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LD-RSUB16-0005-Storm Drainage Calcs for Reflection Ridge Phase 6
STORM DRAINA GE CALCULATIONS ` FOR :.0.,1 ti•1 Reflection Ridge Phase 6 T LOCATED IN MERIDIAN, IDAHO _ y r PREPARED BY: T=O ENGINEERS John G. Carpenter, P.E. - �yANAL jr r y 332 BROADMORE WAY, STE fOl NAMPA, /D 83687 STORM DRAINAGE SUMMARY Reflection Ridge Subdivision is generally located north of E Amity Road and West of S Locust Grove Road. This report is for phase 6 of the subdivision, an extension of phase 4 and 5. This portion of the site is currently undeveloped and mostly covered with native grasses. Small portions have been graded and disturbed as part of the existing development.. There is an existing irrigation lateral on the south — Farr Lateral. A large portion of this phase will drain to existing catch basins and disposal system in phase 5. Phase 5 has contemplated this flow and is included in the phase 5 storm drainage calculations and plans. A portion of the project drains to phase 4 of Reflection Ridge. See attached map depicting this drainage. Along with our drainage, there is a roughly 8 acre portion of ground (off-site) that appears to have historically drained through Reflection Ridge. While it has not noticeably drained in the last few years it has the potential. Currently the drainage is staying on the field and percolating to the subsurface. Because of the potential we have included this off-site in our calculations. Also noted is this ground has not been irrigated for a long time based upon old Aerials and my limited experience. I have watched the property for the last 3 years. There are old hand line irrigation pipes on the property that indicate to me that it was sprinkled with water from the Farr lateral at some point in the past. The property has a head gate out of the Farr Lateral. We have situated S. Timbercrest to align with flow from this said 8 acres. I attach aerials starting in 2004 which indicate no farming on the adjacent property. Seepage Bed No. 4 in Reflection Ridge No. 4 was designed for a portion of this phase 6 drainage. Seepage Bed No. 4 was designed for the 100 year storm event and did not include the historic flow. In reviewing the site, it appears that we can utilize the Run-off Reduction as there is an easy overflow route — see attached map. With this seepage bed No. 4 is still undersized and needs to be lengthened by 30' for the design storm. Peak flows to existing pipes are very similar to that which was originally contemplated. Existing seepage bed is adequate for additional flow as shown in the attached calculations. There is approximately 30 feet of elevation change across the entire property. The purposed grading plan uses steep slopes to create appealing view lots. All slopes will be constructed with a topsoil covering and planted with native grasses to help stabilize the slopes. All drainage will be directed away from the slopes. We have prepared the calculations and design so that all lot drainage is accounted for in the seepage beds. L;\150182\40_ Final DesignTeports\Storm Drainage Calcs\150182 STORM DRAINAGE REPORT PHASE 6,docx ACHD storm facilities will include the following drainage: 1. All drainage from right of way 2. Planter strip between sidewalk and curb 3. Sidewalks along the roadways 4. 440 sf for driveway for all lots 5. 3000 sf for houses 6. Full lot drainage No cross lot drainage is allowed as part of the CC&R's. A geotechnical report has been prepared specific for this site and is included in the appendix. The report showed no evidence of groundwater presence in the areas tested for seepage bed construction and bottom of beds appear to be in free draining material. The ACHD drainage system has been designed in accordance with policy. Calculations are based on ACHD spreadsheet and policy requirements. DESIGN CRITERIA • Rational method is used for calculating the peak runoff flows: Q = C * I * A • Runoff coefficients based on land use from the Ada County Highway District Development Policy Manual • Rainfall intensity of design storm based on NOAA Atlas 2 • Percolation rate = 8 in/hr based on Geotechnical Engineering Report. List of Materials: 1. Contributing Areas Sheet 2. Peak Flow Sheet 3. Seepage Bed No. 4 a. ACHD Volume Calculation b. ACHD Sand and Grease Calculation c. ACHD time of concentration Calculations 4. Aerial mapping 5. Master Utility Plan 6. Drainage basin map 7, Soils Report L:\150182\40_Final Design\ReponAStorm Drainage Calcs\150182 STORM DRAINAGE REPORT PHASE 6.docx 2 O J 1� N 10 --1 Y IV, n p w U c m -j n W, ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is Intended to be a guideline to standardize ACRO checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations In order to be accepted. e . ... Calculate Post Development Flows (for pre development flows, increase number of storage facilities to create new tab) -- User input in yellow cells. 3 Project Name Reflection Ridge afi 2 Is area drainage basin map provided? YES (map must be induded with stermwater rnkuktions/ 3 Enter Design Storm 1100 -Year or 25 -Year With loo -Year Flood Route) 100 4 Enter number of storage facilities (25 max) 1 1 subbasin2 3 4 5 in 5 Area of Oraage Subbasln(SF or Acres) Acres 716 2.91 Acres 30.67 60etermine the Weighted Runoff Coefficient (C) 0.15 0.56 C=[[Cix%l)+(C2x )a[CnxAn))/A Weighted Avg 0.26 7 Calculate Overland Flow Time of Concentration In Minutes (Tc) or use default 10 loser Celmlin min low Pipe Size ID [In) Slope(ff/ft) Intercept Cliff. length Manningn Hydraulic Radius A/Wet Perm Flow VelocltyV f s Flow Time (min) Segment 1: Pipe Flow a 9,655 9,655 ft V = CI (Tc -60)W600 MA-fix-oly also 075 if 11 Calculate Volume of Runoff Redvctmr, Vrr Apartment dwelling are. 070 Segment 2: Gutter Shallow Concentrated Flow b 0.032 0.619 718 Ll,htarex 95th 3.6 1 3.3 V„ E. 6,039 ff' 12 Detention: Approved Discharge Rah to Surface Waters (If applicable) Railroadyard xos Segent 3: Overland Sheet Flowg TR -55,x300 -ft C 0.030 300 0.150 9.2 32.8 13 Volume Summary Computed Tc = 36.1 User -Entered Tc= 60.0 8 Determine the avenge rainfall intensity (1) from IDF Curve based on 1 0.96 0.96In/ffr 9 Calculate the Post -Development peak discharge (QPeak) Q. 2.641 2,68 cis 30 Calculate total runoff vol W) (for siting primary storage) V 9,655 9,655 ft V = CI (Tc -60)W600 MA-fix-oly also 075 Reudenthl(rural] 11 Calculate Volume of Runoff Redvctmr, Vrr Apartment dwelling are. 070 Indu4nel and Corgrerclel Enter Percentile Storm I(95th percentiles0.60 in) Ll,htarex 95th 0.60 in Enter Runoff Reduction Vol (95th Pementle4.60-In a Area) V„ E. 6,039 ff' 12 Detention: Approved Discharge Rah to Surface Waters (If applicable) Railroadyard xos 020 OAO Ch 13 Volume Summary streets Asphalt Surface Storage: Pond Genas!. 095 en'k WQ Pond Forebay V 6,034 ft' Primary Treatment/Storage Basin V 3,621 ft' Subsurface Storage 0 Flat 02% 004 Volume With 15% Sediment Factor V 11,103 ft, 0.09 // 76 •yes 4-6ale5i Subbasin I Subleasin Subbluin I guilts flat treated Runoff Coefficients for Vmwus surtaxes type of Surixe Runoff CoeRkienU'C' g.nness Devmtervn areas 0.70-0.95 neighborhood areas 0.50 0.70 -urban Pesldenxal %rF.-atony 035 0.50 MA-fix-oly also 075 Reudenthl(rural] 0.25-0.40 Apartment dwelling are. 070 Indu4nel and Corgrerclel Ll,htarex 080 He. ere. 090 Parks. ce"Wrles 0.20-025 Playaraunds 030.0.35 Railroadyard xos 020 OAO Unlmpmved areas 0.10-0.30 streets Asphalt 0.95 Genas!. 095 en'k 0.85 Main, 095 Fields: Send, soli Soo Type Slope A a C 0 Flat 02% 004 O.o7 0.11 0.15 Average T -fief 0.09 0.12 ,a5 020 Shap>6% 0.f3 0.1g 033 028 Adapted from ASCE L:\150182\40_Final Design\Reports\Phase6ACHD0edsizing 2-4-2016,633 PM Version 8.4, December 2015 With New IDF Curves ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet Is Intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineers methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak QV" tab User input in yellow cells. 1 Project Name Reflection Ridge #6 2 Enter number of Seepage Beds 125 max) 1 3 Design Storm 25 4 Weighted Runoff Coefficient C 0.26 Unkto:Of v� 5 Area A(Acres) 10.67 acres QV TR55 6 Approved discharge rate (if applicable) 0.00 cfs 7 Design Vol W115% Sediment V 7,980 kr 8 Set Total Design Width of All Drain Rock W 20.0 it 9 Set Total Design Depth of All Drain Rock D 8.5 it Rock Only, Do Not Include Filter Sand Depth or Cover 119 10 Vold Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2" drain rock and 3/4" Chips 11 Design Infiltration Rate is in/hr max) Parc 8.0 m/hr 12 Size of WQ Pert Pipe( Perf 1800) Dia pipe 18 In 13 Size of Overflow Perf Pipe (Paris 360% REQD if 0100>3.3 efs 121n 14 Calculate Total Storage per Foot Spf 68.3 68.3 ft`/ft Spf=Apf=W%D-A,,r L,v,xVolds-1/2 Pert Area 15 Calculate Design Length Override Value Requiredfor Chambers 16 Variable Infiltration Window L 17 Variable Infiltration Window W 18 Time to Drain 90% volume in 48 -hours minimum 19 Length of WQ & Overflow Perf Pipes 20 Perf Pipe Checks, Qperf>= Qpeak; where QPerf=CdxAvJ)2xgx H) are organized in a 1 Type of Chambers 2 Volume to Store L 117 119 k SWL 117 ft SWW 20.0 ft 4.6 hours 119 h 3 Installed Chamber Width Installed Chamber Depth Installed Chamber Height 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 6 Chamber Storage Volume, With Rock, Per Manuf 7 Total Number of Units Required 8 Area of Infiltration 9 Volume Infiltration 10 Time to Drain 90% Volume in 48 -hours minimum 1-StormTech, SC740 V 0 fts Cw 4.25 ft Cd 2.50 ft Ch 7.12 ft 45.90 fts/Unit 74.90 ft,/Unit D ea Aperc it, Vperc 0 ft'/hr hours L:\150182\40 Final Design\Reports\Phase6ACHDBedsizing 2-4-2016, 6:33 PM Version 8.4, December 2015 With New IDF Curves ACHD Calculation Sheet for Sand/Grease Traps NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. User input in yellow cells. 1 Project Name Reflection Ridge p6 enter numoer or �a eference for Throat widths (inch) Number of Peak Flow Baffle Throat Boise Velocity Is the Vault Size Traps Lar -ken Spacing width Area (ft) 0.5 fps I Velocity S/G Q-cfs inch (inch) 48.0 max. ok? 1000 G 1 2.03 20 48 6.67 0.30 60 eference for Throat widths (inch) L:\150182\40_Final Design\Reports\Phase6ACHDBedsizing 2-4-2016, 6:54 PM Version 8.4, December 2015 With New IDF Curves ADS Boise Lar -ken WOU, Vault BMP 16 000 G 48.0 50.5 n/a 500 G 60.0 61.5 n/a VQU1000 n/a n/a 60 VQU1500 n/a n/a 60 L:\150182\40_Final Design\Reports\Phase6ACHDBedsizing 2-4-2016, 6:54 PM Version 8.4, December 2015 With New IDF Curves Catch Basin 5A ID Pipe Size (in) Slope (ft/ft) Intercept Coeff. Length Manning n Hydraulic Radius A/Wet Perm Flow VelocityV (fps) Flow Time (min) Segment 1: Pipe Flow a 0.01 0 0.130 0.00 0.0 0.130 0.25 0.5 0.0 Segment 2: Gutter Shallow Concentrated Flow b Segment 2: Gutter Shallow Concentrated Flow 0.030 0.619 718 422 4.3 1.6 3.5 3.4 Segment 3: Overland Sheet Flow By TR -55, < 300 -ft c 0.010 110 0.150 4.8 22.8 Segment 3: Overland Sheet Flow By TR -55, < 300 -ft c 0.030 � 300 0.150 9.2 32.8 Q, Computed Tc = 36.2 7-z/ User -Entered Tc = 60.0 Catch Basin 5B ID Pipe Size (in) Slope (ft/ft) Intercept Coeff. Length Manning n Hydraulic Radius A/Wet Perm Flow VelocityV (fps) Flow Time (min) Segment 1: Pipe Flow a 12 0.01 0 0.130 0.25 0.5 0.0 Segment 2: Gutter Shallow Concentrated Flow b 0.045 0.619 422 4.3 1.6 Segment 3: Overland Sheet Flow By TR -55, < 300 -ft c 0.010 110 0.150 4.8 22.8 Computed Tc = 24.4 User -Entered Tc = 30.0 PTT,71' V* t r R 41 1 I reflection ridge 4 " w Ask, .14 LAV'644 ' ." 11 344 fY IL ALIla `s< st."�• yr. ar ' } ��i V �, i � ti•Nar ,..H y S ♦ y2 p�lw� ^y nn x 9 r, MATERIALS TESTING & INSPECTION 19 January 2016 Page # 1 of 2 b 160096gletter U Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing i7 Special Inspections Mr. Matt Schultz Schultz Development, LLC PO Box 1115 Meridian, ID 83680 208-880-1695 Re: Infiltration Rates Letter Reflection Ridge Phases 5 and 6 Infiltration Testing Rumple Lane Meridian, ID Dear Mr. Schultz: In compliance with your instructions, MTI has prepared this letter to address the need for infiltration testing for the above referenced development as required by the Ada County Highway District (ACHD). Per Section 8009.2.3 of the ACHD Policy Manual, "The number of required explorations may be reduced, with ACHD approval; at infiltration sites where satisfactory data from adjacent areas is available that demonstrates a hydraulic conductivity greater than 8 inches per hour." This letter presents data to support that the site will exhibit hydraulic conductivity values greater than 8 inches per hour. Phases 5 and 6 of the Reflection Ridge Subdivision are located in the Gravel of Amity Terrace. The Amity Terrace is the fifth terrace above the modern Boise River and represents the first level of Quaternary incision by the Boise River. The terrace, which has been correlated with Deer Flat terrace deposits to the west, is modified extensively by erosion and faulting. Where little erosion has taken place the terrace is mantled with loess 1.6-7 feet thick. This is further evidenced by the test pits advanced within this portion of the development in 2014, which indicate free draining gravels were encountered at depths varying between 2.8 to 5.3 feet. During previous investigations performed near the site and on the Amity Terrace gravels were encountered at depths of 10 feet or shallower and were deemed free draining. In addition, the site directly southwest of this development was previously used as a gravel pit. Furthermore, water added to the gravel sediments in one of the test pits advanced onsite readily infiltrated. Poorly graded gravel and sand sediments are considered free draining with infiltration rates much greater than 8 inches per hour. A table of Typical Values of Hydraulic Conductivity of Saturated Soils presented by Braja M. Das in Principles of Geotechnical Engineering, Fifth Edition, indicates that gravels have a saturated hydraulic conductivity between 2.0 and 200 feet per minute (14 and 1440 inches per hour). Therefore, based on the presence of poorly graded gravels onsite, the previous demonstration that these gravels readily infiltrate water, and the published data that gravels have hydraulic conductivity values greater than 8 inches per hour, MTI recommends that infiltration testing as required by the ACHD Policy Manual be waived. However, confirmation that free -draining gravels are present in the bottom of the infiltration facilities during the time of construction is recommended. 