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Home My WebLink About21 - Design Report - Gibson Guitar - Water, Sewer, Storm, Road JOB NO. B19-110 MONTANA | WASHINGTON | IDAHO | NORTH DAKOTA | PENNSYLVANIA REV. MARCH 2021 406.586.0277 tdhengineering.com 234 East Babcock Street Suite 3 Bozeman, MT 59715 CLIENT ENGINEER SMA Architect s 109 E. Oak St. Suite 2E Bozeman, MT 59715 TD&H Engineering 234 East Babcock Street, Suite 3 Bozeman, MT 59715 Engineer: Cody Croskey, PE GIBSON GUITAR DESIGN BUILD BOZEMAN, MONTANA BASIS OF DESIGN REPORT Image from SMA Architects B19-110 GIBSON GUITAR Page 1 of 4 GIBSON GUITAR DESIGN BUILD DESIGN REPORT Revised March 2021 Purpose and Introduction The purpose of this report is to explain how water, sanitary sewer, storm drainage, and street improvements will be designed to meet the City of Bozeman requirements and Montana Public Works Standard Specifications (MPWSS) to provide service to the expanded Gibson Guitar manufacturing facility located on Orville Way. The report will provide information on the detailed design of the above-mentioned infrastructure. The project is located at the intersection of Orville Way and Simmental Way and is encompassed within Lots 1, 2, & 3 of Tract 4 of the Gardiner-Simmental Plaza Subdivision. The proposed new Gibson Guitar expansion includes construction of approximately 25,000 square feet of new building space to improve and expand the manufacturing operation. To accommodate the new building and operational needs, new asphalt parking lots, truck loading areas, access drives, sidewalks, and landscaping are proposed. While the building expansion is proposed on the same lot as the existing building, the main employee parking lot, truck loading area, and storm drainage improvements are proposed within multiple lots. Design Report Fire Protection Fire protection will be provided by the City of Bozeman Fire Department. The existing building has a four-inch fire service line connected to the building and is sprinklered. It is our understanding this existing fire service will be maintained, and the existing sprinkler system will be expanded throughout the new building addition. An existing City of Bozeman fire hydrant is located at the intersection of Orville Way and Simmental Way. This hydrant is directly adjacent to the Gibson Guitar property and is located to the southeast of the building. Emergency response access will be through the new east driveway and parking lot to the existing FDC, and through the west end of Orville Way which will provide access around the west and north sides of the building and incorporate a standard hammerhead turnaround with public access easement. Water & Sewer Services Water and sewer utilities for the existing building are connected to the City of Bozeman water and sewer system, and plumbing will be extended internally throughout the new building addition to serve new bathrooms and fixtures without adding additional external services. There is currently an active 1” water service and meter servicing the existing building. However, projected water demands with the proposed addition require the existing 1” service be abandoned and upsized to a new 1-1/2” water service and meter. Construction or extensions of new water and sewer mains are not anticipated with this project. B19-110 GIBSON GUITAR Page 2 of 4 Water Demand Because this is an expansion project with continued similar use, the estimated water demand is based on existing water utility records and projected metrics for the enlarged facility and increased operations. Water meter records from Jan 2015 – July 2020 show an average use of 3,067 gal/day at the existing facility. The current peak employment at the facility is 160 employees, which is anticipated to increase to a maximum 286 employees in the years following the expansion. Assuming all current demand is attributable to employee domestic use only, the proportional water demand to employee increase is estimated as follows: Table 1. Estimated Annual Domestic Water Demands per Employee Employees Average Use Daily Use/ Employee Current Metered Use = 160 3,067 gpd 3.44 ac-ft/yr 19.2 gpd Projected Use = 286 5,482 gpd 6.14 ac-ft/yr 19.2 gpd Increased Demand = +126 +2,415 gpd +2.70 ac-ft/yr Additionally, irrigation supply is expected to be connected to the City water supply with this project as original water rights for the two existing irrigation wells at the property were unable to be located through coordination with DNRC. These wells are also not currently eligible to be permitted for irrigation use without mitigation due the project location with the Bozeman Solvent Site Controlled Ground Water Area (BSS-CGWA). Therefore, it is assumed these wells will need to be disconnected until such time as the BSS-CGWA is absolved or existing water rights for these wells are discovered. Based on the current project irrigation design and assuming a typical 24-week irrigation season from mid-May through mid-October, the estimated annual irrigation water demand is as follows: Estimated Annual Irrigation Demands: Irrigated turf area: 30,252 s.f. = 0.69 acres Turf watering rate (May-Oct): 24 in/yr Annual turf irrigation volume: 1.38 ac-ft/yr ¶ Individual plant watering rate (24-weeks May-Oct): 1,699 gal/wk Annual plant irrigation volume: 0.13 ac-ft/yr Projected Total Irrigation Water Use: 1.5 ac-ft/yr A payment for cash-in-lieu of water rights (CILWR) is anticipated to be required to offset the estimated municipal water demand increase for domestic and irrigation use with this project. B19-110 GIBSON GUITAR Page 3 of 4 Sewer Demand Sewer demand increases for this project are calculated in proportion to the domestic water demand increases identified above. Based on the metered average daily water demand of 3,067 gal/day, the current estimated peak-hour and average daily sewer flows for the existing facility are 12.16 gpm and 4,024 gal/day respectively, including the design infiltration rate of 150- gal/acre/day for the 6.38 acre site. Based on the estimated projected average daily water demand increase to 5,482 gal/day, the estimated peak-hour and average daily sewer flows for the proposed expanded facility are 19.26 gpm and 6,439 gal/day respectively, also including infiltration for 6.38 acres. Therefore, the estimated increases to the peak-hour and average daily sewer flows as a result of this project are 7.09 gpm and 2,415 gal/day respectively. Sewer flow rate and sewer service capacity calculations are provided in the attached appendix. Storm Drainage The existing project site is partially developed with existing buildings, parking lots, and a large gravel parking/storage area. The local streets adjacent to the project currently have roadside ditches and no curb. The proposed site development includes adding additional impervious areas such as an expanded building footprint and new paved parking and circulation areas. Reconstruction of existing paved areas and conveyance of new roof drainage across existing roofs make it difficult to separate pre- vs. post-project runoff patterns. The site also has minimal stormwater controls in place currently. Therefore, the project design seeks to capture and infiltrate design storm runoff from all new improvement areas as well as runoff from most existing improved areas at the site. The site generally slopes to the northwest but is relatively flat. Existing drainage patterns will generally be maintained with stormwater collection/retention ponds located to the north and west of the project areas and overflowing toward the roadside drainage ditch along N. 19th Avenue. Localized storm drain inlets and pipes are necessary to accommodate drainage at isolated low points, such as at the base of the loading dock or the sag curve in Orville Way once curb is added. Roof drain pipes are prosed to collect and convey roof runoff around the south face of the building where there is limited space next to the road right-of-way to address storm water. A public drainage easement is proposed for storm drainage that will be concentrated/conveyed across the multiple lot boundaries to reach the NW retention pond where there is more space available. Runoff volume, retention pond sizing, and pipe flow calculations are provided in the attached appendix. A concrete drainage chase is proposed to direct stormwater runoff across the trail to the roadside drainage ditch along N. 19th Avenue. The contributing drainage basin and 25-yr runoff flow rate calculations are included in Appendix A along with channel flow sizing calculations for the prosed chase. Groundwater was observed at the site during the geotechnical investigation at depths ranging from 4.5 to 10.8 feet below the ground surface. Seasonal groundwater B19-110 GIBSON GUITAR Page 4 of 4 fluctuations from 2008-2019 for the area were obtained for the nearby MBMG GWAAMON Network monitoring well ID:241692 located at the MDOT rest area 0.40 miles north of the site. Based on this data, groundwater levels are expected to fluctuate up and down 3.6 feet seasonally on average. An actual groundwater measurement was taken at the Gibson site on August 4, 2020, which corresponds to the time of year when groundwater has receded approximately 64% (or 2.3 feet) below its seasonal high on average. This information combined with the general valley contours in the area were used to estimate the seasonal high groundwater elevation beneath the proposed stormwater infiltration ponds. The pond bottoms are currently designed to be 2.4 to 2.8 feet above the estimated seasonal high groundwater elevation at each location. The GWAAMON monitoring well hydrograph and associated calculations are attached. Roadway Improvements This project is adjacent to Orville Way and Simmental Way which were originally constructed to County roadway standards with shoulders and roadside ditches. A requirement of the project is to bring the sides of the roadways fronting the property into conformance with the City of Bozeman local street standards (i.e., curb & gutter, boulevards, sidewalks, street lighting, and defined roadway width). Typical roadway sections for Orville Way and Simmental Way showing the widening and standard improvements along the property are provided in the design drawings (See Sheet C5.1). A new street light is also proposed at the corner of Orville Way and Simmental Way. The pavement section design is per the attached Geotechnical Investigation Report prepared by TD&H Engineering for the project. All roadway work is to be per the Montana Public Works Standard Specifications (MPWSS), and the latest City of Bozeman Modifications to the MPWSS and Standards and Specifications Policy. Simmental Way has the standard 60-foot right-of-way for a local street and the proposed curb on the Gibson side is located to create the standard 35-foot roadway with respect to the partially existing curb on the west side of the street. Orville Way only has a 50-foot right-of-way width, so an additional 5’ right-of-way width is being provided via easement along the property frontage. An alternate 