at the locations indicated on the attached figure in Appendix B. This any variations, which may occur between borings. While the borings are subsurface conditions at their respective locations and for their vertical ns characteristic of the subsurface soils of the region are anticipated and The delineation between soil types shown on the soil logs is approximate presents our interpretation of the subsurface conditions at the designated particular date drilled. nce of our geotechnical report or parts thereof is strictly prohibited without n consent of GFA International. The applicable SPT methodology (ASTM odology (ASTM D-3441), and Auger Boring methodology (ASTM D-1452) our borings and sounding, and for determining penetration and cone to the sampling tools utilized and does not reflect the ease or difficulty to or materials. Gfl III °� � � \ � elev 0 ft eye dlL 14098 ft 1( WR NOTES RELATED TO RECORDS OF TEST BORING AND GENERALIZED SUBSURFACE PROFILE 1. Groundwater level was encountered and recorded (if shown) following the completion of the soil test boring on the date indicat ld. Fluctuations in groundwater levels are common; consult report text for a discussion. 2. The boring location was identified in the field by offsetting from existing reference marks and using a cloth tape and survey whi el. 3. The borehole was backfilled to site grade following boring completion, and patched with asphalt cold patch mix when pavemept was encountered. 4. The Record of Test Boring represents our interpretation of field conditions based on engineering examination of the soil samples. 5. The Record lof Test Boring is subject to the limitations, conclusions and recommendations presented in the Report text. I 6. "Field TestlData" shown on the Record of Test Boring indicated as 11/6 refers to the Standard Penetration Test (SPT) and means I 1 hammer blows drove the sampler 6 inches. SPT uses a 140-pound hammer falling 30 inches. 7. The N-val le from the SPT is the sum of the hammer blows required to drive the sampler the second and third 6- inch increments. 8. The soil/rock strata interfaces shown on the Records of Test Boring are approximate and may vary from those shown. The soilfrock conditions shown on the Records of Test Boring refer to conditions at the specific location tested; soIR/rock conditions may vary between test locations. 9. Relative density for sands/gravels and consistency for silts/clays are described as follows: SPT I CPT SANDS/GRAVELS SPT -CPT SILTS/CLAYS BLOWS/FOOT KG/CM- RELATIVE DENSITY BLOWS/FOOT KG/CM- CONSISTENCY 0-4 1 0-16 Very loose 0-1 0-3 Very soft 5-10 I 1740 Loose 2-4 4-6 Son 11-30 1 41-120 Medium Dense 5-8 7-12 Firm 31-50 I 121-200 Dense 9-15 13-25 Stiff 50+ 1 over200 I Very Dense 16-30 1 25-50 1 Very stiff I >30 1 >50 Hard 10. Grainlsize descriptions are as follows: NAME I SIZE LIMITS Boulder I 12 Inches or more Cobbles 1 3 to 12 Inches Coarse Gravel N to 3 Inches Fine GraSel No. 4 sieve to % inch Coarse Sand No. 10 to No. 4 sieve MediumlSand No. 40 to No. 10 sieve Fine Sand No. 200 to No. 40 sieve Fines I Smaller than No. 200 sieve 11. Definitions related to adjectives used in soil/rock descriptions: PROPORTION ADJECTIVE APPROXIMATE ROOT DIAMETER ADJECTIVE <5% 1 Trace Less than 1/32" Fine roots 5%to 120/. Little 1/32" to''/<" Small roots 12% to 30% Some W. to I" Medium roots 30% to 50% And Greater than 1" Large roots Organic Soils: Soils containing vegetable tissue in various stages of decomposition that has a fibrous to amorphous texture, usually a dark brown to black color, and an organic odor. Organic Content <25%: Slightly to Highly Organic; 25% to 75%: Muck; >75%: Peat I I 1 FILE C' GFA INTERNATIONAL I521 N.W. ENTERPRISE DRIVE, PORT ST. LUCIE, FLORIDA 34986 PHONE: (772) 924-3575 - FAx: (772) 924-3580 STANDARD PENETRATION TEST BORING (ASTM D-1586) Client: Donald L. Snodgrass Project No.:13-0616.00 ILab No.: Project: 10701 S Ocean Dr. (Lot B-7 Venture 3) Page: 1 of 2 St. Lucie County, FL Date: 3/28/2013 Elevation: Existing Grade Drill Rig: Simco-24 Water Level: 4% feet after 01hours Drilling Fluid commenced at depth of 10 feet Field Party: JC/AR Hand Auger with Hand Cope Pentrometer Test (HCP in ksf) performed in top 4 feet TEST LOCATION: I SPT - 1 N27.269120 W80.208550 Laboratory Tests Depth Blows/ N Sample Layer: USCS Description Passing Moisture Organic (feet) 6 in. Value No. From/to No. 200 Content Content 0-2 SP Gray fine sand, trace silt and shell HCP= 15 2-4 SP Brown fine sand, trace silt and shell 3 HCP= 30 4 HCP= 25 I 1 4 - 5%2 SP Gray fine sand, trace silt and shell ---- i 5 i.......... 31 6 1 ............. 5'/2 - 6 SP Gray sand, trace organic roots and silt 6 - 8% PT Dark brown fine sand, some organic. silt 0 I _ - -- 7 1 -- -�2 _ I (muck) 1- 4 1 ...same, sandy 8 --- i 7_ 8/2 - 9/2 SP Gray fine sand, trace silt, trace to little shell 9 ._ - 16 _ _._ 23 - 15 __-- 9'/2 - 26 SP Gray fine sand, trace silt, trace shel 10 ......... i ll..............I -- 12 .............. I --- 13 ------ ------ -- 14 . 