2791 S Victory View Way • Boise, ID 83709 - (208) 376-4748 -Fax (208) 322-6515 www.mti-id.com • mtiOnili-Id corn ".' ; C MATERIALS TESTI NG £r INSPECTION 19 January 2016 Page # 2 of 2 61600968_ letter ❑ Environmental Services ❑ Geotechnical Engineering Q Construction Materials Testing ❑ Special Inspections MTI appreciates this opportunity to be of service to you and looks forward to working with you in the future. If you have questions, please call (208) 376-4748. Respectfully Submitted, Materials Testing & Inspection, Inc. 14898 El zabeth Brown P. 11y-16 Geotechnical Eng lqT P� !w FOF10/ Reviewed by: Attachment: 2014 Geotechnical Engineering Report General Manager 2791 S Victory View Way • Boise, to 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(mmti-id.com MATERIALS TESTING & INSPECTION 7 Environmental Services i c , )technical Engineering J Construction Materials Testing U Special Inspections GEOTECHNICAL ENGINEERING REPORT of Reflection Ridge Subdivision Phases 3-5 Wrightwood Drive Meridian, ID Prepared for: Mission Coast Properties ID, Inc. 13402-13A Avenue Surrey, BC V4AIC3 MTI File Number B140414g 2791 South Victory View Way Boise, ID 83709 - (208) 376-4748 • Fax (208) 322-6515 mti@mtI-id.com • www.mti-Id.com MATERIALS kdTESTING & INSPECTION 6 May 2014 Page # 1 of 36 b140414g-9cotech ❑ Environmental Services i !:geotechnical En ineering U Construction Materials Testin t7 Special Inspections Lorne Duthie Mission Coast Properties ID, Inc. 13402-13A Avenue Surrey, BC V4AIC3 (604) 535-1714 Re: Geotechnical Engineering Report Reflection Ridge Subdivision Phases 3-5 Wrightwood Drive Meridian, ID Dear Duthie: In compliance with your instructions, M'fI has conducted a soils exploration and foundation evaluation for the above referenced development. Fieldwork for this investigation was conducted on 23 April 2014. Data have been analyzed to evaluate pertinent geotechnical conditions. Results of this investigation, together with our recommendations, are to be found in the following report. We have provided a PDF copy for your review and distribution. Often questions arise concerning soil conditions because of design and construction details that occur on a project. Nfrl would be pleased to continue our role as geotechnical engineers during project implementation. Additionally, MTI can provide materials testing and special inspection services during construction of this project. If you will advise us of the appropriate time to discuss these engineering services, we will meet with you at your convenience. MTI appreciates this opportunity to he of service to you and looks forward to working with you in the future. If you have questions, please call (208) 376-4748. Respectfully Submitted, Materials Testing & Inspection, Inc. QUp4w4`c�^+ED Eli beth I3wt P p Reviewed by; David O. Cr , P.L. 4898 General Man ger Geotechnical Engin er s -to • iq C1 cc: John Carpenter and Brendon Daniels, TO Engineers (PDF copies); Matt Schultz, Schultz Development (PDF copy) Copyright (OD 2014 Malcrinls Tcatiog & lnspccdnn, Inc 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS �TESTING & . INSPECTION 6May 2014 Page# 2 of 36 Geotechnical Engineering 0 Cons1ructionMmtehalTesting Special Inspections TABLE � ��BLE��F CONTENTS \orxoovcT[ON -'-.,...................... ---- .............. ^.~..~~.... .,.~^..... 1~-~~. ... ................. ~~~,'» project Description ... --- .... --- ...... --- ------ ....... _.......... -... s Authorization......... ..... ...... ..... .... ,--- ------------------ -------------------- .............................. ...... ...... ........... Purpose......... ....... ...... ....... ............ .......... .__,,__^-^~`~--`~~^^.3 ScopevfInvestigation ------ _................ ........ ...................... ...... ................... ........... ........ '^........ -... 3 Warranty and Limiting CondNous....................... .......... ,~........................ .-........... -......... -.... SITEDESCRIPTION .... ........ .......... ............ ..... ---- ................................... .......... .............. "^,~,_'........... 5 SheAccess ................... ............ ... .......... .... ........ ......... ....... ........ ......... .... _......... .... ..... ... ~^,... ,5 RegionalGeology ..... ................. ... ....... ........ ^.~~............................ ....... -.......................... ^... ,~^5 General Site Characteristics ,'' --__—'_'._'-............. ................... .,................................. �5 Regional Site Climatology and Geochemistry ... ... ............ .... ........ ....... ................................ ......... ..... .-.» 8cvs»<onioSetting ........................ ..... ,,...... ..... -....... ........ ....... ..................... ........... ,....-.a SOILS 8zpu/xxrmw.............................. ........... ......... ............ ~--.^'.,~- ... ^'^^.'o Exploration and Sampling Procedures .... ........ .... -'.......... .._-'-.^.......... Laboratory Testing Program ............... ............ ............. .... ..... ........ .... ,...--.................... ........... / Soiland Sediment Profile ... .... .................... ......... ---'.................... ^. ........................ ................ .J VolatileOrganic Scan ..... ....... ............ ......................... ......... ................. ......... -.7 SHnRroxoLoV,................... .... .... -.......... ........................... ........ 7 Groundwater... ........... ........ ............. '..... -........ ..... ...... .............. -... -- .... ...... ......... -...0 Soil Infiltration Rates ............... ........... ........ ...... ......... ..... .�-��-,.& SLOPES AND SETBACKS ... ... ...... .............. ........ ..... ... .`.`.............. ......... ............. -_.—�'.-' LATERAL SxuTnPRESSURES ... ... ----- ... ........ -...... --- ..... --- ....... ........ ,.'. -........ ... ...... .-.... ..^� RetainingWall BuokfiVMaterials .-................ .............. ....................... .... ''. ... ........ ... ..... --- ---- ... 0 Retaining Wall Drainage ......... -........ ...... .,'...... ------...... ......... ...... -..... ....... `... ... ..-.|| ROCKERY RETAINING WALL -_----- ...... ... -- ..... ''.'.'.�,..l) KodmryWall Foundation Recommendations --.-... .-. ------- '-..|| Rockery Wall Construction Recommendations.---'--'. - ' -- ' -------Jl Rockery Wall Drainage Recommendations ..................................... ......... ...... .............................. ........ ....... ]1 FOUNDATION, SLAB, xwuP^vomemrDISCUSSION AND kEcuwmc°uxzmw`......... ........ ........ ............... u Foundation Design Recommendations ........ -....... ................. ..-.......... ..... .......... |} Crawl Space Recommendations ................... ... . . . . ,- ............ ........... ............ .... w Phor, Patio, and Garage Slab -on Grade ..... .-... ................................ Recommended Pavement Sections ---............ ... ..................... ..... ... .,-............................. -.... l5 Flexible Pavement Sections .......... ..... - ---_-..... ... .... --..... '.... ... .'.............. ........................ 5 Common Pavement Section Construction Issues ... '........ ............ -....... ....... ... . ..'-.,............ ...... J6 CowxrnucrmwCONSIDERATIONS .............. ...... ..... ... ..... ........................... -.--- -- ............ �|7 Earthwork..... ... .............. ......................... .......... ... ...... ........ .... ............... ... '...... ................ 7 DryWeather. .�............ ..... ............. .... --.... .............. -........ .... .... ... —........... —,.......... WetWeuUcr..,......... .............. ........................... -...... -.... ... -.... ..... ... ........ ,......... .... ..... \8 Sob Subgrade Soils -.' ....... ... .......... ,.... ..... ........ ..... ............... ....... ........ , ...... .,,.-...... .J0 Frozen Suh[yo6eSoils ... .......... ...... .................................................. .--........... �...�l8 Structural Fill ................. .-^--,-'..--..--.-.........J� BackfillvfWalls ............................ ........ ............................. ............................................................. ............... «/ Dxouvmk,ns-................ ......... ..... ............... ........... .................... �-20 Groundwater Comm|. ........ -'-.................. .......... ...... -............... --- —_^^^^-/v GENERALCOMMENTS .............................. ........ ........................ .... .................................. I ......................... .... ... .2| REFERENCES..................................... ......................... ........ ....................... ............... ........................... ............. 'zz A,Pm"oosS.......,...--- -_-_—.'^.~_......---........ ~......,._,—_--23 AcronymList ..... ..... .................. -............................................... .-........ ,.,",-.,. ..... '..... ........ ......... 3 6cotcknic*|General Notes .... ............................... ........................... ... ...... .... 24 Geotechnical Investigation Test Pit Log- ...... ------ ...... .... -....... ........ ...... ....... .... .... ................ ---2J Gravel Equivalent Method - Pavement ThickneoDesign Procedures ........................... --~-...... ............ J] K'Valo°Laboratory Test Data ... ........... ........................................ ............. -....... ......... -....... ---- .. 34 PlatetVicinity Map ............. ............. ..... .... ....... ........ ........... ....... ..... .,...,...-. .J5 Plate1:Site Map ...................... ... ....... .... ................ '..... -...... -....................... ...... ....... ......... .,,-J6 Copyright @ 2014 Matcrials I esting & Inspection, Inc. 2791South Victory View Way ^ Boise, 0087V9^(2VQ37;'4748"Fax (200322-6515 MATERIALS TESTING & INSPECTION 6 May 2014 Page # 3 of 36 b140414g_geotech ❑ Environmental Services J Geotechnical Engineering 0 Construction Materials Testing ❑ Special Inspections INTRODUCTION This report presents results of a geotechnical investigation and analysis in support of data utilized in design of structures as defined in the 2012 International Building Code (IBC). Information in support of groundwater and storm water issues pertinent to the practice of Civil Engineering is included. Observations and recommendations relevant to the earthwork phase of the project are also presented. Revisions in plans or drawings for the proposed development from those enumerated in this report should be brought to the attention of the soils engineer to determine whether changes in foundation recommendations are required. Deviations from noted subsurface conditions, if encountered during construction, should also be brought to the attention of the soils engineer. Project Description The proposed development is in the southern portion of the City of Meridian, Ada County, ID, and occupies the central portion of Section 30, Township 3 North, Range 1 East, Boise Meridian. This project will consist of construction of 182 residential lots to be developed on approximately 62 acres. Total settlements are limited to 1 inch. Loads of up to 4,000 pounds per lineal foot for wall footings, and column loads of up to 50,000 pounds were assumed for settlement calculations. Additionally, assumptions have been made for traffic loading of pavements. Retaining walls in the form of boulder walls are anticipated as part of the project. MTI has not been informed of the proposed grading plan. Authorization Authorization to perform this exploration and analysis was given in the form of a written authorization to proceed from Lome Duthie of Mission Coast Properties ID, Inc. to Elizabeth Brown of Materials Testing and Inspection, Inc. (MTI), on 14 April 2014. Said authorization is subject to terms, conditions, and limitations described in the Professional Services Contract entered into between Mission Coast Properties ID, Inc. and MTI. Our scope of services for the proposed development has been provided in our proposal dated 3 April 2014 and repeated below. Purpose The purpose of this Geotechnical Engineering