31-foot roadway width is proposed as identified in Table IV-2 (and note 3) of the City’s design standards and specifications policy. This narrower width is expected to be adequate for this location as it is not a through street, it has a posted 10 MPH speed limit, and additional off-street parking is proposed with this project beyond the minimum required so as not to necessitate a parking lane on the street in front of the facility. APPENDIX A Storm Water Design Calculations MOTORCYCLEPARKINGBASIN 1:C = 0.81I = 0.41A = 1.18V = 2,819 CFBASIN 2:C = 0.78I = 0.41A = 1.59V = 3,657 CFBASIN 3:C = 0.58I = 0.41A = 0.39V = 676 CFBASIN 5:C = 0.77I = 0.41A = 0.29V = 667 CFBASIN 4:C = 0.82I = 0.41A = 1.36V = 3,288 CFREVISIONSHEETDESIGNED BY:QUALITY CHECK:JOB NO.FIELDBOOKDRAWN BY:DATE:B19-110 BMREV DATE NOT FORCONSTRUCTION GIBSON GUITAR DESIGN BUILD BOZEMAN, MT DRIANAGE BASINS & STORM POND SIZING B19-11012.9.20.DWGEX-1CJCEngineering 234 E. BABCOCK ST., SUITE 3 • BOZEMAN, MONTANA 59715 406.586.0277 • tdhengineering.com TD&H Storm Drain Calculations Project: Gibson Guitar Retention Pond Volume Sizing 12-9-20 Rational Formula "C" Values Per MTDEQ 8 "C" Impervious Area/Pond Surface 0.9 Gravel Area 0.8 Unimproved Area 0.3 Lawn/landscape 0.1 Post-Development Drainage Basins: Basin #Basin Description Total Area (SF) Total Area (Acres) Composite Cave 10 yr - 2hr i (in/hr) Flow Q10 (cfs) Runoff Volume (cf) 1 North Roof Area and Utility Yard 51,347 1.18 0.81 0.41 0.39 2,819 2 West Truck Loading Existing Gravel Yard 69,192 1.59 0.78 0.41 0.51 3,657 3 Front Entry Cannopy and East Parking Lot 17,191 0.39 0.58 0.41 0.09 676 4 SW Parking Lot 59,174 1.36 0.82 0.41 0.46 3,288 5 Orville Way 12,775 0.29 0.77 0.41 0.09 667 Total Site Retention Volume =11,107 Retention Pond Sizing: Retention Pond Contributing Basins Design Volume (cf) NW Basins 1, 2, & 5 7,150 East Basin 3 700 SW Basin 4 3,300 Total Design Retention Volume =11,150 TD&H Stormwater CalculationsProject: Gibson Guitar25-yr Pipe Flow Calculations25-Year Flow Calcs:Pipe Capacity Calcs (94% full):Location Basin Size (Acres)Cave CCf Tc (min)25 yri(in/hr)FlowQ25(cfs)Pipe Dia. (d)(ft)Pipe Slope(%)Manning'sn 94% Flow Depth (y)(ft)Theta (Θ)(rad.)Area (A)(ft2)Hydraulic Radius (R)(ft)Qfull(cfs)Vfull(ft/sec)V25(ft/sec)South Bldg Roof Drain 0.29 0.9 0.99 5 3.83 1.10 0.83 0.50%0.013 0.78 5.29 0.53 0.24 1.67 3.14 3.09Orville Inlet + Roof Drain 0.58 0.88 0.97 5 3.83 2.15 1.25 0.50%0.013 1.18 5.29 1.20 0.36 4.93 4.12 3.67Truck Dock Inlets 0.08 0.9 0.99 5 3.83 0.30 1.00 1.00%0.013 0.94 5.29 0.77 0.29 3.84 5.02 2.80Pipe to NW Pond 3.55 1.25 1.00%0.013 1.18 5.29 1.20 0.36 6.97 5.82 5.41Main Entry Bldg Roof Drain 0.08 0.9 0.99 5 3.83 0.30 0.50 1.00%0.013 0.47 5.29 0.19 0.14 0.61 3.16 2.94Pipe to East Pond 0.26 0.9 0.99 5 3.83 0.98 1.00 1.00%0.013 0.94 5.29 0.77 0.29 3.84 5.02 3.89Manning's Eqn:Q = 1.49/n*A*R2/3*S00.5 Rational Method Cf = 1.1 for 25-yr event IDF curve equation for 25-yr stormTc = time to concentration in hoursCombined Flows (Above) = AiCCQf=64.25 78.0 −=cTi MOTORCYCLEPARKINGBASIN:POST-DEVELOPMENT SITEC = 0.67A = 6.25REVISIONSHEETDESIGNED BY:QUALITY CHECK:JOB NO.FIELDBOOKDRAWN BY:DATE:B19-110 BMREV DATE NOT FORCONSTRUCTION GIBSON GUITAR DESIGN BUILD BOZEMAN, MT DRIANAGE BASIN & DRAINAGE CHASE SIZING B19-1101.27.21.DWGEX-2CJCEngineering 234 E. BABCOCK ST., SUITE 3 • BOZEMAN, MONTANA 59715 406.586.0277 • tdhengineering.com TD&H Stormwater CalculationsProject: Gibson Guitar25-yr Drainage Chase FlowTc*Tc*10 yr FlowSlope DistanceCCft1Slope k Velocity Distancet2Velocity Distancet3TotalCaveCCfArea TotaliQ% ft min % fps ft min fps ft min minac min in/hr cfs1.87 70 0.11 12.57 0.70 0.619 1.70 105 1.03 3 43 0.240.85 0.457 1.38 736 8.88*Tc minimum of 5 minutesEstimate average flow of 3 fpsFHWA HEC 22, Eqn 3-4Cf = 1.1 for 25-year storm event K=0.457 Grassed Water Way (Roadside Ditch)K=0.619 Paved AreaK=0.491 Unpaved shallow concentrated flowIDF curve equation for 25-yr stormTc = time to concentration in hoursRational MethodCf = 1.1 for 25-yr 0.74Post-Development Site22.72 0.67 6.25 22.72 1.452TIME OF CONCENTRATION25 YEAR FLOW CALCOverland Flow Shallow Concentrated Flow Pipe Flow6.083111871/fcSD)CC.(.T-=SkV=28.3AiCCQf=64.2578.0-=cTi Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Jan 27 2021 Gibson Guitar Drainage Chase Rectangular Bottom Width (ft) = 2.00 Total Depth (ft) = 0.50 Invert Elev (ft) = 100.00 Slope (%) = 1.50 N-Value = 0.013 Calculations Compute by: Known Q Known Q (cfs) = 6.08 Highlighted Depth (ft) = 0.47 Q (cfs) = 6.080 Area (sqft) = 0.94 Velocity (ft/s) = 6.47 Wetted Perim (ft) = 2.94 Crit Depth, Yc (ft) = 0.50 Top Width (ft) = 2.00 EGL (ft) = 1.12 0 .5 1 1.5 2 2.5 3 Elev (ft)Depth (ft)Section 99.75 -0.25 100.00 0.00 100.25 0.25 100.50 0.50 100.75 0.75 101.00 1.00 Reach (ft) Groundwater Information Center Well Hydrograph The following chart represents the current hydrograph for this well. Data reported are static water levels in feet below ground surface. A filter has been applied to the data to remove all dry and/or non-static measurements. GWIC Id: 241692 Site Name: GLWQD - MDOT VISITOR CENTER Location: 01S05E35AADB Total Depth: 8.9 feet Number of Measurements: 62691 Period of Record: 5/27/1993 - 7/4/2020 9:40:00 AM Disclaimer The preceding materials represent the contents of the GWIC databases at the Montana Bureau of Mines and Geology at the time and date [8/26/2020 2:14:27 PM] of the retrieval. The information is considered unpublished and is subject to correction and review on a daily basis. The Bureau warrants the accurate transmission of the data to the original end user at the time and date of the retrieval. Retransmission of the data to other users is discouraged and the Bureau claims no responsibility if the material is retransmitted. There may be wells in the request area that are not recorded at the Information Center. Water level data downloaded from GWIC are not filtered and will contain all measurements. Date Static Water Level 8 6 4 2 Jan 2008 Jan 2009 Jan 2010 Jan 2011 Jan 2012 Jan 2013 Jan 2014 Jan 2015 Jan 2016 Jan 2017 Page 1 of 1Montana's Groundwater Information Center (GWIC) | SWL Hydrograph 8/26/2020https://mbmggwic.mtech.edu/sqlserver/v11/reports/WellHydrograph.asp?gwicid=241692& GWIC ID:241692 SITE NAME:GLWQD - MDOT VISITOR CENTER TOTAL DEPTH:8.9 FEET YEAR 2008 2008 2008 2009 2009 2009 2010 2010 2010 2011 2011 2011 2012 2012 2012 2013 2013 2013 2014 2014 2014 2015 2015 2015 2016 2016 2016 2017 2017 2017 2018 2018 2018 2019 2019 2019 =3.2 Feet below ground level =6.8 Feet below ground level AVERAGE EARLY AUGUST =5.5 Feet below ground level GIBSON GUTIAR EXPANSION: B19-110 GWIC WELL MONITOR LEVELS DATE HIGH LOW NEAR AUGUST 4-Aug 2-Jan 6.78 17-Jan 6.65 2-Jun 2.37 2-Feb 6.39 30-Jun 2.9 1-May 2.3 4-Aug 2-May 2.25 11-Aug 2-Aug 4-Oct 6.69 4.65 5.76 4.48 4.98 2-Jan 7.05 15-Jun 4.1 2-Aug 6.59 2-Oct 7.44 29-May 4.78 8-Aug 4.19 3-Aug 5.88 3-Feb 6.72 26-May 4.7 STATIC WATER DEPTH (BELOW GROUND) FEET 3-Aug 5.76 28-Aug 7.02 17-Oct 6.45 3-Jun 5.2 29-Mar 3.86 28-Apr 3.16 3-Aug 5.74 1-Aug 6.33 20-Jan 7.35 6-Aug 5.61 10-Mar 6.7 7-Oct 6.57 7-May 2.36 AVERAGE LOW AVERAGE HIGH 21-Apr 0.57 3-Aug 5.5 GWIC ID:241692 SITE NAME:GLWQD - MDOT VISITOR CENTER TOTAL DEPTH:8.9 FEET GIBSON GUTIAR EXPANSION: B19-110 GWIC WELL MONITOR LEVELS Monitoring Well Location Project Site APPENDIX A Sewer Flow Calculations Gibson GuitarDate: 12-09-20Sewer Demand Calculation Existing Facility Sewer Demand: Avg. Daily Water Use =3,067 gpd Average water use from Jan 2015-July 2020 meter records Equivalent Population =30.67 people DEQ-2 requires 100 gpcd; Design flow (gpd) ÷ 100 gpcd Total Site Area =6.38 acres Infiltration Rate =957 gpd (site area)*(150 gpd/acre) Avg. Daily Sewer Demand =4,024 gpd water use + infiltration rate Peaking Factor =4.35 Peak Demand =17,517 gpd (avg. day demand)*(peaking factor) Peak Hour Sewer Flow =12.16 gpm (peak demand)/(24 hrs/day)/(60 min/hr) Expanded Facility Sewer Demand: Avg. Daily Water Use =5,482 gpd Projected water use with increase to 286 employees Equivalent Population =54.82 people DEQ-2 requires 100 gpcd; Design flow (gpd) ÷ 100 gpcd Total Site Area =6.38 acres Infiltration Rate =957 gpd (site area)*(150 gpd/acre) Avg. Daily Sewer Demand =6,439 gpd water use + infiltration rate Peaking Factor =4.31 Peak Demand =27,729 gpd (avg. day demand)*(peaking factor) Peak Hour Sewer Flow =19.26 gpm (peak demand)/(24 hrs/day)/(60 min/hr) 𝑄𝑚𝑎𝑥 𝑄𝑎𝑣𝑔 =18 +𝑠ℎ𝑛𝑠𝑠𝑎𝑛𝑑𝑠𝑛𝑑𝑛𝑑𝑛𝑛𝑙𝑑1/2 4 +𝑠ℎ𝑛𝑠𝑠𝑎𝑛𝑑𝑠𝑛𝑑𝑛𝑑𝑛𝑛𝑙𝑑1/2 𝑄𝑚𝑎𝑥 𝑄𝑎𝑣𝑔 =18 +𝑠ℎ𝑛𝑠𝑠𝑎𝑛𝑑𝑠𝑛𝑑𝑛𝑑𝑛𝑛𝑙𝑑1/2 4 +𝑠ℎ𝑛𝑠𝑠𝑎𝑛𝑑𝑠𝑛𝑑𝑛𝑑𝑛𝑛𝑙𝑑1/2 Gibson Guitar Date: 12-09-20 4" Sewer Service Capacity Check Input Values d =0.33 ft =4" y =0.250 ft Calculated Values (Equations from Fluid Mechanics by Chow) Theta (Θ)4.19 rad 2*arccos(1-y/(d/2)) Area (A)0.07 ft2 (1/8)*(Θ-sinΘ)d2 Wetted Perimeter (P)0.70 ft 0.5Θd Hydraulic Radius (R )0.10 ft (.25)*(1-(sinΘ)/Θ)d Top Width (T)0.29 ft (sin 0.5Θ)d Mannings Equation (Equation from Fundamentals of Mechanics by Munson) n =0.013 (For PVC per COB Design Standards) S0 =0.02 ft/ft Q =0.25 cfs Q = 1.49/n*A*R2/3*S00.5 Q =110.1 gpm Q gpm = (Q cfs)(7.48 gal/ft3)(60 sec/min) V =3.50 ft/s V = Q/A Results A 4" diameter sewer service at 2% slope flowing 75% full has available capacity for 110.2 gpm. J:\2019\B19-110 Gibson Guitar Expansion\DOCUMENTS\REPORTS\Design Report\Parts\B19-110 Sewer Calcs.xls1 OF 1 APPENDIX C Storm Water Maintenance Plan JOB NO. B19-110 MONTANA | WASHINGTON | IDAHO | NORTH DAKOTA | PENNSYLVANIA AUGUST 2020 406.586.0277 tdhengineering.com 234 East Babcock Street Suite 3 Bozeman, MT 59715 CLIENT ENGINEER SMA Architects 109 E. Oak St. Suite 2E Bozeman, MT 59715 TD&H Engineering 234 East Babcock Street, Suite 3 Bozeman, MT 59715 ON-SITE STORM WATER MAINTENANCE PLAN GIBSON GUITAR DESIGN BUILD BOZEMAN, MONTANA Gibson Guitar Design Build Storm Water Maintenance Plan B19-110 1 GIBSON GUITAR DESIGN BUILD STORM WATER MAINTENANCE PLAN PURPOSE AND INTRODUCTION This maintenance plan identifies the recommended maintenance procedures necessary for the proper function of the on-site storm water management system proposed at the Gibson Guitar facility expansion in Bozeman, Montana. The maintenance responsibility for the on-site stormwater ponds and storm drain collection system belongs to the landowner. The landowner may delegate routine inspection and maintenance responsibilities to the on-site facility operations management team, or may hire a qualified professional entity or individual to perform certain monitoring and maintenance tasks as necessary. A log shall be kept for all required inspections and maintenance. These logs shall be made available to the City of Bozeman Public Works Department for review as requested. A sample maintenance log is included in the attached Appendix. STORM WATER MANAGEMENT SYSTEM The on-site storm water management system includes curb and gutter, curb inlets, area inlets, drainage chases, downspout collectors, roof drain piping, storm water retention ponds, drainage ditches, and dry wells. These various components of storm water management infrastructure are designed to collect, convey, clean, detain, and/or