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HomeMy WebLinkAbout05 - Design Report - Valley West Ph 3 - Pavement MOFMSJN ENGINEERS SCIENTISTS J SURVEYORS Al 91 IMERLE, INC. 901 TECHNOLOGY BLVD • P.O.BOX 1113 • BOZEMAN MT 59771 . 406-587-0721 • FAX:4 6-587-111R76 An Employee-Owned Company I n 7 li August 26, 2005 j Sue Stodola, P.E. AUG 2 6 225� � ! City of Bozeman, Engineering Department 20 East Olive Street ' t-.J U PO Box 1230 - -_--•-___-_______a Bozeman,MT 59771-1230 Re: Valley West Subdivision—Phase#3 Miscellaneous Items MMI#: 3384.025 Dear Sue: Attached are the documents you requested per our phone conversation yesterday: 1. Water Design Report 2. Sewer Design Report 3. Storm Drainage Design Report 4. Geotechnical Investigation Report for Valley West Subdivision 5. Geotechnical Investigation Report for Durston Road Improvements gw> 6. City of Bozeman Planning Department Conditions of Approval ti I also attached the pavement design for the proposed Durston Road section adjacent to the project. The pavement design shows it meets the requirements of the Durston Road Improvements. We are considering using the pavement section from the Durston Road Improvements and adjusting quantities via i S change order with the contractor. Please advise as to your preference concerning this matter. Qccy If you have any questions or concerns please call me at 587-0721. Sincerely, Morriso -Maierle, Inc. (I Kevin Jac bsen, P.E. Design En ineer Enclosure H:\3384\025\Docs\Corres\SUE-82605.doe "Providing resources in Partnership with clients to achieve their goals" SpectraPave2--Tensar Earth Technologies,Inc. Page 3 of � Copyright©1998,2001 Printed on 8/26/2005 10:02:47 AM BASE COURSE REINFORCEMENT INPUT DATA Course Name Type(in) Thickness(in) Layer Coefficient Drainage Factor Asphalt Surface Dense-Graded Asphalt 4 0.44 N/A N/A Dense-Graded Asphalt 0 0.40 N/A Base Course Dense-Graded Asphalt 3 0.12 .85 Subbase Course Dense-Graded Asphalt 24 0.08 .85 Subgrade Resilient Modulus = 6900 (psi) Reliability = 90(1/9) Standard Normal Deviate =-1.282 Standard Deviation = 0.45 Initial Serviceability=4.2 Terminal Serviceability= 2.0 Geogrid Type =Tensar®None Depth from Surface to Geogrid = 11.0(in) Traffic Benefit Ratio (TBR) = 1 ANALYSIS RESULTS Structure Number(Unreinforced) = 3.7 Unreinforced Pavement, ESALs = 1,707,418 Reinforced Pavement, ESALs = 1,707,418 H:\0417\035\docs\PRE-ROAD DES I GN\DurstonPavSect.spr Project Name:Durston Road SID Design Case: REC'0 AUG 14 ZG0Z 1392 13"Avenue SW � � �?Q� Tel. (406)453-5400 P.O.Box 3269 o Fax. (406)761-6655 Great Falls,MT 59403-3269 / ntlengineering.com CNGINCLRING GCU1CI ir. r. \ .Tr August 12, 2002 Morrison-Maierle, Inc. 901 Technology Blvd. Bozeman,MT 59715 Attention: Mr. Greg Stratton, P.E. Subject: Geotechnical Investigation Addendum Durston Road Improvements Gallatin County,Montana Mr. Stratton: Per our telephone conversation on August 7, 2002, we have prepared the following Addendum to our Geotechnical Investigation Report dated March 18, 2001. This addendum presents changes to our flexible pavement design based on review of design assumptions and the use of the 1993 AASHTO Guide for Design of Pavement Structures. Introduction Design subgrade materials used in our analysis for the Durston Road Improvements and presented in our Geotechnical Investigation Report dated March 18,2001 were selected as the near- surface lean clay and clayey gravel with sand. We conducted flexible pavement analysis for these subgrade materials and, per your request, we also conducted pavement analysis for an"improved subgrade"using a locally available 12-inch minus poorly graded gravel with sand and cobbles in the section design.The following Structural Number requirements,as presented in our Geotechnical Investigation Report,were determined using AASHTO design procedures: Subgrade Structural Number Lean Clay 3.7 Clayey Gravel with Sand 3.2 12" Minus Subgrade Improvement Fill 2.7 Geotechnical Investigation Addendum-Durston Road Improvements August 12,2002 NTL Engineering cQc Genscience Pn;zc 2 The tabulated Structural Numbers were then used to proportion section thicknesses for pavement section recommendations. Based on structural coefficients provided in the 1991 Montana Department of Transportation Pavement Manual,pavement section thicknesses were selected and presented in our Geotechnical Report. Upon further review of correlations between MDT surfacing coefficients and subgrade modulus in the 1993 AASHTO Guide for Design of Pavement Structures we have found that the pavement option with 3-inches of asphalt may be structurally deficient based on assumed traffic loading and your design life criteria. We were also informed by your office that the 12-inch minus gravel material was no longer an option for the project. Therefore, we have included the following addendum to our pavement section recommendations. Pavement Design The pavement thickness analysis has been checked using a component equivalency method consistent with the procedures of the 1993 AASHTO Pavement Manual and structural coefficients selected from the 1991 Montana Department of Transportation Pavement Design Manual. Pavements were designed using an equivalent daily ESAL of 205.5 over a 20 year design life. The required Structural Numbers given above were found based on a terminal serviceability index P'= 2.0 and a 20-year design period with a Reliability of 90 percent and an Overall Standard Deviation of0.45. The AASHTO procedure for pavement design is a layered design philosophy in which each component of the layered system must have adequate strength individually and likewise the entire section must have sufficient strength as a whole. With this design procedure, a minimum asphalt thickness of 7.0 inches is required for pavement sections using a traditional leveling course and crushed base course below asphalt. Likewise, a minimum combined thickness of leveling course and base course of 13.0 inches (6.0 inches of base course) is required for pavement sections with a subbase course. These minimums were determined by calculating the required Structural Number for each element of the section using modulus values for base and subbase materials. The modulus values for base and subbase materials were determined by correlations to structural coefficients presented in the 1993 AASHTO Pavement Manual. The minimum asphalt thickness determined by this methodology is nearly double the recommended minimum published by MDT for interstate design. The following section recommendations include Alternates la-3a for section construction on lean clay subgrade and Alternates lb-3b for section construction on clayey gravel with sand subgrade. We have included the AASHTO minimum options(Alternates 1 a and 1 b) for pavement section thicknesses discussed above;however,current MDT standards(June 28,2002)recommend 4 to 6 inches of Plant Mix for daily ESAL's in the range of 200 to 300. We,therefore,recommend considering Alternates 2a, 2b, 3a, or 3b for design of the flcxible pavement section. We also recommend considering historical performance of pavements in the general project vicinity as an indicator of pavement performance for the 4-inch plant mix section. Geotechnical Investigation Addendum—Durston Road Improvements August 12,2002 NTL Engineering&Geoscience Pace 3 Recent MDT studies on geosynthetic reinforcement suggest that base course sections may be reduced through the appropriate placement of geosynthetics:We will assist in preparing alternate sections using geogrid reinforcement if desired. Component Coefficient Alternate la Alternate 2a Alternate 3a (1/in) (in) (in) (in) Asphalt Concrete 0.33 7 4 4 Crushed Base Course Grade 6A 0.12 6 10 20 Subbase Course 4-inch minus 0.09 7.5 13 Total Section Thickness 20.5 27 24 SN of Section: 3.71 3.69 3.72 Recommendations Figure 1. Pavement Sections on Lean Clay Subgrade Component Coefficient Alternate la Alternate 2a Alternate 3a (1/in) (in) (in) (in) Asphalt Concrete 0.33 7 4 4 Crushed Base Course Grade 6A 0.12 7.5 8 16 Subbase Course(4-inch minus) 0.09 10 Total Section Thickness 14.5 22 20 SN of Section 1 3.21 3.18 3.24 Recommendations Figure 2. Pavement Sections on Clay Gravel with Sand Subgrade These recommendations supersede our pavement section alternates presented in our Geotechnical Investigation Report dated March 18, 2001. All other recommendations remain as presented in said report. We have also enclosed specification requirements for proposed base course and subbase course materials as requested. If you have further questions regarding this project, please contact our office. Sincerely, Jo/JHep er,P. . Project Geotechnical Engineer ��ar7y inn, P.E. JJH/GAQ/11 Senior Geotechnical Engineer Enclosures N A x ENGINEERING GEOSCIE1 NCE ...... ................. ........ y.. RECOM MENDED SPECIFICATIONS FOR FLEXIBLE PAVEMENT MATERIALS 1. Ay: reQ:ate Base Course (MT Public Works Specification] Screen or 3/4 Inch 1-1/2 Inch Sieve Size Percent Passing Percent Passing 1-1/2" 100 1ll 95-100 3/4" 100 --- 1/2" --- 50-80 No. 4 40-70 25-60 No. 10 25-55 --- No. 200 2-10 0-8* Mechanically Fractured Faces, one or more on plus No. 4 aggregate, %minimum 50* 50* *Deviates from the MT.Public Works Specification. In addition to the gradation presented above, aggregate base course quality should conform to the MT. Public Works Specification, Crushed Base Course, Section 02235, Subsection 02. 2. Aggregate Subbase Course (MT Public Works Specification) Screen or 4" Minus 3" Minus 1-1/2"Minus Sieve Size Percent Passing Percent Passing Percent Passing 4" 100 3" 100 1-1/2" 100 No. 4 25-60 25-60 25-60 No. 200 2-12 2-12 2-12 Fractured Faces, one or more on the plus No. 4 aggregate, %minimum 35 35 35 In addition to the gradation presented above,aggregate base course quality should conform to the MT. Public Works Specification, Crushed Base Course, Section 02234,Part 2. 3. Asphaltic Concrete Aggregate (MT Public Works Specification 02503) Asphalt Concrete Surfacing Percent Passing Screen or Sieve Size Type B Grading_Requirements 3/4" 100 1/2" 80 - 100 3/8" 70.- 90 No. 4 45 - 65 No. 10 32 -45 No. 40 15 -25 No. 200 4- 10 In addition to the grading requirements shown,the aggregate quality should conform to the applicable portions of the MT.Public Works Specifications,Section 02232,Aggregates for Surfacing and Asphalt Plant Mixes and the requirements of MT.Public Works Specification 02503,Hot Plant Mix Asphalt Concrete. 4. Asphalt Concrete Mix Designs Asphalt concrete mix designs should be provided by the contractor, or materials supplier, and should meet the following requirements, consistent with the MT. Public Works Specification Section 02503, Hot Plant Mix Asphalt Concrete: Pro a Test Method Specifications Stability,pounds, minimum ASTM D1559* 1200 min. Flow, 1/100 Inch Units ASTM D1559* 8 - 18 Air Voids, percent ASTM D3203 3 - 5 Voids in Mineral Aggregate Asphalt Institute 14 Minimum (VMA), Percent Minimum Manual MS-2 *50 blows each end of specimen. 5. Minimum Density Requirements Percent of Material Test Method Maximum Asphaltic Concrete Surfacing ASTM D1559 (Marshall)* 97 Crushed or Uncrushed Granular Base/Subbase Course ASTM D698 95 Subgrade (top 12 inches)** ASTM D698 95 *50 blows each end of specimen;sampled from truck or paver at time of lay-down. **For all pavement types. Clay subgrades should be compacted at moisture contents within +3 percent of optimum,or above as recommended specifically in the report. Maximum compacted lift thickness should be 12 inches for granular base/subbase courses. Also,minimum lift thickness for gravel should be twice the maximum size of the aggregate. GEOTECHNICAL INVESTIGATION REPORT PROJECT Durston Road Improvements Bozeman, Montana PROJECT NUMBER 02-306 CLIENT Morrison Maierle,Inc.' Bozeman, Montana PREPARED BY NTL ENGINEERING & GEOSCIENCE, INC. Great Falls, Montana March 18, 2002 Engineering Summary Durston Road, located near the north end of Bozeman, is scheduled to undergo reconstruction to improve roadway capacity for increased traffic demands. It is our understanding that the roadway section will be completely reconstructed and that the reconstruction will generally follow the existing horizontal alignment. NTL Engineering and Geoscience has been requested to perform a geotechnical investigation and develop recommendations for design and construction of the flexible pavements for the project. In general, subsurface materials consist of existing pavement fill materials overlying lean clay.and clayey gravel with sand. Pavement design was conducted using the subgrade soil strength for the two predominant soil types,and alternates were developed for consideration of different fill materials per your design team's request. Table of Contents Introduction 1 Field and Laboratory Investigation 1 Site Conditions 2 Engineering Analysis 3 Recommendations 4 Conclusion 8 Limitations 9 Appendix Geotechnical Engineering Report Information Sheet Explanations of Field Investigation and Laboratory Testing Logs of Boring Plates Fence Diagram Pavement Materials Specifications Durston Road Improvements NTL Engineering&Geoscience,Inc. Introduction The following report,conducted in accordance with our contract dated December 20,2001, summarizes the geotechnical investigation and analysis for the design and construction flexible pavements for the Durston Road Improvements project in Bozeman,Montana. Approximately 1.5 miles of Durston Road is scheduled for reconstruction between North 191h Street and Fowler Road. The purpose of this geotechnical investigation was to obtain sufficient subsurface data to perform an engineering analysis and provide recommendations for flexible pavement design and general construction earthwork construction. These recommendations are presented in the following report along with discussion of our investigation and engineering analysis. NTL Engineering has strived to conduct the analysis and recommendations consistent with the degree of care that is presently standard to the geotechnical engineering. Field and Laboratory Investigation Following visual reconnaissance of surface conditions, 6 borings were drilled along the shoulder of Durston Road to depths ranging between 5.5 to 11.5 feet. Boring locations and elevations shown on the attached Logs of Boring were determined by Morrison-Maierle survey. The field investigation was performed under the direction of our engineer. Continuous logs of the subsurface conditions were recorded, Standard Penetration Testing(SPT)performed,Shelby tube samples obtained,and bulk samples collected during the drilling. Observations for groundwater .or seepage zones were made at the time of the investigation. A generalized description of field investigation methods is further provided in the Appendix. Subsurface materials encountered during the field investigations are described on the attached Logs of Boring. The Logs present delineation of subsurface strata as could be determined from auger cuttings and samples recovered during the field investigation. Stratification lines shown on the Logs represent the approximate boundaries between soil types. Differences in stratification are likely to occur between boring locations, and the in-situ transition between materials may be variable Soil samples recovered during the field investigation were transported to our laboratory where they were carefully logged and visually classified in accordance with ASTM methods D2487/D2488 which are based on the Unified Soils Classification System. The laboratory investigation consisted of physical and engineering property testing including: • Natural Moisture Content • Atterberg Limits 1 Durston Road Improvements NTL Engineering&Geoscience,Inc. • Particle Size Distribution • Moisture-Density Relations • California Bearing Ratio Testing Testing was conducted in general accordance with ASTM or other approved procedures. Further reference to specific testing procedures is presented in the Appendix. The laboratory test results are presented on the attached Logs and Plates. All soil samples obtained during the field investigation will be retained in our laboratory for 60 days after report publication. Samples will be retained for an extended period only if notice