Report is to determine various soil profile components and their engineering characteristics for use by either design engineers or architects in: • Preparing or verifying suitability of foundation design and placement • Preparing site drainage designs • Indicating issues pertaining to earthwork construction • Preparing residential pavement section design requirements Scope of Investigation The scope of this investigation included review of geologic literature and existing available geotechnical studies of the area, visual site reconnaissance of the immediate site, subsurface exploration of the site, field and laboratory testing of materials collected, and engineering analysis and evaluation of foundation materials. The scope of work did not include design recommendations specific to individual residences. Cpyright ® 2014 Materials Testing & Inspection, Inc 2791 South Victory View Way • Boise, ID 63709 • (208) 376-4748 • Fax (_208) 322-6515 mtlCetmti-id.com • www mtkd.rcm MATERIALS TESTING & INSPECTION 6 May 2014 Page 9 4 of 36 h140414g_gwlech J Environmental Services J Geotechnical Enguleenny ❑ Construction Materials Testing ❑ Special Inspections Warranty and Limiting Conditions MTI warrants that findings and conclusions contained herein have been formulated in accordance with generally accepted professional engineering practice in the fields of foundation engineering, soil mechanics, and engineering geology only for the site and project described in this report. These engineering methods have been developed to provide the client with information regarding apparent or potential engineering conditions relating to the site within the scope cited above and are necessarily limited to conditions observed at the time of the site visit and research. Field observations and research reported herein are considered sufficient in detail and scope to form a reasonable basis for the purposes cited above. Exclusive Use This report was prepared for exclusive use of the property owner(s), at the time of the report, and their retained design consultants ("Client'). Conclusions and recommendations presented in this report are based on the agreed-upon scope of work outlined in this report together with the Contract for Professional Services between the Client and Materials Testing and Inspection, Inc. ("Consultant'). Use or misuse of this report, or reliance upon findings hereof, by parties other than the Client is at their own risk. Neither Client nor Consultant make representation of warranty to such other parties as to accuracy or completeness of this report or suitability of its use by such other parties for purposes whatsoever, known or unknown, to Client or Consultant. Neither Client nor Consultant shall have liability to indemnify or hold harmless third parties for losses incurred by actual or purported use or misuse of this report. No other warranties are implied or expressed. Report Recommendation are Limited and Subject to Misinterpretation There is a distinct possibility that conditions may exist that could not be identified within the scope of the investigation or that were not apparent during our site investigation. Findings of this report are limited to data collected from noted explorations advanced and do not account for unidentified fill zones, unsuitable soil types or conditions, and variability in soil moisture and groundwater conditions. To avoid possible misinterpretations of findings, conclusions, and implications of this report, MTI should be retained to explain [he report contents to other design professionals as well as construction professionals. Since actual subsurface conditions on the site can only be verified by earthwork, note that construction recommendations are based on general assumptions from selective observations and selective field exploratory sampling. Upon commencement of construction, such conditions may be identified that required corrective actions, and these required corrective actions may impact the project budget. Therefore, construction recommendations in this report should be considered preliminary, and MTI should be retained to observe actual subsurface conditions during earthwork construction activities to provide additional construction recommendations as needed. Since geotechnical reports are subject to misinterpretation, do not separate the soil logs from the report. Rather, provide a copy, or authorize for their use, of the complete report to other design professional or contractors. This report is also limited to information available at the time it was prepared. In the event additional information is provided to MTI following publication of our report, it will be forwarded to the client for evaluation in the form received. Copyright @)2014 Materials Testing$ Inspect ion.. Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 - Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 5 of 36 b14G4I4g_gcoIeeh Environmental Services ❑ Geotechnical Engineering l7 Construction Materials Testing Q Special Inspections Environmental Concerns Comments in this report concerning either onsite conditions or observations, including soil appearances and odors, are provided as general information. These comments are not intended to describe, quantify, or evaluate environmental concerns or situations. Since personnel, skills, procedures, standards, and equipment differ, a geotechnical investigation report is not intended to substitute for a geoenvironmental investigation or a Phase II/III Environmental Site Assessment. If environmental services are needed, MTI can provide, via a separate contract, those personnel who are trained to investigate and delineate soil and water contamination. SITE DESCRIPTION Site Access Access to the site may be gained via Interstate 84 to the Meridian Road exit. Proceed south on Meridian Road approximately 1.2 miles to its intersection with Victory Road. From this intersection, proceed east 1.0 mile to Locust Grove Road. Proceed south on Locust Grove Road approximately 0.75 mile to Wrightwood Drive. Follow Wrightwood Drive west approximately 0.3 mile where it dead ends. The site is located in the empty field to the west and north of where the road dead ends. The location is depicted on site map plates included in the Appendix. Regional Geology The project site is located within the western Snake River Plain of southwestern Idaho and eastern Oregon. The plain is a northwest trending rift basin, about 45 miles wide and 200 miles long, that developed about 14 million years ago (Ma) and has since been occupied sporadically by large inland lakes. Geologic materials found within and along the plain's margins reflect volcanic and fluvialllacustrine sedimentary processes that have led to an accumulation of approximately 1 to 2 km of interbedded volcanic and sedimentary deposits within the plain. Along the margins of the plain, streams that drained the highlands to the north and south provided coarse to fine-grained sediments eroded from granitic and volcanic rocks, respectively. About 2 million years ago the last of the lakes was drained and since that time fluvial erosion and deposition has dominated the evolution of the landscape. The project site is underlain by "Gravel of Amity Terrace" as mapped by Othberg and Stanford (1993). The Amity terrace is the fifth terrace above the modern Boise River and represents the first level of Quaternary incision by the Boise River. The terrace, which has been correlated with Deer Flat terrace deposits to the west, is modified extensively by erosion and faulting. Where little erosion has taken place the terrace is mantled with loess 1.6-7 feet thick. General Site Characteristics This proposed development consists of approximately 62 acres of gently sloping to moderately steep land. Throughout the majority of the site, surficial soils consist of fine-grained clay -silt mixtures or granular materials. Vegetation primarily consists of bunchgrass and other native grass varieties typical of and to semi- arid environments. Copyright © 2014 Materials Testing & Inspection. Inc 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS EWi TESTING & INSPECTION 6 May 2014 Page # 6 of 36 b 140414g_geoTcch ❑ Environmental Services U Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections Regional drainage is north and west toward the Boise River. Storm water drainage for the site is achieved by both sheet runoff and percolation through surficial soils. Runoff predominates for the steeper slopes while percolation prevails across the gently sloping and near level areas. The site is situated so that it is unlikely that it will receive any storm water drainage from off-site sources. Storm water drainage collection and retention systems are not in place on the project site, but are planned as part of the development. Regional Site Climatology and Geochemistry According to the Western Regional Climate Center, the average precipitation for Treasure Valley is on the order of 10 to 12 inches per year, with an annual snowfall of approximately 20 inches and a range from 3 to 49 inches. The monthly mean daily temperatures range from 21° F to 95° F with daily extremes ranging from -25° F to 111° F. Winds are generally from the northwest or southeast with an annual average wind speed of approximately 9 miles per hour (mph) with a maximum of 62 mph. Soils and sediments in the area are primarily derived from siliceous materials and exhibit low electro -chemical potential for corrosion of metals or concretes. Local aggregates are generally appropriate for Portland cement and lime cement mixtures. Surface waters, groundwaters, and soils in the region typically have pH levels ranging from 7.2 to 8.2. Geoseismic Setting Soils on site are classed as Site Class D in accordance with Chapter 20 of the American Society of Civil Engineers (ASCE) publication ASCE/SEI 7-10. Structures constructed on this site should be designed per IBC requirements for such a seismic classification. Our investigation did not reveal hazards resulting from potential earthquake motions including: slope instability, liquefaction, and surface rupture caused by faulting or lateral spreading. Incidence and anticipated acceleration of seismic activity in the area is low. SOILS EXPLORATION Exploration and Sampling Procedures Field exploration conducted to determine engineering characteristics of subsurface materials included a reconnaissance of the project site and investigation by test pit. Test pit sites were located in the field by means of visual approximation from on-site features or known locations and are presumed to be accurate to within a few feet. Upon completion of investigation, each test pit was backfilled with loose excavated materials. Re -excavation and compaction of these test pit areas are required prior to construction of overlying structures. In addition, samples were obtained from representative soil strata encountered. Samples obtained have been visually classified in the field by professional staff, identified according to test pit number and depth, placed in scaled containers, and transported to our laboratory for additional testing. Subsurface materials have been described in detail on logs provided in the Appendix. Results of field and laboratory tests are also presented OD these logs. MTI recommends that these logs not be used to estimate fill material quantities. Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com (0 MATERIALS TESTING & INSPECTION 6 May 2014 Page # 7 of 36 b 1404148_geoteclt ❑ Environrnental Services J Geotechnical Engineering O Construction Materials Testing J Special Inspections Laboratory Testing Program Along with our field investigation, a supplemental laboratory testing program was conducted to determine additional pertinent engineering characteristics of subsurface materials necessary in an analysis of the anticipated behavior of the proposed structures. Laboratory tests were conducted in accordance with current applicable American Society for Testing and Materials (ASTM) specifications, and results of these tests are to be found on the accompanying logs located in the Appendix. The laboratory testing program for this report included: Atterberg Limits Tests - ASTM D4318, Grain Size Analysis - ASTM C117/C136, and Resistance Value (R -Value) and Expansion Pressure of Compacted Soils — Idaho T-8. Soil and Sediment Profile The profile below represents a generalized interpretation for the project site. Note that on site soils strata, encountered between test pit locations, may vary from the individual soil profiles presented in the logs, which can be found in the Appendix. The materials encountered during exploration were quite typical for the geologic area mapped as Gravel of Amity Terrace. In general, fine grained lean clay, sandy silt, sandy elastic silt, sandy silt fill, and silty sand soils were encountered at the ground surface and in the upper portions of the soil profile. In some exploration sites poorly graded gravel fill, silty gravel, and poorly graded sand sediments were observed. The fine grained soils were brown to light brown, dry to slightly moist, and medium stiff to stiff. The granular sediments were light brown, dry to slightly moist, and medium dense. At depth, poorly graded gravel sediments were encountered except for in test pit 1. These gravels were light brown, dry to slightly moist, and medium dense to dense with fine to coarse grained sand, fine to coarse gravel, and cobbles up to 10 inches in diameter. Competency of test pit walls varied little across the site. In general, fine grained soils remained stable while more granular sediments readily sloughed. However, moisture contents will also affect wall competency with saturated soils having a tendency to readily slough when under load and unsupported. Volatile Organic Scan No environmental concerns were identified prior to commencement of the investigation. Therefore, soils obtained during on-site activities were not assessed for volatile organic compounds by portable photoionization detecto. Samples obtained during our exploration activities exhibited no odors or discoloration typically associated with this type contamination. No groundwater was encountered. SITE HYDROLOGY Existing surface drainage conditions are defined in the General Site Characteristics section. Information provided in this section is limited to observations made at the time of the investigation. Either regional or local ordinances may require information beyond the scope of this report. Copyright @2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS TESTING £r INSPECTION 6 May 2014 Page # 8 of 36 b140414g_geotech ❑ Environmental Services ❑ Geotechnical Engineering J Construction Materials Testing ❑ Special Inspections Groundwater During this field investigation, groundwater was not encountered in test pits advanced to a maximum depth of 17.0 feet bgs. Soil moistures in the test pits were generally dry to slightly moist. In the vicinity of the project site, groundwater levels are controlled in large part by residential irrigation activity and leakage from nearby canals. Maximum groundwater elevations likely occur during the later portion of the irrigation season. During previous investigations performed in June 2005 and June 2013 within the Reflection Ridge Subdivision groundwater was noted within test pits advanced in the lower elevation portions of the site at depths varying between 9.0 and 9.4 feet bgs. However, the test pit excavated in the lowest elevation portion of the site for Phases 3-5 did not encounter groundwater to a depth of 17.0 feet bgs. For construction purposes, groundwater depth can be assumed to remain greater than 15 feet bgs throughout the year, However, in areas adjacent to the Ridenbaugh Canal water seepage may be encountered during portions of the year. Soil Infiltration Rates Soil permeability, which is a measure of the ability of a soil to transmit a fluid, was not tested in the field. Soil permeability, which is a measure of the ability of a soil to transmit a fluid, was tested in the field for the poorly graded gravel sediments. For this report, an estimation of infiltration is also presented using generally recognized values for each soil type and gradation. Of soils comprising the generalized soil profile for this study, lean clay and elastic silt soils generally offer little permeability, with typical hydraulic infiltration rates of less than 2 inches per hour. Sandy silt soils will commonly exhibit infiltration rates from 2 to 4 inches per hour. Silty sand sediments usually display rates of 4 to 8 inches per hour. Calcium carbonate cementation present within the elastic silt, sandy silt, and silty sand soils may reduce the stated values to near zero Poorly graded gravel and sand sediments typically exhibit infiltration values in excess of 12 inches per hour. Infiltration testing is generally not required within these sediments because of their free -draining nature. Five gallons of water was added to test pit 4 at a depth of 10.0 feet bgs and readily infiltrated within the poorly graded gravel with sand sediments. Therefore, infiltration testing as specified in the City of Boise Storm Water Management Design Manual (August 2010) was not conducted. It is recommended that infiltration facilities constructed on the site be extended into native poorly graded gravel with sand sediments. Excavation depths of approximately 1.5 to 12.0 feet bgs should be anticipated to expose these poorly graded gravel with sand sediments. Because of the high soil permeability, ASTM C33 filter sand, or equivalent, should be incorporated into design of infiltration facilities. An infiltration rate of 8 inches per hour should be used in design. Actual infiltration rates should be confirmed at the time of construction. SLOPES AND SETBACKS Native slopes onsite are generally shallower than 3 feet horizontal to 1 foot vertical (3:1). However, construction is expected to alter existing slopes. If slopes are altered to 3:1 or greater it will be necessary for structures constructed near slopes like these to apply slope setback requirements as outlined in the IBC. No potential slope stability deficiencies were noted during the investigation. Copyright 0 2014 Malcrials Tcstiag & hispection, Inc. 2791 South Victory View Way • Boise. ID 83709 • (208) 376-4748 Fax (208) 322-6515 mti@mti-id com • www.mti-id-com MATERIALS MOTESTING & INSPECTION 6 May 2014 Page # 9 of 36 h140414g_gentcch ❑ Envuonmental Services _Q Geotechnical Enyineerin ❑ Construction Materials Testing ❑ Special Inspections Soils onsite are not sufficiently stable to allow vertical cuts greater than 4 feet to stand for an extended period Of time. Soil types throughout the area are variable, and existing slopes will be dependent upon soil composition. Proposed cut -fill sections constructed from these soils should not be steeper than 2:1 for fine- grained soils and 2.5.1 for granular soils At the time of construction slope angles Wray need to be ad'usted based on stabihky of the granular soils, Fill slopes should be placed and compacted in ain a controlled manner as detailed in the Structural Fill section of this report. Fills to be constructed on existing slopes steeper than 20 percent (approximately 5:1) should be benched a minimum of 10 feet into competent native soils. To ensure slope stability with respect to surficial movement and gullying, cohesive soils should be placed on the face of slopes. This will help limit downslope creep and aid in re -vegetation of slope surfaces. When slopes are steeper than 2:1, soils must be aggressively protected from erosion. More granular soils will require an even greater degree of protection. Setbacks from constructed slopes should adhere to provisions of Section 1808.7 of the 2012 IBC. Footing loads on soil masses adjacent to slopes must be setback in accordance with the provisions of the IBC. For buildings constructed above slopes steeper than 3:1, the horizontal setback distance from the face of slope to the face o1' an upslnpe fooling must be no less than V, the vertical height of the total slope, however, need not exceed 40 feet. Benches or steps in the slope do not modify slope height. For buildings constructed below Slopes steeper than 3:1, the horizontal setback distance from the toe of slope to the face of a downslope structure must be no less than Yz the vertical height of the total slope, however, need not exceed 15 feet. Retaining walls can be constructed to alter the dimensional parameters of a slope. The top of the retaining W811 constitutes the toe ofthe slope, and slope height is determined from the top ofwall, Downslope setback requirements can be reduced to zero if the retaining wall reduces the upslope gradient to 3;1 or flatter. Because upslope setbacks are determined at faoting elevation, top ot'slope setbacks can be managed through the footing depth. In some cases, it may be desirable to use a foundation based on tip bearing piles or caissons to achieve greater footing depths. LATF.RAt, EARTH PRESSURES Retaining, below -grade, or basement walls will be subject to lateral earth pressures. The magnitude of earth pressure is a function of both type and compaction of backfill behind walls within the "active" zone, and allowable rotation of the top of the wall, The active zone is defined as the wedge of soil between the surface of the wall and a plane inclined 31 degrees for fine grained soils and 28 degrees for granular soils from vertical passing through the base o1'the wall. All claysoils Inust c ]ictimoletely removed from within the active 7Anc. The Hollowing recommendations should be used when dealing Gvith lateral earth pressures on it gravity block: I ) a sliding frictional coefficient of 0,35 is appropriate considering native silty sand/sandy silt (SM/ML) soils, and 2) a sliding frictional coefficient of 0.45 is appropriate considering native granular soils and granular structural fill (SP/GP) under typical conditions. Copyright 02014 Materials Testing & Inspection, Inc 2791 South Victory View Way - Boise, ID 83709 • (208) 376-4748 - Fax (208) 322-6515 mti@mti-id.com • www.mti-id,com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 10 of 36 bl40414g_gcotech Environmental Services _J Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections A state of plastic equilibrium is when the subject material is considered to be 1) homogeneous and unbounded and 2) at the point of incipient instability. This state is evaluated on the basis of unit weight, mechanical properties, and the definition of instability. For the purpose of this report, it is assumed that native relatively free draining soils and imported granular fill material will be the materials of concern regarding lateral earth pressures. If other materials arc considered for use, MTI must be contacted to provide revised lateral pressure information. Furthermore, changes in natural soil moisture, such as can be imposed by site storm water systems, can change the values listed below. Below -grade restrained walls, such as basement walls, should be designed based on at -rest pressures. Active pressures are appropriate under conditions where the wall moves or rotates away from the soil mass at failure. Passive pressures are used for conditions where the wall moves toward the soil mass at failure. Rotation, or lateral movement, of the top of the wall equal to 0.002 times the height of the wall will be necessary for on- site fine-grained soil backfill to achieve an "active" loading condition. Lateral movement of the top of the wall equal to 0.001 times the height of the wall will be necessary for the "active" pressure condition for native granular soils and imported SP/GP structural backfill. Retaining Wall Backfill Materials For lateral earth pressure analysis, MTI anticipates that the soils of interest will be the native sandy silt/silty sand (ML/SM) soils. Clay soils are not suitable for use as backfill on the soil side of walls. For ML/SM soils, the following values are applicable under non -surcharged, drained conditions: Lateral Earth Pressure Values for Native Soil Soil Type: Sandy Silt/Silty Sand 35 ° Internal Friction Angle: 28 ° Cohesion: 200 psf Natural Void Ratio: 0.7 At rest lateral earth pressure: 65 pcf Active lateral earth pressure: 44 pcf Passive lateral earth pressure: 337 per Dry Unit Weight: 105 pcf Buoyant Unit Weight: 68 pcf Natural Moisture: 16 % K°= 0.5 Ka 0.4 Kp= 2.8 Native granular soils and imported, compacted, structural material, which is used to backfill the soil side of walls, must demonstrate following characteristics: Lateral Earth rressure values for rill lvtaterlals Soil Type: Compacted Sandy Gravel Internal Friction Angle: 35 ° Cohesion: NA Natural Void Ratio: 0.4 At rest lateral earth pressure: 57 pcf Active lateral earth pressure: 36 pcf Passive lateral earth pressure: 496 per Dry Unit Weight: 128 per Buoyant Unit Weight: 83 pcf Natural Moisture: 5 % Ko 0.4 Ka— 0.3 Kr= 3.7 Copyright ® 2014 Materials Testing k Inspection, Inc. 2791 South Victory View Way • Boise. ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com (wMATERIALS r TESTING & INSPECTION 6 May 2014 Page # 11 of 36 b 1404149_9cotech 1.7 Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections In the case that another material is used for backfill, MTI should be consulted for alternate lateral earth pressure values. Granular structural fill should consist of 4 -inch -minus select, clean, granular soil with no more than 30 percent oversize (greater than 3/4 -inch) material and no more than 5 percent fines (passing the No. 200 sieve). Retaining wall and basement backfill must be placed in accordance with recommendations in the Structural Fill section of this report and must be properly compacted and tested Lateral earth pressure values do not incorporate specific factors of safety, and are only applicable for non - surcharged, drained conditions. Factors of safety, if applicable, should be integrated into the structural design of the wall. The preceding values are presented for idealized conditions relating to simple shallow structures. For complex structures, deep structures, or structures with signilicant perimeter landscaping, a soils engineer should be retained as part of the design team in developing appropriate project design parameters and construction specifications. Retaining Wall Drainage MTI recommends that a drainage system be incorporated into the retained soil mass. This can be accomplished by installing wall and toe drains as a pan of each soil -supporting wall system. In areas where there is potential for significantly high soil moistures within the supported soil mass, installation of drains within the soil mass is recommended. Particular consideration of roof drain effluent and irrigation water must be made. Further, these drainage systems must be separate from other retaining wall/foundations stems. If the granular structural fill option to reduce lateral pressures is used, a compacted low permeability soil cap is recommended within the upper 2 feet of the surface to limit surface water infiltration behind the walls. ROCKERY RETAINING WALL Rockery construction is a craft and depends largely on the skill and experience of the builder. A rockery is a protective system which helps retard the weathering and erosion process on an exposed soil face. While by its nature (mass, size, and shape of the rocks) it will provide some degree of retention, it is not a designed or engineered system in the sense a reinforced concrete retaining wall would be considered designed or engineered. The degree of retention achieved is dependent on the size of the rock used: that is, the mass or weight, and the height of the wall being constructed. The larger the rock, the more competent the rocket} should be. Rockeries should be considered maintenance items that will require periodic inspection and repair. They should be located so that they can be reached by a contractor if repairs become necessary. Rock wall construction shall be performed in accordance with the Associated Rockery Contractor (ARC) Rock Wall Construction Guidelines. In addition, the rockery should be installed under periodic observation of the geotechnical engineer. See Plate 3 for graphical representation of the wall. Rockery Wall Foundation Recommendations The rockery wall shall bear on native silty sand or better soils compacted to at least 95% of the maximum dry density in accordance with ASTM D1557. If silty sand or better soils are not encountered at the bearing elevation, over -excavation and replacement with granular structural fill as outlined in the Structural Fill section will be required. The bottom boulder must be embedded at least 12 inches. Copyright @2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376.4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-ld.com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 12 of 36 b 1404149-gcotech 0 Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections Rockery Wall Construction Recommendations Boulders to be placed along the toe of the fill slopes must adhere to size and placement limitations. The boulders comprising the rockeries should consist of hard igneous or metamorphic rock conforming to the ARC Rock Wall Construction Guidelines. Boulders shall not be stacked vertical. A minimum batter of 9 degrees is required. They shall be placed in a manner that will ensure no movement or toppling will occur. The width of the bottom boulder must be at least one third the height of the wall. All boulders placed in the lower two-thirds of the wall should be 5- to 6 -man boulders, 4,000 pounds or larger. Boulders placed above this level should gradually decrease in size with increasing wall height using 3- to 5 -man boulders, 700 to 6,000 pounds. The long dimension of the rocks should extend back towards the slope to provide maximum stability. Boulders should be placed to avoid continuous joint planes in vertical or lateral directions. Each boulder should bear on two or more boulders below it, with good flat -to -flat contact. To fill voids, I- and 2 - man rock may be used; however, the use of 1 -and 2 -man rock should be kept to a minimum. After installation of the boulders, 3/ inch drain rock shall be placed between the slope and the boulders. All rockeries over 4 feet in height should be constructed on the basis of wall mass, not square footage of the face. Maximum inclination of the slopes above and behind rockeries should be 2 feet horizontal to 1 foot vertical (2:1). No surcharge loadinp can be placed in the area encompasscd by the wedge of soil between the surface of the wall and a plane inclined 30 degrees from vertical passing through the base of the wall Rockeries are not to exceed 8 feet in height. Rockery Wall Drainage Recommendations MTI recommends that a drainage system be incorporated into the retained soil mass. The drainage zone must be at least 18 inches wide. A 4 -inch diameter perforated drain pipe should be installed at the toe of the slope behind the rockery for the entire length of the wall. The drain pipe should be designed to collect and move water to a suitable discharge point away from the wall. The wall should be backfilled with 3/4" drain rock. Filter fabric should be placed along the existing slope prior to placement of drain rock. A compacted low permeability soil cap is recommended within the upper 2 feet of the surface to limit surface water infiltration behind the walls. FOUNDATION, SLAB, AN]) PAVEMENT DISCUSSION AND RECOMMENDATIONS Various foundation types have been considered for support of the proposed structures. Two requirements must be met in the design of foundations. First, the applied bearing stress must be less than the ultimate bearing capacity of foundation soils to maintain stability. Second, total and differential settlement must not exceed an amount that will produce an adverse behavior of the superstructure. Allowable settlement is usually exceeded before bearing capacity considerations become important; thus, allowable bearing pressure is normally controlled by settlement considerations. Considering subsurface conditions and the proposed construction, it is recommended that the structure be founded upon conventional spread footings and continuous wall footings. Total settlements should not exceed 1 inch iI'the following design and construction recommendations are observed. Presently, there are approximately 182 lots proposed for the project site. The following recommendations are not specific to the individual structures, but rather should be viewed as guidelines for the subdivision — wide develoRment Copyright ® 2014 Materials Testing & Inspection, Inc 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 13 of 36 b140414g_gcolech J Environmental Services J Geotechnical Engineering J Construction Materials Testing J Special Inspections Foundation Design Recommendations Based on data obtained from the site and test results from various laboratory tests performed, MTI recommends following guidelines for the net allowable soils bearing capacity: Soil Bearin itv - Phase 4 Footing Depth ASTM D1557 Net Allowable Sub rade Compaction Soil Bearing Capacity Phase 4 - Footings must bear on at least 12 inches of compacted structural fill bearing on 1,500 lbs/ft2 compacted, non -expansive, native soils or compacted structural fill. Existing fill materials 95% for Native Soil and A 1/3 increase is allowable must be completely removed from below Structural Fill for short-term loading, foundation elements.' Excavation depths ranging which is defined by seismic from 1.0 to 4,5 feet bgs should be anticipated to events or designed wind expose Droner bearing soils.2 sneeds. 'Depending on the time of )ear construction takes place, the subgradc sails may be. unstable because of high moisture contents. If unstable conditions are encountered, over -excavation and replacement with granular structural fill and/or use of geotextiles may be required. Soil Bearing Canacitv - Phases 3 & 5 Footing Depth ASTM D1557 Sub rade Com action Net Allowable Soil Bearing Capacity Footings must bear on competent, undisturbed, native sandy silt, silty sand, silty gravel, or poorly 1,500 lbs/ft' graded sand soils or compacted structural fill. Not Required for Existing fill materials must be completely Native Soil A 1/3 increase is allowable removed from below foundation elements.' for short-term loading, Excavation depths ranging from 1.0 to 1.6 feet 95% for Structural Fill which is defined by seismic bgs should be anticipated to expose proper events or designed wind bearing soils. speeds. Footings must bear on competent, undisturbed, native silty sand, silty gravel, poorly graded sand, 2,500 lbs/ft' or poorly graded gravel sediments or compacted Not Required for structural fill. Existing lean clay, elastic sill, and Native Soil A 1/3 increase is allowable sandy silt soils and fill materials must be for short -tern loading, completel removed from below foundation u 95 /o for Structural Fill which is defined seismic elementsExcavation depths ranging from 1.0 to events or designed d wind 5.0 feet bgs should be anticipated to expose speeds. proger bearing soils. 'It will be retim" for MTI oersnnnel to verify tba hearin soil suitability for each structure at the time of construction. 'Depending on the time of year construction takes place, the subjtvade soils may be unstable bCCOLI6e of high moisture contents. If unstable conditions are encountered, over -excavation and replacement with granular structural fill and/or use of geotextiles may be required Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 14 of 36 b 140414g_gcotech U Environmental Services U Geotechnical Engineering ❑ Construction Materials Testing 1J Special Inspections The following sliding frictional coefficient values should be used: 1) 0.35 for footings bearing on native sandy silt.silty sand (MUSM) soils and 2) 0.45 for footings bearing on native granular sediments and granular structural fill. A passive lateral earth pressure of 337 pounds per square foot (psf) should be used for sandy silt/silty sand (MUSM) soils. For compacted sandy gravel fill, a passive lateral earth pressure of 496 psf should be used. Footings should be proportioned to meet either the stated soil bearing capacity or the 2012 IBC minimum requirements. Total settlement should be limited to approximately 1 inch, and differential settlement should be limited to approximately %3 inch. Objectionable soil types encountered at the bottom of footing excavations should be removed and replaced with structural fill. Excessively loose or soft areas that are encountered in the footing subgrade will require over -excavation and backfilling with structural fill. To minimize the effects of slight differential movement that may occur because of variations in character of supporting soils and seasonal moisture content, MTT recommends continuous footings be suitably reinforced to make them as rigid as possible. For frost protection, the bottom of external footings should be 24 inches below finished grade. Crawl Space Recommendations All residences constructed with crawl spaces should be designed in a manner that will inhibit water in the crawl spaces. MTI recommends that roof drains carry storm water at least 5 feel away from each residence. Grades should be greater than 5% for a distance of 10 feet away from all residences. In addition, rain gutters should be placed around all sides of residences, and backfill around stem walls should be placed and compacted in a controlled manner. Flour, Patio, and Garage Slab -on Grade Uncontrolled fill was encountered in portions of the site MTI recommends that these fill soils be excavated to a sufficient depth to expose competent native Soils or to a minimum depth of 1%z feet below finished subgrade. 1 f fill, materials remain after over -excavation, exposed subgrade must be compacted to at least 95% of the maximum dry density in accordance with ASTM D1557. MTI personnel must be present during excavation to identify these materials. Native clay soils are moderately plastic and will be susceptible to shrink/swell movements associated with moisture changes. If areas of the site within the proposed structures expose lean clay the soils should be scarified to a depth of 6 inches and re -compacted between 92 percent and 98 percent of the maximum density as determined by ASTM D698. The moisture content should range from 1 to 4 percentage points above optimum. Structural till should be placed as soon as possible after re -compaction of clay soils in order to limit moisture loss within the upper clays. Ground surfaces should be sloped away from structures at a minimum of 5 percent for a distance of 10 feet to provide positive drainage of surface water away from buildings. Grading must be provided and maintained following construction. Copyright 0 2014 Materials Testing & Inspection, Int. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 15 of 36 b 140414g_gcotcch ZI Environmental Services ❑ Geotechnical Engineering U Construction Materials Testing U Special Inspections Organic, loose, or obviously compressive materials must be removed prior to placement of concrete floors or floor -supporting fill. In addition, the remaining subgrade should be treated in accordance with guidelines presented in the Earthwork section. Areas of excessive yielding should be excavated and backfilled with structural fill. Fill used to increase the elevation of the floor slab should meet requirements detailed in the Structural Fill section. Fill materials must be compacted to a minimum 95 percent of maximum density as determined by ASTM D1557. A free -draining granular mat (drainage fill course) should be provided below slabs -on -grade. This should be a minimum of 4 inches in thickness and properly compacted. The mat should consist of a sand and gravel mixture, complying with Idaho Standards for Public Works Construction (ISPWC) specifications for'/4-inch (Typed) crushed aggregate. A moisture -retarder should be placed beneath floor slabs to minimize potential ground moisture effects on moisture -sensitive floor coverings. The moisture -retarder should be at least 15 -mil in thickness and have a permeance of less than 0.01 US perms as determined by ASTM E96. Placement of the moisture -retarder will require special consideration with regard to effects on the slab -on -grade and should adhere to recommendations outlined in the ACI 302.1R and ASTM E1745 publications. The granular mat should be compacted to no less than 95 percent of maximum density as determined by ASTM Dl 557. Upon request, MTI can provide further consultation regarding installation. Recommended Pavement Sections As required by Ada County Highway District (ACHD), MTI has used a traffic index of 6 to determine the necessary pavement cross-sections for the site. MTI has made assumptions for traffic loading variables based on the character of the proposed construction. The Client should review these assumptions to make sure the reflect intended use and loading of pavements both now and in the future. MTI collected a sample of near - surface soils for Resistance Value (R -value) testing representative of soils to depths of 2.5 feet below existing ground surface. This sample, consisting of sandy elastic silt collected from test pit 1, yielded a R -value of 11. The following are minimum thickness requirements for assured pavement function. Depending on site conditions, additional work, e.g. soil preparation, may be required to support construction equipment. These have been listed within the Soft Subgrade Soils subsection. Results of the test are graphically depicted in the Appendix. Flexible Pavement Sections The Gravel Equivalent Method, as defined in Section 500 of the State of Idaho Department of Transportation (ITD) Materials Manual, was used to develop the pavement section. ACHD parameters for traffic index and substitution ratios, which were obtained from the ACHD Policy Manual, were also used in the design. Calculation sheets provided in the Appendix indicate the soils constant, traffic loading, traffic projections, and material constants used to calculate the pavement sections. MTI recommends that materials used in the construction of asphaltic concrete pavements meet the requirements of the ISPWC Standard Specification for Highway Construction. Construction of the pavement section should be in accordance with these specifications and should adhere to guidelines recommended in the section on Construction Considerations. Copyright 0 2014 Materials Testing & Inspation, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.rnti-id.com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 16 of 36 b140414g_gcotcch ❑ Environmental Services J ueaechnical Engineering J Construction Materials Testing U Special Inspections Gravel Equivalent Method Flexible Pavement Specifications Pavement Section Component[ I Roadway Section Asphaltic Concrete 2.5 Inches Crushed Aggregate Base 4.0 Inches Structural Subbase 12.0 Inches Compacted Subgrade I Not Required Asphaltic Concrete: Asphalt mix design shall meet the requirements of ISPWC, Section 810 Class III plant mix. Materials shall be placed in accordance with ISPWC Standard Specifications for Highway Construction. Aggregate Base: Material complying with ISPWC Standards for Crashed Aggregate Materials. Structural Subbase: Material complying with requirements for granular structural fill (uncrushed) as defined in ISPWC. Common Pavement Section Construction Issues The subgrade upon which above pavement sections are to be constructed must be properly stripped, inspected, and proof -rolled. Proof rolling of subgrade soils should be accomplished using a heavy rubber - tired, fully loaded, tandem -axle dump truck or equivalent. Verification of subgrade competence by MT'I personnel at the time of construction is required. Fill materials on the site must demonstrate the indicated compaction prior to placing material in support of the pavement section. MTI anticipates that pavement areas will be subjected to moderate traffic. MTI does not anticipate pumping material to become evident during compaction, but subgrade clays and silts near and above optimum moisture contents may tend to pump. Pumping or soft areas must be removed and replaced with structural fill. Fill material and aggregates in support of the pavement section must be compacted to no less than 95 percent of the maximum dry density as determined by ASTM D698 for flexible pavements and by ASTM D1557 for rigid pavements. If a material placed as a pavement section component cannot be tested by usual compaction testing methods, then compaction of that material must be approved by observed proof rolling. Minor deflections from proof rolling for flexible pavements are allowable. Deflections from proof rolling of rigid pavement support courses should not be visually detectable. MTI recommends that rigid concrete pavement be provided for heavy garbage receptacles. This will eliminate damage caused by the considerable loading transferred through the small steel wheels onto asphaltic concrete. Rigid concrete pavement should consist of Portland Cement Concrete Pavement (PCCP) generally adhering to PCD specifications for Urban Concrete. PCCP should be 6 inches thick on a 4 -inch drainage fill course (see Floor Slab -on -Grade section), and should be reinforced with welded wire fabric. Control joints must be on 12 -foot centers or less. Copyright 02014 Materials Testing & Inspection. Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376.4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com I MATERIALS TESTING & INSPECTION 6 May 2014 Page # 17 of 36 1,140414g-geolech .D Environmental Services J Geotechnical Engineering '7 Construction Materials Testing ❑ Special Inspections CONSTRUCTION CONSIDERATIONS Recommendations in this report are based upon structural elements of the project being founded on competent, undisturbed, native sandy silt, silty sand, silty gravel, or poorly graded sand soils or compacted structural fill. Structural areas should be stripped to an elevation that exposes these soil types. Earthwork Excessively organic soils, deleterious materials, or disturbed soils generally undergo high volume changes when subjected to loads, which is detrimental to subgrade behavior in the area of pavements, floor slabs, structural fills, and foundations. Brush and thick grasses with associated root systems were noted at the time of our investigation. It is recommended that organic or disturbed soils, if encountered, be removed to depths of 1 foot (minimum), and wasted or stockpiled for later use. Stripping depths should be adjusted in the field to assure that the entire root zone or disturbed zone or topsoil are removed prior to placement and compaction of structural Fill materials. Exact removal depths should be determined during grading operations by MTI personnel, and should be based upon subgradc soil type, composition, and firmness or soil stability. If underground storage tanks, underground utilities, wells, or septic systems are discovered during construction activities, they must be decommissioned then removed or abandoned in accordance with governing Federal, State, and local agencies. Excavations developed as the result of such removal must be backfilled with structural fill materials as defined in the Structural Fill section. MTI should oversee subgrade conditions (i.e., moisture content) as well as placement and compaction of new fill (if required) after native soils are excavated to design grade. Recommendations for structural fill presented in this report can be used to minimize volume changes and differential settlements that are detrimental to the behavior of footings, pavements, and floor slabs. Sufficient density tests should be performed to properly monitor compaction. For structural fill beneath building structures, one in-place density test per lift for every 5,000 square feet is recommended. In parking and driveway areas, this can be decreased to one test per lift for every 10,000 square feet. Dry Weather If construction is to be conducted during dry seasonal conditions, many problems associated with soft soils may be avoided. however, some rutting of subgradc soils may be induced by shallow groundwater conditions related to springtime runoff or irrigation activities during late summer through early fall. Solutions to problems associated with soft subgrade soils are outlined in the Soft Subgrade Soils section. problems may also arise because of lack of moisture in native and fill soils at time of placement. "Chis will require the addition of water to achieve near -optimum moisture levels. Low -cohesion soils exposed in excavations may become friable, increasing chances of sloughing or caving. Measures to control excessive dust should be considered as part of the overall health and safety management plan. Copyright OO 2014 Mntcrinls Testing & Inspection, Inc 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti0a mti-id.com • www,mti-id.com LMATERIALS TESTING >s INSPECTION 6 May 2014 Page # 18 of 36 b140414g_gcotech Environmental Services J Geotechnical Engineering ❑ Construction Materials Testing O Special Inspections Wet Weather If construction is to be conducted during wet seasonal conditions (commonly from mid-November through May), problems associated with soft soils must be considered as part of the construction plan. During this time of year, fine-grained soils such as silts and clays will become unstable with increased moisture content, and eventually deform or rut. Additionally, constant low temperatures reduce the possibility of drying soils to near optimum conditions. Soft Subgrade Soils Shallow subgrade soils that are high in moisture content should be expected to pump and rut under construction traffic. During periods of wet weather, construction may become very difficult if not impossible. The following recommendations and options have been included for dealing with soft subgrade conditions: • Track -mounted vehicles should be used to strip the subgrade of root matter and other deleterious debris. Heavy rubber -tired equipment should be prohibited from operating directly on the native subgrade and areas in which structural till materials have been placed. Construction traffic should be restricted to designated roadways that do not cross, or cross on a limited basis, proposed roadway or parking areas. • Construction roadways on soft subgrade soils should consist of a minimum 2 -foot thickness of large cobbles of 4 to 6 inches in diameter with sufficient sand and fines to fill voids. Construction entrances should consist of a 6 -inch thickness of clean, 2 -inch minimum, angular drain -rock and must be a minimum of 10 feet wide and 30 to SO feet long. During the construction process, top dressing of the entrance may be required for maintenance. • Scarification and aeration of subgrade soils can be employed to reduce the moisture content of wet subgrade soils. After stripping is complete, the exposed subgrade should be ripped or disked to a depth of 1 %z feet and allowed to air dry for 2 to 4 weeks. Further disking should be performed on a weekly basis to aid the aeration process. • Alternative soil stabilization methods include use of geotextiles, lime, and cement stabilization. MTI is available to provide recommendations and guidelines at your request. Frozen Subgrade ,Soils Prior to placement of structural fill materials or foundation elements, frozen subgrade soils must either be allowed to thaw or be stripped to depths that expose non -frozen soils and wasted or stockpiled for later use. Stockpiled materials must be allowed to thaw and return to near -optimal conditions prior to use as structural fill. Copyright @2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti©mti-id.com • www.mti-id.com MATERIALS TESTING it INSPECTION 6 May 2014 Page # 19 of 36 b I40414gyeotech -i J Geotechnical Engineering U Construction Materials Testing 17 Special Inspections Structural Fill Soils recommended for use as structural fill are those classified as GW, GP, SW, and SP in accordance with the Unified Soil Classification System (USCS) (ASTM D2487). Use of silty soils (USCS designation of GM, SM, and ML) as structural fill may be acceptable. However, use of silty soils (GM, SM, and ML) as structural fill below footings is prohibited. These materials require very high moisture contents for compaction and require a long time to dry out if natural moisture contents are too high and may also be susceptible to frost heave under certain conditions. Therefore these materials can be quite difficult to work with as moisture content, lift thickness, and compactive effort becomes difficult to control. If silty soil is used for structural fill, lift thicknesses should not exceed 6 inches (loose), and fill material moisture must be closely monitored at both the working elevation and the elevations of materials already placed. Following placement, silty soils must be protected from degradation resulting from construction traffic or subsequent construction. Recommended granular structural fill materials, those classified as GW, GP, SW, and SP, should consist of a 6 -inch minus select, clean, granular soil with