infiltrate storm water runoff that is generated on the property before it leaves the site or enters local waterways. Storm water systems require proper maintenance to prevent sediment clogging, overgrown vegetation, erosion of detention ponds, obstruction of inlets, pipes, and structures, and prolonged standing water. Such issues may result in downstream pollution, unpleasant odors, unsightly areas, nuisance insects, or algae blooms, and must be mitigated. Scheduled inspections, times of inspections, locations inspected, maintenance completed, corrective actions taken, and any modifications or reconstruction performed shall be documented in the maintenance logs to be readily available upon request. Disposal of accumulated sediment must be in accordance with all applicable local, state and federal regulations. Wetlands may be present within the boundaries of retention ponds, drainage ditches and surrounding areas, and should be considered when planning maintenance activities. Wetland permitting is generally not required for maintenance of constructed storm water management features. However, maintenance of locations where pond outlet pipes or pond overflows discharge to protected water bodies within wetland areas may require wetland or stream bank permitting. If unsure of the regulatory status of wetland features observed at the site, consult the local authorities prior to undertaking any activities that may cause disturbance. Gibson Guitar Design Build Storm Water Maintenance Plan B19-110 2 STORM WATER MAINTENANCE PROCEDURES The following maintenance procedures are intended to prolong the life of installed system components and ensure their continued functionality: General Storm Water System Maintenance – 1. Parking lot areas and curbs & gutters should be cleared of leaves and other debris once after primary leaf drop in the fall and once after snow melt in early spring at a minimum. This will minimize the potential for debris to enter the system which could lead to premature clogging of structures, reduced storage capacity, and/or blockage of inlets. 2. Inspect the storm drain inlets, manholes, downspout connections, and cleanouts, for sediment build-up or clogging and flush/clear as needed. Inspect for snow/ice buildup at least once weekly during winter months and clear the inlet as needed. Do not pile snow over inlets. 3. Snow storage should be performed in designated areas during winter months and should not be allowed to be piled in front of or over inlets. Piled snow around or over the inlets could block early snowmelt run-off from entering the system, possibly causing overflows and icy conditions. 4. Sanding of the parking lots and truck loading areas should be done sparingly or avoided completely. Sand or other sediment on the parking lot will likely be washed into stormwater system components which can lead to buildup and reduced capacity or blockages over time. Storm Water Pond Maintenance – 1. Routine Maintenance Activities (every 3 months): a. Mow vegetation around each stormwater pond regularly throughout the spring/summer months. b. Designate a “no-mow” zone at the bottom of the ponds. This area will be trimmed once a year and protected from regularly scheduled grass mowing. Excessive mowing causes debris buildup and compaction of the soils in the bottom of the pond, reducing the pond’s infiltration ability. c. Remove trash, leaves, plant trimmings, grass clippings, pet waste and other debris from the pond area. d. Inspect pond inlets, outlets, and internal dry well grates for any obstructions that would prevent stormwater from entering or leaving the pond and remove obstructions as needed. 2. Annual Maintenance Activities (annually): a. At the end of each fall, cut plants in the “no-mow” zone to a height of six inches and rake and remove all clippings and leaves. Gibson Guitar Design Build Storm Water Maintenance Plan B19-110 3 b. Re-establish vegetation on eroded or barren areas of the pond. 3. Long-Term Maintenance Activities (as observed/required): a. Survey the pond elevations to determine the amount of sediment buildup, if any, in the pond. b. Excavate sediment and re-establish the pond to its initial design volume per the construction plans if sediment build-up is found to be greater than six inches or if the pond volume has decreased by more than ten percent. c. Flush sediment from outlet structures/piping and from the outfall location if build- up is observed. Remove sediment build-up from outlet structure or dry well sumps if needed. APPENDIX City of Bozeman Stormwater Basin Maintenance Guide Sample Maintenance & Inspection Log FIGURE 5 Storm Water Facilities Inspection and Maintenance Log Facility Name Begin Date End Date Date Location Facility Description Inspected by: Cause for Inspection Exceptions Noted Comments and Actions Taken Instructions: Record all inspections and maintenance for all storm water facilities on this form. Use additional log sheets and/or attach extended comments or documentation as necessary. Save all completed logs in one place and have them readily available for the City of Bozeman’s review upon request.  Location — Specify the exact location of the facility either by its name, facility ID or physical location.  Inspected by — Note all inspections and maintenance on this form, including the required independent annual inspection.  Cause for inspection — Note if the inspection is routine, pre-rainy-season, post-storm, annual, or in response to a noted problem or complaint.  Exceptions noted — Note any condition that requires correction or indicates a need for maintenance.  Comments and actions taken — Describe any maintenance performed and need for follow-up. FIGURE 1FIGURE 1 FIGURE 6 Appendix D Project Geotechnical Report MONTANA | WASHINGTON | IDAHO | NORTH DAKOTA | PENNSYLVANIA JOB NO. B19-110-001 FEBRUARY 2020 REPORT OF GEOTECHNICAL INVESTIGATION CLIENT ENGINEER Langlas & Associates 1019 E. Main Street, Suite 101 Bozeman, MT 59715 Craig Nadeau, PE Craig.nadeau@tdhengineering.com REPORT OF GEOTECHNICAL INVESTIGATION PROJECT NAME PROJECT LOCATION 406.586.027 7 tdhengineering.com 234 E. Babcock, Suite 3 Bozeman, MT 59715 GIBSON GUITAR EXPANSION BOZEMAN, MONTANA Gibson Guitar Expansion Table of Contents Bozeman, Montana i Table of Contents 1.0 EXECUTIVE SUMMARY ......................................................................................................... 1 2.0 INTRODUCTION ..................................................................................................................... 2 2.1 Purpose and Scope .......................................................................................................... 2 2.2 Project Description ........................................................................................................... 2 3.0 SITE CONDITIONS ................................................................................................................. 3 3.1 Geology and Physiography .............................................................................................. 3 3.2 Surface Conditions ........................................................................................................... 3 3.3 Subsurface Conditions ..................................................................................................... 4 3.3.1 Soils ........................................................................................................................... 4 3.3.2 Ground Water ........................................................................................................... 5 4.0 ENGINEERING ANALYSIS .................................................................................................... 6 4.1 Introduction ....................................................................................................................... 6 4.2 Site Grading and Excavations.......................................................................................... 6 4.3 Conventional Shallow Foundations ................................................................................. 6 4.4 Foundation and Retaining Walls ...................................................................................... 7 4.5 Floor Slabs and Exterior Flatwork .................................................................................... 7 4.6 Pavements ....................................................................................................................... 8 5.0 RECOMMENDATIONS ......................................................................................................... 10 5.1 Site Grading and Excavations........................................................................................ 10 5.2 Conventional Shallow Foundations ............................................................................... 11 5.3 Floor Slabs and Exterior Flatwork .................................................................................. 13 5.4 Pavements ..................................................................................................................... 14 5.5 Continuing Services ....................................................................................................... 15 6.0 SUMMARY OF FIELD AND LABORATORY STUDIES ....................................................... 17 6.1 Field Explorations ........................................................................................................... 17 6.2 Laboratory Testing ......................................................................................................... 17 7.0 LIMITATIONS ........................................................................................................................ 