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Geotech Engineering ReportMATERIALS* TESTING & INSPECTION GEOTECHNICAL ENGINEERING REPORT Of Gladys Subdivision NEC of Amity & Eagle Roads Meridian, ID Prepared for: The Land Group, Inc. 462 East Shore Drive, Suite 100 Eagle, ID 83616 MTl File Number B1406189 2791 South Victory View Way * Boise, ID 83709 (208) 376-4748 * Fax (208) 322-6515 mti@mti-id.com # www.mti-id.com MATERIAVg L 7 July 2014 TESTING & Page # 1 of 28 INSPECTION b140618g_geotech.docx J I"iiilii4"�I s 1 a ,4 (Si lVzt:E?.`' J i.E„ r '`.!"il(:i . J : pcciii! li ,,pulcliunS Ms. Tamara Thompson The Land Group, Inc. 462 East Shore Drive, Suite 100 Eagle, ID 83616 (208) 939-4041 Re: Geotechnical Engineering Report Gladys Subdivision NEC of Amity & Eagle Roads Meridian, ID Dear Ms. Thompson: In compliance with your instructions, MTI has conducted a soils exploration and foundation evaluation for the above referenced development. Fieldwork for this investigation was conducted on 16 June 2014. Data have been analyzed to evaluate pertinent geotechnical conditions. Results of this investigation, together with our recommendations, are to be found in the following report. We have provided a PDP copy for your review and distribution. Often questions arise concerning soil conditions because of design and construction details that occur on a project. MTI would be pleased to continue our role as geotechnical engineers during project implementation. Additionally, MTI can provide materials testing and special inspection services during construction of this project. If you will advise us of the appropriate time to discuss these engineering services, we will meet with you at your convenience. MTI appreciates this opportunity to be of service to you and looks forward to working with you in the future. If you have questions, please call (208) 376-4748. 49Q�,oF>:ss�o,� � Respectfully Submitted, Materials Testing & Inspe Flu KEVIN L �0 SCHROEDER �CENS oNCy " y i 1,� sT P� g o 1 vin . Schroeder P.G. OF t0 Mon ca Saculles P.E. - Reviewed b : e , Geotechnical Engineer g Geotechnical Services Manager �t h O FOF X 40p �cA SAC11�� Reviewed by: Elizabeth Brown, P.E. Geotechnical Engineer Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com TABLE OF CONTENTS INTRODUCTION.................................................................................................................................................. MATERIALS5 ProjectDescription.................................................................................................................................... 7 July 2014 Authorization............................................................................................................................................. TESTING & Purpose...................................................................................................................................................... 3 Page # 2 of 28 - INSPECTIONb140618g_geotech.doex 4 SITEDESCRIPTION............................................................................................................................................. 5 SiteAccess................................................................................................................................................5 P "'It"""fials RegionalGeology......................................................................................................................................5 TABLE OF CONTENTS INTRODUCTION.................................................................................................................................................. 3 ProjectDescription.................................................................................................................................... 3 Authorization............................................................................................................................................. 3 Purpose...................................................................................................................................................... 3 Scopeof Investigation............................................................................................................................... 3 Warrantyand Limiting Conditions............................................................................................................ 4 SITEDESCRIPTION............................................................................................................................................. 5 SiteAccess................................................................................................................................................5 RegionalGeology......................................................................................................................................5 GeneralSite Characteristics....................................................................................................................... 5 Regional Site Climatology and Geochemistry .......................................................................................... 6 GeoseismicSetting.................................................................................................................................... 6 SOILSEXPLORATION......................................................................................................................................... 6 Exploration and Sampling Procedures....................................................................................................... 6 LaboratoryTesting program.....................................................................................................................6 Soiland Sediment Profile..........................................................................................................................7 VolatileOrganic Scan................................................................................................................................7 SITEHYDROLOGY.............................................................................................................................................7 Groundwater..............................................................................................................................................8 SoilInfiltration Rates................................................................................................................................ 8 FOUNDATION, SLAB, AND PAVEMENT DISCUSSION AND RECOMMENDATIONS .................................................. 9 Foundation Design Recommendations...................................................................................................... 9 CrawlSpace Recommendations................................................................................................................. 10 Floor, Patio, and Garage Slab -on Grade.................................................................................................... 10 RecommendedPavement Sections............................................................................................................ 11 FlexiblePavement Sections....................................................................................................................... H Common Pavement Section Construction Issues...................................................................................... 12 CONSTRUCTIONCONSIDERATIONS.................................................................................................................... 12 Earthwork.................................................................................................................................................. 12 DryWeather.............................................................................................................................................. 13 WetWeather.............................................................................................................................................. 13 SoftSubgrade Soils................................................................................................................................... 13 FrozenSubgrade Soils............................................................................................................................... 14 StructuralFill, ............................... ............................................................................................................ 14 Backfillof Walls..............................................................................................................................I.........15 Excavations...............................................................................................................................................15 GroundwaterControl................................................................................................................................. 16 GENERAL_ COMMENTS....................................................................................................................................... 16 REFERENCES......................................................................................................................................................17 APPENDICES...................................................................................................................................................... 18 AcronymList............................................................................................................................................. 