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PZ - GeoTech ReportWATERIALS TESTING & I NSPECTIQN © Environmentai Services G Geotechnical Engineering U Construction Materials Testing T❑ Special Inspections GEt�TECHNICAL ENGINEEI�IVG REP'C�RT of Calvary Chapel Treasure valley Lake Hazel Road Ada County, Idaha Prepared far: Calvary Chapel Tr�aSurE 'Valley 5312 Overland o Road Boise, Idaho 837 05 MTI File I1lumber 83C'iC'�54g 7446 W. Lemhi St., Boise, iD 837Q9 E-Mail mti@mti-id.com 2C}8 376-474$ Fax 2Q8 322-8818_..._ _.. www.mti-id.com MATERIALS TESTING & NSPECTION ❑ Environmental Services ❑ Geotechnicai IYIr, Daryl Zachman Calvary Chapel Treasure Valley 5312 Overland Road Boise, Idaho 83705 (2 08) 3424 072 Dear Mr. Zachman: ❑ Construction Materials Test] March 7, 2003 Page # 1 of 30 ❑ Special ins llmtiserverireports12003 1epo1 ts1000-1991b300846\b30084geotech.doc Re: Geotechnical Engineering I7.epprt -Soil Engineering, Engineering Geology,.and Engineering Hydrology Proposed Public Development Calvary Chapel Treasure Valley Ada County, Idaho In compliance with your instructions, we have conducted a soils expl©ration and foundation evaluation fox the above mentioned development. Field work .for this investigation was conducted on 5 February 2003. Data have been analyzed to evaluate pertinent geotechnical conditions. Provided geotechnical, groundwater and construction recommendations 'are listed in the Table of Contents. Results of this investigation, together with our recommendations, are to be found in the following report. we have provided three copies for your review and distribution. Often, because of design anal construction details chat occur on a project, questions arise concerning soil conditions. we would be pleased to continue our role as geoteemucal engineers during project implementation. MTr also has great interest in providing 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 be pleased to meet with you at your convenience. We appreciate this opportunity to be of service to you and we look forward t .work-ing with you in the future. If you have questions please call us at �208) 37�-4748. o�'��l�`�'�! Respectfully Submitted, L.SCHRO��EDER Mat rials 'Testing & Inspection, Inc. Jennifer 1Vfiller reviewed by Kevin Staff Geologist Geot��cal S�i a ed General dd P?'E. tiWO ri; 74461N. �.emhi St., Boise, ID 83709 E-Mail mti @ mti-id.com 2Q8 376-4748 ;CQn aterials:Testirtg &Inspection, Inc. 208222 www.mti-id.com MATERIALS 'reSTING & NSPECTION March 7, 2003 Page # 2 of 30 U Environmental Services 0 Geotechnical Engineering O Construction Materials Testing ❑ Special inspections 1lmtiserverlrepQrts12D03 reportsi0fl{1-199\b30D84g1b30084geotecl1.doc TABLE OF CONTENTS EXX'rCUTIVE SUMMARY........................................................................................................3 �NTRODUCTION.................................................................................................................... S ProjectDescripfion....................................................:.......................................... S Authorization........................................................................................................ S Scope...................................................................................................................... S Warranty And Limiting Conditions................................................................... 6 General...............................................................................,.......................... , ....... 6 DESCRIPTIONOF SITE.............................................1......,....................................................7 SiteAccess............................................................................................................. 7 General Geology Of Area................................................................................... 7 Site Topography, Drainage And Vegetation......................................................7 Site Climatology And Geochemistry................................................................... $ GeoseismicSetting...............................................................................................8 SOILSEXPLQRATION.......RN.HH.f...HH.{..H....f.............u..N....Jl..a.JI.H.J.......M.H.HN.................. V Exploration and Sampling Pracedures............................................................... 8 Laboratory Testing Frogram.............................................................................. 9 Soil And Sediment Profile................................................................................... 9 SoilsSurvey Review............................................................................................. 9 'Volatile Organic Scan.................onto ............. as, ... man ..... memo ..........,..... name .................,14 SITE�YDROLOGYf..ua......►..u.w...........r.....a.....r.•..•,.«.•..................u..................u............r..• 10 GeneralNotes...................................................................................................... i0 Graundwater........................................................................................................ IO f-Iydraulic Conductivity.......................................................................................11 FOUNDATION, SLAB ANU �"AVEMENT DISCUSSION ANll RECOMMENDATIONS .................12 GeneralNotes.......................................................................................................12 Foundation Design Recammendations...............................................................12 FloorSlab -On -Grade ....................................... ..................................................13 fiecommended Pavement Sections.......... W** 0 *be *Roma *got step One one a 0 **to Teammate 0 a,w*9 e 13 CCs1YSTItUCTI4N CONSIDERATIONS.....................................................................................15 Earthwork............................................................................................................15 DryWeather.........................................................................................................16 WetWeather........ to Was****#$* memo 0 *WrmW&4XaOA 0*2 was**** met mean a war* 0 fo*qa*jo%o 16 SoftSubgrade Soils.......... &of* *80n44 00 fees IVOA* 0*6 6RUa04****o name 0 a A* 6 *000 a e at 4 0#40 sweet 6*09 1 TV** lb Frozen Subgrade Soils........................................................>................. .017 StructuralFill .......................................................................................................17 Backfill..................................................................................................................17 Excavations...........................................................................................................1$ GraundwaterControl.********* *Rea Menomonee Us +40aa*4 none" *bananas At 4 6 one *40* btwv4o%o *6 #000 0 see 18 GENERALCOhII�IENTS......................................................................................................... 18 REFERENCES........................................................................................................................ X9 APPENDIXLIST.................................................................................................................... 20 Geotechnical General Notes................................................................................ 21 Unified Soil Classification....................................................................................22 TestPit Logs......................................................................................................... 23 Pavement Thickness Tlesign.................................................................................29 .__.___.. ~VW _._.__._....w.....__...._.._._._........_.._..........._..__.___._____._.___ __ �.CQpyright ©7003_Mater1a1q jesting & Inspection, Inc. 7446 W. Lemhl St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E-Mail mti@mti-id.com www.mtl-id.com NIATeRIALS reSTI NG & NSPCECTION March 71 2003 Page # 3 of 30 ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special inspections 1lmtiserverkeports12003 1eports100fl-I491b30084gib30084geotech.doc EXECtJTY'c� Str�� The following is a brief summary of significant geotechnical issues for the proposed development, presented with conclusions and recommendations. This summary must be read in conjunction with the entire accompanying report for proper interpretation of the overall investigation. Subsurface Conditions: Test pits were advanced to depths of 4.0 to 6.5 feet across the site. Groundwater was encountered in all test pits. Because of the areal extent of the studied parcel, the developed soil profile .represents only a generalized case. The following soils were not encountered in each test pit, but instead represent a hypothesized profile as compiled from observations in each of the six test pits advanced: Surficial Sandy Lean Clay PI.Q'W ZQl� {CL-PLQ'VV ZQI�IE} -- This soil was encountered at the ground surface in all six test pits, consisting of dark brown, slightly moist to moist, soft to stiff, sandy lean clay with excessive organic content in the upper 6 inches. Plow zones extended to depths ranging from 0.8 to 1.5 feet across the site. Sandy Lean Clay (CL) — Underlying the surficial plow zone is undisturbed sandy lean clay. The clay soils were found to be dark brown, slightly moist to moist, stiff, and extended to depths 1.3 to 3.6 feet below existing grades. Poorly Graded Gravel (GP) Poorly graded gravels were encountered below the clay soils. The gravel sediments were light brown to brown, moist to saturated, medium dense, and consisted of 4-inch minus cobbles and coarse grained sand. Poorly graded gravels extended through termination depths within the test pits. Groundwater Conditions: Groundwater vvas encountered within all test pits advanced during the field investigation. Soil moistures in the test pits were generally slightly moist to moist within the upper 3 feet and moist to saturated as the water table was encountered. Groundwater was encountered at depths ranging from approximately 3.5 to 4.5 feet below the ground surface. The estimation of the extent to which groundwater levels fluctuate under seasonal influences is problematic without regular monitoring. However, based on the evidence of this investigation, and background knowledge of the area, groundwater will likely be encountered at depths as shallow as 18 inches below the ground surface during irrigation season. 7446 W. Lemhi St., Boise, !D 83709 E-Mail mti C�3 mti-id.com Go�yrigE��Q..Z�.Q3 M��ial��ti�� &Inspection, Inc. 208 376-4748 Fax 2q8 q22-6515 www.mti-id.com MATERIALS reSTING & NSPECTION 0 Environmental Services 0 Geotechnical ineering 0 Construction Materials CI S March 7, 2003 Page # 4 of 30 ons �lmtiserverlr%mrF%j 2Q03 reports1Q00- 611V 84geotec1.doc Devvaterrng of Site: Groundwater was encountered in the investigation and is likely to impede construction. Excavations below the water table will require a dewatenn9 program. It may be possible to discharge dewatermg effluent to remote portions of the site or to a strategically located sump or pit. MTI should be contacted to provide more detailed groundwater control measures Building Foundations: On the basis of data obtained from the site and test results from various laboratory tests performed, MTZ recommends following guidelines be used for the net allowable soils bearing capacity. Footin De th ASTM D 1557 Subgrade Compaction Net Allowable Soils Bearing Footings should bear on compacted structural fill -Capacity extending to competent, native, poorly graded sand or Not required for native soil 2,500 lbslfe poorly graded sandy gravel soils. All clay