19 Gibson Guitar Expansion Appendix Bozeman, Montana ii APPENDIX  Test Pit Location Map (Figure 1)  Logs of Exploratory Test Pits (Figures 2 through 8)  Laboratory Test Data (Figures 9 through 16)  USGS Design Maps Summary Report  LTTPBind Online PG Asphalt Binder Analysis Summary  Soil Classification and Sampling Terminology for Engineering Purposes  Classification of Soils for Engineering Purposes Gibson Guitar Expansion Executive Summary Bozeman, Montana Page 1 GEOTECHNICAL REPORT GIBSON GUITAR EXPANSION BOZEMAN, MONTANA 1.0 EXECUTIVE SUMMARY The geotechnical investigation for the proposed expansion of the Gibson Acoustic facility located at 1894 Orville Way in Bozeman, Montana, encountered varying thickness of surficial clay overlying water bearing native poorly-graded gravel with sand. The seismic site class is D, and the risk of seismically-induced liquefaction or soil settlement is considered low and does not warrant additional evaluation. The primary geotechnical concern regarding this project is the presence of relatively soft surficial clays of varying thickness which pose a risk of differential settlement to the planned expansion. Based on the site conditions encountered, we do not recommend foundations supported on the native clay soils. Conventional shallow foundations are suitable for this site but should be placed on properly compacted structural fill extending down to the native gravel stratum. Based on the site conditions, structural fill thicknesses of up to six feet are anticipated below conventional frost depth footings. Ground water was also encountered near the top of the native gravel in all test pits performed. A confined ground water condition may exist on this property; thus, dewatering of all construction excavations should be anticipated following the removal of the native clay to facilitate the placement and compaction of the structural fill. The native clay soils are relatively soft and exhibit elevated moisture contents which are likely above typical optimum values for compaction of the clay. Thus, any reuse of the native clay for backfill or site grading applications should anticipate the need for moisture conditioning of the material prior to reuse. Furthermore, elevated moisture can significantly weaken these clay soils impeding access to construction equipment and subgrade strengths for pavement systems. Thus, increased gravel thicknesses and the incorporation of separation geotextiles beneath parking lots and access roads should be expected. Gibson Guitar Expansion Introduction Bozeman, Montana Page 2 2.0 INTRODUCTION 2.1 Purpose and Scope This report presents the results of our geotechnical study for the proposed expansion to the Gibson Acoustic facility located at 1894 Orville Way in Bozeman, Montana. The purpose of the geotechnical study is to determine the general surface and subsurface conditions at the proposed site and to develop geotechnical engineering recommendations for support of the proposed structure and design of related facilities. This report describes the field work and laboratory analyses conducted for this project, the surface and subsurface conditions encountered, and presents our recommendations for the proposed foundations and related site development. Our field work included excavating seven test pits across the proposed site. Samples were obtained from the test pits and returned to our Great Falls laboratory for testing. Laboratory testing was performed on selected soil samples to determine engineering properties of the subsurface materials. The information obtained during our field investigations and laboratory analyses was used to develop recommendations for the design of the proposed foundation systems. 2.2 Project Description It is our understanding that the proposed project consists of a 21,500 square foot addition to the existing structure. The addition is planned to utilize either precast concrete or steel frame construction with conventional shallow foundation systems with interior slab-on-grade construction matching the finished floor elevation of the current building. Structural loads had not been provided at the time of this report. However, for the purpose of our analysis, we have assumed that wall loads will be less than 4,000 pounds per lineal foot and column loads, if any, will be less than 100 kips. Site development will most likely include landscaping, exterior concrete flatwork, and asphalt pavement for parking lots and access roads. If the assumed design values presented above vary from the actual project parameters, the recommendations presented in this report should be reevaluated. Gibson Guitar Expansion Site Conditions Bozeman, Montana Page 3 3.0 SITE CONDITIONS 3.1 Geology and Physiography The site is geologically characterized as upper tertiary sediment or sedimentary rock (Tsu). This formation is comprised of conglomerate, tuffaceous sandstone and siltstone, marlstone, and equivalent sediment and ash beds. These materials are generally overlain by varying thicknesses gravel (Qgr). These gravels are comprised of variable deposits ranging in size from pebble to boulder sized rock including sand, silt, and clay. Geologic Map of Montana, Edition 1.0 Montana Bureau of Mines & Geology Based on the subsurface conditions encountered, the site falls under seismic Site Class D. The appropriate 2015 International Building Code (IBC) seismic design parameters for the site include site coefficients of 1.224 and 1.98 for Fa and Fv, respectively. The recommended design spectral response accelerations at short periods (SDs) and at 1-second period (SD1) are 0.588g and 0.277g, respectively. These values represent two-thirds of the mapped response accelerations following correction for the appropriate site classification and assume the proposed construction to fall into risk category II. The likelihood of seismically-induced soil liquefaction or settlement for this project is low and does not warrant additional evaluation. 3.2 Surface Conditions The proposed project site is located at 1894 Orville Way in Bozeman, Montana. The site is at the location of the current Gibson Acoustics facility which consists of an existing structure estimated to be approximately 21,000 square feet in plan and a large asphalt parking lot. Two smaller support structures and a gravel surfaced yard are located to the west of the parking lot. Based on PROJECT LOCATION Gibson Guitar Expansion Site Conditions Bozeman, Montana Page 4 background information and site observations, the site is considered relatively flat with limited grade change across the property. 3.3 Subsurface Conditions 3.3.1 Soils The subsurface soil conditions appear to be relatively consistent with respect to the depositional layering of the site; however, the thickness of the stratum varies some across the property. All seven test pits encountered surficial topsoil underlain by native lean clay and native poorly-graded gravel with sand. The lean clay varied from 3.6 to 10.4 feet in thickness and generally increased in thickness towards the east side of the property. The lean clay is underlain in all test pits by native gravels which extend to depths of at least 10.8 feet, the maximum depth investigated for this project. The subsurface soils are described in detail on the enclosed test pit logs and are summarized below. The stratification lines shown on the logs represent approximate boundaries between soil types and the actual in situ transition may be gradual vertically or discontinuous laterally. TOPSOIL Topsoil consisting of organic rich lean clay were encountered in all seven borings and ranged in thickness from 0.5 to 1.8 feet. The topsoil is considered firm based on the ease of excavation and may have had some frost within this zone at the time of our investigation. LEAN CLAY Native lean clay was encountered directly below the upper topsoil horizon in all test pits and extends to depths of 3.6 to 10.4 feet. The lean clay is considered firm to soft with increasing moisture at depth based on the ease of excavation and observations of our field engineer. Pocket penetrometer tests performed within several test pits at varying depths indicated an unconfined compressive strength of less than 0.5 tons per square foot, which is supportive of a soft soil consistency. Samples of the material contained between 0 and 6 percent gravel, between 9 and 10 percent sand, and between 85 and 91 percent fines (clay and silt). The lean clay samples also exhibited liquid limits of 34 to 38 percent and plasticity indices of 14 to 19 percent. The natural moisture contents varied from 21 to 32 percent and averaged 27 percent. A bulk sample of the lean clay material was tested and exhibited a maximum dry density of 107.0 pounds per cubic foot (pcf) when compacted at its optimum moisture content of 18.2 percent. This test was performed using the standard proctor method outlined in ASTM D698. A California Bearing Ratio (CBR) test was then performed on the same sample to evaluate its strength when utilized as a subgrade beneath a pavement system. This test Gibson Guitar Expansion Site Conditions Bozeman, Montana Page 5 which was performed in accordance with ASTM D1883 resulted in a CBR value of 2.0 percent when compacted to at least 95 percent of the maximum dry density outlined above. POORLY-GRADED GRAVEL WITH SAND Native gravels, visually classified as poorly-graded gravel with sand, were encountered below the native clay in all seven borings at depths of 3.6 to 10.4 feet and extend to depths of at least 10.8 feet, the maximum depth investigated. The gravel is considered relatively dense based on observations of our field engineer during excavation. A single natural moisture content of 7.0 percent was measured for this stratum. 3.3.2 Ground Water Ground water was encountered within all seven test pits performed for this project at depths ranging from 4.5 to 10.8 feet below the ground surface. At all seven test pit locations, the ground water was encountered in close proximity to the transitions between the lean clay and native gravel strata. This indicates that a confined ground water condition may exist seasonally in which the native clay resists rises in the ground water table and creates a temporary pressurized ground water table. We anticipate seasonal fluctuations in the ground water table to occur and expect dewatering to be required during construction to facilitate the removal of the native clay and replacement with properly compacted structural fill. However, numerous factors contribute to seasonal ground water fluctuations, and the evaluation of the magnitude or presence of seasonal ground water fluctuations is beyond our scope of work for this project. Gibson Guitar Expansion Engineering Analysis Bozeman, Montana Page 6 4.0 ENGINEERING ANALYSIS 4.1 Introduction The primary geotechnical concern regarding this project is the presence of soft, compressible clay soils at and below the anticipated bearing elevation for foundations associated with the addition. The clay thickness is also highly variable across the property which increases the risk of differential behavior and is the primary source of building distress related to foundation movement. The soft clay is also expected to be encountered at moisture contents which are well beyond the compaction range for the material. This will impact the strength of the clay in pavement applications and any planned reuse of this material should anticipate the need for moisture conditioning prior to compaction. 4.2 Site Grading and Excavations The ground surface at the proposed site is considered relatively flat; thus, significant cut or fill thickness for site development are not anticipated for this project. Based on our field work, topsoil, lean clay, and native water-bearing gravels will be encountered in foundation and utility excavations to the depths anticipated. Based on the test pits, ground water should be expected in all foundation and utility excavations extending below a depth of four feet and dewatering systems should be provided by the contractor to temporarily lower the water table and facilitate the proper placement and compaction of structural fill below foundation elements. 