18 GeotechnicalGeneral Notes...................................................................................................................... 19 Geotechnical Investigation Test Pit Log.................................................................................................... 20 Gravel Equivalent Method - Pavement Thickness Design Procedures...................................................... 25 R -Value Laboratory Test Data.................................................................................................................. 26 Plate1: Vicinity Map.................................................................................................................................27 Plate2: Site Map....................................................................................................................................... 28 Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way Boise, ID 83709 (208) 376-4748 Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com ` MATERIALS� • 7 July 2014 TESTING & Page# 3of28 INSPECTION n140618 _geotech.aocx J INTRODUCTION This report presents results of a geotechnical investigation and analysis in support of data utilized in design of structures as defined in the 2012 International Building Code (IBC). Information in support of groundwater and storm water issues pertinent to the practice of Civil Engineering is included. Observations and recommendations relevant to the earthwork phase of the project are also presented. Revisions in plans or drawings for the proposed development from those enumerated in this report should be brought to the attention of the soils engineer to determine whether changes in foundation recommendations are required. Deviations from noted subsurface conditions, if encountered during construction, should also be brought to the attention of the soils engineer. Project Description The proposed development is in the southeastern portion of the City of Meridian, Ada County, ID, and occupies a portion of the SW'/4SW'/4 of Section 28, "Township 3 North, Range 1 East, Boise Meridian. This project will consist of developing a residential subdivision with roughly 60 residential lots and associated streets. The site is approximately 22 acres in size. Total settlements are limited to 1 inch. Loads of up to 4,000 pounds per lineal foot for wall footings, and column loads of up to 50,000 pounds were assumed for settlement calculations. Additionally, assumptions have been made for traffic loading of pavements. Retaining walls are not anticipated as part of the project. MTI has not been informed of proposed grading. Authorization Authorization to perform this exploration and analysis was given in the form of a written authorization to proceed from Mr. Jason Densmer of The Land Group, Inc. to Monica Saculles of Materials Testing and Inspection, Inc. (MTI), on 30 May 2014. Said authorization is subject to terms, conditions, and limitations described in the Professional Services Contract entered into between The Land Group, Inc. and MTI. Our scope of services for the proposed development has been provided in our proposal dated 28 May 2014 and repeated below. Purpose The purpose of this Geotechnical Engineering Report is to determine various soil profile components and their engineering characteristics for use by either design engineers or architects in: • Preparing or verifying suitability of foundation design and placement • Preparing site drainage designs • Indicating issues pertaining to earthwork construction • Preparing residential pavement section design requirements Scope of Investigation The scope of this investigation included review of geologic literature and existing available geotechnical studies of the area, visual site reconnaissance of the immediate site, subsurface exploration of the site, field and laboratory testing of materials collected, and engineering analysis and evaluation of foundation materials. The scope of work did not include design recommendations specific to individual residences. Copyright @ 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way Boise, ID 83709 (208) 376-4748 Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com Warranty and Limiting Conditions MTI warrants that findings and conclusions contained herein have been formulated in accordance with generally accepted professional engineering practice in the fields of foundation engineering, soil mechanics, and engineering geology only for the site and project described in this report. These engineering methods have been developed to provide the client with information regarding apparent or potential engineering conditions relating to the site within the scope cited above and are necessarily limited to conditions observed at the time of the site visit and research. Field observations and research reported herein are considered sufficient in detail and scope to form a reasonable basis for the purposes cited above. Exclusive Use This report was prepared for exclusive use of the property owner(s), at the time of the report, and their retained design consultants ("Client"). Conclusions and recommendations presented in this report are based on the agreed-upon scope of work outlined in this report together with the Contract for Professional Services between the Client and Materials "Testing and Inspection, Inc. ("Consultant"). Use or misuse of this report, or reliance upon findings hereof, by parties other than the Client is at their own risk. Neither Client nor Consultant make representation of warranty to such other parties as to accuracy or completeness of this report or suitability of its use by such other parties for purposes whatsoever, known or unknown, to Client or Consultant. Neither Client nor Consultant shall have liability to indemnify or hold harmless third parties for losses incurred by actual or purported use or misuse of this report. No other warranties are implied or expressed. Report Recommendation are Limited and Subject to Misinterpretation There is a distinct possibility that conditions may exist that could not be identified within the scope of the investigation or that were not apparent during our site investigation. Findings of this report are limited to data collected from noted explorations advanced and do not account for unidentified fill zones, unsuitable soil types or conditions, and variability in soil moisture and groundwater conditions. To avoid possible misinterpretations of findings, conclusions, and implications of this report, MTI should be retained to explain the report contents to other design professionals as well as construction professionals. Since actual subsurface conditions on the site can only be verified by earthwork, note that construction recommendations are based on general assumptions from selective observations and selective field exploratory sampling. Upon commencement of construction, such conditions may be identified that required corrective actions, and these required corrective actions may impact the project budget. Therefore, construction recommendations in this report should be considered preliminary, and MTI should be retained to observe actual subsurface conditions during earthwork construction activities to provide additional construction recommendations as needed. Since geotechnical reports are subject to misinterpretation, do not separate the soil logs from the report. Rather, provide a copy, or authorize for their use, of the complete report to other design professional or contractors. This report is also limited to information available at the time it was prepared. In the event additional information is provided to MTI following publication of our report, it will be forwarded to the client for evaluation in the form received. Copyright 0 2014 Materials Testing & Inspection, Inc. 2791 South VictorV � 8 - . — ......_ Victory View Way •Boise, ID 83709 3 (208) 376-4748 •Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS* 7 July 2014 TESTING Fr Page # 4 of 28 INSPECTION b 14061 8g_geotech.docx . �:::":, .3r(i. ��; Ilt�Ei £1��•j lliE, {;,':;r J { 1{.{ tl:;!...3'�3. x113 : 3.1 �+i.`c;ii3 {.} � �...v .i i.il{t{4.t i. )(� �t�:z3t (�<. ;� it. .I !(�' J \>(i�. \.ifs: ii3.'�i.l �; t.t C.(1J Warranty and Limiting Conditions MTI warrants that findings and conclusions contained herein have been formulated in accordance with generally accepted professional engineering practice in the fields of foundation engineering, soil mechanics, and engineering geology only for the site and project described in this report. These engineering methods have been developed to provide the client with information regarding apparent or potential engineering conditions relating to the site within the scope cited above and are necessarily limited to conditions observed at the time of the site visit and research. Field observations and research reported herein are considered sufficient in detail and scope to form a reasonable basis for the purposes cited above. Exclusive Use This report was prepared for exclusive use of the property owner(s), at the time of the report, and their retained design consultants ("Client"). Conclusions and recommendations presented in this report are based on the agreed-upon scope of work outlined in this report together with the Contract for Professional Services between the Client and Materials "Testing and Inspection, Inc. ("Consultant"). Use or misuse of this report, or reliance upon findings hereof, by parties other than the Client is at their own risk. Neither Client nor Consultant make representation of warranty to such other parties as to accuracy or completeness of this report or suitability of its use by such other parties for