5 ._. 6- - 7 13 I I 6 ...same - -- 18 .............I 19 5 I -- 7 1 10 17 7 ...same i GFA INTERNATIONAL 521 N.W. ENTERPRISE DRIVE, PORT ST. LUCIE, FLORIDA 34986 PHONE: (772) 924-3575 - FAx: (772) 924-3580 STANDARD PENETRATION TEST BORING (ASTM D-1586) • Client: Donald L. Snodgrass Project No.:13-0616.00 Lab No.: Project: 10701 S Ocean Dr. (Lot B-7 Venture 3) Page: 1 of 2 St. Lucie County, FL 'Date: 3/28/2013 Elevation: Existing Grade I Drill Rig: Simco-24 Water Level: 4'/a feet after 0 hours Drilling Fluid commenced at depth of 10 feet Field Party: JC/AR Hand Auger with Hand Cone Pentrometer Test (HCP in kst) performed in top 4-feet TEST LOCATION: SPT - 2 N27.269050 W80.208730 Laboratory Tests Depth Blows/ N Sample I Layer: USCS De Description Passing Moisture Organic (feet) 6 in. Value No. From/to No. 200 Content Content _ 0 0 - 2%2 SP Brown fine sand, trace silt and shell 1 HCP= 80+ ---- 1 2 HCP= 30 I 3 HCP= - 30-- 2%2 - 3 SM Brown fine sand, some silt 2 I 3-4 SP-SM Brown fine sand, little silt, trace shell and 4 HCP= 80+ cemented shell I 1 4-5 SP-SM Brown fine sand, little silt, trace organic root _- 5 1 5 - 8% PT Dark brown fine sand, some organic silt 2 3 3 6 -- 1--- ----•- (muck) 0 7 1 -1 .2 " - -- 4 8 1 --1-- --- 3--- 8%2 - 12 SP Gray fine sand, trace silt, little shell 9 __ 9 - -- _ 12 5 Io--1 --- ------ 9 11 --15-- - ---- 30 5I 12 20 ... Boring terminated at 12 feet _- 13 ------ ------ 14 .. ... --- 15 .... ... I i` ---- 16 .... ... I 17 -------------- is ... ... I I I DISCUSSION OF SOIL GROUPS COARSE GRAINED SOILS GW and SW GROUPS. These groups comprise well -graded gravelly and sandy soils having little or no plastic fines (less than percent passing the No. 200 sieve). The presence of the fines must not noticeably change the strength characteristics of the coarse-gralned friction and must not interface with it's free -draining characteristics. GP and SP GROUPS. Poorly graded gravels and sands containing little of no plastic fines (less than 5 percent passing the No. 200 sieve) are classed in GP and SP groups. The materials may be called uniform gravels, uniform sands or non -uniform mixtures of very coarse materials and very fine sand, with intermediate sizes lacking (sometimes called skip -graded, gap graded or step - graded). This last group often results from borrow pit excavation in which gravel and sand lavers are mixed. GM and SM GROUPS. In general, the GM and SM groups comprise gravels or sands with fines (more than 12 percent the No. 200 sieve) having low or no plasticity. I The plasticity index and liquid limit of soils in the group should plot below the "A" line on the plasticity chart. The gradation of the material is not considered significant and both well and poorly graded materials are included. GC and SC GROUPS. In general, the GC and SC groups comprise gravelly or sandy soils with fines (more than 12 percent passing the No, 200 sieve) which have a fairly high plasticity. The liquid limit and plasticity index should plat above the "A" line on the plasticity chart. ML ai desigr high li at a li( silts o) soils a CL a H de 50. 1 CL a piasti andl: I I I FINE GRAINED SOILS d MH GROUPS. In these groups, the symbol M has been used to ite predominantly silty material. The symbols L and H represent low and uid limits, respectively, and an arbitrary dividing line between the two set jid limit of 50. The soils in the ML and MH groups are sandy silts, clayey inorganic silts with relatively low plasticity. Also included are loose type id rock flours. hd CH GROUPS. In these groups the symbol C stands for clay, with L and noting low or high liquid limits, with the dividing line again set at a liquid of the soils are primarily organic clays. Low plasticity clays are classified as id are usually lean clays, sandy clays or silty clays. The medium and high city clays are classified as CH. These include the fat clays, gumbo clays ome volcanic clays. 0 Appendix F - Important Information About Your Geotechnical Engineering Report By ASFE subsurface conditions revealed during construction. The geolechnical engineer who developed your report cannot assume responsibiff y or liabifity for the report's recommendations ff that engineer does not perform construction observation. A Geotechnical Engineering Report is Subject to Other design team members' misinterpretation of geolechnical engineering reports has resulted in costly problems. lower that risk by having your geo- technical engineer confer with appropriate members of the design team after submitting the report. Also retain yourigeotechnical engineer to review perti- nent elements of the design team's plans and specifications, Contractors can also misinterpret a geolechnical engineering report. Reduce that risk by having your geolechnical engineer participate in prebid and preconslruction conferences, and by providing construction observation. Do Not Redraw the Engilileer's Logs Geotechnical engineers prepare final boring and testing logs based upon their