4.3 Conventional Shallow Foundations Considering the subsurface conditions encountered and the nature of the proposed construction, the addition can be supported on conventional shallow foundations bearing on properly compacted structural fill extending down to native gravels. Based on the test pits performed, structural fill thickness are anticipated to range from 0 to 6 feet beneath conventional frost depth foundation elements. The thickness of structural fill should increase from west to east across the project limits. Based on our experience, the theory of elasticity, and using an allowable bearing pressure of 5,000 psf, we estimate the total settlement for footings constructed as described above will be less than ¾-inch. Differential settlements within the limits of the planned addition should be on the order of one-half this magnitude. The lateral resistance of spread footings is controlled by a combination of sliding resistance between the footing and the foundation material at the base of the footing and the passive earth pressure against the side of the footing in the direction of movement. Design parameters are given in the recommendations section of this report. New footings for additions which are placed adjacent to the existing building foundation will increase the stress on the subgrade beneath the existing footing and depending on the soil type which Gibson Guitar Expansion Engineering Analysis Bozeman, Montana Page 7 supports these footings can induce additional settlements beneath the existing structure. If similar over-excavation and replacement methods were utilized on the original building construction, the potential for additional settlements associated with the addition will be minor; however, if native clays were left in place beneath the existing structure, this can have significant impacts to the original building both in long-term performance and constructability of the planned addition. At this time, we have no information regarding how the original foundation system was supported; thus, it is prudent to assume worst-case scenarios in which the structure is founded on the soft compressible clay soils. To help reduce the potential for constructability issues and future settlements of existing structure, new spread footings placed adjacent to the existing structure should be separated from the existing footings by a lateral distance of at least six feet. This will help to prevent potential undermining of the existing foundation during the removal and replacement of the clay soils by maintaining a maximum construction slope of 1:1 (horizontal to vertical) near existing foundation elements and provide separation between foundations so that new foundation loads are not applied to subgrade beneath the existing structure. The structure would need to utilize cantilevered elements within this separation zone. This separation may not be warranted if additional investigation is performed or construction documents are available which indicate that the clay soils were removed from beneath the existing structure. The need for separation will be controlled by the limits of the original structural fill and the potential for undermining the existing foundations during the construction of the planned addition. 4.4 Foundation and Retaining Walls Foundation walls and other soil retaining structures which will retain differential soil heights are not anticipated for this project based on the intended use of interior slab-on-grade construction and the relative flat conditions on site. If similar soil retaining structures are needed as part of the final design or if the planned foundation system is changed in include either crawlspace or basement features, we should be contacted to provide suitable design recommendations for these structures. 4.5 Floor Slabs and Exterior Flatwork The natural on-site soils, exclusive of topsoil, are suitable to support conventional exterior concrete flatwork. A leveling course of granular fill directly beneath the slab is recommended to provide a structural cushion, a capillary-break from the subgrade, and a drainage medium. Construction typically utilizes four to six inches of compacted granular fill beneath exterior flatwork; however, the requirements may vary locally. Similar construction is considered typical for exterior flatwork and has not been evaluated for expected performance or potential settlement risks. The natural on-site soils are also suitable to support interior floor slabs but warrant the use of an increased structural gravel layer beneath the concrete to account for the high clay moistures and the anticipated difficulties with compaction of the subgrade layer. All interior slab systems should utilize at least 18 inches of compacted structural fill which is separated from the prepared subgrade by a geotextile fabric. Gibson Guitar Expansion Engineering Analysis Bozeman, Montana Page 8 4.6 Pavements A pavement section is a layered system designed to distribute concentrated traffic loads to the subgrade. Performance of the pavement structure is directly related to the physical properties of the subgrade soils and the magnitude and frequency of traffic loadings. Pavement design procedures are based on strength properties of the subgrade and pavement materials, along with the design traffic conditions. Traffic information was not available at the time of this report. We have assumed that traffic for the parking lots will be primarily limited to passenger-type vehicles; however, some routes will be utilized for heavier truck traffic and warrant a stronger pavement system. We have provided two pavements sections as part of this report for use in general parking lot and heavy truck routes within the site development. The pavements sections provided below consider the anticipated traffic for the development after completion of construction only and have not considered construction traffic as part of their intended use. Thus, if areas are to be utilized by the contractor for access of concrete trucks, delivery vehicles, or other large construction equipment they should be evaluated further based on the size and number of vehicles anticipated in order to adjust the pavement section accordingly. Use of the pavement sections provided without modification to account for construction traffic will reduce the overall life expectancy of the asphalt or lead to unstable subgrades which require repair prior to paving. The potential worst-case subgrade material is the soft lean clay soils, which are classified as an A-7 soil in accordance with the American Association of State Highway and Transportation Officials (AASHTO) classification. AASHTO considers this soil type to be a poor subgrade material due to its inferior drainage properties and loss of strength at elevated moistures. Laboratory testing measured a California Bearing Ratio (CBR) value for the lean clay of two percent assuming the subgrade could be compacted to at least 95 percent of the maximum dry density for the material. However, in-situ moisture contents indicate that moisture contents at a two-foot depth range from 21 to 32 percent and average 25.5 percent. These values are 3 to 14 percent above the optimum moisture content for this material; thus, compaction to the levels required for this CBR value are unlikely. For this reason, the pavement sections provided in this report have utilized a CBR value of only one percent to account for the low density expected at the subgrade elevation for this project. During construction, the subgrade should be cleared of all loose soil and construction debris and rolled smooth prior to the installation of a separation geotextile and the gravel materials associated with the pavement system. Excessive compaction, especially using vibratory methods, could induce subgrade pumping and instability and should be avoided. A geotextile acting as a separator is recommended between the pavement section gravels and the prepared clay subgrade. The geotextile will prevent the upward migration of fines and the loss of aggregate into the subgrade, thereby prolonging the structural integrity and performance of the pavement section. Gibson Guitar Expansion Engineering Analysis Bozeman, Montana Page 9 The pavement section presented in this report is based on an assumed CBR value of one percent, assumed traffic loadings, recommended pavement section design information presented in the Asphalt Institute and AASHTO Design Manuals, and our past pavement design experience in Bozeman. Gibson Guitar Expansion Recommendations Bozeman, Montana Page 10 5.0 RECOMMENDATIONS 5.1 Site Grading and Excavations 1. All topsoil and organic material, asphalt, concrete and related construction debris should be removed from the proposed addition and pavement areas and any areas to receive site grading fill. For planning purposes, stripping thicknesses of up to two feet may be required to remove detrimental organics; however, thicker stripping depths are anticipated to remove existing asphalt and other site features within the planned addition. 2. All fill and backfill should be non-expansive, free of organics and debris and should be approved by the project geotechnical engineer. The on-site soils, exclusive of topsoil, may be utilized as backfill and general site grading fill on this project. However, native clay exhibit moisture contents which are elevated beyond typical compaction levels and moisture conditioning should be expected prior to use. This often requires the material to be spread out over a relatively large area and worked to facilitate drying to suitable moisture levels. All fill should be placed in uniform lifts not exceeding 8 inches in thickness for fine- grained soils and not exceeding 12 inches for granular soils. All materials compacted using hand compaction methods or small walk-behind units should utilize a maximum lift thickness of 6 inches to ensure adequate compaction throughout the lift. All fill and backfill shall be moisture conditioned to near the optimum moisture content and compacted to the following percentages of the maximum dry density determined by a standard proctor test which is outlined by ASTM D698 or equivalent (e.g. ASTM D4253-D4254). a) Structural Fill Below Foundations ................................................ 98% b) Structural Fill Below Interior Slabs .............................................. 95% c) Foundation Wall Backfill (Interior / Exterior) ......................... 95 / 92% d) Gravel Courses Below Streets & Parking Lots ........................... 95% e) General Landscaping or Nonstructural Areas ............................. 