purposes whatsoever, known or unknown, to Client or Consultant. Neither Client nor Consultant shall have liability to indemnify or hold harmless third parties for losses incurred by actual or purported use or misuse of this report. No other warranties are implied or expressed. Report Recommendation are Limited and Subject to Misinterpretation There is a distinct possibility that conditions may exist that could not be identified within the scope of the investigation or that were not apparent during our site investigation. Findings of this report are limited to data collected from noted explorations advanced and do not account for unidentified fill zones, unsuitable soil types or conditions, and variability in soil moisture and groundwater conditions. To avoid possible misinterpretations of findings, conclusions, and implications of this report, MTI should be retained to explain the report contents to other design professionals as well as construction professionals. Since actual subsurface conditions on the site can only be verified by earthwork, note that construction recommendations are based on general assumptions from selective observations and selective field exploratory sampling. Upon commencement of construction, such conditions may be identified that required corrective actions, and these required corrective actions may impact the project budget. Therefore, construction recommendations in this report should be considered preliminary, and MTI should be retained to observe actual subsurface conditions during earthwork construction activities to provide additional construction recommendations as needed. Since geotechnical reports are subject to misinterpretation, do not separate the soil logs from the report. Rather, provide a copy, or authorize for their use, of the complete report to other design professional or contractors. This report is also limited to information available at the time it was prepared. In the event additional information is provided to MTI following publication of our report, it will be forwarded to the client for evaluation in the form received. Copyright 0 2014 Materials Testing & Inspection, Inc. 2791 South VictorV � 8 - . — ......_ Victory View Way •Boise, ID 83709 3 (208) 376-4748 •Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIAL 7 July 2014 TESTING & Page # 5 of 28 INSPECTION h14061ag_gcotech.aocx �.. . Environmental Concerns Comments in this report concerning either onsite conditions or observations, including soil appearances and odors, are provided as general information. These comments are not intended to describe, quantify, or evaluate environmental concerns or situations. Since personnel, skills, procedures, standards, and equipment differ, a geotechnical investigation report is not intended to substitute for a geoenvironmental investigation or a Phase II/I11 Environmental Site Assessment. If environmental services are needed, MTI can provide, via a separate contract, those personnel who are trained to investigate and delineate soil and water contamination. SITE DESCRIPTION Site Access Access to the site may be gained via Interstate 84 to the F,agle Road exit. Proceed south on South Eagle Road approximately 2.5 miles to its intersection with Amity Road. The site occupies a portion of northeast corner of this intersection. Presently the site exists as a rural residential area and agricultural fields. The location is depicted on site map plates included in the Appendix. Regional Geology The project site is located within the western Snake River Plain of southwestern Idaho and eastern Oregon. The plain is a northwest trending rift basin, about 45 miles wide and 200 miles long, that developed about 14 million years ago (Ma) and has since been occupied sporadically by large inland lakes. Geologic materials found within and along the plain's margins reflect volcanic and fluvial/lacustrine sedimentary processes that have led to an accumulation of approximately 1 to 2 km of interbedded volcanic and sedimentary deposits within the plain. Along the margins of the plain, streams that drained the highlands to the north and south provided coarse to fine-grained sediments eroded from granitic and volcanic rocks, respectively. About 2 million years ago the last of the lakes was drained and since that time fluvial erosion and deposition has dominated the evolution of the landscape. The project site is underlain by the "Gravel of Gowen Terrace" as mapped by Othberg and Stanford (1993). Sediments of the Gowen terrace consist of sandy pebble and cobble gravel. The Gowen terrace is the fourth terrace above modern Boise River floodplain, is thickest toward its eastern extent, and is mantled with 2-6 feet of loess. General Site Characteristics This proposed development consists of approximately 22 acres of relatively flat and level terrain. Throughout the majority of the site, surficial soils consist of fine-grained lean clay soils. Vegetation primarily consists of agricultural crops and native weed and grass varieties typical of arid to semi -arid environments. Relatively shallow irrigation ditches are present on some of the edges of the agricultural fields. Regional drainage is north toward the Boise River. Storm water drainage for the site is achieved by percolation through surficial soils. The site is situated so that it is unlikely that it will receive any storm water drainage from off-site sources. Storm water drainage collection and retention systems are not in place on the project site, but are proposed as part of the development. Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS 7 July 2014 TESTING & Paged 6of28 � INSPECTION b 140618g__geotech.docx JC:C� C',C,�t111C:+tF + t71,t(.;ui!„ J ("ol ,,4�,3(:;t((r1i J Spedal I�ISIif3{�'t1011S Regional Site Climatology and Geochemistry According to the Western Regional Climate Center, the average precipitation for Treasure Valley is on the order of 10 to 12 inches per year, with an annual snowfall of approximately 20 inches and a range from 3 to 49 inches. The monthly mean daily temperatures range from 21° F to 95° F with daily extremes ranging from -25° F to I I I° F. Winds are generally from the northwest or southeast with an annual average wind speed of approximately 9 miles per hour (mph) with a maximum of 62 mph. Soils and sediments in the area are primarily derived from siliceous materials and exhibit low electro -chemical potential for corrosion of metals or concretes. Local aggregates are generally appropriate for Portland cement and lime cement mixtures. Surface waters, groundwaters, and soils in the region typically have pH levels ranging from 7.2 to 8.2. Geoseismic Setting Soils on site are classed as Site Class D in accordance with Chapter 20 of the American Society of Civil Engineers (ASCE) publication ASCE/SEI 7-10. Structures constructed on this site should be designed per IBC requirements for such a seismic classification. Our investigation did not reveal hazards resulting from potential earthquake motions including: slope instability, liquefaction, and surface rupture caused by faulting or lateral spreading. Incidence and anticipated acceleration of seismic activity in the area is low. SOILS EXPLORATION Exploration and Sampling Procedures Field exploration conducted to determine engineering characteristics of subsurface materials included a reconnaissance of the project site and investigation by test pit. Test pit sites were located in the field by means of visual approximation from on-site features or known locations and are presumed to be accurate to within a few feet. Upon completion of investigation, each test pit was backfilled with loose excavated materials. Re -excavation and compaction of these test pit areas are required prior to construction of overlying structures. In addition, samples were obtained from representative soil strata encountered. Samples obtained have been visually classified in the field by professional staff, identified according to test pit number and depth, placed in sealed containers, and transported to our laboratory for additional testing. Subsurface materials have been described in detail on logs provided in the Appendix. Results of field and laboratory tests are also presented on these logs. MTI recommends that these logs not be used to estimate fill material quantities. Laboratory Testing Program Along with our field investigation, a supplemental laboratory testing program was conducted to determine additional pertinent engineering characteristics of subsurface materials necessary in an analysis of the anticipated behavior of the proposed structures. Laboratory tests were conducted in accordance with current applicable American Society for Testing and Materials (ASTM) specifications, and results of these tests are to be found on the accompanying logs located in the Appendix. The laboratory testing program for this report included: Atterberg Limits Tests - ASTM D4318, Grain Size Analysis - ASTM CI 17/C136, and Resistance Value (R -Value) and Expansion Pressure of Compacted Soils — Idaho T-8. Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALSo 7 July 2014 3 g TESTING & Page# 7of28 INSPECTION b 140618g_geotech. docx r.tlE€=� t Ir3C 3 .rpt �,a:• Soil and Sediment Profile The profile below represents a generalized interpretation for the project site. Note that on site soils strata, encountered between test pit locations, may vary from the individual soil profiles presented in the logs, which can be found in the Appendix. The materials encountered during exploration were quite typical for the geologic area mapped as Gravel of Gowen Terrace. Surficial soils were predominately lean clays, which were underlain by sandy silt soils in most cases. Lean clays were primarily dark brown, dry to slightly moist, stiff to hard, and contained fine- grained sand. Organic materials were noted to depths of up to I foot and plow zones, where present, extended to depths of roughly 1 foot. Sandy silts were light brown, dry, and very stiff to hard, with many of these firmer soil horizons containing some degree of calcium carbonate cementation (hardpan). In many of the more deeply developed soils, poorly graded gravel with sand sediments were encountered, and in test pit 4, clayey sands were present beneath the gravel sediments. Poorly graded gravel with sand sediments were light brown, dry to saturated, and medium dense to dense. Fine to coarse-grained sand and cobbles up to 8 inches in diameter were present throughout the gravel horizon. Clayey sand was found to be brown, slightly moist, and dense, with fine to coarse-grained sand and 4 -inch -minus cobbles. Competency of test pit walls varied little across the site. In general, fine grained soils remained stable while more granular sediments readily sloughed. However, moisture contents will also affect wall competency with saturated soils having a tendency to readily slough when under load and unsupported. Volatile Organic Scan No environmental concerns were identified prior to commencement of the investigation. Therefore, soils obtained during on-site activities were not assessed for volatile organic compounds by portable photoionization detector. Samples obtained during our exploration activities exhibited no odors or discoloration typically associated with this type contamination. Groundwater encountered did not exhibit obvious signs of contamination. SITE HYDROLOGY Existing surface drainage conditions are defined in the General Site Characteristics section. Information provided in this section is limited to observations made at the time of the investigation. Either regional or local ordinances may require information beyond the scope of this report. Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 (208) 376-4748 Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS* is 7 July 2014 TESTING & Page # 8 of 28 ` INSPECTION b140618g__geotech.docx J ..i.C•(:icli Inspections Groundwater During this field investigation, groundwater levels varied widely. Levels as shallow as 5.7 feet bgs and deeper than 14.2 feet bgs were observed. Soil moistures in the test pits were generally dry to slightly moist within surficial soils. Within the poorly graded gravels with sand, soil moistures graded from dry to saturated as the water table was approached and penetrated. MTI believes that the shallow groundwater levels encountered have been influenced by the flood irrigation activities that take place onsite. However, the amount of influence the irrigation has on the high groundwater level is unknown. As the area is developed and flood irrigation activities cease, groundwater levels should decrease. In the vicinity of the project site, groundwater levels are controlled in large part by residential and agricultural irrigation activity and leakage from nearby canals. Maximum groundwater elevations likely occur during the later portion of the irrigation season. During a previous investigation performed in May 2004 roughly '/z mile north of the project site, no groundwater was encountered within test pits advanced to depths as great as 15.5 feet bgs. However, during a previous investigation performed in August 2013 roughly '/2 mile to the south of the project site, groundwater was encountered at depths as shallow as 3.9 feet bgs. Based on evidence of this investigation and background knowledge of the area, MTI estimates groundwater depths to remain greater than approximately 3.5 feet bgs throughout the year. This depth can be confirmed through long-term groundwater monitoring of piezometers installed in test pits 3 and 5. If desired, MTI is available to perform this monitoring. Soil Infiltration Rates Soil permeability, which is a measure of the ability of a soil to transmit a fluid, was not tested in the field. Given the absence of direct measurements, for this report an estimation of infiltration is presented using generally recognized values for each soil type and gradation. Of soils comprising the generalized soil profile for this study, lean clay soils generally offer little permeability, with typical hydraulic infiltration rates of less than 2 inches per hour. Sandy silt soils will commonly exhibit infiltration rates from 2 to 4 inches per hour; though calcium carbonate cementation may reduce this value to near zero. Clayey sand sediments usually display rates of 2 to 6 inches per hour. Poorly graded gravel with sand sediments typically exhibit infiltration values in excess of 12 inches per hour. Infiltration testing is generally not required within these sediments because of their free -draining nature. Five gallons of water was added to test pit 2 at a depth of 6.8 feet bgs and readily infiltrated within the poorly graded gravel with sand sediments. Therefore, infiltration testing as specified in the Idaho Department of Environmental Quality (1DEQ) Technical Guidance Manual was not conducted. After water was added to the test pit at 6.8 feet, the test pit was advanced to its termination depth of 10.7 feet bgs. It is recommended that infiltration facilities constructed on the site be extended into native poorly graded gravel with sand sediments. Excavation depths ranging from approximately 2.4 to 6.1 feet bgs should be anticipated to expose these poorly graded gravel with sand sediments. Because of the high soil permeability, ASTM C33 filter sand, or equivalent, should be incorporated into design of infiltration facilities. An infiltration rate of 8 inches per hour should be used in design. Actual infiltration rates should be confirmed at the time of construction. Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS 7 July 2014 4' TESTING Page# 9of28 INSPECTION bl406l8"eotech.docx a' YIL'II(` !}lE''il#ll a"�E rIC"t `z A'Spucial FOUNDATION, SLAB, AND PAVEMENT DISCUSSION AND RECOMMENDATIONS Various foundation types have been considered for support of the proposed structures. Two requirements must be met in the design of foundations. First, the applied bearing stress must be less than the ultimate bearing capacity of foundation soils to maintain stability. Second, total and differential settlement must not exceed an amount that will produce an adverse behavior of the superstructure. Allowable settlement is usually exceeded before bearing capacity considerations become important; thus, allowable bearing pressure is normally controlled by settlement considerations. Considering subsurface conditions and the proposed construction, it is recommended that the structures be founded upon conventional spread footings and continuous wall footings. Total settlements should not exceed 1 inch if the following design and construction recommendations are observed. Presently, there are approximately 60 lots proposed for the project site. The following_ recommendations are not specific to the individual structures but rather should be viewed as guidelines for the subdivision — wide development. Foundation Design Recommendations Based on data obtained from the site and test results from various laboratory tests performed, MTI recommends the following guidelines for the net allowable soils bearing capacity: C.�:1 Rn.�r•inn !'�n..anity X34g (Y►twi Q t}i a l -"d NSi,V. 2 1,500 lbs/ft Footings must bear on competent, undisturbed, Footings native sandy silt soils or compacted structural fill. Not Required for Existing lean clay soils and fill materials, if Native Soil A 1/3 increase is allowable encountered, must be completely removed from for short-term loading, below foundation elements.' Excavation depths 95% for Structural Fill which is defined by seismic ranging from roughly 1.2 to 3.0 feet bgs should be events or designed wind anticipated to expose proper bearing soils.2 speeds. 'It will be required for MTI personnel to verify the bearing soil suitability for eacn structure at the time ul cunstruLuvII. 2Dependinc on the time of year construction takes place, the subarade soils may be unstable because of high moisture contents. If unstable conditions are encountered, over -excavation and replacement with granular structural fill and/or use of geotextiles i -nay be required. The following sliding frictional coefficient values should be used: 1) 0.35 for footings bearing on native sandy silt (ML) sediments and 2) 0.45 for footings bearing on granular structural fill. A passive lateral earth pressure of 332 pounds per square foot (psf) should be used for sandy silt (Ml) soils. For compacted sandy gravel fill, a passive lateral earth pressure of 496 psf should be used. Copyright 0 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way Boise, ID 83709 (208)376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS* 7 July 2014 TESTING & Page# 10of28 INSPECTION b140618g_geotech.doex (;,,C ti;C.ttiR;<zI.>1C!�CIC f'!