is received prior to the 60-day limit. Site Conditions Site Geology Bozeman lies in a wide valley between the Bridger and the Gallatin Ranges. The valley is in-filled by a thin veneer of recent alluvium underlain by valley fill sediments of the Renova formation extending to significant depths. Surficial geology of the project area consists of recent alluvial deposition including clayey sand and gravel and a thin layer of lean clay near the surface. Site Seismicity Bozeman lies in the Intermountain Seismic Belt,and the 1997 Uniform Building Code maps this area in Seismic Zone 3 which is characterized by potentially major ground motion intensity. Mapping by the U.S. Geological Survey indicates bedrock accelerations of approximately 0.20g as having a 90 percent probability of non-exceedance in a given 50-year period for the Bozeman area. Surface Conditions The Durston Road reconstruction limits extend approximately from North 19rh Street west to Fowler Road. Topography of the alignment is gently rolling and generally drops in elevation to the west. The area is largely residential to the south and un-developed to the north. The roadway has shallow ditch sections along the majority of the alignment except near the intersections of Meagher Street and Valley Street along the west end of the project where a deeper drainage ditch (approximately 10 feet)occurs on the north side of the roadway. The pavement has reportedly been overlain and has undergone numerous repairs. Subsurface Conditions Subsurface materials generally consist of pavement section fill materials overlying a thin veneer of lean clay. The clay extends to depths of approximately 1.5 to 5.5 feet below the surface and is underlain predominantly by clayey gravel soil for the remainder of our drilled depths. The major material types encountered in our investigation are summarized in the following paragraphs: • Lean Clay,(with Sand/Gravel) Native lean clay materials with some sand and gravel were encountered below roadway fill in all of the borings except Boring B-14. The depth of clay extended approximately 1.5 to 2 Durston Road Improvements NTL Engineering R Geoscience,Inc. 4.5 feet below pavement grade. Consistency of the lean clay was generally stiff with Standard Penetration Testing(SPT)N-values of approximately 11 blows per foot. Moisture contents ranged from approximately 26 to 29 percent. Atterberg limits testing found Liquid Limit and Plasticity Index values of 45 and 29 percent respectively for the clay. Moisture- density testing found a maximum dry density of 111.9 pounds per cubic foot at an optimum moisture content of 16.2 percent for Standard Proctor (ASTM D698) effort. California Bearing Ratio(CBR) testing, performed at approximately 95 percent of the maximum dry density, found a CBR of 4.6 percent. • Clayey Gravel with Sand Below the pavement fill and lean clay materials,gravel soils with varying quantities of clay to sand-size particles were encountered. Relative density of the gravel was determined to be very dense as indicated by SPT N-values of more than 50 blows per foot. Moisture contents of 2 to 5 percent were commonly found. Moisture-density testing found a maximum dry density of 128.5 pounds per cubic foot at an optimum moisture content of 10.1 percent for Standard Proctor(ASTM D698)effort. California Bearing Ratio(CBR)testing performed at approximately 95 percent of the maximum dry density found a CBR of 6.7 percent. The relatively low CBR value is not uncommon for materials with clay contents exceeding 20 percent. Groundwater Conditions Groundwater was not encountered in any of the borings during drilling; however, drilling was conducted in winter months and based on high groundwater conditions in the general project area, it is likely that seasonal groundwater levels may establish near the base of the pavement section. Numerous factors contribute to groundwater fluctuations and occurrence of seepage, and evaluation of these factors requires special study that is beyond the scope of this report. Engineering Analysis Pavement Design Flexible pavement designs have been conducted in accordance with procedures outlined in the 1993 AASHTO Guide for Design of Pavement Structures using a 20=year design period and a terminal serviceability index of P,= 2.0. Roadway sections have been designed based on total Equivalent Single Axle Loads (ESALs) of 1,500,000 for the design period as provided by the Morrison-Maierle. The design subgrade materials used in our analysis were selected as the near-surface lean clay and clayey gravel with sand. Moisture-density relationships were determined for both material types per ASTM D-698, and CBR samples were tested at 95 percent of the maximum dry density as applicable for subgrade construction per AASHTO specifications. CBR values of 4.6 and 6.7 3 Durston Road Improvements NTL Engineering&Geoscience,Inc. percent (See Plate Nos. 4 and G) were used for the lean clay and clayey gravel with sand respectively. The correlation,Resilient Modulus(MR)=1500*CBR(psi),was used indetermination of Structural Numbers (SN) along with a Reliability of 90 percent and Standard Deviation of 0.45. A Structural Number was also determined for an alternate subgrade improvement material consisting of 12-inch minus poorly graded gravel with sand and cobbles based on an assumed MR= 15,000 psi; i.e. assuming this material would have a fines content less than 20 percent and a corresponding minimum CBR value of 10 percent. The following Structural Numbers were then determined using AASHTO design procedures: Subgrade Structural Number Lean Clay 3.7 Clayey Gravel with Sand 3.2 12" Minus Subgrade Improvement Fill 2.7 Based on these Structural Numbers and materials discussed subsequently, two options have been analyzed and proposed for pavement thickness design. These options include sections designed for use with lean clay and clayey gravel with sand. Pavement alternates have also been developed for each option using poorly graded gravel with sand and cobble improved subgrades. Pavement Section Recommendations Pavement Materials Several;options are available for pavement materials. The pavement sections have been designed assuming the use of conventional imported gravel base and subbase course materials with structural coefficients typically used by the Montana Department of Transportation; individual component thicknesses are provided in subsequent paragraphs based on various subgrade treatments. Provisions have also been made for the use of on-site materials including clayey gravel with sand, and locally available 12-inch minus poorly graded gravel with sand and cobbles as roadway fill materials. In recent conversations with your design team, we have been asked to consider the use of locally available 12-inch minus poorly graded gravel with sand and cobbles in the section design. As this material contains aggeragate sizes beyond the range of AASHTO and MDT accepted pavement section materials, we have limited this material to a subgrade improvement usage. A presumptive CBR value of 10 has been assigned to the material for design purposes and the Structural Number of sections utilizing the cobble material have been verified for suitability on the design subgrade by assigning a conservative structural coefficient of 0.05/inch. This material will be somewhat difficult to compact, particularly in shallow lifts, due to the cobble size particles. However,the material will likely have an added benefit as an effective capillary break between the 4 Durston Road Jmprovements NTL Engineering&Geoscience Inc. native subgrade and the pavement section. This characteristic will tend to reduce the potential for pavement section saturation as a result of capillary suction acting above a shallow groundwater table. Individual component thicknesses with the use of this material as a subgrade improvement are provided in the Pavement Options sections. The use of asphalt millings as a portion of the subbase section can be considered if it is desirable to salvage on-site materials. The use of asphalt millings creates some difficulty in the control of field density and assignment of structural coefficient values. The pavement section alternates have not been developed for use with asphalt millings; therefore, if asphalt millings are to be used, we will provide alternate pavement sections upon request for final design. General Earthwork and Pavement Preparation The following recommendations are to be used in conjunction with pavement options provided in subsequent sections. • The removal of topsoil and other organic material, including the clearing and grubbing of surficial vegetation and roots,should be accomplished within the construction zone prior to any earthwork or foundation construction. All existing structures, pavements, culverts, sidewalks, and other obstructions to planned work should be removed prior to construction. Cavities left by obstruction removal should be backfilled with on-site clayey gravel with sand or other approved materials that are moisture conditioned to within f2 percent of the optimum moisture content, placed in uniform lifts of maximum 8 loose thickness, and compacted to 95 percent of the maximum ASTM D698 dry density. • Surface drainage should be established to direct runoff away from the construction area. The contractor should be prepared to dewater the pavement excavations in the event that groundwater or seepage is encountered. • A geotextile separation fabric should be considered between pavement materials and native subgrade to reduce the potential for degradation of subgrade caused by migration of fines into the pavement materials. if saturated subgrade conditions are encountered in the excavations,a fabric is strongly recommended to aid in placement of subgrade improvement materials or pavement structure materials. The geotextile should be selected to conform to the following specifications for medium survivability(MDT Standard Specifications,Table 713-1). Reported specifications are Minimum Average Roll Values (MARV). Grab Strength: ASTM D4632 180 lbf Tear Strength: ASTM D4533 70 lbf Puncture Strength: ASTM D4833 70 lbf Grab Elongation: ASTM D4632 <50% Apparent Opening Size: No.40 Sieve(maximum) • The stability of construction excavations and associated worker safety are the responsibility of the contractor in accordance with current OSHA regulations; this responsibility may 5 Durston Road Improvements NTL Engineering&Geoscience,Inc. require design by a registered professional engineer. Based on the predominant soil types encountered during our investigation,temporary construction excavations to be planned in accordance with OSHA provisions should assume Type B material conditions for native soils and Type C conditions for fill soils above the groundwater level. Slope flattening/bracing and dewatering should be anticipated below groundwater level. Actual subsurface conditions at the time of excavation should be observed by a geotechnical engineer to determine whether slope flattening, bracing or other stabilization is necessary due to seepage or other unexpected conditions. • In preparation for base/subbase courses, the subgrade,should be scarified, disked, or otherwise mechanically reworked to a depth of 6 inches to allow moisture adjustment. If moisture adjustment in areas where moisture contents are considerably above optimum cannot be attained, geotextile reinforcement should be considered in conjunction with the selective subexcavation and additional base/subbase gravel to provide suitable support at subgrade level. Any areas where rutting, yielding, or other non-uniform subgrade performance is observed, should be repaired and improved as recommended by a geotechnical engineer. Pavement Option I—Lean Clay Subgrade Alternate pavement sections for Option 1 are based on a controlling subgrade of lean clay. We have assumed that one of the Alternates provided below will be selected as a single pavement section to be utilized along the entire reconstruction alignment for Durston Road. This option would eliminate the need to estimate the extent (station-to-station classification) of lean clay and clayey gravel subgrade materials for different pavement sections. This would also make project material costs easier to estimate and reduce the need for geotechnical observation to verify subgrade condition limits during construction. Based on assumptions stated in the Engineering Analysis,the following alternate pavement sections are appropriate for the lean clay subgrade. Option 1 Pavement Section Alternates Component Alternate 1 Alternate 2 Alternate 3 Alternate 4tAlternate 5t Alternate 6t (in) (in) (in) (in) (in) (in) Asphalt 3 4 4 3 4 4 Base 8 6 20 14 12 4 Subbase 20 19 0 0 0 .09 Improved Subgradet(minimum) — — — 24 24 24 Total Section Thickness 31 29 24 41 40 42 SN of Section 3.75 3.75 3.72 2.67 2.76 2.7 Alternates 1 through 3 assume the use of conventional base course and subbase course gravel selected from specifications given in the Appendix. fAlternates 4 through 6 also assume the use of conventional base and subbase course materials and are intended to be used in conjunction with the available 12-inch minus poorlvgraded gravel with sand and cobbles as a subgrade improvement material. The nominal improvement zone must contain a minimum 2-foot thickness of the 12-inch 6 urston Road Improvements _ NTL Engineering&Geoscience,Inc. - _ - ---- -- - -..._.._--- - - -- minus material. Structural Numbers given for these sections do not consider the improved subgrade as part of the section for structural calculation. Pavement Option 2—Clayey Gravel with Sand Subgrade Option 2 is based on the clayey gravel with sand subgrade. This option may be used in conjunction with alternates presented for Option 1 if a station-by-station specification for pavement section thickness is to be used, or it may be universally applied along the entire project alignment under the strict condition that all lean clay materials are removed from the subgrade. A fence diagram(Plate 7)showing boring strata,location,and elevation has been provided in the Appendix to assist in developing station-by-station section recommendations if that methodology is desired. This option will require thorough geotechnical observation to verify that lean clay removal and subgrade conditions are reasonably consistent with our analysis and recommendations. The pavement excavation will likely be irregular in depth once the full extent of lean clay materials has been removed. This non-uniformity can be leveled to the foundation base elevation with properly compacted,on-site clayey gravel with sand or the 12-inch minus poorly graded gravel with sand and cobbles. The following pavement section alternates are appropriate only for native clayey gravel subgrade conditions. Component Alternate 1 Alternate 2 Alternate 3 Alternate 4 f Alternate 5tAlternate 6t (in) (in) (in) (in) (in) (in) Asphalt 3 4 4 3 4 4 Base 8 6 16 14 12 4 Subbase 14 13 0 0 0 10 Improved Subgrade 1 (minimum) — — — 12 12 12 Total Section Thickness 25 23 20 29 28 30 SN of Section 3.21 3.21 3.24 2.67 2.76 2.7 Alternates 1 through 3 assume the use of conventional base course and subbase course gravel selected from specifications given in the Appendix. 'Alternates 4 through 6 also include conventional base and subbase course materials and are intended to be used in conjunction with the available 12-inch minus poorlygraded gravel with sand and cobbles as a subgrade improvement material or general site fill to raise the pavement section base elevation to a consistent level for pavement section construction. If the 12-inch minus material is used as a subgrade improvement in the case ofAlternates 4 through 6, a nominal improvement zone with a minimum .7-foot thickness of the 12-inch material must be placed across the entire site. Structural Numbers given for these sections do not consider the improved subgrade as part of the section for structural calculation. It is our understanding that storm drainage capacities in the general project area are limited, and therefore, pavement drainage is generally not specified for projects in this area. Our analysis has not included drainage provisions; however, we will supply drainage recommendations upon request. Subgrade drainage would improve support characteristics of the pavement section and would tend to reduce some frost heave potential. 