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HomeMy WebLinkAbout18 - Design Report - North 7th & Griffin - Stormwater 1982 Stadium Drive,Suite 3 Bozeman,MT 59715-0697 406 4041849 KUENGXOM North 71" & Griffin Site Plan Stormwater Drainage Plan Date: 3/9/2018 Prepared By: Matt Corcoran, PE Introduction: 7&G Enterprises, LLC is proposing a light industrial development at the northeast corner of the intersection of North 7th Avenue and West Griffin Drive. The project is located within the Tract 14 of the Gordon Mandeville State School Section Subdivision. North 7th Avenue runs along the western boundary of the site and West Griffin Drive runs along the southern boundary of the site. There are existing commercial and light industrial developments to the north and east of the site. The site was previously a veterinary clinic but has been vacant since 2005. Existing Conditions: The existing conditions of the site are depicted in Exhibit A attached to this plan. The site consists of approximately 1.934 acres of vacant land. The site generally drains from west to east at an average slope of 3%. There are no off-site areas draining onto the site. The site discharges to the east near the midpoint of the eastern boundary, where it is directed around the buildings in Tract 27 of the Gordon Mandeville State School Section Subdivision by rock swales to the south and east along West Griffin Drive. Proposed Conditions: The proposed conditions of the site are depicted in Exhibit B attached to this plan. The development will include paved parking areas,two proposed buildings and sidewalks. On-site runoff will be conveyed by curbs and gutters around the perimeter of the site and collected in inlets,where it will be retained in an underground retention system and allowed to infiltrate into the ground. Design Criteria: According to the City of Bozeman Design Standards, site developments should be design according to the following criteria: 1. Limit storm water runoff from the development to pre-development rates. 2. Stormwater storage and treatment facilities shall be designed to remove solids, silt, oils,grease and other pollutants. 3. Retention ponds shall be sized based on a 10-year, 2-hour storm intensity. ENGINEERING, REIMAGINED Page 1 of 4 4. The rational method shall be used to determine peak runoff rates with a slight modification of the method to determine runoff volumes. The basic assumptions that apply to the rational method are: a. Rainfall is uniformly distributed over the area for the duration of the storm. b. The peak runoff rate occurs when the duration of the storm equals the time of concentration. c. The runoff coefficient for the particular watershed is constant for a similar land use. Analysis: Per the City of Bozeman Design Standards, the retention was sized using the following equations: Q = CIA V = 7200Q Where: C= Runoff Coefficient as in Table 1:Weighted C Value. 1 =0.41 in/hr (per Figure 1-3 for 10-year, 2-hour storm event) A=Area (1.934 acres) Q= Flow rate (0.571 cfs) V= Runoff volume (cf) Table 1:Weighted C Value 4p�4`s® Pavement 0.624 0.95 0.593 Sidewalk 0.108 0.95 0.103 Roof 0.542 0.95 0.515 Gravel 0.117 0.70 0.082 Landscape 0.543 0.20 0.109 Total 1.934 0.72 1.402 Based on these calculations the required retention volume is 4,111 cf or 0.094 acre-ft. The existing runoff flows and volumes were not estimated because total retention is proposed in accordance with City of Bozeman Design Standards. Design: The proposed underground retention system utilizes of ADS StormTech MC-4500 chambers with endcaps and drainage stone surrounding the chambers. The available storage within the system is calculated in Table 2: Available Storage. ENGINEERING, REIMAGINED Page 2 of 4 Table 2:Available Storage MC-4500 Chamber 106.5 19 2,023.5 MC-4500 Endcap 35.7 2 71.4 Stone (40%Voids) 2,117.9 - 2,117.9 Total: 4,212.8 As shown, the proposed system has adequate capacity for the runoff associated with the 10-year, 2- hour storm event. The product submittal sheet for ADS StormTech MC-4500 chambers is included in Exhibit C attached to this report. For longevity and serviceability of the retention system, the chambers will be installed per the "Isolator Row" specifications, which require the chambers to be completely wrapped in filter fabric so all solids, silt, oils,grease and other pollutants typically found in parking lots remain in the chambers while stormwater is allowed to disperse throughout the stone and infiltrate into the surrounding soils. The chambers can be inspected regularly, and materials can be jetted and vacuumed as needed. The proposed retention system requires adequate infiltration into adjacent soils to operate. Allied Engineering prepared a geotechnical report for the site in September 2016, and it is attached in Exhibit D. According to the Allied report,the soils on-site consist of silt/clay to depths between 17 and 20 feet with sandy gravel underlying the silt/clay,and groundwater at 29 feet in depth. Allied performed a percolation test on the silt/clay layer per MT DEQ Circular 4, which yielded an average percolation rate of 4.98 min/inch. The average percolation rate was converted to an infiltration rate using the following calculation: 1 60 minutes _ 12.05 inches 4.98 minutes/inches x 1 hour hour In order to maintain a conservative design,the design was based on half the infiltration rate. Based on this assumption, the drain down time of the retention system is as follows: 84inches 6.025 inches/hour = 13.94 hours Based on this conservative estimation the on-site soils are sufficient to infiltrate the retention volume within the required 48-hour period.Additional longevity and capacity will be gained by the installation of dry-wells connecting the retention system directly to the sandy gravel layer. As shown,the retention has been sized to hold the 10-year, 2-hour storm per the City of Bozeman Design Standards. Larger storm events will surcharge the retention system and flow south to West Griffin Drive and continue east as it does in the preexisting condition. Conclusion: The site is designed to retain and infiltrate the 10-year, 2-hour storm per the City of Bozeman Design Standards. ENGINEERING, REIMAGINED Page 3 of 4 ENGINEERING, REIMAGINED Page 4 of 4 ExhibitExisting ENGINEERING, REIMAGINED ENGINEERING, REIMAGINED EXHIBIT A: EXISTING CONDITIONS D i ! ! N S 30 0 30 60 Ii I I SCALE FEET I Ewa" Westlake Holdings, LLC w 1 Keith L. Miller l --------------------- t Cb I -f � ! i I I ~ ► 7&G Enterprises, LLC I I Z I ► Tr I '. act 14 I I I Gordon Mandeville State School I Griffin Drive t I I I t Section Subdivision (Plat E-38) Business Suites ! 1.93 acres I I Condo Master t General Delivery It ` I ! I W. Griffin DriveKLI I / I PRELIMINARY NOT FOR CONSTRUCTION Mar 07,2018-12:55pm-P:\PrivateIMRCity\Bozeman\16617101 N.7lh-Griffin Commercial\Prelim\SWMP\Figures\Stormwater.dwg(Layoull) ©KLJ 2018 Exhibit rConditions ENGINEERING, REIMAGINED ENGINEERING, REIMAGINEQ EXHIBIT B : PROPOSED CONDITIONS o I I tw N I I F . 3 CO ^'!- u 1- 30 0 30 60 .. k SCALE FEET -T1 0 I I �; — ; Westlake Holdings, LLC — _ Keith L. Miller _l I ----------------------- I st� i°�• �•+ I _ - I I DEPTH r I CD rnn � ,- I(, I I JI i ' r Y x°ia..'•f n4{•._r� sc jix' i.ilk. }a 5; RETENTION SYSTEM Q BUILDING 4 1 FENC YARD i I v 8,208 SF 5,0 SF F.F. =474250 I 10 I I I Y) Z} 9 �! Griffin Drive 8"STEEL n -- - CASING FILLED WITH Business Suites DRAIN ROCK ' Condo Master c40%volDs> PHASE 2 General Delivery ( FUTURE BUILDING t` 15,000 SF 11 x' F.F. =4742.50 (1 ® I 20 c a a PERFORATED P I RETENTION FACILITY l c CASING ) dx \ STO N E INV.=4729.55, °a) 73.52'L X 12.33'W X 7.00 D 4 CHAMBER INV.=4730.55 w 16-STORMTECH MC-4500 CHAMBER •• I I I 2-STORMTECH MC-4500 END CAPS i 1s ,a• Z°z w"""""mot � • zo _. v F DRY WELL DETAIL vr NO SCALE W. Griffin Drive I ;rr I KLI h .. PRELIMINARY-NOT FOR CONSTRUCTION Mar 09,2018-12:10pm-P:\Private\MT\City\Bozeman\16617101 N.7th-Griffin Commercial\Prelim\SWMP\Figures\Stormwaler.dwg(Layoutl(2)) 0 KLJ 2018 ExhibitrChambers ENGINEERING, REIMAGINED ENGINEERING, REIMAGINED •� f ( L _ LL�L«■ MC-4500 CHAMBER Designed to meet the most stringent industry performance standards for superior structural integrity while providing designers with a cost-effective method to save valuable land and protect water resources.The StormTech system is designed primarily to be used under parking lots,thus maximizing land usage for private(commercial)and public applications.StormTech chambers can also be used in conjunction with Green Infrastructure,thus t' enhancing the performance and extending the service life of these practices. 