(?1C %;��t`f3i('l,tC;Il.5�1 �V1Cdit;i'IFi�S Td? Idl'1Ci J ` (7i .i,�i itl;;�)E3CtiC+CiS Footings should be proportioned to meet either the stated soil bearing capacity or the 2012 IBC minimum requirements. "Total settlement should be limited to approximately I inch, and differential settlement should be limited to approximately 'h inch. Objectionable soil types encountered at the bottom of footing excavations should be removed and replaced with structural fill. Excessively loose or soft areas that are encountered in the footing subgrade will require over -excavation and backfilling with structural fill. To minimize the effects of slight differential movement that may occur because of variations in character of supporting soils and seasonal moisture content, MTI recommends continuous footings be suitably reinforced to make them as rigid as possible. For frost protection the bottom of external footings should be 24 inches below finished gr ade. Crawl Space Recommendations Considering the presence of shallow cemented soils and groundwater across the site, all residences constructed with crawl spaces should be designed in a manner that will inhibit water in the crawl spaces. MTI recommends that roof drains carry storm water at least 5 feet away from each residence. Grades should be greater than 5% for a distance of 10 feet away from all residences. In addition, rain gutters should be placed around all sides of residences, and backfill around stem walls should be placed and compacted in a controlled manner. The bottom of crawl spaces must be at least 2 feet above the high groundwater elevation. This may require elevating the building pad in some areas. Based on test pit logs, areas with shallow cementation are likely to be encountered across much of the site, with cementation present as shallow as 1.7 to 3.3 feet across the site. In areas where cemented soils will be within 2 feet of the crawl space elevation, construction of subsurface drains is also recommended. Review of proposed grading in conjunction with soils data presented by MTI will be required to identify these areas. Subsurface drains should be placed at storm water and irrigation water collection points within the lawn area. These drains will require over -excavation through cemented soils to underlying free -draining soils and backfilling with permeable soils to permit drainage. Floor, Patio, and Garage Slab -on Grade Native clay soils are moderately plastic and will be susceptible to shrink/swell movements associated with moisture changes. Areas of the site within the proposed structures should be excavated to sufficient depths to expose lean clay. The clay soils should be scarified to a depth of 6 inches and re -compacted between 92 percent and 98 percent of the maximum density as determined by ASTM D698. The moisture content should range from 1 to 4 percentage points above optimum. Structural fill should be placed as soon as possible after re -compaction of clay soils in order to limit moisture loss within the upper clays. Ground surfaces should be sloped away from structures at a minimum of 5 percent for a distance of 10 feet to provide positive drainage of surface water away from buildings. Grading must be provided and maintained following construction. Organic, loose, or obviously compressive materials must be removed prior to placement of concrete floors or floor -supporting fill. In addition, the remaining subgrade should be treated in accordance with guidelines presented in the Earthwork section. Areas of excessive yielding should be excavated and backfilled with structural fill. Fill used to increase the elevation of the floor slab should meet requirements detailed in the Structural Fill section. Fill materials must be compacted to a minimum 95 percent of maximum density as determined by ASTM D1557. Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS• 7 July 2014 ^fA TESTING & Page # 11 of28 INSPECTION b140618_geotech.docx I ^�t'1rf7�S r1a'>'� i� �'' VEt�'�: ] (� 7Pr�aC Ince' { :C"iC�?i1GL1I?C Ji, I>>¢IU';�l(„ll� 1Ye �i,tldl7> If5lili .�:>i) t,#i#� Ii1S��E?fiktiil.'i A free -draining granular mat (drainage fill course) should be provided below slabs -on -grade. This should be a minimum of 4 inches in thickness and properly compacted. The mat should consist of a sand and gravel mixture, complying with Idaho Standards for Public Works Construction (ISPWC) specifications for'/4-inch (Type 1) crushed aggregate. A moisture -retarder should be placed beneath floor slabs to minimize potential ground moisture effects on moisture -sensitive floor coverings. The moisture -retarder should be at least 15 -mil in thickness and have a permeance of less than 0.01 US perms as determincd by ASTM E96. Placement of the moisture -retarder will require special consideration with regard to effects on the slab -on -grade and should adhere to recommendations outlined in the ACI 302.1R and ASTM E1745 publications. The granular mat should be compacted to no less than 95 percent of maximum density as determined by ASTM D1557. Upon request, MTI can provide further consultation regarding installation. Recommended Pavement Sections As required by Ada County Highway District (ACRD), MTI has used a traffic index of 6 to determine the necessary pavement cross-sections for the site. MTI has made assumptions for traffic loading variables based on the character of the proposed construction. The Client should review these assumptions to make sure they reflect intended use and loading of pavements both now and in the future. MTI collected a sample of near - surface soils for Resistance Value (R -value) testing representative of soils to depths of 2 feet below existing ground surface. This sample, consisting of lean clay collected from test pit 4, yielded a R -value of 9. The following are minimum thickness requirements for assured pavement function. Depending on site conditions, additional work, e.g. soil preparation, may be required to support construction equipment. These have been listed within the Soft Subgrade Soils subsection. Results of the test are graphically depicted in the Appendix. Flexible Pavement Sections The Gravel Equivalent Method, as defined in Section 500 of the State of Idaho Department of Transportation (ITD) Materials Manual, was used to develop the pavement section. ACHD parameters for traffic index and substitution ratios, which were obtained from the ACHD Policy Manual, were also used in the design. A calculation sheet provided in the Appendix indicates the soils constant, traffic loading, traffic projections, and material constants used to calculate the pavement sections. MTI recommends that materials used in the construction of asphaltic concrete pavements meet the requirements of the ISPWC Standard Specification for Highway Construction. Construction of the pavement section should be in accordance with these specifications and should adhere to guidelines recommended in the section on Construction Considerations. Gravel Equivalent Method Flexible Pavement Specifications Asphaltic Concrete 2.5 Inches Crushed Aggregate Base 4.0 inches Structural Subbase 12.0 Inches Compacted Subgrade Not Required 'It will be required for MTI personnel to verify subgrade competency at the time of construction. Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com 5 =" MATERIALS 7 July 2014 sr TESTING, & Page # 12 of 28 INSPECTION htaobiag_geotech.docx ( 1,;:;,trU,°ic i1 Male.'ais 1 c stinq J Special Inspections Asphaltic Concrete: Asphalt mix design shall meet the requirements of ISPWC, Section 810 Class III plant mix. Materials shall be placed in accordance with ISPWC Standard Specifications for Highway Construction. Aggregate Base: Material complying with ISPWC Standards for Crushed Aggregate Materials. Structural Subbase: Material complying with requirements for granular structural fill (uncrushed) as defined in ISPWC. Common Pavement Section Construction Issues The subgrade upon which above pavement sections are to be constructed must be properly stripped, inspected, and proof -rolled. Proof rolling of subgrade soils should be accomplished using a heavy rubber - tired, fully loaded, tandem -axle dump truck or equivalent. Verification of subgrade competence by MTI personnel at the time of construction is required. Fill materials on the site must demonstrate the indicated compaction prior to placing material in support of the pavement section. MTI anticipates that pavement areas will be subjected to moderate traffic. MTI does not anticipate pumping material to become evident during compaction, but subgrade clays and silty soils near and above optimum moisture contents may tend to pump. Pumping or soft areas must be removed and replaced with structural fill. Fill material and aggregates in support of the pavement section must be compacted to no less than 95 percent of the maximum dry density as determined by ASTM D698 for flexible pavements and by ASTM D1557 for rigid pavements. If a material placed as a pavement section component cannot be tested by usual compaction testing methods, then compaction of that material must be approved by observed proof rolling. Minor deflections from proof rolling for flexible pavements are allowable. Deflections from proof rolling of rigid pavement support courses should not be visually detectable. CONSTRUCTION CONSIDERATIONS Recommendations in this report are based upon structural elements of the project being founded on competent sandy silt soils or compacted structural fill. Structural areas should be stripped to an elevation that exposes these soil types. Earthwork Excessively organic soils, deleterious materials, or disturbed soils generally undergo high volume changes when subjected to loads, which is detrimental to subgrade behavior in the area of pavements, floor slabs, structural fills, and foundations. Agricultural crops and thick weeds and grasses with associated root systems were noted at the time of our investigation. It is recommended that organic or disturbed soils, if encountered, be removed to depths of 1 foot (minimum), and wasted or stockpiled for later use. Stripping depths should be adjusted in the field to assure that the entire root zone or disturbed zone (plow depths) or topsoil are removed prior to placement and compaction of structural fill materials. Exact removal depths should be determined during grading operations by MTI personnel, and should be based upon subgrade soil type, composition, and firmness or soil stability. If underground storage tanks, underground utilities, wells, or septic systems are discovered during construction activities, they must be decommissioned then removed or abandoned in accordance with governing Federal, State, and local agencies. Excavations developed as the result of such removal must be backfilled with structural fill materials as defined in the Structural Fill section. Copyright ® 2014 Materials'resting & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS 7 July 2014 TESTING & Page# 13 of 28 INSPECTION bI4o61sg_geotech.docx t i U'¢t) is 1`s €e ✓it r `' J t t.