7 Durston Road Improvements _ NTL Engineering&Geoscience,Inc. Continuing Services If changes in traffic loading or material selection are made during the design, our geotechnical engineer should assist in developing appropriate design parameters. Geotechnical observation should be provided during the earthwork and foundation phases of the project. These geotechnical services should ascertain that subsurface conditions are reasonably consistent with those determined by our investigation, and should ascertain that construction materials and placement are as recommended herein. Conclusion The foregoing recommendations present our initial geotechnical input for design and construction of the project. In order for these recommendations to be properly incorporated in the subsequent design and construction stages we recommend that our geotechnical and construction materials engineering staff remain involved with the project to ascertain that our recommendations have been properly interpreted both during design and construction. These services will reduce the potential for misinterpretation of subsurface conditions and geotechnical design recommendations that are important in the preparation of project plans, specifications, and.bid documents. NTL is a member of the Association of Engineering Firms Practicing in the Geosciences (ASFE), which is a professional organization whose purposes include the reduction of potential liabilities to member firms and project owners by quality-based engineering selection and positive owner-engineer interaction during the design and construction processes. Attached in the Appendix is an information sheet regarding geotechnical engineering reports and their limitations prepared by ASFE. 8 Durston Road"p,mcmcnts_ ,­ _ NTL Engineering&Gcoscicnce,Inc. Limitations This report has been prepared in accordance with generally accepted geotechnical engineering practices in this area solely for use by the client for design purposes and is not intended as a construction or bid document representing subsurface conditions in their entirety. The conclusions and recommendations presented are based upon the data obtained during the investigation as applied to the proposed site grading and construction details discussed in this report. The nature and extent of variations between the borings may not become evident until construction. If variations are then exposed,it will be necessary to reevaluate the recommendations of this report. If changes in the concept, design data, or location of the project are planned, the recommendations contained in this report shall not be considered valid unless the changes are reviewed by our geotechnical engineer,and the recommendations of this report modified or verified in writing. Prepared By: Jon . Hepfner,P.1V Geotechnical Engineer Reviewed By: Quinn, P.E. Sr. Geotechnical Engineer 9 IMPORTANT WORMATION ABOUT Y016GEOTECHMCAL ENGINEERING REPORT As the client of a consulting geotechnical engineer,you MOST GEOTECHNICAL FINDINGS ARE should know that site subsurface conditions cause more PROFESSIONAL JUDGMENTS construction problems than any other factor.ASFEII'he Site exploration identifies actual subsurface conditions Association of Engineering Firms Practicing in the only at those points where samples are taken.The data Geosciences offers the following suggestions and were extrapolated by your geotechnical engineer who observations to help you manage your risks. then applied judgment to render an opinion about overall subsurface conditions.The actual interface A GEOTECHNICAL ENGINEERING REPORT IS BASED between materials may be far more gradual or abrupt ON A UNIQUE SET OF PROJECT-SPECIFIC FACTORS than your report indicates.Actual conditions in areas Your geotechnical engineering report is based on a not sampled may differ from those predicted in your subsurface exploration plan designed to consider a report.While nothing can be done to prevent such unique set of project-specific factors.These factors situations,you and your geotechnical engineer can work typically include: the general nature of the structure together to help minimize their impact.Retaining your involved,its size,and configuration;the location of the geotechnical engineer to observe construction can be structure on the site;other improvements,such as particularly beneficial in this respect. access roads,parking lots, and underground utilities; and the additional risk created by scope-of-service A REPORT'S RECOMMENDATIONS limitations imposed by the client.To help avoid costly CAN ONLY BE PRELIMINARY problems, ask your geotechnical engineer to evaluate The construction recommendations included in your how factors that change subsequent to the date of the geotechnical engineer's report are preliminary,because report may affect the report's recommendations. they must be based on the assumption that conditions revealed through selective exploratory sampling are Unless your geotechnical engineer indicates otherwise, indicative of actual conditions throughout a site. do not use your geotechnical engineering report: Because actual subsurface conditions can be discerned only during earthwork,you should retain your geo- • when the nature of the proposed structure is technical engineer to observe actual conditions and to changed, for example, if an office building will be finalize recommendations. Only the geotechnical erected instead of a parking garage,or a refrigerated engineer who prepared the report is fully familiar with warehouse will be built instead of an unrefrigerated the background information needed to determine one; whether or not the report's recommendations are valid • when the size, elevation,or configuration of the and whether or not the contractor is abiding by appli- proposed structure is altered; cable recommendations.The geotechnical engineer who • when the location or orientation of the proposed developed your report cannot assume responsibility or structure is modified; liability for the adequacy of the report's recommenda- • when there is a change of ownership;or tions if another parry is retained to observe construction. • for application to an adjacent site. GEOTECHNICAL SERVICES ARE PERFORMED Geotechnical engineers cannot accept responsibility for FOR SPECIFIC PURPOSES AND PERSONS problems that may occur if they are not consulted after Consulting geotechnical engineers prepare reports to factors considered in their report's development have meet the specific needs of specific individuals.A report changed. prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer. SUBSURFACE CONDITIONS CAN CHANGE Unless indicated otherwise,your geotechnical engineer A geotechnical engineering report is based on condi- prepared your report expressly for you and expressly for tions that existed at the time of subsurface exploration. purposes you indicated. No one other than you should Do not base construction decisions on a geotechnical apply this report for its intended purpose without first engineering report whose adequacy may have been conferring with the geotechnical engineer. No party affected by time.Speak with your geotechnical consult- should apply this report for any purpose other than that ant to learn if additional tests are advisable before originally contemplated without first conferring with the construction starts.Note,too,that additional tests may geotechnical engineer. be required when subsurface conditions are affected by construction operations at or adjacent to the site,or by GEOENVIRONMENTAL CONCERNS natural events such as floods,earthquakes.or ground ARE NOT AT ISSUE water fluctuations. Keep your geotechnical consultant Your geotechnical engineering report is not likely to apprised of any such events. relate any findings,conclusions,or recommendations EXPLANATION OF FIELD INVESTIGATION METHODS Prior to drilling and sampling of subsurface materials,a preliminary field reconnaissance was conducted to verify utility clearance,note surface drainage patterns,and identify pertinent geologic features that may have bearing on analysis. The preliminary reconnaissance includes literary review of geology and soils-related problems identified for other sites nearby or for similar expected soil conditions. Boring locations and planned depths are reviewed based on this reconnaissance. The drilling program was conducted using a Mobile B-59 truck mounted drill rig with 4-1/4 inch hollow-stem auger equipment and either smooth-blade or tri-cone rock bits. The hollow-stem augers serve as a casing for the boring and allow sample recovery by Standard Penetration Testing (SPT), ring sampling using a modified California Sampler, and by using thin-walled steel tube (Shelby Tube). The soils are continuously logged by an engineer or geologist and classified by visual examination in accordance with the Unified Soils Classification System;observation and grab sampling of auger cuttings is necessary to completely log the boring. Groundwater levels and seepage zones were noted as encountered and measured in the hollow-stem augers once stabilized. Slotted PVC observation wells may be installed to record long-term groundwater levels. Samples of soils are taken at frequent intervals in the boring typically by SPT methods. The SPT testing was conducted in general accordance with ASTM D 1586 using a split spoon sampler with a 2-inch outside diameter driven 18 inches into the soil by dropping a 140-pound hammer 30 inches. The total number of hammer blows required to advance the sampler the second and third 6-inch increments is the standard penetration resistance,or N-value. Split spoon samples were also recovered using a larger sampler having an outside diameter of 3-inches. NTL ENGINEERING AND GEOSCIENCE,INC., PO BOX 3269, GREAT FALLS,MT 59403 EXPLANATION OF LABORATORY TESTING PROGRAM California Bearing Ratio The California Bearing Ratio test, CBR, is conducted in general accordance with the procedures of ASTM D1883-87. The testis performed on a subgrade soil sample that has been compacted to 95 percent of the maximum dry density per ASTM D698, and allowed to soak in water for a three-day period in a standard 6-inch diameter mold. A surcharge weight of 10 pounds (50 psf) is maintained on the sample during the soaking period to simulate the pressure that will exist on the subgrade due to the pavement structure. This pressure will tend to reduce swell and increase bearing capacity similar to the pavement. After the soaking period, any swelling of the sample is measured, and the bearing test performed by forcing a piston with an end area of three square inches into the sample while measuring stress and strain (penetration). The data is then compared with similar standardized results for tests on high-quality crushed aggregate. The bearing ratio is typically determined by comparing the stress required for 0.1-inch penetration of the soil sample versus the standard 1000 psi stress required for the same penetration of the crushed aggregate. Proctor The moisture-density relationship was determined in accordance with ASTM D698, also known as the Standard Proctor Compaction Test. The laboratory test supplies compaction energy to the soil in a mold by the impact of a 5.5 pound hammer dropped a distance of 12 inches. From this test, the maximum dry density and optimum moisture content can be determined for a specified energy imparted to the soil for purposes of comparing in-place field densities and moisture contents. Soil Index Testing This testing includes water content as a;percent of dry soil weight representative of in situ conditions in general accordance with the procedures of ASTM D2216,and may include one or more of the following: Atterberg Limits(soil plasticity determined by the moisture range through which a soil passes from a plastic to liquid consistency) in accordance with ASTM D4318,grain size distribution indicating the percent by weight of clay,silt,sand,and gravel comprising the soil aggregate per ASTM D421/422,and the grain size distribution of silt and clay-size material by the procedure of ASTM D1140. The results of these tests have been presented on the Logs as well as the accompanying Plates. NTL ENGINEERING AND GEOSCIENCE,INC., PO BOX 3269, GREAT FALLS,MT 59403 v - ---a l\V "-i fr a.v page 1 of I 7 n ErcrPERYVCs PROJECT: stop Road Improvements L XION: E 4,766 N 2,430 CEOSCiENCE:WC Bozeman, Montana JOB NO.: 02-306 SURFACE ELEVATION: 4763.8 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: - none observed METHOD: _ DRILLER: Boland Drilling DATE STARTED: 1/14/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/14/02 LABORATORY TEST DATA w Q a H MATERIAL dV n w o H do vo x 0 a w H 3 CLASSIFICATION AND DESCRIPTION W A U U H E H w w ,w or U A a s a U' rn to U 0.2 LSK TOPSOIL Organic Mattcr 41 22 63 17 20 FILL,Clayey Gravel with Sand,dense,moist, subround gravel,brown 3.5 Lean CLAY,stiff,moist,trace sand, brown (CL) I 5 j/ SSS 65/0.9 26 5.6 Clayey GRAVEL with Sand,very dense,saturated, subrounded ravel brown (GC) l End of Boring 13-12(a)5.9' 10 *SAMPLE TYPE KEY: ®SSS - STANDARD SPLIT SPOON(SPT) REMARKS 8 LSS - LARGE SPLIT SPOON m ST - SHELSYTUBE O RS - RING SAMPLE 12 SK - SACK SAMPLE ^ page 1 of 1 PROJECT: ton Road Improvements Li .•ION: Not Included in Survey � EfEr cE,uc Bozeman, Montana JOB NO.: 01-306 SURFACE ELEVATION: N/R DRILLINO Mobile B-39 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: none observed METHOD: DRILLER: Boland Drilling DATE STARTED: 1/16/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/16/02 LABORATORY TEST DATA OH U w W :� H E- H Q a MATERIAL H z x a A W E 4 W 3 CLASSIFICATION AND DESCRIPTION n W wn a a H H w w azzo da ao A Ea ai H a W W H z >4 a H a H A `� a a 0.3 — TOPSOIL,Organic Matter FILL,Clavey Gravel with Sand,medium dense, slightly moist,subround gravel,brown 1.5 Lean CLAY with Gravel,stiff,moist,brown (CL) 2.5 « LSK Clayey GRAVEL with Sand,very dense,saturated, 40 23 50 26 24 .ram brown (GC) 1 5 • V 1 t / End of Boring B-12a'@ 8.0' 10 *SAMPLE TYPE KEY: ®SSS - STANDARD SPLIT SPOON(SPT) REMARKS 8 LSS - LARGE SPLIT SPOON (E ST - SHELBYTUBE E RS - RING SAMPLE 2 SK - SACK SAMPLE Nq LL)U UJN BUK NU B-13 \^ page 1 of 1 n PROJECT: L ,ton Road Improvements L, -ATION: E 6,210 N 2,429 See Site Plan a SOE O n EIvCfE s ^ GESQENCENC Bozeman,Montana JOB NO.: 02-306 SURFACE ELEVATION: 4767.6 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: 4 none observed METHOD: _ DRILLER: Boland Drilling DATE STARTED: 1/14/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/14/02 LABORATORY TEST DATA U U E ow E >+ � MATERIAL v m -- -- H dO ao w Q a O E z w a dp V -- -- — H O w E ti CLASSIFICATION AND DESCRIPTION E-i z w O H -- H x a do do d. W rE� H IW W M o aEn s a H � z > ca a w a r. V q v FILL,Clayey Gravel with Sand,medium dense, moist,subround to subangular gravel,brown 1.8 / Gravelly Lean CLAY with Sand,very stiff,moist, brown (CL) 3. +, Clayey GRAVEL with Sand,very dense,moist, subround gravel,caliche coating on gravel,brown (GC) 5 W" X SSS 50/0.4 3 less clay,larger gravel LIV 10 IX SSS 50/0.3 4 land ol'Boring B-13 a 10.3' 'SAMPLE TYPE KEY: ©SSS STANDARD SPLIT SPOON(SPT) REMARKS B LSS - LARGE SPLIT SPOON m ST SHELBYTUBE RS RING SAMPLE 0 SK SACK SAMPLE Lvt.; ur liurulvli 13-14 ^ page 1 of 1 4^ PROJECT: 1 ,ton Road Improvements _ATION: E 7,705 N 2,444 See Site Plan y^Er'�c o�F-W Bozeman, Montana JOB NO.: 02-306 SURFACE ELEVATION: 4769.6 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: - none observed METHOD: -T DRILLER: Boland Drilling DATE STARTED: 1/14/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/14/02 LABORATORY TEST DATA 0 U F' E+ >1 F a E-' MATERIAL z v -- H ao ao x a a W H 3 CLASSIFICATION AND DESCRIPTION m W A a a H H w w do d a. W E 1 n H W W o�0 H z ?' v a In U) C14 U A a a LD V) Cl) FILL,Silty Gravel with Sand,medium dense, moist,suhround to subangular gravel,brown y Clayey GRAVEL with Sand,very dense,moist, d subround to subangular gravel,caliche coating on gravel,brown (GC) LSS 50/0.4 5 i A ,xy 5 i SSS 82/0.9 4 End of Boring B-14 @ 5.9' 10 'SAMPLE TYPE KEY: SSS - STANDARD SPLIT SPOON(SPT) REMARKS e LSS - LARGE SPLIT SPOON m ST - SHELBY TUBE E RS - RING SAMPLE ❑ SK - SACK SAMPLE V1 17V11.1AU D-In ^ page 1 of 1 ^ PROJECT: D in Road Improvements LG ioN: E 8,939 N 2,457 See Site Plan c o�N CEW Bozeman, Montana JOB NO.: 02-306 SURFACE ELEVATION: 4766.7 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: - none observed METHOD: _ DRILLER: Boland Drilling DATE STARTED: 1/14/02 LOGGED BY: I. Hepfner DATE COMPLETED: 1/14/02 LABORATORY TEST DATA w Q a vo E+ MATERIAL Hw o ff ' a0a oa ° a CLASSIFICATION AND DESCRIPTION N w ] Fww °" d0H wH U A A a U U FILL,Clayey Gravel with Sand,medium dense, moist,subround to subangular gravel,brown 1.5. LSK Lean CLAY with Sand,stiff,moist,brown (CL) 45 29 15 33 52 3. ;, Clayey GRAVEL with Sand,very dense,moist, subround gravel,caliche coating on gravel,brown (GC) 5 •��� SSS 50/0.5 3 End of Boring B-15 @ 5.5' 10 'SAMPLE TYPE KEY: ® SSS - STANDARD SPLIT SPOON(SPT) REMARKS 8 LSS - LARGE SPLIT SPOON Irl ST - SHELBYTUBE RS - RING SAMPLE 0 SK - SACK SAMPLE page 1 of 1 n � PROJECT: r '-on Road Improvements Lc ION: E 10,050 N 2,469 See Site Plan EK1,EER W S I ^ CEOSCeNCE W L. Oman, Montana JOB NO.: 02-306 SURFACE ELEVATION: 4769.7 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: -7 none observed METHOD: T_ DRILLER: Boland Drilling DATE STARTED: 1/14/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/14/02 LABORATORY TEST DATA U E- d° F >+ F a N MATERIAL a V n -- -- H dp a° H w w w H 3 CLASSIFICATION AND DESCRIPTION w o w H E w w °i° a° d° A E In H a W x1 2 ly a x L) o a a w w U FILL,Clayey Gravel with Sand,rriedium dense, moist,subround to subangular gravel,brown I LSs 37 21 2.7 FILL,Lean Clay with Gravel,very stiff,moist, some organic debris,dark brown 22 SSS 11 �g 3.8 Lean CLAY with Sand,stiff,slightly moist to moist,silt zones,light brown (CL) 5 5.3 / SSS 82/0.9 Clavey GRAVEL with Sand,very dense,moist, .