1 STORMTECH MC-4500 CHAMBER STORMTECH MC-4500 END CAP not to scale) ) (not toscale) Nominal Chamber Specifications Nominal End Cap SpecificationsAi 1; Size(Lx W x H) Size(Lx W x H) ---' 52"x 100"x 60" 35.1"x 90.2"x 59.4" 52.0" (1321 mm) 1,321 mm x 2,540 mm x 1,524 mm 891 mm x 2,291 mm x 1,509 mm ACTUAL_ LENGTH Chamber Storage End Cap Storage 30.7" 106.5 ft3(3.01 m3) 35.7 ft3(1.01 m3) (781 mm) r— NSTALLED I Min.Installed Storage* Min.Installed Storage* 509 ) 162.6 ft3(4.60 m3) 108.7 ft3(3.08 m3) Weight Weight ( 1 mm) --� ALo mm 59 mm 'I I— 902"(2291 mm) 120 Ibs(54.4 kg) 120 Ibs(54.4 kg) 46.3"(1227 mm) _ INSTALLED LENGTH I (- Shipping Shipping 7 chambers/pallet 7 end caps/pallet (1524 mm) 11 pallets/truck 11 pallets/truck I—100.0"(2540 mm)---i *Assumes a minimum of 12"(300 mm)of *Assumes a minimum of 12"(300 mm)of stone stone above,9"(230 mm)of stone below above,9"(230 mm)of stone below,6"(150 mm) chambers,9"(230 mm)of stone between of stone perimeter,9"(230 mm)of stone between chambers/end caps and 40%stone porosity. chambers/end caps and 40%stone porosity. EMBEDMENT STONE SHALL BE A CLEAN,CRUSHED AND ANGULAR GRANULAR WELL-GRADED SOIUAGGREGATE MIXTURES,-35% STONE WITH AN AASHTO M43 DESIGNATION BEEN#3 AND FINES,COMPACT IN 12'(300 mm)MAX LIFTS TO 95%PROCTOR CHAMBERS SHALL MEET ASTM F2416"STANDARD#4 DENSITY.SEE THE TABLE OF ACCEPTABLE FILL MATERIALS. SPECIFICATION FOR POLYPROPELENE(PP)CORRUGATED WALL STORMWATER COLLECTION CHAMBERS". CHAMBERS SHALL BE BE DESIGNED IN ACCORDANCE WITH ASTM F2767 RMWAT "STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTIC ADS GEOSYTHETICS 601T NONWOVEN CORRUGATED WALL STORMWATER COLLECTION CHAMBERS", GEOTEXTILE ALL AROUND CLEAN,CRUSHED, PAVEMENT LAYER(DESIGNED ANGULAR EMBEDMENT STONE `BY SITE DESIGN ENGINEER) / ! 7.0' PERIMETER STONE (2.1 m) 24" (600 mm)MIN* MAX 12'(300 mm)MIN EXCAVATION WALL pp S, ti (CAN BE SLOPED I 60' OR VERTICAL) I � (1525 mm) L DEPTH OF STONE TO BE DETERMINED 17'(300 mm)MIN-- BY SITE DESIGN ENGINEER 9"(230 mm)MIN MC-4500 END CAP (230 mm)MIN 100(25, mm) —17'(300 mm)TYP SITE DESIGN ENGINEER IS RESPONSIBLE FOR ENSURING THE REQUIRED BEARING CAPACITY OF SOILS 'MINIMUM COVER TO BOTTOM OF FLEXIBLE PAVEMENT.FOR UNPAVED INSTALLATIONS WHERE RUTTING FROM VEHICLES MAY OCCUR,INCREASE COVER TO 30"(750 mm). K-P MC-4500 CHAMBER SPECIFICATIONS STORAGE VOLUME PER CHAMBER FT3(M3) Bare Chamber and Stone I Ch. Foundation Depth Storage mber trit it tillr WChambr06.5(3,02) 162.6(4.60) 166.3(4.71) 169.6(4.81) 173.6(4.91) MC-4500 End Cap J 35.7(1.0) 108.7(3.08) 111.9(3.17) 115.2(3.26) 118.4(3.35) Note:Assumes 9"(230 mm)row spacing,40%stone porosity,12"(300 mm)stone above and includes the bare chamber/end cap volume.End cap volume assumes 12"(300 mm)stone perimeter. AMOUNT OF STONE PER CHAMBER Off,19 NE R MMCC-4451 r 00 Chamber 7.4(5.2) 7.8(5.5) 8.3(5.9) 8 0.8(6.2 500 En 9.6(6.8) 10.0(7.1) 10.4(7.4) .9(7.7)) 375 MC-4500 Chamber 6,681(4.0) 7,117(4.2) 755 7,987(4.7 ) MC-4500 End Cap 8,691(5,2) 9,075(5.4) 9,460 ) 9,845(5.9) Note:Assumes 12"(300 mm)of stone above and 9"(230 mm)row spacing and 12"(300 mm) of perimeter stone in front of end caps. VOLUME EXCAVATION PER CHAMBERYD3(M3) DepthStone Foundation 91 r rr r MC-4500 Chamber 10.5(8.0) 10.8(8.3) 11.2(8.5) 11.5(8.8) MC-4500 End Cap 9.3(7.1) 9.6(7.3) 9.9(7,6) 10.2(7.8) Note:Assumes 9"(230 mm)of separation between chamber rows,12"(300 mm)of perimeter in front of the end caps,and 24"(600 mm)of cover.The volume of excavation will varyas depth of cover increases. /� Working on a project? [ui�i{ir�-JJk7.st.Tech•., Visit us at 1lJ�IJFfJ.e ZG'lir��C �.G�.�t�Bu� DES60,11a 4 `) 9_ and utilize the StormTech Design Tool For more information on the StormTech MC-4500 Chamber and otherADS products,please contact our Customer Service Representatives at 1.800-821-6710 DrainageAdvanced THE MOST ADVANCED NAME IN WATER MANAGEMENT SOLUTIONSTIA 4640 Trueman Blvd.,Hilliard,OH 43026 :ii i ADS"Terms and Conditions of Sale"are available oil the ADS website,wwvi.ads-pipe.com The ADS logo and the Green Stripe are registered trademarks Drainage Systems,Inc. . i • . Exhibit i ENGINEERING, REIMAGINED ENGINEERING, REIMAGINED GEOTECHNICAL REPORT FOR: Griffin Commercial Development Bozeman, Montana September 2016 Project 16-156 �s ti L rIED ENGINEERING SERVICES,INC, o�J 5 �7yerse Pro�e��s' 32 Discovery Drive Bozeman,Montana 59718 (406)582-0221 Fax(406)582-5770 . vAvw.alliedengineering.com Civil Engineering Geotechnical Engineering Land Surveying ' Construction Services Corporate Office North Dakota Office ALLIED 32 Discovery Drive 299 Prairie Drive ENGINEERING Bozeman, MT 59718 PO Box 1251 SERVICES,INC. Ph: (406) 582-0221 Stanley, ND 58784 Fax: (406) 582-5770 Ph: (701) 628-0221 'verse Prate September 15, 2016 Shane Strong, PE KU 1982 Stadium Dr. Suite 3 Bozeman, MT 59715-0697 email: timothy.strong@klieng.com RE: Final Geotechnical Report for Griffin Commercial Development- Bozeman, Montana Dear Mr. Strong: Please find enclosed three (3) bound copies of our geotechnical report for the above- referenced project. An electronic PDF copy of the complete report has also been provided to you. As per our scope of work, this report presents our geotechnical assessment of the project site and provides recommendations pertaining to foundation and slab support, seismic site classification, allowable bearing and lateral earth pressures, estimated foundation settlements, footing subgrade improvement, wall backfill materials and compaction, foundation-related fill materials, utilities, surface and subsurface drainage, asphalt pavement section materials and design thickness, and general site earthwork. This report was prepared for use by all associated parties during the planning, design, and construction phases of this site development project. It is important that all Contractors that are involved with the site grading, foundation earthwork, underground utility installation, and pavement construction are provided with copies of the report such that they are informed of the site conditions and our construction recommendations. if you have any questions regarding this report, please give us a call. Thank you. Sincerely, Allied Engineering Services, Inc. rai R. Madson, PE Principal Geotechnical Engineer enc: Final Geotechnical Report P:\2016\16-156 Griffin Commercial Development Project Geotech\05 Design\Geotech\Report\Griffin Commercial Development Project Geotech 09.15.16.docx www.alliedengineering.com TABLE OF CONTENTS INTRODUCTION AND PROJECT DESCRIPTION................................................................................. 1 SCOPEOF WORK............................................................................................................................. 1 GEOLOGYOF SITE............................................................................................................................ 2 EXPLORATIONS AND SUBSURFACE CONDITIONS........................................................................... 3 SubsurfaceExplorations.............................................................................................................. 3 SubsurfaceConditions................................................................................................................. 3 LaboratoryTesting ...................................................................................................................... 4 GEOTECHNICAL RECOMMENDATIONS........................................................................................... 4 FoundationDesign ...................................................................................................................... 4 Recommended Foundation Bearing Pressures........................................................................... 5 LateralEarth Pressures................................................................................................................ 5 FoundationWall Backfill.............................................................................................................. 6 Re-Use of Excavated Foundation Soils........................................................................................ 6 Interior and Exterior Concrete Slabs........................................................................................... 6 Vapor Barrier under Interior Concrete Slabs.............................................................................. 6 SubsurfaceDrainage ................................................................................................................... 7 SurfaceDrainage......................................................................................................................... 7 SeismicDesign Factors................................................................................................................ 8 Construction Recommendations................................................................................................. 8 RetentionPonds.......................................................................................................................... 8 FOUNDATION-RELATED FILL MATERIAL RECOMMENDATIONS ..................................................... 