<,1 ',(;I E Ix }' i::C1C�lr}{ [ i9;t J i; 71i, jr:,tt) (f..11 i i i%£iiE i!.`} iC `tiil{"j J ipect tl 111'spe(;iioi,s MTI should oversee subgrade conditions (i.e., moisture content) as well as placement and compaction of new fill (if required) after native soils are excavated to design grade. Recommendations for structural fill presented in this report can be used to minimize volume changes and differential settlements that are detrimental to the behavior of footings, pavements, and floor slabs. Sufficient density tests should be performed to properly monitor compaction. For structural fill beneath building structures, one in-place density test per lift for every 5,000 square feet is recommended. In parking and driveway areas, this can be decreased to one test per lift for every 10,000 square feet. Dry Weather If construction is to be conducted during dry seasonal conditions, many problems associated with soft soils may be avoided. However, some rutting of subgrade soils may be induced by shallow groundwater conditions related to springtime runoff or irrigation activities during late summer through early fall. Solutions to problems associated with soft subgrade soils are outlined in the Soft Subgrade Soils section. Problems may also arise because of lack of moisture in native and fill soils at time of placement. "This will require the addition of water to achieve near -optimum moisture levels. Low -cohesion soils exposed in excavations may become friable, increasing chances of sloughing or caving. Measures to control excessive dust should be considered as part of the overall health and safety management plan. Wet Weather If construction is to be conducted during wet seasonal conditions (commonly from mid-November through May), problems associated with soft soils must be considered as part of the construction plan. During this time of year, fine-grained soils such as silts and clays will become unstable with increased moisture content, and eventually deform or rut. Additionally, constant low temperatures reduce the possibility of drying soils to near optimum conditions. Soft Subgrade Soils Shallow fine-grained subgrade soils that are high in moisture content should be expected to pump and rut under construction traffic. During periods of wet weather, construction may become very difficult if not impossible. The following recommendations and options have been included for dealing with soft subgrade conditions: • Track -mounted vehicles should be used to strip the subgrade of root matter and other deleterious debris. Heavy rubber -tired equipment should be prohibited from operating directly on the native subgrade and areas in which structural fill materials have been placed. Construction traffic should be restricted to designated roadways that do not cross, or cross on a limited basis, proposed roadway or parking areas. • Construction roadways on soft subgrade soils should consist of a minimum 2 -foot thickness of large cobbles of 4 to 6 inches in diameter with sufficient sand and fines to fill voids. Construction entrances should consist of a 6 -inch thickness of clean, 2 -inch minimum, angular drain -rock and must be a minimum of 10 feet wide and 30 to 50 feet long. During the construction process, top dressing of the entrance may be required for maintenance. Copyright @ 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIAL! 7 July 2014 TESTING it Page 4 14 of 28 INSPECTION bI40618g_geotech.docx i.L'1-1( r'tt@?tk?iCj J 1,cwstrllt'.Jon Kl utclals eslif _j Special n"'PeCl1on" • Scarification and aeration of subgrade soils can be employed to reduce the moisture content of wet subgrade soils. After stripping is complete, the exposed subgrade should be ripped or disked to a depth of 1 %2 feet and allowed to air dry for 2 to 4 weeks. Further disking should be performed on a weekly basis to aid the aeration process. • Alternative soil stabilization methods include use of geotextiles, lime, and cement stabilization. MTI is available to provide recommendations and guidelines at your request. Frozen Subgrade Soils Prior to placement of structural fill materials or foundation elements, frozen subgrade soils must either be allowed to thaw or be stripped to depths that expose non -frozen soils and wasted or stockpiled for later use. Stockpiled materials must be allowed to thaw and return to near -optimal conditions prior to use as structural fill. Structural Fill Soils recommended for use as structural fill are those classified as GW, GP, SW, and SP in accordance with the Unified Soil Classification System (USCS) (ASTM D2487). Use of silty soils (USCS designation of GM, SM, and ML) as structural fill may be acceptable. However use of silty soils (GM, SM, and ML) as structural fill below footings is prohibited. These materials require very high moisture contents for compaction and require a long time to dry out if natural moisture contents are too high and may also be susceptible to frost heave under certain conditions. Therefore these materials can be quite difficult to work with as moisture content, lift thickness, and compactive effort becomes difficult to control. If silty soil is used for structural fill, lift thicknesses should not exceed 6 inches (loose), and fill material moisture must be closely monitored at both the working elevation and the elevations of materials already placed. Following placement, silty soils must be protected from degradation resulting from construction traffic or subsequent construction. Recommended granular structural fill materials, those classified as GW, GP, SW, and SP, should consist of a 6 -inch minus select, clean, granular soil with no more than 50 percent oversize (greater than'/4-inch) material and no more than 12 percent fines (passing No. 200 sieve). These fill materials should be placed in layers not to exceed 12 inches in loose thickness. Prior to placement of structural fill materials, surfaces must be prepared as outlined in the Construction Considerations section. Stmetural fill material should be moisture - conditioned to achieve optimum moisture content prior to compaction. For structural fill below footings, areas of compacted backfill must extend outside the perimeter of the footing for a distance equal to the thickness of fill between the bottom of foundation and underlying soils, or 5 feet, whichever is less. All fill materials must be monitored during placement and tested to confirm compaction requirements, outlined below, have been achieved. Each layer of structural fill must be compacted, as outlined below: • Below Structures and Rigid Pavements: A minimum of 95 percent of the maximum dry density as determined by ASTM D1557. • Below Flexible Pavements: A minimum of 92 percent of the maximum dry density as determined by ASTM D1557 or 95 percent of the maximum dry density as determined by ASTM D698. Cop)Tight ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS • 7 July 2014 TESTING Page # IS of 28 INSPECTION b 140618g_geotech.docx J Gk3GitP hlliC,�=? i`>J{ lufials Te Aill1yjspecial nspo'clions The ASTM D 15 57 test method must be used for samples containing up to 40 percent oversize (greater than 3/4 -inch) particles. If material contains more than 40 percent but less than 50 percent oversize particles, compaction of fill must be confirmed by proof rolling each lift with a 10 -ton vibratory roller (or equivalent) until the maximum density has been achieved. Density testing must be performed after each proof rolling pass until the in-place density test results indicate a drop (or no increase) in the dry density, defined as the maximum density or "break over" point. The number of required passes should be used as the requirement on the remainder of fill placement. Material should contain sufficient fines to fill void spaces, and must not contain more than 50 percent oversize particles. Backfill of Walls Backfill materials must conform to the requirements of structural fill, as defined in this report. For wall heights greater than 2.5 feet, the maximum material size should not exceed 4 inches in diameter. Placing oversized material against rigid surfaces interferes with proper compaction, and can induce excessive point loads on walls. Backfill shall not commence until the wall has gained sufficient strength to resist placement and compaction forces. Further, retaining walls above 2.5 feet in height shall be backfilled in a manner that will limit the potential for damage from compaction methods and/or equipment. It is recommended that only small hand -operated compaction equipment be used for compaction of backfill within a horizontal distance equal to the height of the wall, measured from the back face of the wall. Backfill should be compacted in accordance with the specifications for structural fill, except in those areas where it is determined that future, settlement is not a concern, such as planter