no more than 50 percent oversize (greater than'/4-inch) material and no more than 12 percent fines (passing No. 200 sieve). These fill materials should be placed in layers not to exceed 12 inches in loose thickness. Prior to placement of structural fill materials, surfaces must be prepared as outlined in the Construction Considerations section. Structural fill material should be moisture - conditioned to achieve optimum moisture content prior to compaction. For structural fill below footings, areas of compacted backfill must extend outside the perimeter of the footing for a distance equal to the thickness of fill between the bottom of foundation and underlying soils, or 5 feet, whichever is less. All fill materials must be monitored during placement and tested to confirm compaction requirements, outlined below. have been achieved. Each layer of structural fill must be compacted, as outlined below: Below Structures and Rigid Pavements: A minimum of 95 percent of the maximum dry density as determined by ASTM D 1557. Below Flexible Pavements: A minimum of 92 percent of the maximum dry density as determined by ASTM D1557 or 95 percent of the maximum dry density as determined by ASTM D698. The ASTM D1557 test method must be used for samples containing up to 40 percent oversize (greater than '/,-inch) particles. If material contains more than 40 percent but less than 50 percent oversize particles. compaction of fill must be confirmed by proof rolling each lift with a 10 -ton vibratory roller (or equivalent) until the maximum density has been achieved. Density testing must be performed after each proof rolling pass until the in-place density test results indicate a drop (or no increase) in the dry density, defined as the maximum density or "break over" point. The number of required passes should be used as the requirement on the remainder of till placement. Material should contain sufficient lines to till void spaces, and must not contain more than 50 percent oversize particles. Copyright ® 2014 Mate rialSTesting & InSpection, tin; 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mtiGnmti-id.com • www.mti-id.com 1►lF-11V1NIa«� TESTING & INSPECTION 6 May 2014 Page # 20 of 36 b I40414g_geotech J Envuunmenta Services U Geotechnical Engineenny U Construction Materials Testing U Special Inspections Backfill of Walls Backfill materials must conform to the requirements of structural fill, as defined in this report. For wall heights greater than 2.5 feet, the maximum material size should not exceed 4 inches in diameter. Placing oversized material against rigid surfaces interferes with proper compaction, and can induce excessive point loads on walls. Backfill shall not commence until the wall has gained sufficient strength to resist placement and compaction forces. Further, retaining walls above 2.5 feet in height shall be backfilled in a manner that will limit the potential for damage from compaction methods and/or equipment. It is recommended that only small hand -operated compaction equipment be used for compaction of backfill within a horizontal distance equal to the height of the wall, measured from the back face of the wall. Backfill should be compacted in accordance with the specifications for structural fill, except in those areas where it is determined that future settlement is not a concern, such as planter areas. In nonstructural areas. backfill must be compacted to a firm and unyielding condition. Excavations Shallow excavations that do not exceed 4 feet in depth may be constructed with side slopes approaching vertical. Below this depth, it is recommended that slopes be constructed in accordance with Occupational Safety and Health Administration (OSHA) regulations, section 1926, subpart P. Based on these regulations, on-site soils are classified as type "C" soil, and as such, excavations within these soils should be constructed at a maximum slope of 1'/2 foot horizontal to 1 foot vertical (1 Y1-1: IV) for excavations up to 20 feet in height. )excavations in excess of 20 feet will require additional analysis. Note that these slope angles arc considered stable for short-term conditions only and will not be stable for long-term conditions. During our subsurface exploration, test pit sidewalls generally exhibited little indication of collapse; however, sloughing of fill materials and native granular sediments from test pit sidewalls was observed, particularly after penetration of the water table. For deep excavations, native granular sediments cannot be expected to remain in position. These materials are prone to failure and may collapse, thereby, undermining upper soils layers. This is especially true when excavations approach depths near the water table. Care must be taken to ensure that excavations are properly backfilled in accordance with procedures outlined in this report. Groundwater Control Groundwater was not encountered during the investigation and is anticipated to be below the depth of most construction. However, special precautions may be required for control of surface runoff and subsurface seepage. It is recommended that runoff be directed away from open excavations. Silty and clayey soils may become soft and pump if subjected to excessive traffic during time of surface runoff. Ponded water in construction areas should be drained through methods such as trenching, sloping, crowning grades, nightly smooth drum rolling, or installing a French drain system. Additionally, temporary or permanent driveway sections should be constructed if extended wet weather is forecasted. Copyright ©2014 Materials Testing& Inspection, Inc, 2791 South Victoiy View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 21 of 36 W4e414"eatech J B mw -i mentel '.„-.. U Geotechnical En Ineerin ❑ Construction Materials Testing O Special Inspections GENERAL COMMENTS When plans and specifications are complete, or if significant changes are made in the character or location of the proposed development, consultations with MTI should be arranged as supplementary recommendations may be required. Suitability of subgr3de soils and compaction of structural fill materials must he verified by MTl personnel prior to placement or structural elements. Additionally, monitoring and testing should be performed to verify that suitable materials are used for structural fill and that proper placement and compaction techniques are utilized. Copyright ®2Q I4 Materials Testing & Inspection: Inc. 2791 South Victory View Way • 8oise. ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mtiCc)mti-id.com • www.mti-id.com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 22 of 36 h 140414g_gcotmh O Environmental Service:, J gyral Dip reent q J Construction Materials Testing ❑ Special Inspections REFERENCES Ada County Highway District (ACRD) (2013). Ada County Highway District Policy Manual (May 2013). [Online] Available: <hcpt •//www achdidaho.org/AboutACHD/PolicyManuai.asl)x> (2014). American Concrete Institute (ACI) (2004). Guide for Concrete Floor and Slab Construction: ACI 302.111. Farmington Hills, ML ACI. American Society of Civil Engineers (ASCE) (2013). Minimum Design Loads for Buildgs and Other Structures: ASCE/SEI 7-I0. Reston, VA: ASCE. American Society for Testing and Materials (ASTM) (2004). Standard'hest Method for Materials Finer than 75 -um (No. 200) Sieve in Mineral Aggregates by Washing: ASTM Cl 17, West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2006). Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates: ASTM 0136. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2012). Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort D698. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2012). Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort D1557. Wast Conshohocken, PA: ASTM, American Society for Testing and Materials (ASTM) (2007). Standard Test Methods for Resistance Value R -Value and Expansion Pressure of Compacted Soils, ASTM D2844. West Conshohocken, PA: ASTM, American Society for Testing and Materials (ASTM) (2011). Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System) D2487, West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2010). Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils: ASTM D4318. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2011). Standard SpecificatigP,ror Plastic Water Vapor Retarders_ Used in Contact with Soil or Granular Fill under Concrete Slabs: ASTM E1745. West Conshohocken, PA: ASTM. Desert Research Institute, Western Regional Climate Center. [Online] Available: <httR://www.wrcc.dri.edu/> (2014). International Building Code Council (2012), International Building Code, 2012. Country Club Hills, Il.: Author. Local Highway Technical Assistance Council (LHTAC) (2010). Idaho Standards for Public Works Construction 2010. Boise, ID: Author. Othberg, K. L. and Stanford, L. A„ Idaho Geologic Society (1992). Geologic Map_af_tile Boise Valley and Adjoining Area, Western Snake River Plain, Idaho. (scale 1:100,000). Boise, Idaho: Joslyn and Morris. U. S. Dept. of Labor, Occupational Safety and Ilealth Administration. "CFR 29 Part 1926, subpart P: Safety and Health Regulations for Construction, Excavations (1986)'. [Online] Available: <www.osha.gov> (2014), U. S. Geological Survey. (2011). National Water Infonnation System: Web Interface. [Online] Available: <hn:Hwaterdata.usgs.gov/nwis> (2014). Copyright O 2014 Materials Testing & Inspection.. Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208)322-6515 mti@mti-id.com • www.mtkid.Com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 23 of 36 b1404I4g_gcotcch .3 - ] Geotechnical Engineering O Construction Materials Testin0 ❑ Special Inspections APPENDICES ACRONYM LIST AASHTO: American Association of State Highway and Transportation Officials ACRD: Ada County Highway District ACI American Concrete Institute ASCE American Society of Civil Engineers ASTM: American Society for Testing and Materials bgs: below ground surface CBR: California Bearing Ratio D: natural dry unit weight, pcf ESAL Equivalent Single Axle Load GS: grab sample IBC: International Building Code ISPWC: Idaho Standards for Public Works Construction ITD: Idaho Transportation Department LL: Liquid Limit M: water content MSL: mean sea level N: Standard "N" penetration: blows per foot, Standard Penetration Test NP: nonplastic OSHA Occupational Safety and Health Administration PCCP: Portland Cement Concrete Pavement PERM: vapor permeability PI: Plasticity Index PID: photoionization detector PVC: polyvinyl chloride Qe: cone penetrometer value, unconfined compressive strength, psi Qp: Penetrometer value, unconfined compressive strength. tsf Qu: Unconfined compressive strength, tsf RMR Rock Mass Rating RQD Rock Quality Designation R -Value Resistance Value SPT: Standard Penetration "fest (I40:pound hammer falling 30 in. on a 2:in. split spoon) USCS: Unified Soil Classification System USDA: United States Department of Agriculture UST: underground storage tank V: vane value, ultimate shearing strength, tsr Copyright OO 2014 Mnterials Toting & Inypcclloil, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 Fax (208) 322-6515 mti@mti-id.com • www.mti-id,com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 24 of 36 b 140414g_geotech J Enviwr)rnentdl Services ❑ Geotechnical Engineerin2 J Construction Materials Testing ❑ Special Inspections GEOTECHNICAL GENERAL NOTES Description Field "Pest _ Dry Absence of moisture, dusty, dry to touch Moist Damp but not visible moisture Wet Visible free water, usually soil is below water table Boulders: _ 12 in. _ Cobbles: 12 to 3 m. Gravel: '3 in. to 5 mm PARTICLE Coarse -Grained Sand: -- Medium -Grained Sand: Fine -Grained Sand: Description Field "rest Weakly Crumbles or breaks with handling or - slight finger pressure Moderately Crumbles or beaks with considerable _ finger pressure Strongly Will not crumble or break with finger Sin 06 mm U.0 to U.2. mm 02 to 0.075 mm 0.075 to 0.005 mm <0.005 mm UNIFIED SOIL CLASSIFICATION SYSTEM RELATIVE DENSITY AND CONSISTENCY CLASSIFICATION Symbol CoarseGrained Soils SPT Blow Counts (N Fine -Grained Soils SPT Blow Counts N Ve Loose: <4 Ver Soft: <2 Loose: 4-10 Soft: 2-4 Medium Dense: 10-30 Medium Stiff: 4-8 Dense: 30-50 Stiff: _ 8-15 Very Dense: >50 Veil Stiff: 15-30 SW Hard: >30 Description Field "Pest _ Dry Absence of moisture, dusty, dry to touch Moist Damp but not visible moisture Wet Visible free water, usually soil is below water table Boulders: _ 12 in. _ Cobbles: 12 to 3 m. Gravel: '3 in. to 5 mm PARTICLE Coarse -Grained Sand: -- Medium -Grained Sand: Fine -Grained Sand: Description Field "rest Weakly Crumbles or breaks with handling or - slight finger pressure Moderately Crumbles or beaks with considerable _ finger pressure Strongly Will not crumble or break with finger Sin 06 mm U.0 to U.2. mm 02 to 0.075 mm 0.075 to 0.005 mm <0.005 mm UNIFIED SOIL CLASSIFICATION SYSTEM Major Divisions Symbol Soil Descriptions -- Gravel & Gravelly GW Well -graded gravels; gravel/sand mixtures with little or no fines Soils GP Poorly -graded gravels; gravel/sand mixtures with little or no fines Coarse-Grained <50% coarse fraction GM .