8 ExcavatedFoundation Soils......................................................................................................... 8 StructuralFill ............................................................................................................................... 9 Washed or Screened Crushed Rock............................................................................................ 9 FILL PLACEMENT AND COMPACTION ............................................................................................. 9 ASPHALT PAVEMENT SECTION RECOMMENDATIONS ................................................................. 10 UNDERGROUND UTILITY RECOMMENDATIONS........................................................................... 10 Foundation Support of Utility Lines.......................................................................................... 10 TrenchBackfill........................................................................................................................... 11 COLD/WINTER WEATHER CONSTRUCTION .................................................................................. 11 LIMITATIONS................................................................................................................................. 11 REFERENCES.................................................................................................................................. 12 List of Figures Figure 1—Aerial Map Figure 2—USGS Topographical Map Figure 3 —Geology Map Figure 4—Aerial with Borehole Locations Figure 5 —Site Plan with Borehole Locations Figure 6—Foundation Detail —Slab on Grade List of Appendices Appendix A—Borehole Logs Appendix B—Laboratory Testing Appendix C— Percolation Test Results Appendix D— Limitations of Your Geotechincal Report �s J N ALLIED c ENGINEERING ° SERVICES,INC. 0�0 h I'se PSOje INTRODUCTION AND PROJECT DESCRIPTION This report presents our geotechnical assessment for the proposed Griffin Commercial Development on the north side of Bozeman, Montana. The information contained herein is based on an investigation and analysis of the property's topographical and subsurface conditions, a review of geologic maps and literature for the project area, and previous experience gained during our involvement with similar projects throughout Bozeman. The proposed development is at the northeast corner of North 7t" Avenue and West Griffin Drive. The property just under two acres in size and is legally described as Tract 14 of Plat E-38 found in Section 36, Township 1 South, Range 5 East. The property slopes gently from west to east. Elevation change across the property averages about 4 to 5 feet. Presently, the lot is undeveloped. However, as late as 2004, a series of commercial structures were located on the south side of the property directly adjacent West Griffin Drive (from Google Earth Images, October 2004). In general, there appeared to be about 5 to 6 structures (several of them connected) with associated parking areas directly south of the buildings. Little is known of these structures. Given these structures have been removed and the foundations filled in, the earthwork contractor should be aware that there will be unknown depths of non- engineered random fill that will require removal and replacement under the newly proposed structures. We understand the work will include the construction of two pre-engineered metal warehouse/retail buildings that will be approximately 22 feet in height (measured to the top of the parapet). The veneer will be a combination of brick, metal, and wood. The buildings will be constructed on a slab-on-grade foundation with concrete floors. SCOPE OF WORK Our Scope of Services for this project included: ■ Subsurface explorations (two boreholes drilled to approximately 24 and 30 feet respectively within the building footprints and two boreholes drilled to about 6 feet in the parking area). Shane Strong, PE Jriffin Commercial Development September 15, 2016 Bozeman, Montana ■ Laboratory testing of specific soil samples. ■ Providing foundation support options and allowable bearing criteria as well as associated anticipated settlements. ■ Minimum foundation depth for frost protection. ■ Lateral earth pressures for cantilevered and braced wall conditions, and sliding resistance due to friction and passive pressure. ■ Site-specific seismic classification and analysis. ■ Surface and subsurface drainage recommendations. ■ Backfill material and compaction recommendations. ■ Asphalt pavement section materials and design thickness. ■ Percolation test results in the proposed retention pond area. ■ General site earthwork, utilities, and construction recommendations. The results of the above scope of work are summarized in this geotechnical report. The purpose of the report is to inform the Engineer, Architect, Owner, and associated Contractors of the subsurface conditions underlying the site; and to present geotechnical recommendations for consideration and implementation during the planning, design, and construction of the facilities. GEOLOGY OF SITE According to the "Geohydrologic Conditions & Land Use in the Gallatin Valley, Southwestern Montana" prepared by Steven Slagle (1995), the project site (as well as the majority of the Bozeman area) is underlain by Quaternary-aged alluvial fan deposits. These deposits were derived from the Gallatin Range and Bridger Range and primarily consist of a 30 to 200-foot thick layer of sandy gravel and cobbles interbedded with thin lenses of sand, silt, and clay. Due to the fluvial and aeolian activity that has occurred in the valley since the alluvial deposits were formed, the alluvial sand and gravel materials are typically covered by silt and clay (floodplain and windblown deposits). Organic topsoil usually blankets these fine-grained soils. Underlying the alluvial gravel deposit are consolidated beds of Tertiary-aged silt, clay, sand, and gravel, which are generally considered to be "bedrock" for the area. Allied Engineering Services, Inc. Page 2 Shane Strong, PE uriffin Commercial Development September 15,2016 Bozeman, Montana EXPLORATIONS AND SUBSURFACE CONDITIONS Subsurface Explorations Subsurface conditions were investigated on August 30, 2016 by Gary Fox under the direction of Craig Madson, a professional geotechnical engineer with Allied Engineering. A total of four boreholes (identified as BH-1 through 131-1-4) were drilled by O'Keefe Drilling of Butte, Montana using a hollow stem auger. The explorations were spatially situated to provide coverage of the anticipated building locations plus the parking areas. Please see the attached figure (Figure 5) for the approximate location of these boreholes. Standard Penetration Testing was performed at regular intervals to gather samples and to determine the consistency of the soil. A Standard Penetration Test (SPT) consists of driving a 2- inch diameter split spoon sampler in 6-inch increments (18 inches total) using a 140 pound hammer dropped 30 inches. The number of blows required to drive the sampler each of the 6- inch increments are recorded and the last two increments are added to determine the "N value" which can be correlated to a number of other soil characteristics. In this case, the N values provided in the logs are uncorrected for overburden. During the explorations, soil and groundwater conditions were visually characterized, measured, and logged. Copies of our borehole logs are attached. Each of the logs provides assorted field information such as soil depths and descriptions, groundwater conditions, and a sketch of the soil stratigraphy. Please be aware that the detail provided on the logs cannot be accurately summarized in a paragraph; therefore, it is important to review the logs in conjunction with this report. Following completion of the fieldwork, the borehole locations were backfilled with drill cuttings and staked with lathe. Subsurface Conditions Following is a general description of the subsurface conditions encountered: Fill: In 13H-2, a thin layer of gravel about one foot thick was encountered at the surface. This gravel is likely associated with the parking area for the original buildings. Silt and Clay (Fluvial and Aeolian Deposits): Up to about 18 feet of fine-grain silt and clay was found in BH-1 and 13H-2. This material was generally dry to moist and varied in consistency from soft to stiff. We believe the top several feet of fine-grain soil found in BH-2 may have included some random fill (likely associated with the filling of the old foundations). Blow counts in this material ranged from as low as 3 to as great as 11. Allied Engineering Services, Inc. Page 3 Shane Strong, PE ..griffin Commercial Development September 15, 2016 Bozeman, Montana An undisturbed sample of this material was taken at a depth of about 6.5 feet in BH-1 for the purposes of