areas. In nonstructural areas, backfill must be compacted to a firm and unyielding condition. Excavations Shallow excavations that do not exceed 4 feet in depth may be constructed with side slopes approaching vertical. Below this depth, it is recommended that slopes be constructed in accordance with Occupational Safety and Health Administration (OSHA) regulations, section 1926, subpart P. Based on these regulations, on-site soils are classified as type "C" soil, and as such, excavations within these soils should be constructed at a maximum slope of 1 %2 foot horizontal to 1 foot vertical (1'/21-1:1 V) for excavations up to 20 feet in height. Excavations in excess of 20 feet will require additional analysis. Note that these slope angles are considered stable for short-tenn conditions only, and will not be stable for long-term conditions. During our subsurface exploration, test pit sidewalls generally exhibited little indication of collapse; however, sloughing of fill materials and native granular sediments from test pit sidewalls was observed, particularly after penetration of the water table. For deep excavations, native granular sediments cannot be expected to remain in position. These materials are prone to failure and may collapse, thereby, undermining upper soil layers. This is especially true when excavations approach depths near the water table. Care must be taken to ensure that excavations are properly backfilled in accordance with procedures outlined in this report. Copyright O 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS* • 7 July 2014 4� TESTING £r Page # 16 of 28 INSPECTION el4061gg_geoteeh.docx JJt t>t'i.rue<,IiIlginering J("'Onstrr_c 'n Material", -1 (""Aing Jspecial Inspoctioils Groundwater Control Groundwater was encountered during the investigation but is anticipated to be below the depth of most construction. If recommended, excavations below the water table will require a dewatering program. Dewatering will be required prior to placement of fill materials. Placement of concrete can be accomplished through water by the use of a treme. It may be possible to discharge dewatering effluent to remote portions of the site, to a sump, or to a pit. This will essentially recycle effluent, thus eliminating the need to enter into agreements with local drainage authorities. Should the scope of the proposed project change, MTI should be contacted to provide more detailed groundwater control measures. Special precautions may be required for control of surface runoff and subsurface seepage. It is recommended that runoff be directed away from open excavations. Silty or clayey soils may become soft and pump if subjected to excessive traffic during time of surface runoff. Ponded water in construction areas should be drained through methods such as trenching, sloping, crowning grades, nightly smooth drum rolling, or installing a French drain system. Additionally, temporary or permanent driveway sections should be constructed if extended wet weather is forecasted. GENERAL COMMENTS When plans and specifications are complete, or if significant changes are made in the character or location of the proposed development, consultation with MTI should be arranged as supplementary recommendations may be required. Suitability of subgrade soils and compaction of structural fill materials must be verified by MTI personnel prior to placement of structural elements. Additionally, monitoring and testing should be performed to verify that suitable materials are used for structural fill and that proper placement and compaction techniques are utilized. Copyright @ 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way Boise, ID 83709 (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com ' MATERIALS* • 7 July 2014 TESTING Fr Page # 17 of 28 . INSPECTION b140618g_geotech.docx J L'tlul#4rt7t3 `:"° 41 t`i 1"4�1.�: J (;cc(l ,,ch 6+ ,. 1 r oir€ ,.`Yinq J Go lsirls`cii on I esfi g J Speci,'11 II1S1,iertions REFERENCES Ada County Highway District (ACHD) (2013). Ada County Highway District Policy Manual (May 2013). [Online] Available: <http//www achdidaho.ori(AboutACHD/PolicyManual.aspx> (2014). American Concrete Institute (ACI) (2004). Guide for Concrete Floor and Slab Construction: ACI 302.1 R. Farmington Hills, MI: ACI. American Society of Civil Engineers (ASCE) (2013). Minimum Design Loads for Buildings and Other Structures: ASCE/SEI 7-10. Reston, VA: ASCE. American Society for Testing and Materials (ASTM) (2004). Standard `fest Method for Materials Finer than 75-}tm (No. 200) Sieve in Mineral Aggregates by Washing: ASTM C117. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2006). Standard "fest Method for Sieve Analysis of Fine and Coarse Aggregates: ASTM C 136. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2012). Standard Test Methods. for Laborator Compaction Characteristics of Soil Using Standard Effort D698. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2012). Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort D1557. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2007). Standard Test Methods for Resistance Value (R -Value) and Expansion Pressure of Compacted Soils, ASTM D2844. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2011). Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System) D2487. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2010). Standard "Test Methods for Liquid Limit Plastic Limit, and Plasticity Index of Soils: ASTM D4318. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2011). Standard Specification for Plastic Water Vapor Retarders Used in Contact with Soil or Granular Fill under Concrete Slabs: ASTM E1745. West Conshohocken, PA: ASTM. Desert Research Institute. Western Regional Climate Center. [Online] Available: <http://www.wrcc.dri.edu/> (2014). International Building Code Council (2012). International Building Code, 2012. Country Club Hills, IL: Author. Local Highway Technical Assistance Council (L.HTAC) (2010). Idaho Standards for Public Works Construction, 2010. Boise, ID: Author. Othberg, K. L. and Stanford, L. A., Idaho Geologic Society (1992). Geologic Map of the Boise Valley and Adioining�Area, Western Snake River Plain. Idaho. (scale 1:100,000). Boise, Idaho: Joslyn and Morris. State of Idaho Department of Environmental Quality. (March 2014). Technical Guidance Manual For Individual and Subsurface Sewage Disposal Systems. Boise, Idaho: Author. U. S. Dept, of labor, Occupational Safety and Health Administration. "CFR 29 Part 1926 subpart P Safety and Health Regulations for Construction, Excavations.1( 986)". [Online] Available: < www.osha.gov> (2014). U. S. Geological Survey. (2011). National Water Information System: Web Interface. [Online] Available: <http://waterdata.usps.gov/nwis> (2014). Copyright 0 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way Boise, ID 83709 (208) 376-4748 Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com " MATERIALE4 7 July 2014 TESTING & Page # 18 of 28 INSPECTION ION b140618g_geotech.docx J ! +i r`.tt +11"i ?Cltslf iE'I"VN,i` ; J (..ts[?tf,"c 1nfcal r (1C !rl 'r'r!n l J Co! slrl iction ilial . ! tf`. 14' AilIg J Special Inspections APPENDICES ACRONYM LIST AASHTO: American Association of State Highway and Transportation Officials ACHD: Ada County Highway District ACI American Concrete Institute ASCE American Society of Civil Engineers ASTM: American Society for Testing and Materials bgs: below ground surface CBR: California Bearing Ratio D: natural dry unit weight, pcf ESAL Equivalent Single Axle Load GS: grab sample IBC: International Building Code 1DEQ Idaho Department of Environmental Quality ISPWC: Idaho Standards for Public Works Construction ITD: Idaho Transportation Department LL: Liquid Limit M: water content MSL: mean sea level N: Standard "N" penetration: blows per foot, Standard Penetration Test NP: nonplastic OSHA Occupational Safety and Health Administration PCCP: Portland Cement Concrete Pavement PERM: vapor permeability PI: Plasticity Index PID: photoionization detector PVC: polyvinyl chloride Qe: cone penetrometer value, unconfined compressive strength, psi Qp: Penetrometer value, unconfined compressive strength, tsf Qu: Unconfined compressive strength, tsf RMR Rock Mass Rating RQD Rock Quality Designation R -Value Resistance Value SPT: Standard Penetration Test (140:pound hammer falling 30 in. on a 2:in. split spoon) USCS: Unified Soil Classification System USDA: United States Department of Agriculture UST: underground storage tank V: vane value, ultimate shearing strength, tsf Copyright @ 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com 9 www.mti-id.com ter.... MATERIALS* 7 July 2014 TESTING & Page # 19 of 28 °� INSPECTION 140618g INSPECTION _] [ ,?vi€v? w(. tR{ Services J t'o ISir:!r.;IiO+2 1�1a�tF.i i.z .: 'i r.;?�.?ir�ra :J `ir)ocia( I!t"Pcctson:> GEOTECHNICAL GENERAL NOTES Boulders: >12 in. Coarse -Grained Sand: 5 to 0.6 mm Silts: 0.075 to 0.005 mm Cobbles: 12 to 3 in. Medium -Grained Sand: 0.6 to 0.2 mm Clays: <0.005 mm Gravel: 3 in. to 5 min Fine -Grained Sand: 0.2 to 0.075 mm qq y� $y$ i � p � k 6kmi% B ^'i� 3 1r 'A ta �J _ y6 a'T' ,J,k a.