( subround gravel,caliche coating on gravel,brown (GC) �A i A S � v r , o `s . � sss 78 2 End of Boring B-16 @ 11.5' 'SAMPLE TYPE KEY: 0 SSS - STANDARD SPLIT SPOON(SPT) REMARKS 8 LSS - LARGE SPLIT SPOON ST - SHELBY TUBE O RS - RING SAMPLE ❑ SK - SACK SAMPLE 70 60 i CL CH 50 >C z 40 H U F 30 20 — ML �H 10 / CL-ML Q 0 20 40 60 80 100 LIQUID LIMrr(LL) Specimen Identification LL PL PI Fines Classification • B-12 0.0 41 19 22 19.7 Clayey Gravel With Sand GC M B-12a 2.5 40 17 23 24.0 Clayey Gravel With Sand GC ♦ B-15 1.5 I 45 16 29 51.8 Sandy Lean Clay With Gravel CL l PROJECT Durston Road Improvements JOB NO. 02-306 Bozeman, Montana DATE 3/14/02 _ . ATTERBERG LIMITS NTL Engineering& Geoscience, Inc. Plate No. l "� �= Great Falls, MT 59405 U.S.SIEVE OPENING IN INCHES I U.S.SIEVE NUMBERS I HYDROMETER 6 4z 2 1 5 3/4 1 3/8 3 4 6 810 1416 20 30 40 50 701 r 0200 100 1 1 •\I I I ` I I I II :I ;I 90 80 1 70 60 1 :I U :111 IT: -50 x •. z Z40 LQ a 20 IN :11 1 TFI 10 1 Id 0- - 1 T------T - Iq . 100 10 1 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS COBBLES GRAVEL SAND coarse I fine Icoarsel. medium fine SILT OR CLAY Specimen Identification Classification I MC% I LL I PL PI Cc Cu • B-12 0.0 Clayey Gravel With Sand GC 41 19 22 ZS B-121 2.5 Clayey Gravel With Sand GC 40 17 23 ♦ B-15 1.5 Sandy Lean Clay With Gravel CL 45 16 29 I � Specimen Identification D100 D60 D30 DIO %Gravel I %Sand '%Silt I %Clay • B-12 I1.0 5(I.11(1 1 G.15 1.148 61 17.3 19.7 Z B-12a 2.5 75.00 8.60 0.282 50.2 I 25.8 24.0 ♦ B-15 1.5 37.50 0.25 15.1 33.1 51.8 PROJECT Durston Road Improvements JOB NO. 02 3)06 Bozeman, Montana DATE 3/14/02 GRADATION CURVES NTL Engineering &Geoscicnce, Inc. Plate No. 2 `� - Great Falls, MT 59405 Job No. 02-306 Date 3/14/02 Project Durston Road Improvements Bozeman,Montana Source of Material Lab No. Point ID and Depth . B-12 0.0 Description of Material CLAYEY GRAVEL with SAND GC Test Method ASTM D698 Rammer Type Manual,5.5# TEST RESULTS ATTERBERG LIMITS Maximum Dry Density 128.5PCF LL PL PI Optimum Water Content 10.1% 41% 19% 22% 140 Curves of 100% Saturation \ For Specific Gravity Equal to: 136 2.70 132 \ 2.80 0 LL \ U128 �.•� • \ CAI 24 0 H120 \� �a A116 \ x A 112 108 104 100 6 8 10 12 14 16 18 20 WATER CONTENT(Percent Dry Weight) ul_ MOISTURE-DENSITY RELATIONSHIP NTL Engineering & Geoscience, Inc. Plate No.3 Great Falls, MT 59405 250 i 200 �... �. 1504. -- ,.� � I I 100 -- I Recorded 50 - - -- -- — I --- - '— -- Corrected - y l I I 1 I I o -- 0 0.1 0.2 0.3 0.4 0.5 Penetration (in) California Bearing Ratio @ 0.2 inch penetration: 6.7 (corrected) Specimen Identification: Composite B-12(0.2-3.5)and 13-12a(2.5-8.0) Visual Classification: Clayey Gravel with Sand GC Before Soaking: After Soaking: Moisture Content(%): 10.1 Moisture Content(%): 10.5 Swell (°/o): 0.1 Wet Density(pcf,kN/m^3): 134.1 21.1 Wct Density(pcf,kN/m^3): 134.3 21.1 Surcharge(lb): 10.0 Dry Density(pcf,kN/m^3): 121.8 19.1 Dry Density(pcf,kN/m^3): 121.6 19.1 %of Max Dry Density: 94.8 MC Top 1"Layer(%): 10.7 Project-Durston Road Improvements Job No. 02-306 Bozeman,MT Date 03/14/02 -�- CALIFORNIA BEARING RATIO TEST NTL Enaineerina and Geoscience Plate No. 4 e e Great Falls,Montana Job No. 02-306 Date 3/14/02 Project Durston Road Improvements Bozeman,Montana Source of Material Ammer Cuttings from B-15 Lab No. Point ID and Depth B-15 1.5 Description of Material SANDY LEAN CLAY with GRAVEL CL Test Method ASTM D698 Rammer Type Manual,5.5# TEST RESULTS ATTERBERG LIMITS Maximum Dry Density 111.9PCF LL PL PI Optimum Water Content 16.2% 45% 16% 29% 140 Curves of 100%Saturation For Specific Gravity Equal to: 136 � , � ........... 2.60 2.70 132 2.80 0 o \ 1128 ` Ir 124 K 7 0 H120 \ z I I � M116 A 112 108 104 100 6 8 10 12 14 16 18 20 WATER CONTENT(Percent Dry Weight) MOISTURE-DENSITY RELATIONSHIP + NTL Engineering &Geoscience, Inc. Plate No.5 A^­P"�" Great Falls, MT 59405 120 -- --- - i - 100 --- - I 80 60 .!Edo I j - - - - - - - 40 Recorded i 20 -- =� - -- -- --- -- -- Corrected -- p 0 0.1 0.2 0.3 0.4 0.5 Penetration (in) California Bearing Ratio @ 0.2 inch penetration: 4.6.(corrected) z Specimen Identification: 13-15, 1.5-3.0 Visual Classification: Sandy Lean Clay with Gravel CL Before Soaking- After Soaking: Moisture Content(%): 16.7 Moisture Content(%): 17.1 Swell (%): 0.4 Wet Density(pcf,kN/m^3): 123.4 19.4 Wet Density(pcf,kN/m^3): 123.4 19.4 Surcharge(lb): 10.0 Dry Density(pcf,kN/m^3): 105.8 16.6 Dry Density(pcf,kN/m^3): 105.4 16.6 %of Max Dry Density: 94.6 MC Top 1"Layer(%): 20.3 Project_Durston Road Improvements Job No. 02-306 Bozeman,MT Date 03/14/02 - - CALIFORNIA BEARING RATIO TEST NTL Engineering and Geoscience Plate No. 6 Great Falls,Montana O 0) 00 n (D LO v m N O O) n n to to to to tD to (D to l0 to LO to i n n n to � rn n � n n n n c v v 'IT c e v v v v v v v v ` 0 m � U) c J~Q J Q O CE IL t7> ...... 3 U a 0 co U- o U o co w � .................. ................... _.... o Q Q: to Q 0 E Il c o ❑ to U) ) Z) = m o ❑ �- 0 ..... -........................................ ..... ..-- ..... ................. o o !,AL ,.tip QQm C o ca. a Q `o U Ct U ........:........:. 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V N v to v r _. ..: O O v v v v Q) ® Z N N Nv N N Q N 0 L N _N (h v In (D m m m m m m O O) tb n tD m v C') N O m n n to tD to tD (D (D to (D to to M) N n n n n n n n n n r n n n n UOIIBAG13 Z019tI£ ICE)I1N fd`J90,^.*0 £3ON3-- RECOMMENDED SPECIFICATIONS FOR FLEXIBLE PAVEMENT MATERIALS 1. Aggregate Base Course(MT Public Works Specification) Screen or 3/4-Inch 1-1/2-Inch Sieve Size Percent Passive Percent Passing 1-1/2" 100 i" 95 - 100 3/4" 100 1/2" --- 45 - 80 No. 4 40 - 70 25 - 60 No. 10 25 - 55 25 - 55 No. 200 2 - 10 0 - 8* Mechanically Fractured Faces, one or more on plus No. 4 aggregate, % minimum 50* 50* *Deviates from the MT. Public Works Specification. In addition to the gradation presented above,'aggregate base course quality should conform to theMT.Public Works Specification, Crushed Base Course,Section 02235,Subsection 02. 2. Asphaltic Concrete Aggregate (MT Public Works Specification 02503) Asphalt Concrete Surfacing Percent Passing Screen or Sieve Size Type B Grading Requirements 3/4" 100 1/2" 80 - 100 3/8" 70 - 90 No. 4 45 - 65 No. 10 32 - 45 No. 40 15 - 25 No. 200 4 - 10 In addition to the grading requirements shown, the aggregate quality should conform to the applicable portions of the MT. Public Works Specifications, Section 02232, Aggregates for Surfacing and Asphalt Plant Mixes and the requirements of MT. Public Works Specification 02503, Hot Plant Mix Asphalt Concrete. 3. Asphalt Concrete Mix Designs Asphalt concrete mix designs should be provided by the contractor, or materials supplier, and should meet the following requirements, consistent with the MT.Public Works Specification Section 02503, Hot Plant Mix Asphalt Concrete: Property Test Method Specifications Stability, pounds, minimum ASTM D1559* 1200 min. Flow, 1/100 Inch Units ASTM D1559* 8 - 18 Air Voids, percent ASTM D3203 3 - 5 Voids in Mineral Aggregate Asphalt Institute 14 Minimum (VMA), Percent Minimum Manual MS-2 *50 blows each'end of specimen. 4. Minimum Density Requirements Percent of Material Test Method Maximum Asphaltic Concrete Surfacing ASTM D1559 (Marshall)* 97 Crushed or Uncrushed Granular Base/Subbase Course ASTM.D698 95 Subgrade (top 12 inches)** ASTM D698 95 *50 blows each end of specimen; sampled from truck or paver at time of lay-down. **For all pavement types. Clay subgrades should be compacted at moisture contents within +3 percent of optimum, or above as recommended specifically in the report. Maximum compacted lift thickness should be 12 inches for granular base/subbase courses. Also, minimum lift thickness for gravel should be twice the maximum size of the aggregate. RECOMMENDED SPECIFICATIONS FOR BASE COURSE AGGREGATES 1. Aggregate Base Course 3/4-Inch 1-1/2-Inch Crushed Base Course Crushed Base/Subbase Course (Crushed Top Surfacing (Crushed Base Course Screen or Type A, Grade 2*) Type B, Grade 2*) Sieve Size Percent Passing 1-1/2" 100 3/4" •100 No. 4 40 - 70 25 - 55 No: 10 25 - 55 No. 200 2 - 10 0 - 8 Mechanically Fractured Faces, one or more on plus No. 4 aggregate, % minimum 50 50 *Montana Department of Transportation, Highway Division, Specification (MDOH) In addition to the gradation presented above, aggregate quality should conform to the following MDOH Specifications, 1987 edition: Material MDOH Specification 3/4-Inch Crushed Leveling Course 701.02 (E) (Crushed Top Surfacing, Type A, Grade 2) 1-1/2-Inch Crushed Base Course 701.02 (D) (Crushed Base Course, Type B, Grade 2) REIN 1:. A 7 2002 �� 3 N 139213"Avenue SW Tel. (406)453-5400 P.O.Box 3269 Fax. (406)761-6655 Great Falls,MT 59403-3269 ntlengivegineering.com CNUINCCfUNG UfABCICNC6 J March 5, 2002 Morrison-Maierle, Inc. 901 Technology Blvd. Bozeman, MT 59715 Attention: Mr. Greg Stratton, P.E. Subject: Geotechnical Investigation Valley West Subdivision Development Gallatin County,Montana Mr. Stratton: This Geotechnical Investigation Report presents the results of our investigation for design and construction of foundations for residential structures and pavements at Valley West Subdivision Development in Bozeman,Montana. These services were performed in accordance with your authorization and our proposal dated December 14,2001. The report provides recommendations for earthwork and foundation design along with discussion of our investigation and engineering analysis. We appreciate the opportunity to conduct this investigation and work with you on this project. Please contact our office if you have any questions or concerns regarding this report. Sincerely, NTL Engineering & Geoscience, Inc. Gary A: �uinn, P.E. President JJH/GAQ/jh In Four Copies "cC'C� N 1392 13"'Avenue SW Tel. (406)453-5400 P.O.Box 3269 Fax. (406)761-6655 Great Falls,MT 59403-3269 ntlengineering.com 9=K a at ca March 25, 2002 Morrison-Maierle, Inc. 901 Technology Blvd. Bozeman, MT 59715 Attention: Mr. Greg Stratton, P.E. Subject: Geotechnical Investigation Addendum Valley West Subdivision Development Gallatin County, Montana Mr. Stratton: Per your request we have prepared the following Addendum to our Geotechnical Investigation Report dated March 5, 2001. This addendum presents changes to our flexible pavement design based on the use of special on-site materials which were not previously considered in our original report. The addendum also clarifies the applicability of underdrain systems for residential housing construction. Introduction Pavement recommendations presented in our Geotechnical Investigation Report for the Valley West Subdivision were based on a design subgrade of lean clay; a commonly occurring native material with limiting pavement section strength. A soaked CBR value of 4.5 percent was measured for this material. After reviewing our report, you contacted our office and requested that we consider the use of an alternate material to be used as subgrade improvement for flexible pavements for the project. Your office collected a sample of on-site material obtained from a borrow pit near the western edge of the project. This material was shipped to our laboratory for gradation, Atterberg limits,moisture density, and California Bearing Ratio(CBR)testing. The results of these tests and index testing from other site materials (for comparison with the new borrow material) are attached as Plate Nos. 1 through 5. Analysis was then conducted to verify the applicability of your preferred pavement section. Pavement Design As in our Geotechnical Engineering Report of March 5,2002,a minimum traffic estimate of 50,000 Equivalent 18 kip Single Axle Loads (ESAL's) was assumed over the 20-year design period for subdivision pavements, and flexible pavement sections have been designed in accordance with AASHTO procedures using an initial serviceability index P;=4.2 and a terminal serviceability index Valley West Subdivision Development Gallatin County, Montana Page 2 of Pt 2.0 at the end of design period. The AASHTO procedure for pavement design is a layered design philosophy in which each component of the layered system must have adequate strength individually and as a whole. Your preferred pavement section would consist of 3-inches of asphalt overlying a 6-inch layer of 1- '/z inch crushed base course and a-minimum 15-inches of granular borrow material from the on- site pit. The borrow material was sampled by your personnel and shipped to our office where index and engineering property testing found the material to be a well-graded gravel with sand with a soaked CBR of 19.8 percent. Considering the borrow material as a part of the pavement section with structural coefficients respectively of 0.33, 0.14, and 0.12 (per inch) for asphalt, base and subbase/borrow, a Structural Number of 3.63 was calculated for the overall pavement section. This exceeds the required Structural Number of 2.4 determined for construction on the lean clay subgrade material. The pavement section was also checked by assuming that the borrow material acts as an improved subgrade and the pavement section consists of 3 inches of asphalt and 6 inches of base course. The calculated Structural Number of 1.8 again exceeds the required Structural Number of 1.2 which was calculated assuming the minimum 15-inches of borrow material acts as an improved subgrade material. Since your proposed section exceeds the structural requirements,we feel that the proposed section will be adequate based on available information. Perimeter Drainage Recommendations presented in our Geotechnical Investigation Report include the installation of perimeter underdrainage around permanent housing structures. The underdrain is intended to maintain groundwater near the footing base elevation. If grade-raising is planned such that the footing base is expected to be above the estimated high groundwater level, the underdrain is not necessary If you have further questions regarding this project, please contact our office. Enclosed are test results for the new borrow material and an invoice for additional geotechnical services. Sincerely, Jon J. Hepfn�r, P.E. Project Geotechnical Engineer Gary A. Quinn, RE Senior Geotechnical Engineer JJH/GAQ/ll Enclosures, In two copies 70 60 CL CH 50 w z 40 F U F 30 a m 20 ML �H 10 CL-ML 0 0 20 40 60 80 100 LIQUID LIMIT(LL) Specimen Identification LL PL PI I Fines Classification 01 B-1 5.0 391 19 21 15.7 Clayey Gravel With Sand GC m B-10 2.0 461 21 25 Lean Clay CL ♦ B-12 0.0 41 19 22 19.7 Clayey Gravel With Sand GC * B-12a 2.5 40 17 23 24.0 Clayey Gravel With Sand GC X B-15 1.5 45 16 291 61.1 I Sandy Lean Clay CL 01 B-7 2.0 36 20 16 ';Lean Clay CL O B-9 2.0 41 19 22 Lean Clay CL o Borrow Pit 0.0 24 18 6 4.6 Well-graded Gravel With Sand GW PROJECT Valley West Subdivision JOB NO. 02-305 Bozeman, MT DATE 3/22/02 � _;_ ATTERBERG LIMITS I �...