completing a consolidation test. The purpose of the consolidation test was to evaluate the susceptibility of the fine-grain soils to collapse with saturation as well as settlement under foundation loads. Please refer to the attached lab results in Appendix B. Gravel Alluvium: Very dense, brown, alluvial sandy gravel was encountered at a depth of 17.5 feet in BH-1 and 19.5 feet in BH-2. Blow counts in this material were over 50. Groundwater: Groundwater was encountered at a depth of 29 feet in BH-2. However, please recognize that groundwater levels can fluctuate depending on the time of year and amount of precipitation. The highest groundwater levels are generally found in the spring to early summer. Laboratory Testing Laboratory testing of select samples was conducted as part of our work. In particular the testing included moisture content, atterberg limits (to differentiate if the fine-grain soil was a silt or clay), and standard proctor compaction testing. As described earlier, we also obtained a shelby tube sample of the fine-grain soil in order to conduct a consolidation test (for settlement analysis) as well as an evaluation of the collapse potential in the event of saturation. The consolidation testing and collapse analysis were conducted by a sub-consultant (Pioneer Technical Services). The results of the laboratory testing are provided in Appendix B. GEOTECHNICAL RECOMMENDATIONS Foundation Design Aeolian (wind-blown) soils are generally susceptible to collapse under foundation loads when saturated. Therefore, we evaluated this potential by saturating a sample under the anticipated foundation load of 2,000 pounds per square foot (psf). In general, we found the collapse potential to be negligible. We also evaluated the settlement potential of the clayey silt under a 2,000 psf foundation load. Based on the laboratory testing, we determined that the settlement potential (assuming direct bearing in the silt and clay at about 6.5 feet) would be up to 1.5 inches under a 4 foot by 4 foot spread footing. In order to limit the potential for settlement, we recommend that all foundations bear on a minimum of 24 inches of geogrid reinforced compacted granular structural fill that in turn is founded in the native silt and clay. Structural fill should be compacted in lifts to 98 percent of its Standard Proctor Density (ASTM D-698). The native subgrade should be compacted to an Allied Engineering Services, Inc. Page 4 Shane Strong, PE k3riffin Commercial Development September 15, 2016 Bozeman, Montana unyielding condition prior to structural fill placement. Details for the installation of the geogrid reinforced structural fill are provided in Figure 6. In general, the geogrid reinforcement should consist of two layers of TX-5 Tensar geogrid spaced one foot apart. The geogrid should be installed, overlapped, and tied together as per manufacturer recommendations. A non-woven separator fabric (8 oz minimum) should be used to separate the native soils from the overlying structural fill. 1.5-inch minus road mix gravel should be used within the geogrid reinforced section. As depicted in Figure 6, geogrid reinforced structural fill only needs to be used under foundation elements. The minimum width of the geogrid reinforced structural section under foundation elements is also provided in Figure 6. As discussed earlier, we anticipate that areas of random fill are present across the site (particularly in the locations of the old foundations) which likely was not compacted to an appropriate standard. We therefore recommend budgeting for the removal and replacement of random fill in areas that underlie buildings or other critical areas where settlement needs to be minimized. Assuming the random fill is free of organics and other deleterious materials, is not highly plastic, and the moisture content is close to optimum for compaction, it may be re- used as an engineered (compacted) fill for filling these areas back up to the design subgrade elevation. This material may not be used within the geogrid reinforced structural fill section under footings. Recommended Foundation Bearing Pressures The recommended design bearing pressure is 2,200 pounds per square foot (psf) for continuous and spread footings founded on 24 inches of geogrid reinforced compacted granular structural fill which in turn bears in the native silt and clay. We estimate that the above referenced bearing pressures will result in total settlements of under 1 inch, and differential settlements of less than 0.5 inches. Footings should be founded a minimum of four feet below the adjacent exterior grade for frost protection. Lateral Earth Pressures Any buried foundation walls fixed at the top should be designed for an equivalent fluid pressure of 60 pounds per cubic foot (pcf). Cantilevered retaining walls, which are not connected to the structure, may be designed for an equivalent fluid pressure of 45 pcf. These pressures assume the walls are backfilled and drained as described herein. The lateral earth loads provided are for static conditions and should be factored appropriately to represent lateral earth pressures during seismic events. To avoid damage to the walls, hand operated compaction equipment should be used directly adjacent to foundation walls that are not buried on both sides. Allied Engineering Services, Inc. Page 5 Shane Strong, PE iriffin Commercial Development September 15, 2016 Bozeman, Montana Lateral forces from wind, seismic loadings, or from earth pressures on the opposite side of the building will be resisted by passive earth pressure against the buried portions of structures and by friction against the bottom. Passive earth pressures in compacted backfill can be assumed to have a maximum equivalent fluid pressure of 280 pcf. We recommend that a coefficient of friction of 0.5 be used between cast-in-place concrete and the underlying structural fill. Actual foundation loads (not factored or allowable loads) should be used in calculating frictional resistance to sliding at the base. The above values have no built in factor of safety, so an appropriate factor of safety for each particular load case should be used in all subsequent calculations. Foundation Wall Backfill Foundation wall backfill may consist of the native silt and clay provided the moisture in near optimum. Soils containing organics should only be used in the upper 4 to 6 inches. Re-Use of Excavated Foundation Soils Excavated foundation soils consisting primarily of the silt and clay may be used selectively as foundation wall backfill and random site fill under slabs, parking areas, and access roads. It may not be used as structural fill under foundations. Please recognize that this soil is very moisture sensitive and will be problematic to work with during wet or cold weather. If work is conducted during non-optimal times of the year, sand and gravel fill may be necessary for random site fill and backfilling of foundation walls in order to attain the necessary compaction. Interior and Exterior Concrete Slabs Interior and exterior concrete slabs should be supported on 12 inches of sand and gravel structural fill and 6 inches of crushed rock (directly under the slab). Vapor Barrier under Interior Concrete Slabs In recent years, there has been significant research regarding the importance of vapor barriers even in instances where the groundwater is significantly below the slab and the soils are coarse-grained. This research suggests that the switch from solvent-based to water-based flooring adhesives mandated by the EPA in the late 90's has led to a significant increase in flooring failures. While much safer for the environment, the water based adhesives are very sensitive to moisture conditions and can fail with even slight increases in moisture vapor coming through the slab. Even when conditions were acceptable at the time the flooring was installed, there have been instances when water vapor coming from groundwater below the slab migrated up and eventually caused failure of the flooring years after the original Allied Engineering Services, Inc. Page 6 Shane Strong, PE -,iffin Commercial Development September 15,2016 Bozeman, Montana installation. The research also has suggested that the lightweight 6-mil polyethylene commonly used as a vapor barrier is prone to disintegration over time, leading to flooring problems as more water vapor is allowed to migrate up through the slab. In light of this, we believe it would be sensible to install a heavy-duty vapor barrier under all interior slabs. One product that is satisfactory for this application is Stego 15-mil Vapor Barrier by Stego Industries LLC. The vapor barrier should be installed as per the manufacturer recommendations and ASTM E 1643. The vapor barrier should be installed over the crushed rock already in place. We further recommend strict specifications for concrete to minimize