—�- Silty gravels; poorly -graded gravel/sand/silt mixtures Soils <50% passes No.4 sieve Clayey gravels; poorly -graded gravel/sand/clay mixtures GC Sand & Sandy SW Well -graded sands; gravelly sands with littleor no fines passes No.200 sieve Soros 50% SP Poorly -graded sands; gravelly sands with little or no fines — SM coarse fraction Silty sands; poorly -graded sand/gravel/silt mixtures SC _ passes No.4 sieve Clayey sands; poorly -graded sand/gravel/clay mixtures ML Inorganic silts; sandy, gravelly or clayey silts Silts & Clays CL Lean clays; inorganic, gravelly, sandy, or silty, to medium -plasticity clays Fine Grained LL <50 Soils >50% OL Organic, low -plasticity clays and silts passes No.200 Mil - Inorganic, elastic silts; sandy, gravelly or clayey elastic silts sieve Silts & Clays LL > 50 -- _ ..- Fat clays; high -plasticity, inorganic clays CH OH _ Organic, medium to high -plasticity clays and silts Highly Organic Soils PT Peat, humus, hydric soils with high organic content Copyright OO 2014 Materials'resting & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515---- mti@mti-id.com • www,mti-id.com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 25 of 36 b140414g__gcotcch J Brvironni i -] Geotechnical Engineering J Construction Materials Testing l7 Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP -1 Date Advanced: 23 Apr 2014 Logged by: Elizabeth Brown, P.E. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Depth to Water Table: Not Encountered Total Depth: 16.0 Feet bgs Depth Field Description and Sample Sample Depth Qp Lab (Feet b s) USCS Soil and Sediment Classification Type (Feet b s Test ID Lean Clay (CL): Brown, slightly moist, 0.0-1.8 medium stiff to stiff, fine grained sand. 0.75-1.0 --Organic material to 1.0 oot figs. Sandy Elastic Silt (MII): Light brown, dry, A 1.8-5.8 very stiff to hard, weak calcium carbonate Bulk 2.0-2.5 4,0-4.5 R -value cementation, me rained sand. Sandy Silt (ML): light brown, dry, hard, moderate calcium carbonate cementation, fine 5.8-12.5 grained sand. --.Sand content increased with depth. Silty Sand with Gravel (SM): Brown, dry, dense to very dense, weak to moderate calcium 12.5-16.0 carbonate cementation to 15.5 feet bgs, fine to coarse grained sand, 3 inch minus gravel. Lab Test ID I M LL PI Sieve Analysis #4 #10 #40 #100 #200 A 1 25.8 1 54 15 99 97 80 71 65.7 Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-id.com • www.mti-id corn MATERIALS 6 May 2014 TESTING & Page# 26 of 36 INSPECTION bl404l4g geolech 1 �-i Environmental Services J J Construction Materials Testiinq J Special hispections GEOTECHNICAL INVESTICATION TEST PIT LOC Test Pit Log #: TP -2 Date Advanced: 23 Apr 2014 Logged by: Elizabeth Brown, P.E. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Depth to Water Table: Not Encountered Total Depth: 17.0 Feet bgs Depth Field Description and Sample Sample Depth Qp Lab Feet b s USCS Soil and Sediment Classification T e Feet b s Test ID Poorly Graded Gravel Fill (GP FILL): Light 0.0-4.5 brown, dry, medium dense, fine to medium grained sand, silt and clay content, 5 inch minus cobbles. 4.5-5.5 Lean Clay (CL): Dark brown, slightly moist, medium sti , fine grained sand. Sandy Silt (ML): Light brown, dry, hard, 5.5-12.0 moderate calcium carbonate cementation to 11.0 feet bgs, fine grained sand. Poorly Graded Gravel with Sand (GP): Light 12.0-17.0 brown, dry, dense, fine to medium grained sand, coarse gravel, 5 inch minus cobbles. Copyright ®2014 Materials 'Testing & Inspection, Inv - 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mt1@mtHd.com www.mti-id.com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 27 of 36 b 140414g_geolecb J Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP -3 Date Advanced: 23 Apr 2014 Logged by: Noble Lafferty, E.I. F,xcavated by: Struekman's Backhoe Service Location: See Site Map Plates Depth to Water Table: Not Encountered Total Depth: 11.0 Feet bgs Depth Field Description and Sample Sample Depth QP Lab Feet b USCS Soil and Sediment Classification Type Feet b s Test ID 0.0-1.6 Sandy Silt Fill (ML -FILL): Light bromin, sli htl moist, loose to medium dense. Silty Gravel (GM): Light brown, slightly 1.6-5.3 moist, medium dense, fine grained sand, 3"minus cobbles. Poorly Graded Gravel with Sand (GP): Light brown, slightly moist, medium dense, fine to coarse grained sand, fine to coarse gravel, 4" 5.3-11.0 minus cobbles. — Increase in cobble size with depth, up to 10" minus cobbles. Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 m5@mti-id.coin • www.mti-id.com MATERIALS TESTING £r INSPECTION 6 Mav 2014 Page # 28 of 36 h 140414g_gentcch U Elvironmental Services U Gectechim I �,Iruction Materials Testing U Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOC Test Pit Log #: TP -4 Date Advanced: 23 Apr 2014 Logged by: Noble Lafferty, E.I. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Depth to Water Table: Not Encountered Total Depth: 10.0 Feet bgs Notes: Five gallons of water was added at a depth of 10.0 feet bgs and readily infiltrated. Depth Feet b Field Description and USCS Soil and Sediment Classification Sample T e Sample Depth (Feet bgs) Qp Lab Test ID Silty Sand (SM): Light brown, slightly moist, 0.0-4.0 medium dense, intermittent weak calcium carbonate cementation, fine grainedsand Poorly Graded Gravel with Sand (GP): Light brown, slightly moist, medium dense, fine to coarse grained sand, fine to coarse gravel. 4.0-10.0 --Some silt content in the upper I foot. -- Increase in cobble size with depth, up to 10" minus cobbles. Copyright ® 2014 Materials Testing & Inspection. Inc 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mtAmti-id.com • www.mti-id.com MATERIALS 6 May 2014 TESTING & Page 29 of 36 INSPECTION t, 140414g_geotech J Ewirunnienral j ameering 17 Construction Materials Testing LI Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP -5 Date Advanced: 23 Apr 2014 Logged by: Noble Lafferty, E.I. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Depth to Water Table: Not Encountered Total Depth: 8.0 Feet bgs Depth Field Description and Sample Sample Depth Lab (Feet bus) USCS Soil and Sediment Classification Type Feet b =s QP Test ID 0.0-1.2 Sandy Silt Fill (ML -FILL): Brown, slightly moist, medium dense, 3 " minus cobbles. _ 1.2-2.8 Poorly Graded Sand (SP): White, slightly moist, loose, fine to medium grained sand. Poorly Graded Gravel with Sand (GP): Light brown, slightly moist, medium dense, fine to coarse grained sand, fine to coarse gravel, 5 " 2.8-8.0 minus cobbles. -- Increase in cobble size with depth, up to 12 " minus cobbles. Copyright OO 2014 Materials Testing & Inspection. Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 Fax (208) 322-6515 mti@mti-id.com • www.mti-id.com MATERIALS TESTING & INSPECTION 6 May 2014 Page It 30 of 36 b140414g_gcatcch .-I J Geotechnical Engineering ❑ Construction Materials Testing 7 Special Inspections GEOTECIINICAL INVESTIGATION TEST PIT LOC Test Pit Log It: TP -6 Date Advanced: 23 Apr 2014 Logged by: Noble Lafferty, E.I. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Depth to Water Table: Not Encountered Total Depth: 7.0 Feet bgs Depth Feet b s) Field Description and USCS Soil and Sediment Classification Sample T e Sample Depth Feet b s Qp Lab Test ID Silty Gravel (GM): Light brown, slightly 0.0-3.0 moist, medium dense to dense, fine to medium ravel, 4"minus cobbles. Poorly Graded Gravel with Sand (GP): Light brown, slightly moist, medium dense, fine to 3.0-7.0 coarse grained sand fine to coarse gravel. -- Increase in cobble size with depth, up to 8" minus cobbles. Copyright Co) 2014 Material. Testing & Inspection. Inc 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mtiCmti-id.com • www.mti-id.com MATERIALS TESTING it INSPECTION 6 May 2014 Page # 31 of 36 b 140414g_geotech U Envuonnlental Services J Geotechnical Engineering ❑ Construction Materials Testing J Special Inspections GEOTECHNICAL INVESTIGATION TEST' PCP LOG Test Pit Log #: TP -7 Date Advanced: 23 Apr 2014 Logged by: Noble Lafferty, E.I. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Depth to Water Table: Not Encountered Total Depth: 8.5 Feet bgs Depth (Feet bgs) Field Description and USCS Soil and Sediment Classification Sample Type Sample Depth (Feet bgs) QP Lab Test ID Sandy Silt (ML): Light brown, slightly moist, hard, intermittent moderate cementation, fine 0.0-5.0 grained sand. -- anic material to 6 inches bgs. Poorly Graded Gravel with Sand (GP): Light brown, slightly moist, medium dense, fine to medium grained sand, fine to coarse gravel, 5,0-8:5 4" minus cobbles. -- Increase in cobble sue with depth, 2p to 10 minus cobbles. Copyright OO 2014 Materiuls Costing& Inspecliun, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mtiC?mti-id.com • www,mti-id.com MATERIALS 6 May 2014 TESTING & Page# 32 of 36 INSPECTION la 140414g_geotech J Environmental Services J ;. technical Engineering J Construction Materials Testing J Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP -8 Date Advanced: 23 Apr 2014 Logged by: Noble Lafferty, E.I. Excavated by: Struckman's $ackhoe Service Location: See Site Map Plates Depth to Water Table: Not Encountered Total Depth: 6.0 Feet bgs Depth (Feet b s Field Description and USCS Soil and Sediment Classification Sample T e Sample Depth (Feet b s Qp Lab Test ID Poorly Graded Sand with Gravel (SP): Light 0.0-1.5 bromin, slightly moist, loose to medium dense, fine to medium grained sand, 4" minus cobbles. _ Poorly Graded Gravel with Sand (GP): Light brown, slightly moist, dense, gine to coarse 1.5-6.0 grained sand, fine to coarse gravel, 4" minus cobbles. -- Increase in cobble size with depth, up to 8" minus cobbles. Copyright ® 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 inti@roti-id.com • www .r id.com MATERIALS TESTING & INSPECTION 6 May 2014 Page # 33 of 36 b1404l4g_geotech J rimnunrnenlal Services Juecit,r.. -., nq ❑ •.y -i7 Special Inspections GRAVEL EQUIVALENT MEI IIOD - PAVE'MLNT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: Relfection Ridge Subdivision, Residential Roadways Average Daily Traffic Count: 33,131 All Lanes& Both Directions Design Life: 20 Years Traffic Index: 6.00 Gravel Equivalent, AC'MAL. Climate Factor: I R -Value of Subgrade: 11.00 Subgrade CBR Value: 5 Subgrade Mr: 7,500 R -Value of Aggregate Base: 80 0.773 R -Value of Granular Borrow: 60 Gravel Equivalent (Ballast): Subgrade R -Value: II 0.936 Eble= nc es Expansion Pressure of Subgrade: 0.03 Unit Weight of Base Materials: 130 Total Design Life 18 kip ESAL's: 33,131 ASPHALTIC CONCREM- Gravel Equivalent, Calculated: 0.384 'thickness: 0.1969231 6e -� nc tes Gravel Equivalent, AC'MAL. 0A I CR(ISHED AGGREGATE BASE: 1.95 Gravel Equivalent (Ballast): 0.768 Thickness: 0.329 Use 4 Inches Gravel Equivalent, ACTUAL: 0.773 GRANULAR BORROW: 4 .dlil Gravel Equivalent (Ballast): 1-709 Thickness: 0.936 Eble= nc es Gravel Equivalent, AC'Il1AL: 1.773 TOTAL Thickness: 1.542 'thickness Required by Exp. Pressure: 0.033 Copyright O 2014 Malcrials Testing & Inspection, Inc 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mliCumti-ideom • www.mti-id.com Design Depth Substitution Inches Ratios Asphaltic Concrete (at least 2.5): 1.95 Asphalt Treated Base (at least 4.2): 0.00 Cement Treated Base (at least 4.2):1OAo Untreated Aggregate Base (at least 4.2): 4 .dlil 1.10 Granular Borrow (at least 4.2):1 12.00 I.Oo Copyright O 2014 Malcrials Testing & Inspection, Inc 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mliCumti-ideom • www.mti-id.com MATERIALS 6 May 2014 TESTING & Page# 34 of 36 INSPECTION b 140414gxeotaoh J _ c ronmenlal Services - .,iechnical Engineering J Construction Materials Testing ❑ Special Inspections R -VALUE LABORATORY TEST DATA Source and Description: fest Pit 1 — Sandy Elastic Silt Date Obtained: Aril 23, 2014 Sample ID: 14-7159 Sampling and ASTM D75: 22.0 AASHTO T2: X ASTM 0.00 AASHTO X Preparation: 117 R -Value 14 11 D421: m f87: Test Standard: ASTM AASHTO Idaho T8: X 12.0 D2844: 1'190: � Sample A A 88.7 C 85.4 Dry—Density lb/ 90.5 Moisture Content (%) 18.2 20.3 22.0 Expansion Pressure (psi) 0,24 0.03 0.00 Exudation Pressure (psi) 422 218 117 R -Value 14 11 9 R -Value @ 200 psi Exudation Pressure = 11 Copyright @ 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-idcom • www,mti-ld.com R -Value @ Exudation Pressure 15.0 14.0 m 13.0 2 A 12.0 � 11.0 10.0 9.0 &0 1— - - 450 400 350 300 250 200 150 100 Exudation Pressure (psi) Copyright @ 2014 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti@mti-idcom • www,mti-ld.com U AVE )a w QEF. k E- AVE 'f GROVE RU d CIE 7A0 -E AVE J 7 a K 'I yA *y K a z wl. a C1 Ln tb zea w m n ca .E � g QIs_3'I9U3 E W �j. W E V} w -o € �—to a w PL Q z-4 -- Sa LW N r �JY���brJri,y�AS �ti7 NbfoNf N .d. � ad D N m � o o � 7 � s COLD BAR AVE vAll �n s Gyy S GR,MES CREEK AVE 114089AYOl1 hAR AVE U AVE )a w QEF. k E- AVE 'f GROVE RU d CIE 7A0 -E AVE J 7 a K 'I yA *y K a z wl. a C1 w m n .E q QIs_3'I9U3 d �j. 5 CRATER PL LODER pl V} w -o S ZIMS AVE PL a w ui x �JY���brJri,y�AS �ti7 NbfoNf N d D 7 W � s COLD BAR AVE vAll �IJyty37 s Gyy S GR,MES CREEK AVE 114089AYOl1 hAR AVE w , I �xxI al' � �h anp q.� 3Atl NiX�N3l9Nl N P� G ti Ile WI::UST GRPVE RLS _ 5 CHESAPEAKE AVE ON +H. SELKNOUtLD.PVk c4a w Y fiAR'WAYw oa 3YY� S IlACKSMITH PL � CL'�� Q4 SnPg 3Atl Ntl 1tIHAV41 S oann awn Nqrdma s ' AVM SD3l:1NV S OSIII S 0pRS Wr� II (� n I S���jjj�_ 02f NVId[133W.5=... L7 - w fi COVEY AVE 7� d� s nEa.R cLAw wnv 5 6LUE MARLIN LN Jry 5 BEAR CLAW SClUEtSN PL w C O V O J J 7 a K oY3 PL SClUEtSN PL w C O V O J Nn J 7 a K oY3 Nn