« NTL Engineering&Geoscience,Inc. Plate No. 1 �\? "�"`°" Great Falls,MT 59405 U.S.SIEVE OPENING IN INCHES I U.S.SIEVE NUMBERS I HYDROMETER 6 4 2 .4 1/2 3/8 3 6 810 1416 20 30 40 50 7010, 1200 100 1 \ E 1 90 80 70 I \ Aso \ \ W =50 w � w 40 U cx w t \ a Ti i:Z 30 \ 20 10 0 � �I 100 10 1 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS COBBLES GRAVEL I SAND SILT OR CLAY coarse I fine icoarsel medium 1 fine Specimen Identification 1 Classification MC% I LL PL PI Cc i Cu OI B-1 5.0 Clayey Gravel With Sand GC 5 39 19 21 B-12 0.0 Clayey Gravel With Sand GC I 41 I 19 22 Al B-12a 2.5 Clayey Gravel With Sand GC 40 17 I 23 *1 B-15 1.5 Sandy Lean Clay CL 45 16 29 NJ B-6 7.0 Clayey Gravel with Sand GC 10 Specimen Identification D100 D60 D30 I D10 %Gravel %Sand I %Silt I %Clay 01 B-1 5.0 50.00 12.65 0.814 1 56.7 27.6 15.7 X B-12 0.0 50.00 16.15 1.148 63.0 17.3 19.7 ♦ B-12a 2.5 75.00 8.60 0.282 I 50.2 25.8 24.0 �F B-15 1.5 4.75 I 0.0 I 38.9 I 61.1 X B-6 7.0 37.50 11.31 0.687 54.5 32.7 12.8 PROJECT Valley West Subdivision JOB NO, 02-305 Bozeman, MT DATE 3/22/02 GRADATION CURVES NTL Engineering& Geoscience, Inc. Plate No. 2 Great Falls, MT 59405 MIN ll Mu�a�� '� ii ��.omn■nu�ii i m■ GRAVEL SAND COBBLES SILT OR CLAY coarse fine 1coarsel medium fine 1� Borrow Pit 0.0 Well-graded Gravel With Sand GW Specimen Identification DIM M. . .&- O%,.Sand %Silt %Clay PROJECT Valley West Subdivision JOB NO. 02-305 Bozeman, MT DATE 3/22/02 GRADATION CURVES NTL Engine'ring & Geoscience, Inc. Plate No. 3 Great Falls,NIT 59405 �nnn■�i �Ill��illi d ppp �■1� IIIIII�iIl011�I1Y1 II �■IISII� �II�11�111�11 II IIMII� Job No. 02-305 Date 3/22/02 Project Valley West Subdivision Bozeman, MT Source of Material Lab No. Point ID and Depth Borrow Pit0.0 Description of Material WELL-GRADED GRAVEL with SAND GW Test Method AASHTO T-99 Rammer Type Manual.5.5# TEST RESULTS ATTERBERG LIMITS Maximum Dry Density 135.5PCF LL PL PI Optimum Water Content 8.2% 24% 18% 6% Curves of 100% Saturation 148 For Specific Gravity Equal to: 144 , ----------- 2.60 2.70 140 2 80 0 '136 U ;132 a y a128 I ' \ '-"124 z w �Z120 x Q 116 112 108 104 100 5 7 9 11 13 15 WATER CONTENT(Percent Dry Weight) U� l MOISTURE-DENSITY RELATIONSHIP NTL Engineering& Geoscience, Inc. Plate No.4 Great Falls, MT 59405 350 - — -- - -�- -- -- -- i 300 250- — ----- -- i 200 rA v� 150 100 - - Recorded Corrected 501 0 - -- - 0 0.1 0.2 0.3 0.4 0.5 Penetration (in) California Bearing Ratio @ 0.1 inch penetration: 19.8 (corrected) Specimen Identification: Borrow Pit Visual Classification: Well-graded Gravel with Sand GW Before Soaking: After Soaking: Moisture Content(%): 8.2 Moisture Content(%): 7.5 Swell(%): 0.0 Wet Density(pcf,kN/m^3): 139.4 21.9 Wet Density(pcf,kN/m^3): 138.4 21.7 Surcharge(lb): 10.0 Dry Density(pcf,kN/m^3): 128.8 20.2 Dry Density(pcf,kN/m^3): 128.8 20.2 %of Max Dry.Density: 95.0 MC Top V Layer(%): 7.2 Project Ballet/West Subdivision Job No. 02-306 Bozeman,MT Date 03/25/02 -I- CALIFORNIA BEARING RATIO TEST NTL Engineering and Geoscience Plate No. 5 ` M Great Falls,Montana GEOTECHNICAL INVESTIGATION REPORT PROJECT Valley West Subdivision Development Bozeman,Montana PROJECT NUMBER 01-308 CLIENT Morrison Maierle,Inc. Bozeman, Montana PREPARED BY NTL ENGINEERING & GEOSCIENCE, INC. Great Falls, Montana March 5, 2002 Engineering Summary The construction of several one-story,single family structures to two-story,8-plex structures has been proposed for the Valley West Subdivision development inBozeman,Montana. NTL Engineering and Geoscience has been requested to perform a geotechnical investigation and develop recommendations for design and construction of building foundations and residential street pavements. In general,subsurface materials consist of lean clay overlying clayey gravel with sand The lean clay soils are very weak and moderately to highly compressible near the gravel interface,and settlements of building foundations constructed on the clay would likely exceed acceptable foundation performance criteria. Therefore,since dense gravel exists at shallow depths,removal and replacement ofthe clay below building foundations has been recommended. Foundation options for crawlspace and slab-on-grade structures have been analyzed. Foundation excavations may encounter groundwater or seepage based on water elevations found during our field investigation. Some dewatering and ground improvement may be necessary to facilitate removals and build Structural Fill pads for foundation preparation. Table of Contents Introduction 1 Field and Laboratory Investigation 1 Site Conditions 2 Engineering Analysis 4 Recommendations 7 Conclusion 12 Limitations 12 Appendix Geotechnical Engineering Report Information Sheet Explanations of Field Investigation and Laboratory Testing Logs of Boring Plates Detail Specifications Vallev West Subdivision _ NTL I�Uincering&Geoscience. Inc. Introduction The following report, conducted in accordance with our contract dated December 20,2001, summarizes the geotechnical investigation and analysis for the design and construction shallow foundations and pavements forthe Valley West Subdivision Development in Bozeman,Montana. The Valley West Subdivision will occupy approximately 300 acres and will contain a central golf course bordered by housing units ranging from single family dwellings to 8-plex condominiums. The purpose ofthis geotechnical investigation was to obtain sufficient subsurface data to perform an engineering analysis and provide design recommendations for suitable foundation types,flexible pavement design,and general construction earthwork requirements for the subdivision housing and roadway features. These recommendations are presented in the following report along with discussion of our investigation and engineering analysis. NTL Engineering has strived to conduct the analysis and recommendations consistent with the degree of care that is presently standard to the geotechnical engineering. Field and Laboratory Investigation Following visual reconnaissance of surface conditions, 10 borings were drilled to depths ranging between 11.5 to 20.5 feet in the general subdivision area and an additional 3 borings were drilled along Durston Road near the intersections of Ferguson Road and Meagher Road. Boring locations and elevations shown on the attached Logs of Boring were determined by level survey conducted by Morrison Maierle. The field investigation was performed under the direction of our engineer. Continuous logs of the subsurface conditions were recorded,Standard Penetration Testing(SPT)performed,Shelby tube samples obtained,and bulk samples collected during the drilling. Observations for groundwater or seepage zones were made at the time of the investigation. A generalized description of field investigation methods is further provided in the Appendix. Subsurface materials encountered during the field investigations are described on the attached Logs ofBoring. The Logs present delineation of subsurface strata as could be determined from cuttings and samples recovered during the field investigation. Stratification lines shown on the Logs represent the approximate boundaries between soil types. Differences in stratification are likely to occur between boring locations, and the in-situ transition between materials may be variable Soil samples recovered during the field investigation were transported to our laboratory where they were carefully logged and visually classified in accordance with ASTM methods D2487/D2488 which are 1 Vallev_West Subdivision NTL Engineering&Geoscience Inc based on the Unified Soils Classification System. The laboratory investigation consisted of physical and engineering property testing including: • Natural Moisture Content • In Situ Density • Atterberg Limits • Particle Size Distribution • Consolidation Testing was conducted in general accordance with ASTM or other approved procedures. Further reference to specific testing procedures is presented in the Appendix. The laboratory test results are presented on the attached Logs and Plates. All soil samples obtained during the field investigation will be retained in our laboratory for 60 days after report publication. Samples will be retained for an extended period only if notice is received prior to the 60-day limit. Site Conditions Site Geology Bozeman lies in a wide valley between the Bridger and the Gallatin Ranges. The valley is in-filled by a thin veneer of recent alluvium underlain by valley fill sediments of the Renova formation extending to significant depths. Surficial geology ofthe project area consists ofrecent alluvial deposition including clayey sand and gravel and a thin layer of lean clay near the surface. Site Seismicity Bozeman lies in the Intermountain Seismic Belt,and the 1997 Uniform Building Code maps this area in Seismic Zone 3 which is characterized by potentially major ground motion intensity. Mapping by the U.S.Geological Survey indicates bedrock accelerations ofapproximately 0.20g as having a 90 percent probability of non-exceedance in a given 50-year period for the Bozeman area. Surface Conditions The subdivision lies roughly between Durston Road to the north,West Babcock Street to the south, Ferguson Road to the east, and Baxter Creek to the west. Topography of the site is gently rolling or hummocky and generally slopes to the north. The area is largely un-developed,and existing vegetation consists primarily ofnative grasses. Some small surface streams(presumably used for irrigation)cross the site. Subsurface Conditions Subsurface materials generally consist of a nominal thickness oftopsoil overlying a thin veneer of lean clay. The clay extends to depths of approximately 1.5 to 4.5 feet below the surface and is underlain 2 yalleyWest Subdivision NTL Engineering&Geoscience Inc by predominantly clayey gravel soil for the remainder of our drilled depths. The major material types encountered in our investigation are summarized in the following paragraphs: • Lean Clay (with Sand/Gravel) Native lean clay materials with some sand and gravel were encountered in all ofthe borings below the surficial topsoil. The depth of clay extended approximately 1.5 to 4.5 feet below ground and generally graded from a dark brown to light brown with depth. Consistency ofthe lean clay was widely variable as indicated by the SPT N-value range of approximately 1 to 16 blows per foot, indicating very soft to stiff conditions. Moisture contents ranged from approximately 27 to 33 percent,but generally increased with depth. Atterberg limits testing found Liquid Limit and Plasticity Indices in the range of 36 to 46 percent and 16 to 25 percent respectively. Some ofthe in situ moisture contents were near the Liquid Limit range ofthe tested clays. The in-place dry density of a lean clay sample from Boring B-5 was determined to be 86 pounds per cubic foot which is relatively low and characteristic for poorly-consolidated alluvial material. The clay is moderately compressible at low stress levels(Plate No.3),but becomes highly compressible at stresses above 1000 psf. Based on the relatively low blow counts and consolidation behavior,the clay is expected to have generally low shear strength. • Clayey Gravel with Sand Below the topsoil and lean clay materials,gravel soils with varying quantities of clay to sand-size particles in the matrix were encountered. The predominant classification was clayey gravel with sand;however,some zones ofpoorly graded gravel were also logged. The gravel also contained some seams to zones of interbedded lean clay and poorly graded sand. Relative density ofthe gravel was determined to be medium dense to very dense as indicated by SPT N-values of28 to more than 50 blows per foot. The average N-value for the gravel was greater than 50 blows per foot. Nearly all ofthe gravel materials were below groundwater elevation and were therefore saturated. Moisture contents of 10 to 20 percent were commonly found. • Poorly Graded Sand with Silt and Gravel Approximately 3 feet ofpoorly graded sand with silt and gravel was encountered between the surficial clay and gravel soils in Boring B-6. It is probable that other seams of sand exist between the clay and gravel as localized alluvial variations. The sand was generally fine to medium grained and SPT N-values were in excess of 50 blows per foot indicating very dense conditions. Groundwater Conditions Groundwater was encountered in all borings at depths ranging from 1.5 to 4.5 feet below the surface. When resolved to a groundwater elevation based on data provided by a Morrison-Maierle survey, relative elevations of4748.7 to 4782.3 were determined for the water surface. These elevations do not yield a consistent or consistently grading groundwater surface elevation;however,groundwater appears 3 Valley West Subdivision NIL Enginecrin¢&Geoscience,Inc to generally mirror groundline contours. In many areas,the groundwater appeared to be somewhat "confined"by the surficial clay and rose slightly during the drilling. Numerous factors contribute to groundwater fluctuations and occurrence ofseepage and evaluation ofthese factors requires special study that is beyond the scope of this report. Engineering Analysis The surficial lean clay materials are weak and compressible and are not well suited for shallow foundation support;however,the dense gravel at relatively shallow depths will provide adequate support for shallow foundation systems. High groundwater elevations are likely to add difficulty in shallow foundation construction;however,we have assumed that some dewatering and shallow water construction practices may be effectively used to reduce construction difficulties. We have developed two options for foundation/flooring systems. The first option is for a shallow foundation with a suspended wood floor and vented crawlspace that will require raising the first-floor level above existing grade. Grade raising and crawlspace construction will allow separation between the structure and the high groundwater but will also impact the allowable bearing capacity. The second option is for a shallow foundation with a slab-on-grade flooring system that may have inherent slab dampness due to high groundwater conditions. General Foundation Preparation For either foundation option,spread or strip foundations should be cast in place on the native clayey gravel or Structural Fill extending to the native clayey gravel. The base of the foundations for all structures should extend at least 3.5 feet below the prevailing finished grade for frost protection. If clay soils or uncontrolled fill materials exist at a depth of 3.5 feet below finished grade,these materials should be removed and replaced with Structural Fill. In many instances,these excavations will encounter groundwater. Construction below grounwater is discussed in subsequent paragraphs. Design load information was not available at the time of our analysis;therefore,analysis was conducted for 1.5-foot minimum width footings loaded to our allowable bearing capacity recommendations. Strip footings have been analyzed for design based on the total removal of all clay materials below the footing base elevation with material replacement consisting of approved Structural Fill. Lean clay removal should be accomplished by excavation equipment operating from outside and above the foundation excavation to reduce the potential for disturbance to the underlying native materials. Based on field data,the surficial lean clay is variable in thickness;our analysis has assumed an average clay removal to a depth of4.0 feet below the prevailing ground surface elevation with subsequent replacement of 0.5 feet of excavation depth with Structural Fill. If the excavation does not encounter groundwater or 4 Valley West