the water in the mix. By utilizing water-to-cement ratios of 0.45 or less in conjunction with additives to enhance workability and the use of curing compounds to slow the drying rate, we believe curling of the slab can be adequately controlled. Many practitioners advocate burying the vapor barrier under a layer of sand or gravel "blotter" to reduce curling of the slab; however, this practice often times traps additional moisture between the slab and the vapor barrier. Even with low water-to-cement ratios, adequate cure time before flooring coverings can be placed could be as long as 45 days. Higher water-to-cement ratios or moist subgrades will lengthen the curing period significantly. For this reason, we recommend keeping the vapor barrier directly under the slab. Subsurface Drainage Footing drains around slab-on-grade buildings are not necessary assuming the exterior grade is maintained a minimum of 6 inches below the top of the sill plate. Four inch perforated footing drains encased in crushed rock and completely wrapped in a non-woven drainage fabric should be used adjacent crawlspace foundations and retaining wall footings. The drains should be daylighted to an appropriate location. We recommend damp-proofing all frost walls/crawlspace walls. Damp-proofing products can range from emulsions/plastics applied with a roller, sprayer, or brush, to poly sheeting. These products are not intended to completely water-proof walls, and will typically leak if exposed to a water table/saturated conditions for an extended period. Sub-drains may be placed in the crushed rock directly beneath interior slabs to capture and vent radon gases provided the system is properly designed by a mitigation specialist. Surface Drainage Final site grading around the buildings must establish and promote positive surface water drainage away from the foundation footprint in all directions. No water should be allowed to accumulate against or flow along any exposed foundation walls. Concrete or asphalt surfacing Allied Engineering Services, Inc. Page 7 Shane Strong, PE iriffin Commercial Development September 15, 2016 Bozeman, Montana that abut the foundation should be designed with a minimum grade of 2 percent away from the buildings; while adjacent landscaped areas should have a slope of at least 5 percent within 10 feet of the wall (see the IBC building codes). To further reduce the potential for moisture infiltration along foundation walls, backfill materials should be well compacted. The upper 4 to 6 inches of backfill should consist of low permeable topsoil. With the exception of the locations that will be surfaced by concrete or asphalt, finished grades next to foundation walls should be set no less than 6 inches below the top of the sill plate. Seismic Design Factors Based on our on-site explorations and knowledge of the underlying geology, the site class for the project site should be considered to be Site Class D. Construction Recommendations Based on our review of the topography, we anticipate several feet of fill may be necessary (particularly on the east side of the buildings) to bring up the grades under the buildings. The use of several feet of fill to bring up the grades could induce some settlement in the underlying fine-grain soils. In order to limit the possibility of undesirable differential settlements, we recommend bringing up the site grades to the design subgrade elevation prior to the construction of the foundations. We anticipate the weight of the fill should consolidate the non-saturated silts and clays within a few days of placement. Retention Ponds Percolation test results are provided in Appendix C. As seen, the percolation rates were generally very quick indicating there is a significant sand component within the silt and clay. Please be aware that generally infiltration rates will slow during the life of a retention pond due to siltation over time. We suggest designing for a slower percolation rate and perhaps adding a dry well with crushed rock that is completely wrapped in a non-woven drainage fabric to allow for faster infiltration. FOUNDATION-RELATED FILL MATERIAL RECOMMENDATIONS Excavated Foundation Soils Excavated foundation soils will generally consist of organic topsoil, random fill, and native silt/clay. It should be noted that topsoil should not be used for foundation backfill purposes. The silt and clay may be used selectively as wall backfill provided the moisture content is near optimum. As alluded to earlier, wet or cold weather will make the re-use of the silt and clay Allied Engineering Services, Inc. Page 8 Shane Strong, PE iffin Commercial Development September 15, 2016 Bozeman, Montana very difficult. If adequate compaction is an issue due to the weather conditions, the import of sand and gravel may become necessary. Structural Fill Any import granular structural fill needed for the project should consist of organic free, well- graded 4-inch minus uncrushed gravel or as an alternative 1.5-inch minus crushed road mix gravel. As per manufacturer recommendations, only 1.5-inch minus crushed road mix gravel should be used within the geogrid reinforced structural fill section. The gravel courses shall meet the material and gradation specifications as presented in the Montana Public Works Standard Specifications (MPWSS) for sub-base course and base course gravel. Washed or Screened Crushed Rock Acceptable uses for crushed rock should be limited to placement in the upper 6 inches under interior/exterior concrete slabs and around footings. The crushed rock should be a clean, durable material that has 100 percent passing the %-inch screen and less than 1-percent finer than the #100 standard sieve. This product needs to be manufactured by a crushing process and 50-percent of its particles must have fractured faces. FILL PLACEMENT AND COMPACTION All fill materials should be placed in uniform, horizontal lifts and compacted to an unyielding condition. The "loose" thickness of each layer of fill prior to compaction should not exceed 10 inches for self-propelled rollers, 6 inches for remote-controlled trench rollers, and 4 inches for plate compactors. The moisture content of any fill material to be compacted should be within 2-percent of its optimum value. Provided in Table 1 below are compaction recommendations for general site applications. These recommendations apply to all fill materials and are presented as a percentage of the maximum dry density of the material being placed as defined by ASTM D-698. A common misconception is that washed or screened crushed rock does not require compaction. However, this material does require compaction with a vibratory plate or smooth drum roller. Table 1. Compaction Recommendations(Application vs. Percent Compaction). APPLICATION %COMPACTION Fill for site grading and under exterior slabs and pavements 95 Structural fill under footings and interior slabs 98 Back ill behind foundation and retaining walls 95 Clean crushed rock under slabs N/A—Vibratory Compaction Allied Engineering Services, Inc. Page 9 Shane Strong, PE .,riffin Commercial Development September 15, 2016 Bozeman, Montana ASPHALT PAVEMENT SECTION RECOMMENDATIONS Using conservative estimates for soil strength (CBR = 3.0) and vehicular equivalent single axle loadings (ESAL) = 50,000, we have designed a thickened asphalt paving section that can be supported on the site's upper fine-grain soils. We estimate that the compacted design thickness for a pavement section with a 20-year design life is 21 inches. Assuming the subgrade soil is dry and stable (i.e., the upper 8 inches of native soil can be compacted to 95-percent of ASTM D-698), we recommend the following pavement section: Table 2. Recommended Pavement Section. MATERIAL COMPACTED THICKNESS (IN) Asphalt 3 Base Course Gravel 6 Sub-Base Course Gravel 12 Woven Geotextile Fabric Yes Native Subgrade Soils Upper 8 inches compacted to 95% TOTAL 21 Prior to the placement of the asphalt pavement section, the compacted subgrade surface should be .proof-rolled. Any saturated materials or soft spots observed should be sub- excavated and replaced with suitable compacted structural fill. The sub-base and base course materials that comprise the paving section shall consist of 4-inch minus uncrushed gravel and 1.5-inch minus crushed road mix gravel, respectively. Both of these gravel courses shall meet the material and gradation specifications as presented in the MPWSS. The placement (10-inch maximum thickness of loose lifts) and compaction (95 percent of ASTM D-698) of these materials should be in accordance with the above referenced standard specifications. We further suggest the use of a woven geotextile separator fabric (Mirafi 600X or equivalent) between the fine-grain silt and clay and the gravel subbase. UNDERGROUND UTILITY RECOMMENDATIONS Foundation Support of Utility Lines Exterior utility lines (water, sewer, and dry utilities) will likely be supported in the native silt and clay. These materials will provide suitable support for the utility lines. We suggest proper bedding of these utilities following the specifications found in the Montana Public Works Standard Specifications. Allied Engineering Services, Inc. Page 10 Shane Strong, PE k�,iffin Commercial Development September 15,2016 Bozeman, Montana Trench Backfill Trench backfill can consist of any native material (with the exception of materials containing significant organics) that is not overly wet. We recommend that all trench backfill be compacted to a minimum of 95 percent of ASTM D-698. This includes utility trenches under landscaped areas. COLD/WINTER WEATHER CONSTRUCTION If foundation construction will occur during the cold/winter weather season, the Contractor shall take all necessary precautions to prevent the earthwork from freezing and/or from being contaminated with snow. Exposed subgrade and fill materials (under footings, slabs, and walls) should be adequately covered with concrete insulation blankets to prevent frost penetration and to protect them from snow. All soils that are used for fill under or around foundation components should be relatively dry, free of intermixed snow and frozen clods, and must not be placed when it is snowing. This may necessitate the import of sand and gravel for backfill if work is conducted in cold or wet conditions. Fill materials or footings should not be placed over frozen soils, which may be in a "frost- heaved condition", or layers of snow. Please recognize that the silt and clay will be particularly vulnerable to freezing and heaving. When earthwork will proceed during the non-optimal times of the year, we recommend that it be performed in an expeditious manner; thereby minimizing the time that the foundation excavation is open and exposed to the elements. In addition, positive drainage must be established away from the excavation in order to prevent the entry of surface water runoff and the saturation of the underlying soils. Please be fully aware that carelessness with respect to any of the above-referenced items can potentially lead to foundation settlement problems in the spring when the frost thaws and/or the snow melts. Finally, cold weather concrete practices and methods should be implemented when the conditions dictate. LIMITATIONS This report provides our geotechnical-related recommendations for the Griffin Commercial Development in Bozeman, Montana. These recommendations are based on our observation and evaluation of the site's surface and subsurface conditions, our review and interpretation of available geologic information, and our previous experience in the project area. If during construction, soil and groundwater conditions are found to be inconsistent with those that are described herein, we should be advised immediately so we can reconsider our recommendations if need be. We recommend we be retained both during design and construction to provide input and recommendations as necessary. Allied Engineering Services, Inc. Page 11 Shane Strong, PE Griffin Commercial Development September 15,2016 Bozeman, Montana All individuals directly associated with this project site should consult this report during the planning, design, and construction involved in the development of the site. It should be made available to other parties for information on factual data only and not as a warranty of actual subsurface conditions such as those interpreted herein. We appreciate the opportunity to perform our geotechnical services. Please call if you have questions. Sincerely Allied Engineering Services, Inc. n0'}�`�tt�G � "94�,}t•.i r� Af qai R. Madson, PE Prin Ipal Geotechnical Engineer REFERENCES 1. International Code Council, 2012. "International Building Code". 2. Montana Contractors Association, April 2010. "Montana Public Works Standard Specifications", Sixth Edition. 3. Slagle, Steven (1995). "Geohydrologic Conditions & Land Use in the Gallatin Valley, Southwestern Montana", USGS Water-Resources Investigations Report 95-4034. gajgc: LSE P:\2016\16-156 Griffin Commercial Development Project Geotech\05 Design\Geotech\Report\Griffin Commercial Development Geotech Report.docx Allied Engineering Services, Inc. Page 12 LIST OF FIGURES Figure 1 —Aerial Map Figure 2 — USGS Topographical Map Figure 3 —Geology Map Figure 4—Aerial with Borehole Locations Figure 5—Site Plan with Borehole Locations Figure 6— Foundation Detail — Slab on Grade P1N r • PROJECT SITE - GRIFFIN COMMERCIAL ` ,,E. ) � TAT90• DEVELOPMENT +"'"�!`'•�;'��� I ''`" '��,�'s�y �y{ -'1^,!Y•�"q�� ! �• � t_:� i y 41+y �_1 _� I °' t fF�: :'�yj8 I�o1-e °L l ,;� y� '-� •"' -i_-,_ ...,.,� s....�` �_ ,` a .c- '� Ir�' •� �,�l.i _ '.I'll � � °u \� LY 1 • , 1,l..• / r •-•.. •� �;, _ � .; p ley 'r--- m 32, 4 � {fit • � ✓pt'� � 6lilft! � -:����' jl - J � t T w [�_��w# �. - - � t"n.`:i,fi• o 0 0 0 1,000 2,000 3,000 E Mimi Mimi U SCALE: 1 INCH = 1,000 FEET 0 a GRIFFIN COMMERCIAL DEVELOPMENT Geotech C Engineering _ FIGURE 1 nical Engineering Land Surveying DRAM BY: GDF AERIAL MAP ALLIED DATE: 09/2016 32 DISCOVERY DRIVE BOZEMAN.MT 59718 ENOINEERINO BOZE�IAN 1140NTANA PHONE(406)582-0221 . FAX(406)582.5770 s al,7=INc PROJECT #:16-156 7 wwx.aQledenglneerinp.tom ,•,pr1.�`• FIGURE 1 & 2.DW'G a ° o ° ° r aOo145':c o c°C 4 ° o� o 2_ 29.0 0 c o .° ° 285 ,C v °vv4o�' o° '�pCrgo ° ° t 0"0 ° C °0 .0 .0 q...,p..0.0 0'- 0 1q 0 ;;�o ° oo a b oo O \ o.0 0... °..` .0 0 QTa 0 ravel P3 � 1 °C O° \Qa� '0 q .'q'. PIt o, 50.3 128 37 SEC. 36, T1S, R5E, 1' .a°;o o:a 1 �` GALLATIN COUNTY _ ° °° , d � • 109 r1f Zl j _ o Q Q j s l i ° q0 d P .2 ) 4 0� 0 ° ° r t' S ! d a 6k. o T�¢° c o ` fl' .0 O O O q0 Ts PROJECT SITE ° ° ° Ts 5Q GRIFFIN COMMERCIAL o ° 2 20.1' iJ 3 r. i DEVELOPMENT S.a. b ° 550 ° 1%sewage it Sol at( 011 Y. p R• Q00 u .fir 1, ."..._., _.... _ �•_ — .o° ,� �� r 00 -->�— o ° 167.7 Z ? i 0 V U u LEGEND QTa = ALLUVIAL FAN DEPOSITS E (QUARTERNARY/TERTIARY) 0 0 6000 12000 18000 Qal = FLUVIAL DEPOSITS (QUARTERNARY) `u E E Ts = LACUSTRINE & FLUVIAL DEPOSITS SCALE: 1 INCH = 6000 FEET UNDIFFERENTIATED (TERTIARY) BASE MAP: GEOHYDROLOGIC CONDITIONS & LAND USE IN THE GALLATIN VALLEY, s SOUTHWESTERN MONTANA; BY: STEVEN E SLAGLE, 1995 % a GRIFFIN COMMERCIAL DEVELOPMENT Civil Engineering _ _ FIGURE 3 Geotechnlca/Engineering � ' Land Surveying —Z—a DRAWN BY: GDF GEOLOGY MAP ALLIED DATE: 09/2016 32 DISCOVERY DRIVE BOZEMAN,MT 59718 ENQINEERINO B07EMAN MONTANA PHONE(406)582-0221 . FAX(406)5825770 arawccz rue PROJECT A:16-156 www.alliedenglneedng.com ��.,,,eo„.�" FIGURE 3.DWG r` r !b Y '4 t i y 'to . X i�f *61 104 • a an w � r� s 4, BH 2 BH•3 M MANDEVILLE DRIVE GRIFFIN DRIVE r j PROJECT SITE : iz r GRIFFIN COMMERCIAL DEVELOPMENT a .•�. O ? a R � �•� chi * I ^ o 0 0 200 400 600 E LEGEND BOREHOLE LOCATION SCALE: 1 INCH = 200 FEET (APPROXIMATE) N 0 N GRIFFIN COMMERCIAL DEVELOPMENTCivil Engineering Geotechnical Engineering cxciog—� rIGURE 4 C DRAW17 6Y. GDF AERIAL W/ BOREHOLE LOCATIONS Land Surveying DATE: 09/2016 02 DISCOVERY DRIVE 002EMAN,MT 69718 PHONE(406)582.0221 FAX(406)582-5770 PROJECT N;16-156 BOZEMAN, MONTANA llldi =oY`��� FIGURES 4 & 5.DWG 11 t t 11 ! 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B02E14AN,MT59718 ENGIfJEERIh'G BOZBMAN MONTANA PHONE(406)582-0221 . FAX(406)582.5770 mxTz wa PROJECT N:16-156 / Ww Hledengheering.wm �:�•i.•P.ol��` FIGURES 4 & S.DWG cc anJJJ r'J:q L JJi ri aJJ.ti�rJJ+4 L•JJs 0 , 0 aJJJ J.O• G.+�SR; aJJJJOJJJJ.4 •,. A'J. Ji'JO.JJJ. J.•�• J��i YJi� •w- aJ.;J JJJ,}.L;Ji;i a.•J.bC 1 I 11 1 1 1 �J.;J: J: �.y,.� .. •3�:1 IL a..... � :. ag.•.e. a.. aJyo y aJs Yo�;;ykk:•:S: �:s.n:`%:•tea".v? '+ sa �:•o>� ':• ��O3daa•�0 • SyJa JJ1JJ0 i4'p•� � y��S3 • • �:�J:•' •. �? i to 2D t: w 7E .. . •.$ ��ff' PPP # • '•1{ S 1 co • a ; • i F-I LUWL co .� J.'�a••K�'. '`s �+OJO aJJi.+ ,�oJgJJ.o,.;:y3 ;•J J.o �'.oe • v JJ.i 00 CL • • LIST OF APPENDICES Appendix A— Borehole Logs Appendix B— Laboratory Testing Appendix C— Percolation Test Results Appendix D— Limitations of Your Geotechnical Report APPENDIX A Borehole Logs Civil Engineering .2 DISCOVERY DRIVE Land Surveying ...... MT 59718 LOG O F BORING ALLIED Geoteclmical Engineering PHONE....(40G)582-0221 EHUlNEER1N0 FAX(406)582-5770 ' Structural Engineering PROJECT: Griffin Commercial JOB#: 16-156 DATE: 0 813 0/2 0 1 6 BORING: BH#1 PAGE: 1 of 1 Development LOCATION: Refer to Site Map ELEVATION: Approx.4,739' TOTAL DEPTH: 24.25' DEPTH TO GW: None DRILL TYPE: Truck Mounted CASING/HAMMER/SAMPLER: 4" I.D.Hollow-Stem Auger w/140 lb Hammer CME 55 and 2.0" O.D.Split Spoon Sampler DRILLER: Steve-O'Keefe Drilling(Butte,MT) FIELD ENGINEER: Gary Fox,AESI(Bozeman,MT) U aF G,� E Ca" a DESCRIPTION OF a 3 0.4 z OTHER FIELD OR A z, W00 p MATERIALS -< � p SAMPLE INFORMATION Sl-A @ General Notes: 10' -0.25'1: TOPSOIL o'-IS 12 5.6%(sSs) 1. Drilling is generally Stiff,Light Brown to Brown; Sandy fast/easy in the silt/clay. SI-B @ Some grinding within the SILT with organics and occasional 2'-3.5' 11 5.6% gravel at 17.5' small gravels;Dry. (sss) 2. Two teeth on drill bit broke Sl-C @ off at 24'likely on large 4'-5.5' S 8.6% rocks. (sss) {0.25'-17.5'}: SILT/CLAY Medium Stiff to Stiff;Light Brown to Brown; Sandy SILT/Lean CLAY; Dry to Moist. Sl-D @ Standard Proctor Test Results: 10.0 9'-10.5' 8 11.3% (BH Cuttings from 4'-6.5') (sss) Maximum Dr Density General Notes: sl-� p y �' • Slight increase in moisture with 12'-r @' 9 18.9% optimum Moisture depth. (Sss) =13.2% • Shelby tube samples taken from Sl-r 6.5'-9.5'. 