90% For your consideration, verification of compaction requires laboratory proctor tests to be performed on a representative sample of the soil prior to construction. These tests can require up to one week to complete (depending on laboratory backlog) and this should be considered when coordinating the construction schedule to ensure that delays in construction or additional testing expense is not required due to laboratory processing times or rush processing fees. Gibson Guitar Expansion Recommendations Bozeman, Montana Page 11 3. Imported structural fill should be non-expansive, free of organics and debris, and conform to the material requirements outlined in Section 02235 of the Montana Public Works Standard Specifications (MPWSS). All gradations outlined in this standard are acceptable for use on this project; however, conventional proctor methods (outlined in ASTM D698) shall not be used for any materials containing less than 70 percent passing the ¾-inch sieve. Conventional proctor methods are not suitable for these types of materials, and the field compaction value must be determined using a relative density test outlined in ASTM D4253-4254. Alternative structural fill materials containing rocks larger than those permitted by MPWSS Section 02235 may be considered provided they are approved by the geotechnical engineer prior to use and the field compaction value is determined using the appropriate method to be specified by the geotechnical engineer. However, materials containing rocks larger than 3-inch diameter will not be considered acceptable for structural fill applications. 4. Develop and maintain site grades which will rapidly drain surface and roof runoff away from foundation and subgrade soils; both during and after construction. The final site grading shall conform to the grading plan, prepared by others to satisfy the minimum requirements of the applicable building codes. 5. It is the responsibility of the Contractor to provide safe working conditions in connection with underground excavations. Temporary construction excavations greater than four feet in depth, which workers will enter, will be governed by OSHA guidelines given in 29 CFR, Part 1926. For planning purposes, subsoils encountered in the test pits are considered Type C for the native clay and gravel strata due to the anticipated low strength of the clay material. The soil conditions on site can change due to changes in soils moisture or disturbances to the site prior to construction. Thus, the contractor is responsible to provide an OSHA knowledgeable individual during all excavation activities to regularly assess the soil conditions and ensure that all necessary safety precautions are implemented and followed. 5.2 Conventional Shallow Foundations The design and construction criteria below should be observed for a conventional shallow foundation system. The construction details should be considered when preparing the project documents. 6. Both interior and exterior footings should bear on properly compacted structural fill extending down to native gravels. Structural fill thickness are anticipated to range from 0 to 6 feet and increase from west to east across the site. All structural fill shall be placed and compacted as outlined in Item 2 above. The contractor should Gibson Guitar Expansion Recommendations Bozeman, Montana Page 12 anticipate the need for dewatering at the time of construction to facilitate the proper placement and compaction of the structural fill beneath footing elements. The limits of the structural fill shall extend at least 24 inches beyond the outer face of the footing in all directions. Footings which are designed and constructed as described above, should be designed for a maximum allowable soil bearing pressure of 5,000 psf provided settlements as outlined in the Engineering Analysis are acceptable. 7. To reduce structural distress caused by slab movements, all interior load-bearing walls and columns should be supported on separate spread footings constructed as described in Item 6 above. Conventional slab-on-grade construction consisting of interior walls bearing directly on the slab or thickened portions of the slab is not recommended for this project unless the clay is to be removed and replace within the entire footprint of the planned addition. 8. Soils disturbed below the planned depths of footing excavations should be re- compacted to the requirements of Item 2 above. 9. Footings shall be sized to satisfy the minimum requirements of the applicable building codes while not exceeding the maximum allowable bearing pressure provided in Item 6 above. 10. Exterior footings and footings beneath unheated areas should be placed at least 48 inches below finished exterior grade for frost protection. 11. Lateral loads are resisted by sliding friction between the footing base and the supporting soil and by lateral pressure against the footings opposing movement. For design purposes, a friction coefficient of 0.45 and a lateral resistance pressure of 200 psf per foot of depth are appropriate for footings bearing on properly compacted structural fill and backfilled with compacted native soils. 12. When native soil may be supported by clay soils, new footings placed adjacent to the existing structure should be separated from the existing footings by a distance of at least six feet to reduce the potential for undermining existing footing elements during the removal of the native clay and to limit new foundation stresses beneath existing foundation elements. This distance is measured between the nearest exterior face of two footing elements. If additional investigation or as-built information can confirm that the native clay was removed and replaced, this requirement may not be warranted depending on the limits of the original structural fill placed. Gibson Guitar Expansion Recommendations Bozeman, Montana Page 13 13. A representative of the project geotechnical engineer should be retained to observe all footing excavations and backfill phases prior to the placement of concrete formwork to verify that all clay soils have been removed and that compaction of the subsequent structural fill conforms to these recommendations. 14. Only hand-operated compaction equipment should be used within 5 feet of foundation walls. Foundation backfill should be placed in lifts of equal thickness which alternative from interior to exterior of the foundation wall. 15. Exterior footing drains are not required for this project based on the intended use of slab-on-grade construction assuming the interior finished floor elevation will be higher than the final exterior grade adjacent to the building at all locations. If interior slabs will lie below exterior grade or if a crawlspace of basement configuration is considered, we should be consulted to provide additional recommendations and details pertaining to suitable foundation drain systems. 5.3 Floor Slabs and Exterior Flatwork 16. For normally loaded, exterior concrete flatwork, a typical cushion course consisting of free-draining, crushed gravel should be placed beneath the concrete and compacted to the requirements of Item 2b above. Cushion course thicknesses generally range from four to six inches but may vary based on local requirements. Conventional construction, as has been described, is not intended to mitigate potential settlement concerns associated with the soft clay subsurface conditions encountered. In most cases, the cost to repair and/or replace exterior flatwork when excessive movements occur is far more economical than efforts to mitigate these movements. However, if no acceptable risk of movements for exterior flatwork is acceptable for this project, additional improvements beneath exterior flatwork should be considered. 17. For normally loaded, interior slab-on-grade construction, a minimum 18-inch cushion course consisting of free-draining, crushed gravel should be placed beneath the slab and compacted to the requirements of Item 2b above. Prior to gravel installation, the clay subgrade should be cleared of all loose soil and debris, static rolled, and a separation geotextile consisting of a Mirafi 600X, or equivalent, installed in accordance with all manufacturer recommendations. 18. Cushion course materials utilized beneath slab-on-grade applications should conform to the requirements outlined in Section 02235 of the Montana Public Works Standard Specifications (MPWSS). All gradations outlined in this specification are acceptable based on local availability and contractor preference. Gibson Guitar Expansion Recommendations Bozeman, Montana Page 14 19. Interior floor slabs should be designed using a modulus of vertical subgrade reaction no greater than 100 pci when designed and constructed as recommended above. 20. Geotechnically, an underslab vapor barrier is recommended for this project due to the high soil moisture within the native clay and potential for ground water fluctuations which have not been evaluated for the site. This is especially important in any portions of the addition to receive moisture sensitive flooring materials. The type and grade of vapor barrier shall be specified by the structural engineer or architect. 5.4 Pavements 21. The following pavement section or an approved equivalent section should be selected in accordance with the discussions in the Engineering Analysis. Pavement Component Component Thickness General Parking Section Heavy Truck Route Section Asphalt Pavement 3” 4” Crushed Base Course 9” 6” Crushed Subbase Course 12” 18” Total 24” 28” * The pavement sections provided have not considered construction traffic during in their development. Modification to these sections may be warranted and need additional evaluation if the contractor intends to utilize areas for construction vehicle access during or after the completion of asphalt paving. 22. Final pavement thicknesses exceeding 3 inches shall be constructed in two uniform lifts. 23. Gradations for the crushed base courses shall conform to Section 02235 of the Montana Public Works Standard Specifications (MPWSS). All gradations outlined in this specification are acceptable for this application based on the local availability and contractor preference. The gradation for the subbase shall conform to Section 02234 of the MPWSS. 24. If existing grades will be raised more than the thickness of the pavement section at any location, all fill should be placed, compacted and meet the general requirements given in Item 2 above. Gibson Guitar Expansion Recommendations Bozeman, Montana Page 15 25. A geotextile is recommended between the pavement section and the prepared subgrade to prevent the migration of fines upward into the gravel and the loss of aggregate into the subgrade. A Mirafi 600X or equivalent geotextile is appropriate. 26. Based on the local climate, asphaltic cement should be a Performance Graded (PG) binder having the following minimum high and low temperature values based on the desired pavement reliability. Reliability Min. High Temp Rating Min. Low Temp Rating Ideal Oil Grade 50% 33.8 -30.6 PG 52-34 98% 37.5 -39.5 PG 52-40 In our experience, neither of the ideal oil grades outlined above are locally available for use. Thus, these materials would require the import of a specialized product and custom mid design which is likely not practical for this project. Most local construction utilizes a PG 58-28 product which is a standard asphalt binder discussed in MPWSS specifications. We recommend the use of this material for the asphalt pavements for this project as it will provide the highest level of performance obtainable using readily available products. 