Subdivision NTL Eggineerin eoscience.Inc. saturated material conditions, the surface should be "proof-rolled"with non-vibratory compaction equipment to recover construction disturbance. Upon completion,Structural Fill can then be placed directly on the native gravel materials in accordance with appropriate items in the Recommendations. Since it is possible that groundwater will re-establish seasonally above the base of the foundation zone,the Structural Fill should consist of a"clean"(minimal fines'content),angular gravel material to limit post- construction degradation associated with fluctuation of groundwater elevation. If groundwater is encountered during the excavation, foundation preparation should be\modified as discussed in the Dewatering section below. Dewatering If groundwater is encountered during excavation,localized de-watering should be employed prior to conducting clay removal and Structural Fill placement. Dewatering should be conducted in a separate trench or array of well points beyond the perimeter of the excavation. Water removal should be maintained at a rate sufficient to depress groundwater below the base of the excavation for clay removal and Structural Fill placement. At least 1-foot of Structural Fill is recommended in areas where groundwater is encountered at the footing base elevation to provide a surface that can be compacted and to raise grade to provide some separation between the groundwater and the structure. If groundwater or saturated soil conditions persist near the base of the excavation after constructing dewatering strategies,compaction of the first 1±foot of structural fill is expected to be difficult. In this event,it is possible that conventional earthwork methods will not reach the recommended density for this lift;therefore,a geotextile separation fabric and an alternate Structural Fill material consisting of 1-inch minus,crushed gravel is recommended for the first lift. A slightly lower maximum dry density may be acceptable in this lift;however,subsequent lifts of gravel must reach the recommended minimum compaction density. Gradation specifications for this material are provided in the Recommendations. Foundation Design for Spread Foundations with Suspended Flooring and Vented Crawlspace The preferred option for lightly-loaded,residential housing is to design the structures with a vented crawlspace and a suspended first-level floor system above existing grade. This option may require some exterior grade raising or elevated building entry. An external and/or internal drainage and sump system will be necessary to maintain groundwater levels below the crawlspace elevation. Crawlspace construction will impact the burial depth of the foundations;therefore,an allowable bearing pressure of 2500 psf may be used to proportion spread footings placed on the prepared clayey gravel subgrade or Structural Fill discussed in the section. A minimum footing width of 1.5 feet should be used for strip footings and a minimum burial of 2.0 feet must be maintained to develop the design bearing capacity. A total load settlement of less than''/z-inchhas been calculated for minimum width footings loaded to the allowable bearing pressure. Differential settlements of less than'/2-inch may occur across building foundation lines due to variable foundation soils and performance of these materials. 5 Valley West Subdivision NTL Engineering&Geoscience.Inc. Foundation Design for Spread Foundations with Slab-on-Grade Flooring An alternate foundation design based on full,frost depth burial(interior and exterior)of foundations has also been considered. An allowable bearing capacity of 3500 psf may be used to proportion spread footings with a minimum embedment of 3.5 feet bearing on Structural Fill or native clayey gravel as discussed General Foundation Preparation section. A minimum footing width of 1.5 feet shouldbe used for strip footings. A total load settlement of approximately%Z-inch has been calculated for minimum width footings loaded to the allowable bearing pressure. Differential settlements of/2-inch may occur across building foundation lines due to variable foundation soils and performance of these materials. A perimeter underdrain/sump system is recommended for spread foundation/slab-on-grade construction. Slab Design/Preparation A slab-on-grade flooring system may be considered for building structures assuming some risk of slab dampness(associated with persistent high groundwater conditions)can be accepted. Site preparation for a slab-on-grade system should begin with removal of all topsoil and organic materials from the entire building footprint prior to foundation earthwork and construction. This stage should be conducted by equipment acting outside the building perimeter and construction traffic should be avoided in this area to reduce disturbance to the clay subgrade. By leaving lean clay soils below slab elements,there is some risk of differential slab performance due to the compressible nature of the clay. To improve finished subgrade uniformity and reduce the risk of differential performance for slab-on-grade placement,a minimum 1-foot lift ofLeveling Course Fill consisting of 1-inch minus crushed gravel is recommended beneath the slabs. Due to high groundwater conditions,finished slab grade should be greater than or equal to the prevailing ground surface elevation prior to construction. A sand cushion and vapor barrier should be considered between the concrete slab and the Leveling Course Fill Pavement Design At the time of our investigation,site specific traffic data estimates for the were not available for the subdivision;therefore,the minimum traffic volume from the City of Bozeman Engineering Department for roadway specifications was used. The minimum specified traffic estimate of 50,000 Equivalent 18 kip Single Axle Loads(ESAL's)was assumed over the 20 year design life. Traffic in the subdivision is expected to be limited to light delivery truck and passenger vehicle traffic once housing has been built; however,a larger initial volume of construction vehicles is expected. If total design traffic in excess of 50,000 ESALs is expected,pavement section demands will be greater, and thicker sections may be necessary to achieve the desired performance and design life. Flexible pavement sections have been designed in accordance with AASHTO procedures using an initial serviceability index Pi=4.2 and a terminal serviceability index of P,=2.0 at the end of design life. 6 Val,IeyWest Subdivision NTL En ineerina&Gegscie!Lqe.,Inc The design subgrade material used in our analysis has been selected as the surficial lean clay. Typical clay thicknesses of 1.5 to 4.5 feet were observed during drilling in our various borings. Based on testing from another local project near the proposed subdivision,a soaked CBR value of approximately 4.5 percent has been used for the predominant lean clay subgrade. The design CBR value assumes that the subgrade will be prepared(scarified,moisture conditioned,and recompacted)such that the in-place density is at least 95 percent of the maximum dry density determined by ASTM D-698. A reliability of 90 percent and standard deviation of 0.45,combined with an effective roadbed soil resilient modulus of approximately 6000 psi,have been used to arrive at a design structural number of2.4. Pavement material thickness and suggested material specifications based on this structural number are provided in the Recommendations. Our geotechnical engineering staff should review the pavement thickness recommendations as traffic information becomes available. Recommendations 1.0 Construction Materials 1.1 Structural Fill beneath footings and floor slabs should be selected in accordance with the following gradation and be compacted in uniform lifts not exceeding 12-inch loose thicknesses to achieve a minimum 98 percent of the maximum ASTM D698 dry density. _Screen or Sieve Size Percent Passing by Weight- 3-Inch 100 1-1/2 Inch 85 - 100 No. 4 30 - 60 No. 200 8 maximum 1.2 Slab fill above footing elevation and below the Leveling Course can be selected in accordance with Item 1.1 or be an alternate granular material satisfying the following gradation requirements: _ Screen or Sieve Size Percent Passing_by Weight No. 4 100 No. 40 10 - 30 No. 200 25 maximum The fines content should have Liquid Limit and Plasticity Index not exceeding 40 and 25 percent respectively. This specification has been prepared to include on-site clayey gravel with sand materials and is only to be used as grade raising fill below slabs or non-structural elements. 7 Valley West Subdivision NTL Engineering&Geoscience,Inc 1.3 Select crushed gravel fill for use on saturated subgrade below foundations or as a leveling course for slabs should be hard,durable aggregate with at least 95 percent of the particles having one or more fractured faces. The material shall be well-graded between the 1-inch and 3/8-inch screen sizes and contain not more than 3 percent passing the No. 4 sieve. This material should be compacted by static drum rolling to a stable condition as determined by our geotechnical engineer. 1.4 Backfill materials should be placed in uniform lifts ofmaximum 8-inch loose thickness and be compacted to a minimum 95 percent of the maximum ASTM D698 dry density. On-site clayey gravel with sand and lean clay soils at the site are suitable forperimeter foundation backfill provided that they are free of organic materials and construction debris and are moisture-conditioned to obtain the required density. Many ofthe on-site materials will be at or near,their saturated moisture content which will exceed the optimum moisture content required for compaction. These materials will need to be spread and turned to dry to a moisture content sufficient for proper compaction, or alternate materials imported. The lean clay materials will be particularly moisture sensitive and may require significant handling to obtain near-optimum moisture content. 2.0 Temporary Excavation Guidelines 2.1 The stability of construction excavations and associated worker safety are the responsibility of the contractor in accordance with current OSHA regulations;this responsibility may require design by a registered professional engineer. Since project excavation will occur predominantly in the soft lean clay soils,temporary construction excavations to be planned in accordance with OSHA provisions should assume Type C material conditions. It has been assumed that dewatering will be provided prior to excavation and maintain material conditions consistent with the foregoing classification. Actual subsurface conditions at the time of excavation should be observed by a geotechnical engineer to determine whether slope flattening,bracing or other stabilization is necessary due to seepage or other unexpected conditions. 3.0 SiteIFoundation Preparation 3.1 The complete removal oftopsoil and organic soils should be accomplished within the building footprint prior to construction. Further removal of all lean clay soils should be conducted for all foundations to provide native gravel bearing surface or Structural Fill extending to that depth(see Detail 1 in the Appendix). Acceptable backfill materials per Item 1.4 should be stockpiled separately for use in perimeter backfilling or landscaping. 3.2 Dewatering with well points,perimeter trenches,or other approved dewatering systems should be planned to accomplish the fill removal and replacement. Dewatering should be initiated prior to excavating to draw the water level below the subexcavation depth and should be conducted in a manner that does not disturb the excavation base. 8 Va" Iley West Subdivision NTL Enyincerij?g&Geoscicnce Inc 3.3 The subexcavation and replacement for foundation construction should be conducted using an excavator with a smooth-blade bucket operating from above the subexcavation level. In areas where groundwater is of sufficient depth below the base of the excavation such that saturated soil conditions are not encountered at the foundation base,the native clayey gravel with sand base should be proof rolled with a static vibratory drum roller prior to Structural Fill placement. However,if saturated soil conditions exist at the base ofthe excavation,clean-up of loosened materials should be done by hand shoveling prior to geotextile/select crushed gravel Structural Fill placement. The initial lift of Select Crushed Gravel Fill should be placed in a loose lift thickness of 12-inches before compacting to a stable condition by static drum rolling;any areas of rutting, yielding, or non-uniform performance should be observed by our geotechnical engineer to determine appropriate corrective action. 4.0 Foundation Design 4.1 All spread footings must be founded on native clayey gravel with sand or Structural Fill extending to clayey gravel with sand prepared per the preceding recommendations. Strip foundations should have a minimum width of 1.5 feet and spread footings should have a minimum base width of 2.0 feet. 4.2 For foundations with full frost depth embedment(3.5 feet minimum)on all sides of the foundation as would be typical for slab-on-grade construction,footing size can be proportioned using an allowable bearing pressure not exceeding 3 500 pounds per square foot(psf). A lesser allowable bearing pressure of 2500 psf should be used to proportion foundations with an embedment less than 3.5 feet but at least 2 feet on the interior as would be typical for crawlspace construction. The load bearing pressures provided assume that load-settlement relations discussed in the ENGINEERING ANALYSIS are acceptable. A generalized detail of shallow foundation options is provided in Detail 1 of the Appendix. 4.3 Lateral load resistance can be provided by friction acting along footing bases and passive pressure acting on the footing sides. For design purposes, the following parameters are appropriate: Material Friction Coefficient Passive Resistance (psf/ft depth)* On-site recompacted fill soils --- 200 Structural Gravel Fill 0.50 350 *Assumes foundation backfill compacted per Iteml.4. 4.4 Seismic design following the static procedures outlined in the 1997 Uniform Building Code may be conducted using a Soil Profile Type SD. 9 Valley West Subdivision NTL Engineering&Geoscience,lnc, 5.0 Slab Subgrade Preparation 5.1 Following placement and compaction of structural or slab fill to 1.0 feet below the finished slab elevation,a cushion/leveling course ofminus 1-inch crushed gravel compacted in accordance with Item 1.3 is recommended to improve uniformity of slab support. A sand cushion and vapor barrier should be provided beneath moisture sensitive flooring areas. 6.0 Pavement Subgrade and Construction Materials 6.1 Any fill materials required for subgrade construction to raise grade to the base of the pavement section should have a minimum CBR=4.5 percent(R-value= 10). Classification ofmaterials that are likely to meet or exceed these criteria are as follows: AASHTO Classification USCS Classification A-1-a A-2-5 GW SW A-1-b A-3 GP SP A-2-4 GM SM GC Materials having classifications other than above may be considered if test results indicate conformance to CBR/R-value criteria. Materials should be placed in uniform lifts ofmaximum 8-inch loose thickness andbe compacted to at least 95 percent of the maximum ASTM D-698 or AASHTO T-99 dry density. 6.2 Specifications for recommended Crushed Base Course,Crushed Subbase Course,and Asphalt Aggregate have been included in the Appendix. Materials should conform to these specifications or the latest Montana Public Works Specifications for plant mix surfacing. 6.3 If separation fabric is desired between subgrade and base course materials,the geotextile should be selected to conform to the following specifications for medium survivability(MDT Standard Specifications, Table 713-1). Reported specifications are Minimum Average Roll Values (MARV). Grab Strength: ASTM D4632 180 lbf Tear Strength: ASTM D4533 70 lbf Puncture Strength: ASTM D4833 70 lbf Grab Elongation: ASTM D4632 <50% Apparent Opening Size: No.40 Sieve(maximum) Geotextiles such as Mirafi 50OX and Geotex 180ST conform to these specifications. 