14'-15' 8 17.90/, Atterberg Limits Test Results (sss) (Sl-D @ 91-10.5') PL=15.8 LL=45.2 Sl-G @ PI=29.4 17'-18.5' 50+ 2.4% (sss) )Z—W--" 117.5'-24.25'1: SANDY GRAVEL sr-H @ Very Dense;Brown; Sandy GRAVEL; 19'-20.5' 50+ 2.7% 20.0 Dry (sss) General Notes: • Alluvial Deposit sl-I @ 24'-24.25' 50+ End of Boring (sss) 30.0 • SSS-2.0"O.D.Split Spoon Sample • The beginning and ending depths of the individual soil layers are approximate. Civil Engineering DISCOVERY DRIVE . c Land SUiVeying BOZEMAN,MT 59718 ENGINEEER�lMD(i Geoteclmical Engineering PHONE(406)582-022I LOG OF BORING atnweti M -a FAX(406)582-5770 Structural Engineering �"•rae Prol•` PROJECT: Griffin Commercial JOB#: 16-156 DATE: 08/30/2016 BORING: BH#2 PAGE: 1 of 1 Development LOCATION: Refer to Site Map ELEVATION: Approx.4,739' TOTAL DEPTH: 29.5' DEPTH TO GW: 29' DRILL TYPE: Truck Mounted CASING/HAMMER/SAMPLER: 4" I.D. Hollow-Stem Auger w/140 lb Hammer CME 55 and 2.0" O.D. Split Spoon Sampler DRILLER: Steve-O'Keefe Drilling(Butte,MT) FIELD ENGINEER: Gary Fox,AESI(Bozeman,MT) per. a DESCRIPTION OF 3 k H OTHER FIELD OR A W p MATERIALS 0 cc SAMPLE INFORMATION 0 o S2-A a)(sss) General Notes: {0' - 1'}: GRAVEL Fill °' 1) 25 1.6% 1. Drilling is generally Dense; Light Brown; Sandy fast/easy in the silt/clay. GRAVEL Old Parkin Lot Gravel S2-B @ ° Some grinding within the ( g 2.5'-4' 7 6.8/o gravel at 19.25'. Fill);Dry. (sss) S2-C @ 4'-5.5' 4 10.8% (sss) 11' -19.25'): SILT/CLAY s2-D @ Soft to Medium Stiff; Light Brown to 7•5'-9' 4 18.0% Atterberg Limits Test Results Brown; Sandy SILT to Sandy Lean (sss) (S2-E a,9'-10.5') S2-E @ PL=16.9 CLAY; Slightly Moist to Moist. 9'-10.5' 8 18.4% LL=36.3 10.0 (sss) PI=19.4 General Notes: • Possible fill soil from the old veterinary hospital at the site. s24 @ • Thin layer of tan/whiteish silt and 12.5'-14' 3 33.3% clay between 13.5' and 14'. (sss) • Generally softer and more moist s2-G @ ° than BH-1. 14'-15.5' 7 20.8/o (sss) S2-11 @ 17.5'-19' 11 16.4% (sss) S2-1 @ 19'-20.5' 50+ 4.2% 20.0 (sss) O o 119.5'-29.5'): SANDY GRAVEL Very Dense;Brown; Sandy GRAVEL; Dry to Wet. O O S2-J @ General Notes. 24'-25.5' 50+ 4.4% • Alluvial Deposit (sss) O o O O S2-K @ 29'-29.5' 50+ 15.8% 30.0 End of Boring (sss) • SSS-2.0"O.D.Split Spoon Sample • The beginning and ending depths of the individual soil layers are approximate. .. Civil Engineering 2 DISCOVERY DRIVE Land Surveying PHONE(40BOZEMAN,)58-0221 LOG ®F BORING 9718 ED y Geotechnical Engineering PHONE(406)582-0221 FAX(406)582-5770 Structural Engineering PROJECT: Griffin Commercial JOB#: 16-156 DATE: 08/30/2016 BORING: BH#3 PAGE: 1 of 1 Development LOCATION: Refer to Site Map ELEVATION: Approx.4,739' TOTAL DEPTH: 5.5' DEPTH TO GW: None DRILL TYPE: Truck Mounted CASING/HAMMER/SAMPLER: 4" I.D.Hollow-Stem Auger w/140 lb Hammer CME 55 and 2.0" O.D.Split Spoon Sampler DRILLER: Steve-O'Keefe Drilling(Butte,MT) FIELD ENGINEER: Gary Fox,AESI(Bozeman,MT) a DESCRIPTION OF U 3 rF"i, H OTHER FIELD OR W F O 0 go p SAMPLE INFORMATION A L, W p MATERIALS � z � U S2-A @ o'-1.5' 11 15.8% 10' -5.5'}: SILT/CLAY (SSS) Stiff to Soft;Light Brown to Brown; Sandy SILT to Sandy Lean CLAY; s2-a @ Dry. 21-3.51 5 15.30/0 (sss) General Notes: • Located near proposed parking lot. • Minimal gravel on surface. S2-C @ 5.0 41-5.5' 4 15.8% (sss) End of Boring 10.0 15.0 • SSS-2.0"O.D.Split Spoon Sample • The beginning and ending depths of the individual soil layers are approximate. Civil Englneering DISCOVERY DRIVE E Land Syng ➢ , T 591R INEER DIED En Ge technical LOG OF BORING(jALL eeringrxONE(40o)ssz-o2zl via Structural Engineering FAX(406)582-5770 PROJECT: Griffin Commercial JOB#: 16-156 DATE: 08/30/2016 BORING: BH#4 PAGE: 1 of 1 Development LOCATION: Refer to Site Map ELEVATION: Approx.4,739' TOTAL DEPTH: 5.5' DEPTH TO GW: None DRILL TYPE: Truck Mounted CASING/HAMMER/SAMPLER: 4" I.D.Hollow-Stem Auger w/140 lb Hammer CME 55 and 2.0" O.D.Split Spoon Sampler DRILLER: Steve-O'Keefe Drilling(Butte,MT) FIELD ENGINEEWR: Gary Fox,AESI(Bozeman,MT) w � z per. .. DESCRIPTION OF a U 3 EE" OTHER FIELD OR A w a MATERIALS Q 0 O Zp SAMPLE INFORMATION z � U S2-A @ {0' -0.25'} TOPSOIL o'-1.5' 13 5.5% Stiff,Light Brown to Brown; Sandy (sss) SILT with organics;Dry. S2-s @ 2'-3.5' 8 5.7% (sss) 10.25' -5.5'1: SILT/CLAY Stiff to Soft; Light Brown to Brown; Sandy SILT to Sandy Lean CLAY; 5.0 Dry. S2-C @ 4'-5.5' 4 10.9% (SSS) End of Boring 10.0 15.0 • SSS-2.0"O.D.Split Spoon Sample • The beginning and ending depths of the individual soil layers are approximate. APPENDIX 8 Laboratory Testing NO0 = 0 > r- Nf` N Q lO tl CO 00 00 d' Y N O O O r O r o N i i (n O 00 00 M o i M W r ' CO N 2 U) r r O O d7 J r 00 O CO Q LO Of m o M O� O) O LO cN m M 00 00 r` "t >+ N N rn � > ~ Lo LO O CO CO N LO r � O) M 00 U p OO N = C ( MLI) f` rZ "T � V Iq U) m � N N O X N U CM p O LL Ln Cn = r 0 M 00 O O r N O �- Lo M N N >+ m = N Y r I` I` O N i ND CD CO M N 0) o m r r CO CO = r 00 CO 6 N U) CO O co Cfl CO CDM N m O Mr-- f- r T �t O r r N �Srl IMP l St,0j)� p /O T. r 00 d O CO = N m M w O M f� 0 2' Q u, 'D = 7 - 00 M CO LO M � r •, f` LO O Lo N 00 r O r fl- LO r c`') N = L(1 r 00 CO 1 Z 0 U) m f` M � � (fl N U) m M m 0000 LO T _Wz a r r .�W a, Z w Ln Ln �r- M 07 c Ur N LO 0) f` r CO N \° CO CO LO r 00 a) CV = r w CO O O O M M LU N W u7 m M r- f� co U) CO M CD CD CD Oo 0) 00 d N O � c o E w r M CO N r r Loo LL N V' f- r CO LO O \° N i r p 00 LO LO (O I r Y CV I` CO 00 LO M m O ❑ c, � 00 dj � a0 m Y r 00 CO r LSj �vj ❑ N co 00 � V' r N M f- CO r M M QC Lo Ln U LC) CO O LO c w N 0') r N M \° Z i r m 0 N LO r- 00 M CD 00 M N r = i r 00 r 0') r N = U �- M O 00 L ® U) CO CD M O 0) M UD r U) m O co 00 00 00 N O O O r � Q o U r co ao ao CDO La ❑ Z U') O � Lo m Lo ° CV N (q O — LO N = r � CO Ufa G5 U) m O co 00 f- CO � 00 (n m L(M 00 f- cY I.f � Wm r EO N LO M U N 0) 00 00 0 m r _ (7 Lo co Cf N 00 0 i = L{� J r r f` Lo N J q CS Q U) m 0 M m 0000 M LO U) m 0 co, � ti -;T O� i N N L O Z m > M CO Q r Lo O) M M c1 m N O O O cl o WL O C r �- i r Z 00 � O) O o i d' Q r r N � r o r ❑ (B N N U) CO o Z 0 r- CEO N "t LO U) m �? O r N 00 M f- 00 Z r N M O) 00 LO CO O = � O L o L (D m M N U r >ci yO OE E cop O UU) cOc a .L O. . 0c Oc L U) �O - ir- OWQ U) _ 6 � .. >�L �Uv � � - � � ❑ c p -1 nc p o ❑ O y o QC d N C a) Z U + + ❑ U N C N Z U + + > ❑ V v J ,F+ i, Q m M m m m w c c c ` ca c O c c L o V a E c c FU c �� N Q E °1 c c (0 X (9 0 0 0 0 0 0 (0 X (0 0 0 0 0 ) 0 0 aainin a0 U) w U) wu) UU � � � N 00 O > � N f` S I` N I` o CY) O V >� N N N f— LO L U CO Cfl Nt N p ECO y U 0 0 LPL m m a� 3 LD ZS¢l ael�I SIiG)OW'. >M M Nm O OO O co co O C,, � LO L tu Lq O (D O M�iIN �W l mo � co oI- r-- Nr o N m c ' E d N CD LO M o N C � 00 V � O C _ t N CDL m 0 co r r N 'IT Q 0 U Z o _O N 0 �-' 2E Q Uc, C � cocoocno z i u 19 (N m c) m w r- o 0) L6 C M r r M r F m M L co co co N o co = c? w CO z N CO M W O D = M LO CO CO LO 0 (n m N co m co L r O � r O m Z O (D Q M Lo CO M CO r O o > c �_ � � � rncoroCO00 W 0 (0 O N COm CDO N E �Y uj Cl) N CDM co I- d r Z U = N O L O L (D CO a) O Ln U j � 0 E i 5 C ' ' — _ C ' ' ca _ N U L C� ¢ O C� U (0 n (� O Q� V cp (d J O Q) (n U _ c� c a� cn c o c E c N u) E = U U J Q � O (o ` O J Q � O m O ` U + + � oU �, o, ZU + + U r C7 : N �+ -0 O 0 - 4-- L - a o 0 i v- i - 4-- "-- d '^ Z — N N m — O O N N O O L — N o 0 N o o L �'f/^0� c_ C C w--� � N (0 N C C C .�. � u-a a � E E E Emc �- 000- o .00a ° o co � U nwcU UU � � 2 iL0. oQo s Na0V-- 0 `4 > — N I— �- I— N I-� N N �00 I �N INeFI 00 00 > ~ LO LO O O `y J J = U E N 2 'a � a o o LL m a 70 - m -� a J � rl a. > f t t We ..W? m CD Qw� 0 m rn c J Q O M d' `o ti � g a - - Q U E O v LO -3 a o o v IL J W M W QI � Q E O a Cl) N O O J O Cr Q /a\ �i p N C `J 0 N N J J. _ m m o U E e t o � — — O o E ti W c D oQ N (n m w U E c a a 0 Z ° ui E y m o 0 0 0 0 0 0 LLLU 4i �+ N cu m N (0 LOv co N r y y G L.) CO ~ y E = W w y xapul ApOl}seld Q a` a` cocoa0 � s a) ao o � > -r-- cvr— � r` Nti Q 0-) o V) r M L � COCO u' OU (D ( d E E N a) a) X N m CO a 2 o M NO O IL J y m �c a m ai (L ,SE,lru)suo,), z 0 ci O I �Wz a 0 �zW � W C O QWh --- --- — - -- __ - -- ._ _ o c J Q O O co r Q G � U 2 Z Lo O � 0 U a QN o Z J LU 0 U W � Q E o O O J U) N O� (O - ------ ---- ----- ---__.