�Ntxe a ,'; .. i ,, _-,>. Gravel & Gravelly GW Well -graded gravels; gravel/sand mixtures with little or no fines Soils GP Poorly -graded gravels; gravel/sand mixtures with little or no fines Coarse -Grained <50%coarse fraction GM Silty gravels; poorly -graded gravel/sand/silt mixtures Soils passes No.4 sieve GC Clayey gravels; poorly -graded gravel/sand/clay mixtures <50% passes No.200 Sand & Sandy SW Well -graded sands; gravelly sands with little or no fines sieve Soils SP Poorly -graded sands; gravelly sands with little or no fines >SO% coarse fraction SM Silty sands; poorly -graded sand/gravel/silt mixtures passes No.4 sieve SC Clayey sands; poorly -graded sand/gravel/clay mixtures ML, Inorganic silts; sandy, gravelly or clayey silts Silts & Clays CL' Lean clays; inorganic, gravelly, sandy, or silty, low to medium -plasticity clays Fine Grained 1A, < 50 OL Organic, low -plasticity clays and silts Soils >50% MLi Inorganic, elastic silts; sandy, gravelly or clayey elastic silts passes No.200 sieve Silts & Clays CH Fat clays; high -plasticity, inorganic clays U, > 50 Oli Organic, medium to high -plasticity clays and silts Highly Organic Soils PT Peat, humus, hydric soils with high organic content Copyright 0 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS 47 July 2014 TESTING Page # 20 of 28 ti INSPECTION h140618g__geotech.docx j Geotec"Imlf ad iPiC7'Itf ofiwl Jt3Clri.:Y1! t1C)!1 Niaturials'! u-. t11Xj J Special IrlSPectiorls GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP -1 Date Advanced: 16 June 2014 Logged by: Monica Saculles, P.E. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Depth to Water Table: 5.7 Feet bgs Total Depth: 6.6 Feet bgs Depth Feet bgs) Field Description and USCS Soil and Sediment Classification Sample Type Sample Depth Feet bgs) Qp Lab Test ID Lean Clay (CL): Brown, dry, very stiff to 0.0-2.4 hard, with fine-grained sand. 4.0-4.5 --Organic material to a depth of'6 inches bgs. --Plow zone present in upper 1 fool. Poorly Graded Gravel with Sand (GP): Brown, slightly moist to saturated, medium 2.4-6.6 dense to dense, with fine to coarse-grained sand and 6 -inch -minus cobbles. --Sill content Present to a depth of 3.6 feet bgs. Copyright 0 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS 7 July 2014 TESTING & Page# 21 of 28 {% ' INSPECTION b14U618g_.geotech.docx J f:nvi4"C)C7weTil,al :�#;rVwos I C 3c jti?':IInic ai n(Prtf3t3rinq J Gots iliicBoil Material,; ?rial,; 1 esti g _j Special I135pedions GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP -2 Date Advanced: 16 June 2014 Logged by: Monica Saculles, P.E. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Depth to Water Table: Not Encountered Total Depth: 10.7 Feet bgs Notes: Five gallons of water was added to the test pit at a depth of 6.8 feet bgs. The water readily infiltrated. Depth Field Description and Sample Sample Depth QP Lab Feet b s USCS Soil and Sediment Classification Type Feet bgs) Test ID Lean Clay (CL): Brown, dry, very stiff, with 0.0-1.7 fine-grained sand. 2.25-4.0 --Organic material to a depth of I foot bgs. --Plow zone present in upper 1 foot. Sandy Silt (ML): Light brown, dry, hard, with fine-grained sand. 1.7-4.5 --Weak to moderate calcium carbonate cementation throughout. Poorly Graded Gravel with Sand (GP): Light brown, dry, medium dense to dense, with fine 4.5-10.7 to coarse-grained sand and 8 -inch -minus cobbles. Copyright @ 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way - Boise, ID 83709 - (208) 376-4748 - Fax (208) 322-6515 mti@mti-id.com - www.mti-id.com MATERIAL 7 July 2014 TESTING, Page # 22 of 28 INSPECTION b14061gg_geotcch.doex J E nv,, w,r f w'r Itni . at rvic_e-s J Goot: clinical E nc ine errog t, atel laky '1 r,, tinct J :3iac dad Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP -3 Date Advanced: 16 June 2014 Logged by: Monica Saculles, A.E. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Depth to Water Table: Not Encountered Total Depth: 9.2 Feet bgs Notes: Piezometer installed to a depth of 9.2 feet bgs. Depth Field Description and Sample Sample Depth Qp Lab Feet bgs) USCS Soil and Sediment Classification Type Feet bgs) Test ID 0.0-1.2 Lean Clay (CL): Dark brown, slightly moist, 1.5-2.25 stiff to very stiff, with fine-grained .sand. Sandy Silt (ML): Brown, dry to slightly moist, very stiff to hard, with fine-grained sand. 1.2-6.1 --Weak to moderate calcium carbonate cementation encountered from 2.0 to 6.1 feet bgs. Poorly Graded Gravel with Sand (GP): gown to light brown, dry to saturated, medium dense 6.1-9.2 to dense, with fine to coarse-grained sand and 6 -inch -minus cobbles. Copyright O 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way - Boise, ID 83709 - (208) 376-4748 - Fax (208) 322-6515 roti@mti-id.com - www.mti-id.com x- MATERIAL" • 7 July 2014 TESTING Fr Page# 23 of 28 INSPECTIONb140618g_geotech.doex 1:=_s'sti, ra,,;+tctsir,,i `3c r ic: 1t;; Fn( it ki4,��gs .I (;c,as 7tr�rr flon n m ateli'als "i' -"<s is7g J>i.7t;ci i Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: `ITP -4 Date Advanced: 16 June 2014 Logged by: Monica Saculles, P.E. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Depth to Water Table: Not Encountered Total Depth: 14.2 Feet bgs Depth Field Description and Sample Sample Depth Qp Lab Feet b s USCS Soil and Sediment Classification Type Feet b s Test ID Lean Clay (CL): Dark brown to brown, dry to 0.0-3.0 slightly moist, very stiff to hard, with fine- GS 1.5-2.0 2.5-4.25 Agrained sand Bulk K -value --Organic material to a depth of 4 inches b s. Sandy Silt (ML): Brown, slightly moist to dry, very stiff to hard, with fine-grained sand 3.0-5.1 --Intermittent weak calcium carbonate cementation throughout. Poorly Graded Gravel with Sand (GP): Light brown, slightly moist, medium dense to dense, 5.1-9.5 with fine to coarse-grained sand and 8 -inch - minus cobbles. Clayey Sand (SC): Brown, slightly moist, 9.5-14.2 dense, with fine to coarse-grained sand and occasional 4 -inch -minus cobbles. Lab Test ID M LL PI Sieve Analysis - % - - #4 #10 #40 #100 #200 A 18.5 31 10 98 98 95 92 1 86.7 Copyright ® 2014 Materials "Testing & Inspection, Inc. 2791 South Victory View Way Boise, ID 83709 (208) 376-4748 Fax (208) 322-6515 mti@mti-id.com • www.mti-id.coin MATERIAL TESTING Fr INSPECTION • 7 July 2014 Page # 24 of 28 b 140618g_gcotcch.docr j tm€tvifomr;entad sewice's J Gootochnical 1 {Eclrr;eetirr s _l +;.,t ,;..tr =r'tic7r ivrltc+i<rls Tc;si nq J Spec al Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP -5 Date Advanced: 16 June 2014 Logged by: Monica Saculles, P.E. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Depth to Water Table: 8.0 Feet bgs Total Depth: 8.7 Feet bgs Notes: Piezometer installed to a depth of 8.7 feet bgs. Depth Field Description Sample Depth QP Lab Feet bgs) USCS Soil and Sediment Classification ification Type Feet bgple s) Test ID Lean Clay (CL): Dark brown, slightly moist, very stiff to hard, with fine-grained sand. 2.75- 0.0-1.3 --Organic material to a depth of 4 inches bgs. 4.25 --Plow zone present in upper 1 fool. Sandy Silt (ML): Brown, slightly moist to moist, stiff to hard, with fine-grained sand. 1.3-6.1 --Some clay content present in upper 2 feet. --Intermittent weak calcium carbonate cementationfrom 3.3 to 6.1 eet. Poorly Graded Gravel with Sand (GP): Light brown, moist to saturated, medium dense to 6.1-8.7 dense, with fine to coarse-grained sand and 6 - inch -minus cobbles. Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS* • 7 July 2014 TESTING Fr Page# 25 of 28 n INSPECTION b 14061 8g_gcotech.doex rin,l J Construction fA)tonals i t Sting j Special Inspection's GRAVEL EQUIVALENT METHOD - PAVEMENT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: Amity and Eagle Subdivision Average Daily Traffic Count: 200 All Lanes & Both Directions Design Life: 20 Years Traffic Index: 6.00 Climate Factor: 1 R -Value of Subgrade: 9.00 Subgrade CBR Value: 4 Subgrade Mr: 6,000 R -Value of Aggregate Base: 80 R -Value of Granular Borrow: 60 Subgrade R -Value: 9 Expansion Pressure of Subgrade: 0.95 Unit Weight of Base Materials: 130 Total Design Life 18 kip ESAL's: 33,131 ASPHAIAIC CONCRFW- Depth Substitution Gravel Fquivalent, Calculated: 0.384 Thickness: 0.1969231 Use= nc es Gravel Equivalent, ACTUAL: 0.41 CRUSHED AGG14EGAIF BASE 0.00 Gravel Equivalent (Ballast): 0.768 Thickness: 0.329 Use = 4nc Gravel Fquivalent, ACTUAL: 0.773 GRANULAR BORROW: Gravel Fquivalent (Ballast): 1.747 Thickness: 0.974 Use- nc es Gravel Fquivalent, ACTUAL: 1.773 TOTAL Thickness: 1.542 'thickness Required by Fxp. Pressure: 1.052 Copyright @3 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com Design ACRD Depth Substitution Inches Ratios Asphaltic Concrete (at least 2.5): T.W 1.95 Asphalt Treated Base (at least 4.2): 0.00 Cement Treated Base (at least 4.2): 0.00 Untreated Aggregate Base (at least 4.2): 4.00 1.10 Granular Borrow (at least 4.2): 12.00 1.00 Copyright @3 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIAL , 7 July 2014 TESTING &Page# 26 of 28 INSPECTION b 14061sg_geotech.doex 1:30rv� ut.;ttzr tr r;nt7 r; ?9 E_r4ttit�c c rirrcl t;c rEsttt,<tii r Itilate,�i :. I t lknij J Special Inspections R -VALUE LABORATORY TEST DATA Source and Description: TP -4, 1.5'-2.0' — Lean Clay Date Obtained: June 16, 2014 Sample ID: 14-7268 Sampling and Preparation. ASTM 1375: Moisture Content (%) AASHTOT2: X ASTM 13421: Expansion Pressure (psi) AASHTO T87: X Test Standard: ASTM 132844: 419 AASHTO T 190: _ 92 Idaho T8: X 10 Sam le A B C Dry Density (lb/f3) 92.4 90.1 86.7 Moisture Content (%) 19.8 21.6 23.2 Expansion Pressure (psi) 1.53 1.11 0.78 Exudation Pressure (psi) 419 237 _ 92 R -Value 12 10 8 R -Value (d) 200 psi Exudation Pressure = 9 R Value @ Exudation Pressure 13.0 12.0 11.0 j 10.0 ac 9.0 8.0 7.0 450 400 350 300 250 200 150 100 50 Exudation Pressure (psi) Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com M is e FIVE Mi RP 5` . $ L_. .. y CL N.�GIOVER©AL.E RD LU u i o IS nn�tw N t� J ! 2 � z is RAOar Mdaw m 0a .� w € F WW W a ILb e FIVE Mi RP 5` . $ L_. .. y CL N.�GIOVER©AL.E RD LU u 0-0 o W, E N J ! 2 � z Qt NVI .� w € F WW W a ILb F U� oc2m t N p lCd N ^ Y l� tL 4 r :.. 3 1l _ 0-0 Ln z '� O E N J ! 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