5.5 Continuing Services Three additional elements of geotechnical engineering service are important to the successful completion of this project. 27. Consultation between the geotechnical engineer and the design professionals during the design phases is highly recommended. This is important to ensure that the intentions of our recommendations are incorporated into the design, and that any changes in the design concept consider the geotechnical limitations dictated by the on-site subsurface soil and ground water conditions. 28. Observation, monitoring, and testing during construction is required to document the successful completion of all earthwork and foundation phases. A geotechnical engineer from our firm should be retained to observe the excavation, earthwork, and foundation phases of the work to determine that subsurface conditions are compatible with those used in the analysis and design. 29. During site grading, placement of all fill and backfill should be observed and tested to confirm that the specified density has been achieved. We recommend that the Owner maintain control of the construction quality control by retaining the services of an experienced construction materials testing laboratory. We are available to provide construction inspection services as well as materials testing of compacted Gibson Guitar Expansion Recommendations Bozeman, Montana Page 16 soils and the placement of Portland cement concrete and asphalt. In the absence of project specific testing frequencies, TD&H recommends the following minimum testing frequencies be used: Compaction Testing Structural Fill Beneath Footings 1 Test per Column Footing per Lift 1 Test per 50 LF of Wall Footing per Lift Structural Fill Beneath Interior Slabs 1 Test per 1,500 SF per Lift Foundation Backfill 1 Test per 50 LF of Wall per Lift Parking Lot & Access Roads 1 Test per 2,500 SF per Lift LF = Lineal Feet SF = Square Feet Gibson Guitar Expansion Summary of Field & Laboratory Studies Bozeman, Montana Page 17 6.0 SUMMARY OF FIELD AND LABORATORY STUDIES 6.1 Field Explorations The field exploration program was conducted on January 8, 2020. A total of seven test pits were excavated to depths ranging from 5.9 to 10.8 feet at the approximate locations shown on Figure 1 to observe subsurface soil and ground water conditions. The tests pits were excavated by Earth Surgeons Excavation, LLC using a Komatsu 88 mini-excavator. The subsurface exploration and sampling methods used are indicated on the attached test pit logs. The test pits were logged by Mr. Ahren Hastings, PE of TD&H Engineering. The location of the borings were estimated by Mr. Hastings based on their relative proximity to existing surface features visible on an aerial image of the property. Composite grab samples from the test pits were collected at distinct changes in the subsurface stratigraphy and at regularly spaced intervals within each test pit. Samples were collected from excavation spoils after removal from the test pit. A log of each test pit, which include soil descriptions and sample depths, are presented on the Figures 2 through 8. Measurements to determine the depth of ground water in the test pits were made using a steel tape measure shortly after the completion of excavating. The depths or elevations of the water levels measured, if encountered, and the date of measurement are shown on the test pit logs. 6.2 Laboratory Testing Samples obtained during the field exploration were returned to our materials laboratory where they were observed and visually classified in general accordance with ASTM D2487, which is based on the Unified Soil Classification System. Representative samples were selected for testing to determine the engineering and physical properties of the soils in general accordance with ASTM or other approved procedures. Tests Conducted: To determine: Natural Moisture Content Representative moisture content of soil at the time of sampling. Grain-Size Distribution Particle size distribution of soil constituents describing the percentages of clay/silt, sand and gravel. Atterberg Limits A method of describing the effect of varying water content on the consistency and behavior of fine-grained soils. UU Shear Strength (Field) The undrained, unconfined shear strength (su) of cohesive soils as determined in the field by either a pocket penetrometer or a hand torvane. Gibson Guitar Expansion Summary of Field & Laboratory Studies Bozeman, Montana Page 18 Moisture-Density Relationship A relationship describing the effect of varying moisture content and the resulting dry unit weight at a given compactive effort. Provides the optimum moisture content and the maximum dry unit weight. Also called a Proctor Curve. California Bearing Ratio The measure of a subgrade’s or granular base’s ability to resist deformation due to penetration during a saturated condition. Used to assist in pavement thickness designs. The laboratory testing program for this project consisted of 11 moisture-visual analyses, 3 sieve (grain-size distribution) analyses, and 3 Atterberg Limits analyses. The results of the water content analyses are presented on the test pit logs, Figures 2 through 8. The grain-size distribution curves and Atterberg limits are presented on Figures 9 through 14. In addition, one proctor (moisture- density) test and one California Bearing Ratio (CBR) test were performed. The CBR and moisture density relationships are shown on Figures 15 through 16. The results are shown on the test pit logs at the depths the samples were tested. Gibson Guitar Expansion Limitations Bozeman, Montana Page 19 7.0 LIMITATIONS This report has been prepared in accordance with generally accepted geotechnical engineering practices in this area for use by the client for design purposes. The findings, analyses, and recommendations contained in this report reflect our professional opinion regarding potential impacts the subsurface conditions may have on the proposed project and are based on site conditions encountered. Our analysis assumes that the results of the exploratory test pits are representative of the subsurface conditions throughout the site, that is, that the subsurface conditions everywhere are not significantly different from those disclosed by the subsurface study. Unanticipated soil conditions are commonly encountered and cannot be fully determined by a limited number of soil test pits and laboratory analyses. Such unexpected conditions frequently require that some additional expenditures be made to obtain a properly constructed project. Therefore, some contingency fund is recommended to accommodate such potential extra costs. The recommendations contained within this report are based on the subsurface conditions observed in the test pits and are subject to change pending observation of the actual subsurface conditions encountered during construction. TD&H cannot assume responsibility or liability for the recommendations provided if we are not provided the opportunity to perform limited construction inspection and confirm the engineering assumptions made during our analysis. A representative of TD&H should be retained to observe all construction activities associated with subgrade preparation, foundations, and other geotechnical aspects of the project to ensure the conditions encountered are consistent with our assumptions. Unforeseen conditions or undisclosed changes to the project parameters or site conditions may warrant modification to the project recommendations. Long delays between the geotechnical investigation and the start of construction increase the potential for changes to the site and subsurface conditions which could impact the applicability of the recommendations provided. If site conditions have changed because of natural causes or construction operations at or adjacent to the site, TD&H should be retained to review the contents of this report to determine the applicability of the conclusions and recommendations provide considering the time lapse or changed conditions. Misinterpretation of the geotechnical information by other design team members is possible and can result in costly issues during construction and with the final product. Our engineers are available to assist in reviewing the portions of the plans and specifications which pertain to earthwork and foundations to assess their consistency with our recommendations and to suggest necessary modifications as warranted. This additional service is not included in our current scope of work and would be performed for additional fees when requested. TD&H should be involved throughout the construction process to observe construction, particularly the placement and compaction of all fill, preparation of all foundations, and all other geotechnical aspects. Retaining the geotechnical engineer who prepared your geotechnical report to provide construction observation is the most effective method of managing the risks associated with unanticipated conditions. Gibson Guitar Expansion Limitations Bozeman, Montana Page 20 This report was prepared for the exclusive use of the owner and architect and/or engineer in the design of the subject facility. It should be made available to prospective contractors and/or the contractor for information on factual data only and not as a warranty of subsurface conditions such as those interpreted from the test pit logs and presented in discussions of subsurface conditions included in this report. Prepared by: Reviewed by: Craig Nadeau PE Ahren Hastings PE Geotechnical Manager Geotechnical Engineer TD&H ENGINEERING TD&H ENGINEE RING J:\2019\B19-110 Gibson Guitar Expansion\GEOTECH\REPORTS\Gibson Guitar Expansion.doc GIBSON GUITAR EXPANSION BOZEMAN, MONTANA TEST PIT LOCATION MAP FIGURE 1 0 1.5 3 4.5 6 7.5 9 10.5 TOPSOIL: Lean CLAY, appears firm, dark brown, slightly moist, organics Lean CLAY, appears firm to soft, brown to light brown, slightly moist to moist, increasing moisture with depth - See Figures 15 and 16 for proctor and CBR results. Poorly-Graded GRAVEL with Sand, relatively dense, brown, red, and gray, moist to wet Bottom of Test Pit 1.8 10.0 10.6 G G LEGEND LOG OF TEST PIT TP-1Atterberg Limits Field Moisture content Gibson Guitar Expansion Bozeman, MontanaGroundwater Level Grab/composite sample Logged by:Ahren Hastings, PE Excavated by:Earth Surgeons Komatsu 88GNP = Granular and Nonplastic Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. January 8, 2020 B19-110-001 Figure No.2 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Native Grasses SURFACE ELEVATION:Not Measured DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT 0 10 20 30 40 50 = MOISTURE CONTENT 1 of 1 0 1.5 3 4.5 6 7.5 9 10.5 TOPSOIL: Lean CLAY, appears firm, dark brown, slightly moist, organics Lean CLAY, appears firm to soft, brown to light brown, slightly moist to moist, increasing moisture with depth qu = 0.5 tsf Poorly-Graded GRAVEL with Sand, relatively dense, brown, red, and gray, moist to wet Bottom of Test Pit 1.1 10.4 10.8 G G LEGEND LOG OF TEST PIT TP-2Atterberg Limits Field Moisture content Gibson