interpretation of field logs and laboratory data. To prevent errors or omissions, the logs included in a geolechnical engineering report should never he redrawn for inclusion in architectural or other design drawings. Only photographic or electronic replrotluction is acceptable, but recognize that separating logs from the report can elevate risk Give Contractors a Coflnplete Report and Guidance Some owners and design professionals mistakenly believe they can make contractors liable for unanticipatedlsubsurfaceconditions by limiting what they provide for bid preparation. To help prevent costly problems, give con- tractors the complete geolechnicallengineering report, but preface it with a clearly written letter of transmittal. In that letter, advise contractors that the report was not prepared for purposes of hid development and that the report's accuracy is limited; encourage them to confer with the geotechnical engineer who prepared the reporti(a modest fee may be required) and%or to conduct additional study to obtain the specific types of information they need or prefer. A prebid conference can also be valuable. Be sure contrac- lors have sufficient time to perform additional study. Only then might you be in a position to give contractors the best information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Read Responsibility Provisions Closely Some clients, design professionals, and contractors do not recognize that geolechnical engineering is far less exact than other engineering disci- plines. This tack of understanding has created unrealistic expectations that have led to disappointments, claims, and disputes. To help reduce the risk of such outcomes, geolechnical engineers commonly include a variety of explanatory provisions in their reports. Sometimes labeled "limitations" many of these provisions indicate where geolechnical engineers' responsi- bilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geolechnical engineer should respond fully and frankly. Geoenvironmental Concerns Are Not Covered The equipment, techniques, and personnel used to perform a geoenviron- mental study differ significantly from those used to perform a geotechnical study. For that reason, a geotechnical engineering report does not usually relate any geoenvironmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated. environmental problems have led to numerous project failures. If you have not yet obtained your own geoen- vironmental information, ask your geotechnical consultant for risk man- agement guidance. Do not rely on an environmental report prepared for someone else. Obtain Professional Assistance To Deal with Mold Diverse strategies can be applied during building design, construction, operation, and maintenance to prevent significant amounts of mold from growing on indoor surfaces. To be effective, all -such strategies should be devised for the express purpose of mold prevention, integrated into a com- prehensive plan, and executed with diligent oversight by a professional mold prevention consultant. Because just a small amount of water or moisture can lead to the development of severe mold Infestations, a num- ber of mold prevention strategies focus on keeping building surfaces dry. While groundwater, water infiltration, and similar issues may have been addressed as part of the geotechnical engineering study whose findings are conveyed in this report, the geolechnical engineer in charge of this project is not a mold prevention consultant; none -of the services per- formed in connection with the gentechnlcal engineer's study were designed or conducted for the purpose of mold preven- tion. Proper implementation of the recommendations conveyed in this report will not of itself be sufficient to prevent mold from growing in or an the structure involved. Rely, on Your ASFE-Member Geotechncial Engineer lop Additional Assistance Membership in ASFWHE BEST PEOPLE ON EARTH exposes geolechnical engineers to a wide array of risk management techniques that can be of genuine benefit for everyone involved with a construction project. Confer with you ASFE-member geolechnical engineer for more information. Am THE BEST PEO 8811 Galesville Road/Suite G108, Silver Spring, MD 20910 Telephone:3011565-2733 Facsimile:301/589-2017 e-mail: inio�asfe.org www.asle.org Capyright 2004 by ASFE,1nc.I nupllca0an, reproduction, or capylnQ a/this document, in whole nr in part, by any means whatsoever, is strictly prohibited, except ivilh ASFEk speci0c wd0en permission. Excerpling, quoting, or odfenvlse extracting warding from this document Is permitted only with the express written permission of ASFE, and only far purposes of scholarly research or back reviaw. only members ofASFEmay use this dacomeal as a complemenf to oras an element ofa geotechnfcal eaginearing report. Any other firm, Individual, or other enilly that so uses this document without being an ASFE member could be committing negligent or ialentlonal (fraudblent) misrepresentation. IfGER0MUM i I t I