10 Valley West Subdivision NTL Engineering&Geoscience,Inc 7.0 Pavement Subgrade Preparation 7.1 In areas ofpavement section construction,the subgrade should be scarified,disked,or otherwise mechanically loosened to a depth of 6 inches to allow moisture adjustment to within 1E percent of optimum. Dewatering maybe necessary to conduct removals and prepare subgrade forpavement section placement. The moisture conditioned layer should be compacted to a minimum density of 95 percent of the maximum AASHTO T99 or ASTM D-698 dry density. 7.2 Any areas where rutting,yielding,or other non-uniform subgrade performance is observed,should be removed or recompacted as recommended by a geotechnical engineer. A geotextile separation fabric(per Item 6.3)placed on the prepared subgrade should be considered. The fabric would prevent intermixing between the fine-grained, natural soils and the pavement base course. 8.0 Pavement Thickness Design 8.1 Flexible pavement thickness can be selected from the following section alternates for a 20-year design period provided that traffic assumptions discussed in the Engineering Analysis are acceptable. Pavement Component Required Pavement Thickness,(in) Alternate#1 Alternate#2 Alternate#3 Asphaltic Concrete 4 3 4 Crushed Base/Leveling Course 5 8 9 Crushed Subbase 6 6 -- Total Section Thickness: 15 17 13 9.0 Continuing Services 9.1 If changes in building foundation concepts or loading are made during the design,our geotechnical engineer should assist in developing appropriate design parameters. 9.2 Geotechnical observation should be provided during the earthwork and foundation phases of the project. These geotechnical services should ascertain that subsurface conditions are reasonably consistent with those determined by our investigation,and should ascertain that construction materials and placement are as recommended herein. It is particularly important that our engineer observe installation of drilled shaft foundations. 11 Valley west Subdivision NTL Engineering&Geoscience.Inc. Conclusion The foregoing recommendations present our initial geotechnical input for design and construction of the proj ect. In order for these recommendations to be properly incorporated in the subsequent design and construction stages we recommend that our geotechnical and construction materials engineering staff remain involved with the project to ascertain that our recommendations have been properly interpreted both during design and construction. These services will reduce the potential for misinterpretation of subsurface conditions and geotechnical design recommendations that are important in the preparation of proj ect plans, specifications, and bid documents. NTL is a member ofthe Association of Engineering Firms Practicing in the Geosciences(ASFE), which is a professional organization whose purposes include the reduction ofpotential liabilities to member firms and proj ect owners by quality-based engineering selection and positive owner-engineer interaction during the design and construction processes. Attached in the Appendix is an information sheet regarding geotechnical engineering reports and their limitations prepared by ASFE. Limitations This report has been prepared in accordance with generally accepted geotechnical engineering practices in this area solely for use by the client for design purposes and is not intended as a construction or bid document representing subsurface conditions in their entirety. The conclusions and recommendations presented are based upon the data obtained during the investigation as applied to the proposed site grading and construction details discussed in this-report. The nature and extent of variations between the borings may not become evident until construction. If variations are then exposed,it will be necessary to reevaluate the recommendations of this report. If changes in the concept,design data,or location ofthe project are planned,the recommendations contained in this report shall not be considered valid unless the changes are reviewed by our geotechnical engineer, and the recommendations of this report modified or verified in writing. Prepared By: Z '_� Jo /J. Hepf er, P.E. Geotechnical Engineer Reviewed By: G wnn, P.E. Sr. Geotechnical Engineer 12 WP0RTANT • A ENGINEERING REPORT As the client of a consulting geotechnical engineer,you MOST GEOTECHNICAL FINDINGS ARE should know that site subsurface conditions cause more PROFESSIONAL JUDGMENTS construction problems than any other factor.ASFE/I'he Site exploration identifies actual subsurface conditions Association of Engineering Firms Practicing in the only at those points where samples are taken.The data Geosciences offers the following suggestions and were extrapolated by your geotechnical engineer who observations to help you manage your risks. then applied judgment to render an opinion about overall subsurface conditions.The actual interface A GEOTECHNICAL ENGINEERING REPORT IS BASED between materials may be far more gradual or abrupt ON A UNIQUE SET OF PROJECT-SPECIFIC FACTORS than your report indicates.Actual conditions in areas Your geotechnical engineering report is based on a not sampled may differ from those predicted in your subsurface exploration plan designed to consider a report.While nothing can be done to prevent such unique set of project-specific factors.These factors situations,you and your geotechnical engineer can work typically include:the general nature of the structure together to help minimize their impact. Retaining your involved,its size,and configuration; the location of the geotechnical engineer to observe construction can be structure on the site;other improvements,such as particularly beneficial in this respect. access roads, parking lots, and underground utilities; and the additional risk created by scope-of-service A REPORT'S RECOMMENDATIONS limitations imposed by the client.To help avoid costly CAN ONLY BE PRELIMINARY problems, ask your geotechnical engineer to evaluate The construction recommendations included in your how factors that change subsequent to the date of the geotechnical engineer's report are preliminary, because report may affect the report's recommendations. they must be based on the assumption that conditions revealed through selective exploratory sampling are Unless your geotechnical engineer indicates otherwise, indicative of actual conditions throughout a site. do not use your geotechnical engineering report: Because actual subsurface conditions can be discerned only during earthwork,you should retain your geo- • when the nature of the proposed structure is technical engineer to observe actual conditions and to changed, for example, if an office building will be finalize recommendations.Only the geotechnical erected instead of a parking garage,or a refrigerated engineer who prepared the report is fully familiar with warehouse will be built instead of an unrefrigerated the background information needed to determine one; whether or not the report's recommendations are valid • when the size,elevation,or configuration of the and whether or not the contractor is abiding by appli- proposed structure is altered; cable recommendations.The geotechnical engineer who • when the location or orientation of the proposed developed your report cannot assume responsibility or structure is modified; liability for the adequacy of the report's recommenda- • when there is a change of ownership;or tions if another party is retained to observe construction. • for application to an adjacent site. GEOTECHNICAL SERVICES ARE PERFORMED Geotechnical engineers cannot accept responsibility for FOR SPECIFIC PURPOSES AND PERSONS problems that may occur if they are not consulted after Consulting geotechnical engineers prepare reports to factors considered in their report's development have meet the specific needs of specific individuals.A report changed. prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer. SUBSURFACE CONDITIONS CAN CHANGE Unless indicated otherwise,your geotechnical engineer A geotechnical engineering report is based on condi- prepared your report expressly for you and expressly for tions that existed at the time of subsurface exploration. purposes you indicated.No one other than you should Do not base construction decisions on a geotechnical apply this report for its intended purpose without first engineering report whose adequacy may have been conferring with the geotechnical engineer. No party affected by time.Speak with your geotechnical consult- should apply this report for any purpose other than that ant to learn if additional tests are advisable before originally contemplated without first conferring with the construction starts.Note,too, that additional tests may geotechnical engineer. be required when subsurface conditions are affected by construction operations at or adjacent to the site,or by GEOENVIRONMENTAL CONCERNS natural events such as floods, earthquakes.or ground ARE NOT AT ISSUE water fluctuations. Keep your geotechnical consultant Your geotechnical engineering report is not likely to apprised of any such events. relate any findings,conclusions,or recommendations EXPLANATION OF FIELD INVESTIGATION METHODS Prior to drilling and sampling of subsurface materials,a preliminary field reconnaissance was conducted to verify utility clearance,note surface drainage patterns,and identify pertinent geologic features that may have bearing on analysis. The preliminary reconnaissance includes literary review of geology and soils-related problems identified for other sites nearby or for similar expected soil conditions. Boring locations and planned depths are reviewed based on this reconnaissance. The drilling program was conducted using a Mobile B-59 truck mounted drill rig with 41/4-inch hollow-stem auger equipment and either smooth-blade or tri-cone rock bits. The hollow-stem augers serve as a casing for the boring and allow sample recovery by Standard Penetration Testing(SPT),ring sampling using a modified California Sampler,and by using thin-walled steel tube(Shelby Tube). The soils are continuously logged by an engineer or geologist and classified by visual examination in accordance with the Unified Soils Classification System;observation and-grab sampling of auger cuttings is necessary to completely log the boring. Groundwater levels and seepage zones were noted as encountered and measured in the hollow-stem augers once stabilized. Slotted PVC observation wells maybe installed to record long-term groundwater levels. Samples of soils are taken at frequent intervals in the boring typically by SPT methods. The SPT testing was conducted in general accordance with ASTM D 1586 using a split spoon sampler with a 2-inch outside diameter driven 18 inches into the soil by dropping a 140-pound hammer 30 inches. The total number of hammer blows required to advance the sampler the second and third 6-inch increments is the standard penetration resistance, or N-value. Split spoon samples were also recovered using a larger sampler having an outside diameter of 3-inches. Undisturbed samples are obtained from layers of soil that are critical to the analysis. The Shelby Tube samples were obtained by pushing a 3-inch diameter,thin-walled steel tube into the soil to obtain a reasonably undisturbed sample. These samples are used to determine in-place density and can be trimmed to fit into laboratory consolidation and shear testing devices. NTL ENGINEERING AND GEOSCIENCE,INC., PO BOX 3269, GREAT FALLS,MT 59403 EXPLANATION OF LABORATORY TESTING PROGRAM One-Dimensional Consolidation Testing Consolidation is the process of time-dependent settlement of clayey soil when subjected to an increased loading. This testing is conducted in a fixed-ring consolidometer in general accordance with the procedures ofASTM D2435-90. The test measures sample strain(settlement)with time for a series of increasing loads applied on the sample surface area;pressure versus strain relations are thereby determined. Specimens for the testing are trimmed from"undisturbed"samples retrieved commonly by Shelby tube or California ring sampler. Specimen dimensions for testing are typically 2.5 inches in diameter by 1.0 inch in height. During the test,specimens may be inundated at a selected normal pressure to simulate field conditions. Test data is generally reduced using the square root oftime fitting method to determine specimen strain at 100 percent ofprimary consolidation for each load increment. This strain at progressive load increments is plotted to construct the consolidation curve for which field soil deformation can be approximated. Soil Index Testing This testing includes water content as a percent of dry soil weight representative of in situ conditions in general accordance with the procedures of ASTM D2216,and may include one or more of the following:Atterberg Limits(soil plasticity determined by the moisture range through which a soil passes from a plastic to liquid consistency)in accordance with ASTM D4318,grain size distribution indicating the percent by weight of clay,silt,sand,and gravel comprising the soil aggregate per ASTM D421/422,and the grain size distribution of silt and clay-size material by the procedure of ASTM D 1140. The results of these tests have been presented on the Logs as well as the accompanying Plates. NTL ENGINEERING AND GEOSCIENCE,INC., PO BOX 3269, GREAT FALLS,MT 59403 n LOG OF BORING B-1 n - page 1 of 1 PROJECT: :y West Subdivision L- i ioN: W 2,043 N 1,866 ^^Nc r CEOSCIENIENCE tlVC Bozeman, MT JOB NO.: 02-305 SURFACE ELEVATION: 4752.2 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: -7 3.8 METHOD: T DRILLER: Boland Drilling DATE STARTED: 1/16/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/16/02 LABORATORY TEST DATA 0UE, � H w H o w MATERIAL H z w A °l° U °`° °° _ -- 3 CLASSIFICATION AND DESCRIPTION E� z W u H -- H x a °° °° °w x x a w E� H o U) w ca a � E• E-4 H W a s H E-E a H V] Ca Q� Q EE '+ W U) EH W a 0 a a H H w H ca. co a, U ra a a O co m U 0.4 — — [—TOPSOIL Organic Matter Lean CLAY,fum,moist to saturated,high organic content,trace gravel,dark brown (CL) ST push SSS 41 Clayey GRAVEL with Sand,dense to very dense, 8 saturated,subround gravel,brown (GC) 5 LSK 5 39 21 57 28 18 i 10 SSS 58 13 I 15 SSS 88/0.9 12 End of Boring B-1@ 15.9' 20 i 'SAMPLE TYPE KEY: ®SSS - STANDARD SPLIT SPOON(SPT) REMARKS 8 LSS - LARGE SPLIT SPOON m ST SHELBY TUBE 91 RS RING SAMPLE ❑SK SACK SAMPLE a LOG OF BORING B-2 page I of I n PROJECT: Vu..ey West Subdivision Low-,rlON: W 36 N 1,453 EwteEanx s CEOSCIENCE.9VC Bozeman, MT JOB NO.: 02-305 SURFACE ELEVATION: 4764.2 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: 4 4.5 METHOD: 1 DRILLER: Boland Drilling DATE STARTED: 1/15/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/15/02 LABORATORY TEST DATA _ z w -, r U E+ Ei a -1 MATERIAL - H w a z En H z w C o U H o w � H CLASSIFICATION AND DESCRIPTION z w U H -- H X a 60 x x aw E-4 w Qa zP E• w w -- - E� w a w �*4� + E-1 W [�!] N W a d ° 0 a U) 0+ U ca a s �n �, U 0.6 r TOPSOIL, Organic Matter Lean CLAY,soft,very moist to saturated,frozen near surfhce,ice lenses,high organic content,trace gravel,dark brown (CL) SSS 3 33 3.5 Clayey GRAVEL with Sand,dense to very dense, 2 saturated,subround gravel,brown (GC) 5 ' ST push sss 40 19 10 SSS 60 12 15 sss 50/0.4 11 End of Boring B-2 @ 15A 20 "SAMPLE TYPE KEY: ®SSS - STANDARD SPLIT SPOON(SPT) REMARKS B LSS LARGE SPLIT SPOON m ST SHELBYTUBE ❑ IRS RING SAMPLE ❑SK SACK SAMPLE �� LOU UN' IiUK.1NG I3-3 page 1 of 1 PROJECT: -.ey West Subdivision ATION: W 486 S 175 LENCINEERINC F-NC Bozeman, MT JOB NO.: 02 305 SURFACE ELEVATION. 