Guitar Expansion Bozeman, MontanaGroundwater Level Grab/composite sample Logged by:Ahren Hastings, PE Excavated by:Earth Surgeons Komatsu 88GNP = Granular and Nonplastic Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. January 8, 2020 B19-110-001 Figure No.3 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Native Grasses SURFACE ELEVATION:Not Measured DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT 0 10 20 30 40 50 = MOISTURE CONTENT 1 of 1 0 1.5 3 4.5 6 7.5 9 10.5 TOPSOIL: Lean CLAY, appears firm, dark brown, slightly moist, organics Lean CLAY, appears firm to soft, brown to light brown, slightly moist to moist, increasing moisture with depth qu = 0.5 tsf Poorly-Graded GRAVEL with Sand, relatively dense, brown, red, and gray, moist to wet Bottom of Test Pit 1.0 6.1 8.0 G G LEGEND LOG OF TEST PIT TP-3Atterberg Limits Field Moisture content Gibson Guitar Expansion Bozeman, MontanaGroundwater Level Grab/composite sample Logged by:Ahren Hastings, PE Excavated by:Earth Surgeons Komatsu 88GNP = Granular and Nonplastic Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. January 8, 2020 B19-110-001 Figure No.4 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Native Grasses SURFACE ELEVATION:Not Measured DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT 0 10 20 30 40 50 = MOISTURE CONTENT 1 of 1 0 1.5 3 4.5 6 7.5 9 10.5 TOPSOIL: Lean CLAY, appears firm, dark brown, slightly moist, organics Lean CLAY, appears firm to soft, brown to light brown, slightly moist to moist, increasing moisture with depth qu = 0.5 tsf Poorly-Graded GRAVEL with Sand, relatively dense, brown, red, and gray, moist to wet Bottom of Test Pit 1.8 4.6 7.5 G G LEGEND LOG OF TEST PIT TP-4Atterberg Limits Field Moisture content Gibson Guitar Expansion Bozeman, MontanaGroundwater Level Grab/composite sample Logged by:Ahren Hastings, PE Excavated by:Earth Surgeons Komatsu 88GNP = Granular and Nonplastic Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. January 8, 2020 B19-110-001 Figure No.5 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Native Grasses SURFACE ELEVATION:Not Measured DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT 0 10 20 30 40 50 = MOISTURE CONTENT 1 of 1 0 1.5 3 4.5 6 7.5 9 10.5 TOPSOIL: Lean CLAY, appears firm, dark brown, slightly moist, organics Lean CLAY, appears firm to soft, brown to light brown, slightly moist to moist, increasing moisture with depth qu = 0.5 tsf Poorly-Graded GRAVEL with Sand, relatively dense, brown, red, and gray, moist to wet Bottom of Test Pit 0.5 3.6 7.8 G G LEGEND LOG OF TEST PIT TP-5Atterberg Limits Field Moisture content Gibson Guitar Expansion Bozeman, MontanaGroundwater Level Grab/composite sample Logged by:Ahren Hastings, PE Excavated by:Earth Surgeons Komatsu 88GNP = Granular and Nonplastic Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. January 8, 2020 B19-110-001 Figure No.6 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Native Grasses SURFACE ELEVATION:Not Measured DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT 0 10 20 30 40 50 = MOISTURE CONTENT 1 of 1 0 1.5 3 4.5 6 7.5 9 10.5 TOPSOIL: Lean CLAY, appears firm, dark brown, slightly moist, organics Lean CLAY, appears firm to soft, brown to light brown, slightly moist to moist, increasing moisture with depth qu = 0.5 tsf Poorly-Graded GRAVEL with Sand, relatively dense, brown, red, and gray, moist to wet Bottom of Test Pit 0.6 4.2 6.1 G G LEGEND LOG OF TEST PIT TP-6Atterberg Limits Field Moisture content Gibson Guitar Expansion Bozeman, MontanaGroundwater Level Grab/composite sample Logged by:Ahren Hastings, PE Excavated by:Earth Surgeons Komatsu 88GNP = Granular and Nonplastic Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. January 8, 2020 B19-110-001 Figure No.7 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Native Grasses SURFACE ELEVATION:Not Measured DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT 0 10 20 30 40 50 = MOISTURE CONTENT 1 of 1 0 1.5 3 4.5 6 7.5 9 10.5 TOPSOIL: Lean CLAY, appears firm, dark brown, slightly moist, organics Lean CLAY, appears firm to soft, brown to light brown, slightly moist to moist, increasing moisture with depth Poorly-Graded GRAVEL with Sand, relatively dense, brown, red, and gray, moist to wet Bottom of Test Pit 0.5 4.9 5.9 LEGEND LOG OF TEST PIT TP-7Atterberg Limits Field Moisture content Gibson Guitar Expansion Bozeman, MontanaGroundwater Level Grab/composite sample Logged by:Ahren Hastings, PE Excavated by:Earth Surgeons Komatsu 88GNP = Granular and Nonplastic Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. January 8, 2020 B19-110-001 Figure No.8 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Native Grasses SURFACE ELEVATION:Not Measured DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT 0 10 20 30 40 50 = MOISTURE CONTENT 1 of 1 Tested By: WJC/TF Checked By: 1-27-2020 9 (no specification provided) PL=LL=PI= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= USCS=AASHTO= * Lean CLAY 3/8" #4 #10 #20 #40 #60 #80 #100 #200 100.0 99.9 99.7 99.3 98.6 97.8 96.9 96.1 90.8 CL Report No. A-20734-206 Langlas & Associates Gibson Guitar Expansion Bozeman, Montana B19-110-001 Material Description Atterberg Limits Coefficients Classification Remarks Location: TP-1 Sample Number: A-20734 Depth: 4.0 ft Date: Client: Project: Project No:Figure SIEVE PERCENT SPEC. *PASS? SIZE FINER PERCENT (X=NO)PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.00010.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 0.0 0.1 0.2 1.1 7.8 90.86 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report Tested By: WJC/TF Checked By: 1-27-2020 10 (no specification provided) PL=LL=PI= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= USCS=AASHTO= * Lean CLAY 1.5" 1" 3/4" 1/2" 3/8" #4 #10 #20 #40 #60 #80 #100 #200 100.0 99.9 99.2 98.9 98.6 98.3 97.8 97.4 96.5 95.4 94.2 93.2 89.1 20 38 18 0.0867 CL A-6(16) Report No. A-20735-206 Langlas & Associates Gibson Guitar Expansion Bozeman, Montana B19-110-001 Material Description Atterberg Limits Coefficients Classification Remarks Location: TP-1 Sample Number: A-20735 Depth: 6.0 - 7.0 ft Date: Client: Project: Project No:Figure SIEVE PERCENT SPEC. *PASS? SIZE FINER PERCENT (X=NO)PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.00010.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 0.8 0.9 0.5 1.3 7.4 89.16 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report Tested By: TF/WJC Checked By: 1-27-2020 11 (no specification provided) PL=LL=PI= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= USCS=AASHTO= * Lean CLAY 3/4" 1/2" 3/8" #4 #10 #20 #40 #60 #80 #100 #200 100.0 98.2 97.6 94.5 92.3 91.1 90.3 89.8 89.2 88.6 85.2 0.3201 CL Report No. A-20738-206 Langlas & Associates Gibson Guitar Expansion Bozeman, Montana B19-110-001 Material Description Atterberg Limits Coefficients Classification Remarks Location: TP-3 Sample Number: A-20738 Depth: 2.0 ft Date: Client: Project: Project No:Figure SIEVE PERCENT SPEC. *PASS? SIZE FINER PERCENT (X=NO)PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.00010.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 0.0 5.5 2.2 2.0 5.1 85.26 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report Tested By: BC Checked By: LIQUID AND PLASTIC LIMITS TEST REPORT PLASTICITY INDEX0 10 20 30 40 50 60 LIQUID LIMIT 0 10 20 30 40 50 60 70 80 90 100 110 CL-ML C L o r O L C H o r O H ML or OL MH or OH Dashed line indicates the approximate upper limit boundary for natural soils 47 WATER CONTENT36 36.4 36.8 37.2 37.6 38 38.4 38.8 39.2 39.6 40 NUMBER OF BLOWS 5 6 7 8 9 10 20 25 30 40 MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS Project No.Client:Remarks: Project: Location: TP-1 Sample Number: A-20735 Depth: 6.0 - 7.0 ft Figure Lean CLAY 38 20 18 96.5 89.1 CL B19-110-Langlas & Associates 12 Report No. A-20735-207 Date: 1-27-2020Gibson Guitar Expansion Bozeman, Montana Tested By: BC Checked By: LIQUID AND PLASTIC LIMITS TEST REPORT PLASTICITY INDEX0 10 20 30 40 50 60 LIQUID LIMIT 0 10 20 30 40 50 60 70 80 90 100 110 CL-ML C L o r O L C H o r O H ML or OL MH or OH Dashed line indicates the approximate upper limit boundary for natural soils 47 WATER CONTENT33.5 33.7 33.9 34.1 34.3 34.5 34.7 34.9 35.1 35.3 35.5 NUMBER OF BLOWS 5 6 7 8 9 10 20 25 30 40 MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS Project No.Client:Remarks: Project: Location: TP-4 Sample Number: A-20741 Depth: 4.0 ft Figure Lean CLAY 34 20 14 CL B19-110-Langlas & Associates 13 Report No. A-20741-207 Date: 1-27-2020Gibson Guitar Expansion Bozeman, Montana Tested By: BC Checked By: LIQUID AND PLASTIC LIMITS TEST REPORT PLASTICITY INDEX0 10 20 30 40 50 60 LIQUID LIMIT 0 10 20 30 40 50 60 70 80 90 100 110 CL-ML C L o r O L C H o r O H ML or OL MH or OH Dashed line indicates the approximate upper limit boundary for natural soils 47 WATER CONTENT36.4 36.8 37.2 37.6 38 38.4 38.8 39.2 39.6 40 40.4 NUMBER OF BLOWS 5 6 7 8 9 10 20 25 30 40 MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS Project No.Client:Remarks: Project: Location: TP-6 Sample Number: A-20744 Depth: 2.0 ft Figure Lean CLAY 38 19 19 CL B19-110-Langlas & Associates 14 Report No. A-20744-207 Date: 1-27-2020Gibson Guitar Expansion Bozeman, Montana Tested By: TF Checked By: Moisture-Density Test Report Dry density, pcf90 95 100 105 110 115 Water content, % 11 13 15 17 19 21 23 18.2%, 107.0 pcf ZAV for Sp.G. = 2.65 Test specification:ASTM D 698-12 Method A Standard 6.0 - 7.0 ft CL A-6(16)2.65 38 18 1.7 89.1 Lean CLAY B19-110-Langlas & Associates Report No. A-20735-204 Date: 1-17-2020 15 Elev/Classification Nat.Sp.G. LL PI % > % < Depth USCS AASHTO Moist.#4 No.200 TEST RESULTS MATERIAL DESCRIPTION Project No.Client:Remarks: Project: Location: TP-1 Sample Number: A-20735 Figure Maximum dry density = 107.0 pcf Optimum moisture = 18.2 % Gibson Guitar Expansion Bozeman, Montana BEARING RATIO TEST REPORT ASTM D 1883-07 Project No: B19-110-001 Project: Gibson Guitar Expansion Bozeman, Montana Location: TP-1 Sample Number: A-20735 Depth: 6.0 - 7.0 ft Date: 1-27-2020 Lean CLAY Test Description/Remarks: ASTM D698 with 6-inch Mold 168 hour soak prior to testing Report No. A-20735-210 Date: 2-10-2020 Figure 16 107.0 18.2 38 18CL Material Description USCS Max. Dens. (pcf) Optimum Moisture (%) LL PI Molded Density (pcf) Percent of Max. Dens. Moisture (%) Soaked Density (pcf) Percent of Max. Dens. Moisture (%) CBR (%) 0.10 in. 0.20 in. Linearity Correction (in.) Surcharge (lbs.) Max. Swell (%) 1 101.2 94.6 18.0 101.1 94.5 20.7 1.8 2.3 0.026 10 0.1 2 106.8 99.8 17.9 106.8 99.8 18.3 4.7 4.7 0.000 10 0 3 Penetration Resistance (psi)0 40 80 120 160 200 Penetration Depth (in.) 0 0.1 0.2 0.3 0.4 0.5 Swell (%)0 0.1 0.2 0.3 0.4 0.5 Elapsed Time (hrs) 0 24 48 72 96 120 144 168CBR (%)0 1.5 3 4.5 6 Molded Density (pcf) 99 101 103 105 107 109 10 blows 56 blows CBR at 95% Max. Density = 2.0% for 0.10 in. Penetration TD&H Engineering Consultants Great Falls, Kalispell, Bozeman, MT Spokane, WA; Lewiston, ID, Watford City, ND TD&H Engineering Consultants Great Falls, Kalispell, Bozeman, MT Spokane, WA; Lewiston, ID, Watford City, ND