___. - - --- 0 0 O W U C O N J J a) N . _ (6 N m Ch i CO U) N N N LO E a) in -fl _ O v/ E CO O C Q W C m = o Q c/5U m E E m U m "= ad o W E n m 0 0 0 0 0 00 V V C V H d (O 'd' M N I— o o E = w °' n xapUI f4!311seld Q a` a` u) c000 � STANDARD PROCTOR COMPACTION TEST (ASTM D-698) Project: Griffin Commercial Development mo- Project Number: 16-156 �.r. -1 32 Discovery Drive Sample Identification: BH-1 @ 4.0'-6.5' Bozeman, MT 59718 Soil Classification: Brown Silt/Clay ALL.M Phone (406) 582-0221 Date Sampled: August 30, 2016 4 ENGIN' ING w Fax (406) 582-5770 Date Tested: September 1, 2016 aFrtvrcas rxc. Tested By: CCS averse vcol�c�y~ Summary of Lab Test Data Note: No Oversize Correction Applied Natural Moisture Content: 5.6 % Optimum Moisture Content: 13.2 % Maximum Dry Unit Weight: 109.4 pcf PROCTOR COMPACTION CURVE 130 125 --- . -- - -- 120 - --- y- CL 115 -- �— - — 110 -- — - -- - - i 105 - —*—Compaction Curve 100 _ -- --Z.A.V.for S.G.=2.50 — Z.A.V.for S.G.=2.65 �—Z.A.V.for S.G.=2.80 Poly.(Com action Curve) 95 90 8% 10% 12% 14% 16% 18% 20% 22% Moisture Content Reviewed By: Q-ql� R lVadsoil 0 CONSOLIDATION TEST REPORT 1.00 0.95 0.90 0.85 Water Added 0.80 0 a 0.75 —-- 0 0.70 0.65 0.60 0.55 0.50 100 1000 10000 Applied Pressure-psf Natural Dry Dens. Initial Void Saturation Moisture (pof) LL PI Sp. Gr. USCS AASHTO Ratio 57.2% 19.8% 86.3 2.65 0.917 MATERIAL DESCRIPTION Project No. Client: Allied Engineering Remarks: Project: Job#15-125 Source of Sample:Griffin Commercial Site Sample Number: 16-156(G16392) Pioneer Technical Services, Inc. 106 Pronghorn Trail, Suite A- Bozeman, MT 59718 Ph. 406-388-8578 - Fax 406-388-8579 Figure Tested By: NG APPENDIX C Percolation Test Results MONTANA DEPARTMENT OF ENVIRONMENTAL QUALITY PERCOLATION TEST FORM Owner Name Griffin Drive Properties LLC Project Name Griffin Commercial Development Lot or Tract Number Tract 14 Plat E-38 Test Number PT-1 Diameter of Test Hole 7.5" Depth of Test Hole 24" Start of Soak Period 08.30.2016 @ 10:30 am Ended 11:05 AM Date Test Began 08.30.2016 Test Results Start Time of End Time of Day Time Interval Initial Final Drop in Percolation Rate Day (minutes) Distance Distance water level (minutes/inch) below below (inches) reference reference point(inches) point 11:11:30 AM 11:26:23 AM 0:14:53 25 7/8 28 7/8 3 5.0 11:27:50 AM 11:42:52 AM 0:15:02 25 7/8 28 13/16 2 15/16 5.1 11:44:40 AM 11:59:40 AM 0:15:00 25 3/4 28 7/8 3 1/8 4.8 12:01:41 PM 12:16:25 PM 0:14:44 25 718 28 7/8 3 4.9 12:18:45 PM 12:33:36 PM 0:14:51 25 3/4 28 3/4 3 5.0 12:34:45 PM 12:49:50 PM 0:15:05 25 7/8 28 13/16 2 15/16 5.1 1 certify that this percolation test was done in accordance with DEQ-4, Appendix A. Craig Madson Cyalg R AIMS011 Name (printed) Signature 08.30.2016 Date Allied Engineering Services, Inc. Company APPENDIX D Limitations of Your Geotechnical Report Y 7 r ALLIED ENGINEERING SERVICES,INC. �S verse Pr LIMITATIONS OF YOUR GEOTECHNICAL REPORT GEOTECHNICAL REPORTS ARE PROJECT AND CLIENT SPECIFIC Geotechnical investigations, analyses, and recommendations are project and client specific. Each project and each client have individual criterion for risk, purpose, and cost of evaluation that are considered in the development of scope of geotechnical investigations,analyses and recommendations. For example, slight changes to building types or use may alter the applicability of a particular foundation type, as can a particular client's aversion or acceptance of risk. Also, additional risk is often created by scope-of- service limitations imposed by the client and a report prepared for a particular client (say a construction contractor)may not be applicable or adequate for another client(say an architect, owner, or developer for example), and vice-versa. No one should apply a geotechnical report for any purpose other than that originally contemplated without first conferring with the consulting geotechnical engineer. Geotechnical reports should be made available to contractors and professionals for information on factual data only and not as a warranty of subsurface conditions, such as those interpreted in the exploration logs and discussed in the report. GEOTECHNICAL CONDITIONS CAN CHANGE Geotechnical conditions may be affected as a result of natural processes or human activity. Geotechnical reports are based on conditions that existed at the time of subsurface exploration. Construction operations such as cuts, fills, or drains in the vicinity of the site and natural events such as floods, earthquakes, or groundwater fluctuations may affect subsurface conditions and, thus, the continuing adequacy of a geotechnical report. GEOTECHNICAL ENGINEERING IS NOT AN EXACT SCIENCE The site exploration and sampling process interprets subsurface conditions using drill action, soil sampling, resistance to excavation, and other subjective observations at discrete points on the surface and in the subsurface. The data is then interpreted by the engineer, who applies professional judgment to render an opinion about over-all subsurface conditions. Actual conditions in areas not sampled or observed may differ from those predicted in your report. Retaining your consultant to advise you during the design process, review plans and specifications, and then to observe subsurface construction operations can minimize the risks associated with the uncertainties associated with such interpretations. The conclusions described in your geotechnical report are preliminary because they must be based on the assumption that conditions revealed through selective exploration and sampling are indicative of actual conditions throughout a site. A more complete view of subsurface conditions is often revealed during earthwork;therefore,you should retain your consultant to observe earthwork to confirm conditions and/or to provide revised recommendations if necessary. Allied Engineering cannot assume responsibility or liability for the adequacy of the report's recommendations if another party is retained to observe construction. EXPLORATIONS LOGS SHOULD NOT BE SEPARATED FROM THE REPORT Final explorations logs developed by the consultant are based upon interpretation of field logs (assembled by site personnel), field test results, and laboratory and/or office evaluation of field samples and data. Only final exploration logs and data are customarily included in geotechnical reports. These final logs should not be redrawn for inclusion in Architectural or other design drawings, because drafters may commit errors or omissions in the transfer process. To reduce the likelihood of exploration log misinterpretation, contractors should be given ready access to the complete geotechnical report and should be advised of its limitations and purpose. While a contractor may gain important knowledge from a report prepared for another party, the contractor should discuss the report with Allied Engineering and perform the additional or alternative work believed necessary to obtain the data specifically appropriate for construction cost estimating purposes. OWNERSHIP OF RISK AND STANDARD OF CARE Because geotechnical engineering is much less exact than other design disciplines, there is more risk associated with geotechnical parameters than with most other design issues. Given the hidden and variable character of natural soils and geologic hazards, this risk is impossible to eliminate with any amount of study and exploration. Appropriate geotechnical exploration, analysis, and recommendations can identify and reduce these risks. However, assuming an appropriate geotechnical evaluation, the remaining risk of unknown soil conditions and other geo-hazards typically belongs to the owner of a project unless specifically transferred to another party such as a contractor, insurance company, or engineer. The geotechnical engineer's duty is to provide professional services in accordance with their stated scope and consistent with the standard ofpractice at the present time and in the subject geographic area. It is not to provide insurance against geo-hazards or unanticipated soil conditions. The conclusions and recommendations expressed in this report are opinions based our professional judgment and the project parameters as relayed by the client. The conclusions and recommendations assume that site conditions are not substantially different than those exposed by the explorations. If during construction, subsurface conditions different from those encountered in the explorations are observed or appear to be present, Allied Engineering should be advised at once such that we may review those conditions and reconsider our recommendations where necessary. RETENTION OF SOIL SAMPLES Allied Engineering will typically retain soil samples for one month after issuing the geotechnical report. If you would like to hold the samples for a longer period of time,you should make specific arrangements to have the samples held longer or arrange to take charge of the samples yourself. Allied Engineering Services,hic. page 2