4780.5 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: - 2.0 METHOD: _ DRILLER: Boland Drilling DATE STARTED: 1/16/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/16/02 LABORATORY TEST DATA OUH d° El >+ H a E' MATERIAL a v - - H Hw w w � H o CLASSIFICATION AND DESCRIPTION Ul w q w ] E H w w °�° C] vim] E Wf� � � O P v aH H U fa a a, cn M U 0.4 — — TOPSOIL Organic Matter Lean CLAY,soft to very stiff,very moist to saturated,frozen near surface,ice lenses,high organic content, dark brown (CL) SSS 16 5 4.5 Clayey GRAVEL with Sand;dense,saturated, SSS 50/0.4 subround gravel,brown (GC) 10 SSS 74 8 15 sss 75/0.8 11 End of Boring B-3 @ 15.8' 20 'SAMPLE TYPE KEY: ®SSS - STANDARD SPLIT SPOON(SPT) REMARKS B LSS - LARGE SPLIT SPOON m ST - SHELBY TUBE IRS RING SAMPLE SK - SACK SAMPLE n a LOG UY 130tUNG B-4 n �-}-� page 1 of I ^A 0 PROJECT: ey West Subdivision L ATION: E 757N 155 E`1C GFOSCIENCEAC Bozeman, MT JOB NO.: 02-305 SURFACE ELEVATION: 4780.8 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: V 3.0 METHOD: T DRILLER: Boland Drilling DATE STARTED: 1/15/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/15/02 LABORATORY TEST DATA zw > O U Ei E4 >+ w a H MATERIAL � Q ` °a�°P � P z A ° U 0w CLASSIFICATION AND DESCRIPTION z U H - H x Wa a' �r° °° 0. Ri w H Q Q - y a4 E - Oa i-I E1 d HQ Ma U HH rl i1 0.4 — — TOPSOIL Organic Matter Lean CLAY,soft,very moist to saturated,frozen, 1.5 ice lenses,high organic content,trace gravel,dark brown CL SSS 65 Clayey GRAVEL with Sand,very dense,saturated, 14 subround gravel,brown (GC) 5 SSS 62 7 3 10 , SSS 63 8 15 { SSS 50/0.5 End of Boring B-4 @ 15.5' I I I 20 I { 'SAMPLE TYPE KEY: SSS STANDARD SPLIT SPOON (SPT) REMARKS 8 LSS - LARGE SPLIT SPOON m ST SHELBY TUBE 0 IRS RING SAMPLE 2 SK - SACK SAMPLE A LOG OF BORING B-5 4 page 1 of 1 \' ^ v PROJECT: ___,;y West Subdivision L(—,I•ION: Not Included in Survey cEe.�,c Bozeman, MT JOB NO.: 02-305 SURFACE ELEVATION: N/R DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: Q 2.0 METHOD: T DRILLER: Boland Drilling DATE STARTED: 1/15/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/15/02 LABORATORY TEST DATA H a E z� w MATERIAL z n - -- H a° ow w 4 a H z H o w �a U) 3 CLASSIFICATION AND DESCRIPTION H z w H — H x ono 6\o H w ww w HH QA off cEnQ Q H - >1 W H >+ >+ Z O Z >1 H Z a Q [/? E-� a O Q a fH-lQ4 H 0.5 — — TOPSOIL, Organic Matter Lean CLAY,firm to stiff,very moist to saturated, frozen near surface,ice lenses,high organic content, trace gravel,dark brown (CL) ST push 32 86 3.8 Clayey GRAVEL with Sand,very dense to dense, 5 saturated,subround gravel,brown (GC)' sss 80 12 10 sss 39 9 End of Boring B-5 @ 11.5' 15 20 "SAMPLE TYPE KEY: ® SSS - STANDARD SPLIT SPOON(SPT) REMARKS B LSS - LARGE SPLIT SPOON m ST - SHELBY TUBE 21 RS RING SAMPLE A SK - SACK SAMPLE n LOG OF BORING B-6 n 9 page 1 of 1 A %n 9 PROJECT: V_ _ y West Subdivision L(..._ .i ION: E 2,278 N 87 nENMEERINC S n CEOSCIENCENC Bozeman, MT JOB NO.: 02-305 SURFACE ELEVATION: 4784.8 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: - 2.5 METHOD: T DRILLER: Boland Drilling DATE STARTED: 1/15/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/15/02 LABORATORY TEST DATA O U H w o\o H H a Ei w MATERIAL x -� - H ono 60 w a r~ H o w CLASSIFICATION AND DESCRIPTION H z H x x a w Ho In w A a+ h H w w Ea w w as H Ei - a H v, Q > ca H F-] H P W O p] O a r4 H I H Q M w rJ Q a a, c7 rn U) U — — TOPSOIL, Organic Matter 0.6 Lean-CLAY,stiff,very moist,frozen near surface, ice lenses,trace sand,brown (CL) 4 SSS 56 2.8 . Poorly Graded SAND with Silt and Gravel,very dense,very moist to saturated,fine to medium sand, brown (SP-SM) 5 SSS 55 g 6. Clayey GRAVEL with Sand,very dense,saturated, subround gravel,brown (GC) SK 10 54 33 13 10 SSS 51 11 11.5 1 End of Boring B-6 @ 11.5' 15 20 I _ _ "SAMPLE TYPE KEY: SSS - STANDARD SPLIT SPOON(SPT) REMARKS 8 LSS - LARGE SPLIT SPOON m ST SHELBY TUBE ❑ RS RING SAMPLE C, SK SACK SAMPLE LOG OF BORING B-7 page 1 of 1 n I . PROJECT: 'v—,Ley West Subdivision L__ATION: E 2,216 N 907 nENC CEERINC 6 ^ CEOSCIENCE,NC Bozeman, MT JOB NO.: 02-305 SURFACE ELEVATION: 4777.0 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: V 6.0 METHOD: T DRILLER: Boland Drilling DATE STARTED: 1/15/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/15/02 LABORATORY TEST DATA H U E H w o\9 >+ ^ C4 H H w H o w E MATERIAL H z w A � U � - - -- CLASSIFICATION AND DESCRIPTION E z w H x Owla w HHo � w Q a P w2 as HH -- aH MQ > Q E >4 0.w'. Q� z Z H Z H Q `n M H w ° A a s w 0.4 — — TOPSOIL, Organic Matter Lean CLAY,.firm to stiff,very moist,frozen near surface,ice lenses,brown (CL) sss 11 27 36 16 3.5 Clayey GRAVEL with Sand,medium dense to dense,saturated,subround gravel,brown (GC) 5 SSS 28 11 10 SSS 49 9 End of Boring B-7 @ 11.5' 15 20 "SAMPLE TYPE KEY: ®SSS - STANDARD SPLIT SPOON(SPT) REMARKS B LSS - LARGE SPLIT SPOON m ST SHELBY TUBE EI RS - RING SAMPLE ❑.SK SACK SAMPLE LOG OF BORING B-8 n page 1 of 1 \�^ PROJECT: `—.ey West Subdivision LC._.,TION: E 2,565 N 2,318 EmreEwc S ^ CEOSCIENCFAC Bozeman, MT JOB NO.: 02-305 SURFACE ELEVATION: 4758.2 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: - 4.7 METHOD: T DRILLER: Boland Drilling DATE STARTED: 1/15/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/15/02 LABORATORY TEST DATA ow o i U Ei W d Ei P w H ^ w � a H MATERIAL H z w Q oa. H o w E 3 CLASSIFICATION AND DESCRIPTION H z w H — H >C a ono w H � 114 H co o a -a H I z H : I Ca �+ Ca a a, Ch m cn 0.4 — — TOPSOIL OEganic Matter / Gravelly Lean CLAY with Sand,stiff,very moist, 1.5 frozen ice lenses brown CL Clayey GRAVEL with Sand,very dense,saturated, SSS 74/0.9 subround gravel,brown (GC) 6 i I 5 SSS 57 g 10 SSS 57 6 li 15 SSS 96/0.7 I g End of Boring B-8 @ 15.7' 20 'SAMPLE TYPE KEY: ®SSS - STANDARD SPLIT SPOON (SPT) REMARKS B LSS - LARGE SPLIT SPOON m ST SHELBY TUBE ❑� IRS RING SAMPLE SK SACK SAMPLE LOG OF BORING B-9 ^A +IA' page 1 of 1 n PROJECT: V� _.y West Subdivision LC ,'ION: E 1,081 N 2,353 ^ ENCNEERINC& ^ CEOSCIENCE.NC Bozeman, MT JOB NO.: 02-305 SURFACE ELEVATION: 4756.2 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: Q 5.2 METHOD: T DRILLER: Boland Drilling DATE STARTED: 1/14/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/14/02 LABORATORY TEST DATA >1 U H _ H a 1 MATERIAL a m� -, - H �o ono a w 9 x H z w ca ow U �- - - -- -- H o w � 3 CLASSIFICATION AND DESCRIPTION H z w U H - H X a ono \o o� x rx a w E- CO W H o ra a � E E w E w a s H E-H Off'H m L] w M E t=] O 0x 4 H Q w U ra a a, m V U 0.4 TOPSOIL Organic Matter Lean CLAY with Sand,firm to stiff,very moist, frozen,ice lenses,high organic content,dark brown (CL) 2.2 / LSS 17 Lean Clay with Sand,stiff,very moist, coarse sand, 37 41 22 light brown (CL) a. SSS 74 9 Clayey GRAVEL with Sand,very dense,saturated, 5 subround gravel,brown (GC) SSS 55 15 10 SSS 72 9 15 SSS 50/0.5 15 End of Boring B-9 @ 15.5' 20 �C 'SAMPLE TYPE KEY: SSS STANDARD SPLIT SPOON(SPT) REMARKS B LSS LARGE SPLIT SPOON m ST SHELBYTUBE RS RING SAMPLE ❑ SK SACK SAMPLE LOG OF BORING B-10 page 1 of 1 PROJECT: V.—ey West Subdivision Lc.__.rION: E 259 N 1,247 ENMEERINC 6 GEOS� Bozeman, MT JOB NO.: 02-305 SURFACE ELEVATION: 4766.9 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: Q 3.5 METHOD: T DRILLER: Boland Drilling DATE STARTED: 1/15/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/15/02 LABORATORY TEST DATA Z W P F >4 'O UH W H a44MATERIAL x � c° w � a � H zw Qom U -- -- 3 CLASSIFICATION AND DESCRIPTION P z W U H — H X a ago ono 6. x a 0 4 W C� W C] a+ �' H H -- -- -- W W E W W W W H O H H OI H M Q W H v] H W W W O C4 F4 H H fa U] a4 v U C) a a+ 0 U7 ul U D.s TOPSOIL, Organic Matter Lean CLAY, soft,very moist,frozen near surface, ice lenses,trace sand,dark brown (CL) SSS 1 40 46 25 4.5 5 Clayey GRAVEL with Sand,very dense,saturated, SSS 72/0.8 subround gravel,brown (GC) 17 I 10 SSS 91 7 11 15 SSS 87/0.9 20 ' SSS 50/0.4 9 End of Boring B-10 @ 20.5' 'SAMPLE TYPE KEY: ® SSS - STANDARD SPLIT SPOON(SPT) REMARKS B LSS - LARGE SPLIT SPOON X ST SHELBYTUBE ❑o RS RING SAMPLE ❑ SK SACK SAMPLE LOG OF BORING 13-11 page 1 of 1 ^^ V PROJECT: N jy West Subdivision L 1TION: E 3,805 N 2,382 ^ ENGINEERING G ^ GEOSCIENCE,NC Bozeman, MT JOB NO.: 02-305 SURFACE ELEVATION: 4761.3 DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: Q 4.5 METHOD: 1 DRILLER: Boland Drilling DATE STARTED: 1/14/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/14/02 LABORATORY TEST DATA O U H W 6- Ea114 ✓i w a MATERIAL Z xEi o CLASSIFICATION AND DESCRIPTION E- w ] w o a a W Q aEH W W W W �4 Ho ovo Ei a H ul C] C] Ei >+ W E f] Eli WW a O a a H H H ra U) IP4 v ra a a O cn m v 0.2 x TOPSOIL Organic Matter FILL,Clayey,Gravel with Silt and Sand,medium 1 5 dense frozen near surface ice lenses.brown FILL,Gravelly Lean Clay,stir to hard,moist to SSS 14 saturated,subround gravel,brown 4 5 SSS 78 g 7. Clayey SAND with Gravel,very dense,saturated, j, medium to coarse sand,brown (SC) 10 SSS 76 21 End of Boring B-11 @ 11.5' 15 20 *SAMPLE TYPE KEY: ® SSS - STANDARD SPLIT SPOON(SPT) REMARKS 8 LSS - LARGE SPLIT SPOON m ST - SHELBY TUBE °0 RS RING SAMPLE ❑ SK - SACK SAMPLE LOG OF BORING B-12 '^ page 1 of 1 n t _L PROJECT: N y West Subdivision L% rION: E 4,766 N 2,430 ^ En✓'nEERBVC S � CEOSCIENCE,YVC BozemJOB NO.: 02-3( an, MT SURFACE ELEVATION: 4763.8 \ DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: Q none observed METHOD: 1 DRILLER: Boland Drilling DATE STARTED: 1/14/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/14/02 LABORATORY TEST DATA z H a H MATERIAL a v Cf) - E� m �D E Z [-4 C] ow U -- x a ° a w H H � CLASSIFICATION AND DESCRIPTION In W A w H H w w oo �o ` oo - H —1 QQyaE > z z A > x �+ U C) a a4 C7 V1 cq U 0.2 LSK TOPSOIL Or anic Matter 41 22 63 17 2,O FILL, Clayey Gravel with Sand,dense,moist, subround gravel,brown 3.5 Lean CLAY,stiff,moist,brown (CL) 5 SSS 65/0.9 26 5.6 Clayey GRAVEL with Sand,very dense,saturated, 3 brown (GC) End of Boring 13-12(t7 5.9' 10 15 20 I "SAMPLE TYPE KEY: ® SSS - STANDARD SPLIT SPOON(SPT) REMARKS 8 LSS - LARGE SPLIT SPOON m ST - SHELBYTUBE l ❑o IRS - RING SAMPLE SK - SACK SAMPLE LOG OF BORING B-12a cr-wn page 1 of 1 PROJECT: `»..ey West Subdivision LC,_.,FION: Not Included in Survey Bozeman, MT JOB NO.: 02-305 SURFACE ELEVATION: N/R DRILLING Mobile B-59 4-1/4" Hollowstem Auger GROUNDWATER DEPTH: none observed METHOD: i DRILLER: Boland Drilling DATE STARTED: 1/16/02 LOGGED BY: J. Hepfner DATE COMPLETED: 1/16/02 LABORATORY TEST DATA O U F o\o E >4 w a MATERIAL H o w 9 , 3 CLASSIFICATION AND DESCRIPTION E� z w U H - H X x fx a w E-E H p W Q a+ �:) Ei E- W w W va E E ZM H W O Cr. a HQ U fa a C(d17' V1H rn U 0.3 ,TOPSOIL,Organic Matter , FILL,Clayey Gravel with Sand,medium dense, 1.5 slightly moist,subround gravel,brown Silty CLAY with Gravel, stiff,moist, brown 2.5 CL-ML) LSK Clayey GRAVEL with Sand,very dense,saturated, 40 23 50 26 2.4 brown (GC) 5 I-lv_j� End of Boring B-12a @ 8.0' 10 15 20 `SAMPLE TYPE KEY: ®SSS - STANDARD SPLIT SPOON(SPT) REMARKS 8 LSS - LARGE SPLIT SPOON IF ST - SHELBY TUBE ❑� RS - RING SAMPLE ❑ SK - SACK SAMPLE 70 60 ,CL� CH ""Z 50 w z 40 H U E-� 30 a, m 20 ML MH 10 ! CL-ML 01 1 0 20 40 60 80 100 LIQUID LIMIT(LL) Specimen Identification I LL PL PI Fines Classification • B-1 5.0 39 19 21 15.7 Clayey Gravel With Sand GC m1 B-10 2.0 46 21 25 Lean Clay CL ♦ B-12 0.0 41 19 22 19.7 Clayey Gravel With Sand GC B-12a 2.5 401 17 23 24.0 Clayey Gravel With Sand GC -7 2.0 36 20 16 I I Lean Clay CL 0 B-9 2.0 41 19 22 Lean Clay CL I PROJECT Valley West Subdivision JOB NO. 02-305 Bozeman, MT DATE 2/26/02 ATTERBERG LIMITS ^n ' NTL Engineering & Geoscience, Inc. Plate No. 1 «.� • ^------ Great Falls, MT 59405 0�.��1�1�9��IIIIIY RII��� u����■f�a�a�n�i�■onso COBBLES GRAVEL SAND SILT OR CLAY Specimen Identification PI I Cc Cu Clayey Gravel With Sand GC M Clayey Gravel With Sand GC--- MMMMM MMM PROJECT Valley West Subdivision JOB NO. 02-305 Bozeman, MT DATE 2/26/02 GRADATION CURVES Plate No. 2 Great Falls,MT 59405 �� 0 �� m sn ■in i�■unnn seem m u■idia � �nu�imr�ui 0 2 7 4 0 z H 6 8 10 \ 12 14 100 1,000 10,000 STRESS,psf • FIELD MOISTURE m INUNDATED Specimen Identification Classification DD MC% B-5 2.0 Lean Clay CL 86 35 FINAL MOISTURE CONTENT=26% PROJECT Valley West Subdivision JOB N0. 02-305 Bozeman, MT DATE 2/26/02 CONSOLIDATION TEST NTL Engineering& Geoscience, Inc. Plate No.3 `n uoeaacui;.i i..ll:: Great Falls, MT 59405 —Suspended Wood Floor Foundation Alternate#1-Crawlst.-,;e Footing backfill limits s` Perimeter Foundation T~ VentPawlspace Area :ackfil Zane ................... - .. �linimiiiri ... :. _ •:•I�irafi.•l•40N .... .. ... .. .. or.approved . — 2.0' : alternate geotextilc _ Minimum . ... v ................... ................................ . ................................ Qj .. .................. .......... .................. =1II III I -,�� I I1I Sri • - I� Ii � , � i � II . II 3/8 to 3/4-inch open-graded p en- ded Minimum 3-inch diameter slotted ADS underdrain sloped drainage aggregate at a minimum 0.002 ft/ft to sump or positive discharge Perimeter Foundation Foundation Alternate#2--Slab-on-Grade " Footing backfill limits _ ...... a.:c: • :. • . )r Gb �4 Gravel ::: .. lZo _ ......kn . ... _ .... ........... ... . — — — .or•approved.. ... : alternate geotextilc — - - - � ­ o — — — St — — :....:........ .....:.:::.:::::::::::::::::::.::.:.::.:::::::.................. _► i 1 I i ..........L..1...L .. .......�....L. _1 .. 1 3/8 to 3/4-inch open-graded Minimum 3-inch diameter slotted ADS underdrain sloped drainage aggregate at a minimum 0.002 ft/ft to sump or positive discharge Project: Vallcy West Subdivision Job Number, W-30.5 Location: Bozeman, Montana Datge 2/26/02 A-�- Generalized Foundation Options n NTL Engineering and Geoscience Great Falls,MT Detail No. I RECOMMENDED SPECIFICATIONS FOR FLEXIBLE PAVEMENT MATERIALS 1. Aggregate Base Course (MT Public Works Specification) Screen or 3/4-Inch 1-1/2-Inch Sieve Size Percent Passing Percent Passing 1-1/2" 100 111 95 - 100 3/4" 100 1/2" --- 45 - 80 No. 4 40 - 70 25 - 60 No. 10 25 - 55 25 - 55 No. 200 2 - 10 0 - 8* Mechanically Fractured Faces, one or more on plus No. 4 aggregate, % minimum 50* 50* *Deviates from the MT. Public Works Specification. In addition to the gradation presented above, aggregate base course quality should conform to the MT.Public Works Specification, Crushed Base Course, Section 02235, Subsection 02. 2. Asphaltic Concrete Aggregate (MT Public Works Specification 02503) Asphalt Concrete Surfacing Percent Passing Screen or Sieve Size Type B Grading Requirements 3/4" 100 1/2" 80 - 100 3/8" 70 - 90 No. 4 45 - 65 No. 10 32 - 45 No. 40 15 - 25 No. 200 4 - 10 In addition to the grading requirements shown, the aggregate quality should conform to the applicable portions of the MT. Public Works Specifications, Section 02232, Aggregates for Surfacing and Asphalt Plant Mixes and the requirements of MT. Public Works Specification 02503, Hot Plant Mix Asphalt Concrete. 3. Asphalt Concrete Mix Designs Asphalt concrete mix designs should be provided by the contractor, or materials supplier, and should meet the following requirements, consistent with the MT.Public Works Specification Section 02503, Hot Plant Mix Asphalt Concrete: Property Test Method Specifications Stability, pounds, minimum ASTM D1559* 1200 min. Flow, 1/100 Inch Units ASTM D1559* 8 - 18 Air Voids, percent ASTM D3203 3 - 5 Voids in Mineral Aggregate Asphalt Institute 14 Minimum (VMA), Percent Minimum Manual MS-2 *50 blows each end of specimen. 4. Minimum Density Requirements Percent of Material Test Method Maximum Asphaltic Concrete Surfacing ASTM D1559 (Marshall)* 97 Crushed or Uncrushed Granular Base/Subbase Course ASTM D698 95 Subgrade (top 12 inches)** ASTM D698 95 *50 blows each end of specimen; sampled from truck or paver at time of lay-down. **For all pavement types. Clay subgrades should be compacted at moisture contents within ±3 percent of optimum, or above as recommended specifically in the report. Maximum compacted lift thickness should be 12 inches for granular base/subbase courses. Also, minimum lift thickness for gravel should be twice the maximum size of the aggregate. RECOMMENDED SPECIFICATIONS FOR BASE COURSE AGGREGATES 1. Aggregate Base Course 3/4-Inch 1-1/2-Inch Crushed Base Course Crushed Base/Subbase Course (Crushed Top Surfacing (Crushed Base Course Screen or Type A, Grade 2*) Type B, Grade 2*) Sieve Size Percent Passing 1-1/2" 100 3/4" 100 No. 4 40 - 70 25 - 55 No: 10 25 - 55 No. 200 2 - 10 0 - 8 Mechanically Fractured Faces, one or more on plus No. 4 aggregate, % minimum 50 50 *Montana Department of Transportation, Highway Division, Specification (NIDOH) In addition to the gradation presented above, aggregate quality should conform to the following NIDOH Specifications, 1987 edition: Material NIDOH Specification 3/4-Inch Crushed Leveling Course 701.02 (E) (Crushed Top Surfacing, Type A, Grade 2) 1-1/2 Inch Crushed Base Course 701.02 (D) (Crushed Base Course, Type B, Grade 2)