soils must be removed to expose sand and gravel soils below all footings. Excavation depths of 1 to 4 feet below existing grades should be anticipated. Depending on time of construction, dewatering of foundation excavations should be antic' aced. Because of highly variable soil condi cture performed by a Building Floor Slabs: 1 engineer at of beari �a soils for each coon. Because of the relative i ly shallow groundwater levels in the vicinity of the site, surficial clay soils are likely to be relatvely soft and moist, particularly during the izxigation season. Prior to placement of structural fill below floor slabs, the subgrade must be stripped and proof rolled, with any organic, loose, or obviously compressive materials completely removed. The remaining subgrade should be treated in accordance with Earthwork guidelines and other Construction Considerations presented later in this report. Areas of excessive yielding should be excavated and baekfilled with structural fill. '113 avement: Construction of the pavement section should be in accordance with these specifications and should adhere to guidelines recommended in them section on Construction Considerations. Pavement Section Cornponent Dnvewa s and Parki ij Truck Access Drive%vays and Parkin No Truck Access Crushed Aggreg e Base HIM Structural . Base Rol" " Compacted Subgrade Not Required Depending on timing of construction and prevailing soil moistures, increasing of Granular Borrow section and/or use of stabilization fabric such as Amoco 200612016 maybe required. -Y....�..�...- _.._.____..__.�� _ ..__.�..��..... Ccpyright_Q.2Q03.Materials5esting & Inspection, Inc. 7446 W. t_emhi St., Boise, ID 83709 248 376-474$ Fax 208 322-6515 E-Mail mtic�mti-id.com www.mti-id.com MATMALS TESTING & M NSPIEcTION ❑ Environmental Services ❑ Geotechnical ❑ construction Materials Te March 7, 2003 Page # 5 of 30 ❑ Special I 1lmtiservfu %:;Pv"zl 03 reports1000-199\b30084g1b30084geotech.dac YNTRC}DUCTxO►N 'This report presents results of a geoteclanical investigation and analysis in support of data utilized in design of structures as defined in the 2000 International Building Code (IBQ. Information in support of groundwater and stormwater issues pertinent to the practice of Civil Engineering is included. Observations and recommendations relevant to the earthwork phase of the project are also presented. Project Desexiptzon: The proposed development is south of the City of Boise, Ada County, Idaho, and occupies a portion of the NE'/4NWY4 of Section 4, Township 2 North, Range 1 East, Boise Meridian. The project will consist of construction of 4 buildings and one out maintenance building with associated parking areas. Total settlements are limited to 1 inch. Loads of up to 2,000 pounds per lineal foot for wall footings, and column loads of up to 50,000 pounds were assumed for settlement calculations. Additionally, assumptions have been made for traffic loading of pavements, Retaining walls are not anticipated as part of the project. At this time, proposed finished floor elevations are presently unknown. Authorization: Authorization to perform this exploration and analysis was given in the form of a verbal authorization to proceed from Mr. Daryl Lachman to David O. Cram of Materials Testing and Inspection, Inc. tM11), on 15 January 2003. Said authorization is subject to terms, conditions, and limitations described in the Professional Services Contract entered into between Calvary Chapel Treasure 'Valley and MTI. Our scope of services for the proposed development has been provided below. Purpose: The purpose of this Geotechnical Engineering Report is to determine various soil profile their engineering characteristics far use by design engineers and/or architects in: itability of foundation design and placement, • Preparing or verifying su • Preparing site drainage designs, • Indicating issues pertaining to earthwork construction, connponents and • Addressing the requirements of Ada County Code requirements for Soil Engineering, Engineering Geology, and Engineering Hydrology. Scope: The scope of this investigation included review of geologic literature and existing available geotechnical studies of the area, review of available environmental reports, visual site reconnaissance of the immediate site, subsurface exploration, field and laboratory testing, and an engineering analysis and evaluation of foundation materials. ..._._._.. .... _...Capyright_@. 20D3..MatexiaLslesting & Inspection, Inc. 7446 W. E.emhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E-Mail mt0 Q mti-id.com www.mti-id.com MATERIALS TESTING & i NSPECTION March 7, 2003 Page # 6 of 30 0 Environmental Services ❑ Geoteehnical trIgIneering 0 Construction Materials lestino 0 5 ecial inspections. tlm�iserverkeports120d3 reports\000-1991b30084gtb30Q84geotech.doc 'Warrarxty And Ilimiting Conditions: Meld observations and research reported herein are considered sufficient in detail and scope to form a reasonable basis for the purposes cited above. MTI warrants that findings and conclusions contained herein have been promulgated 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 subject property within the scope cited above and are necessarily limited to conditions observed at the time of the site visit and research. The report is also limited to information available at the time it was prepared. In the event additional information is provided to MTI following the report, it will be forwarded to the client in the form received for evaluation by the client. 'There is a distinct possibility that conditions may exist which could not be identified within the scope of the investigation or which were not apparent during the exclusive use of Calvary Chapel 'Treasure Valley Conclusions and recommendations presented in this site investigation. This report was prepared for the and their retained design consultants ("Client"). report are based upon agree&upon scope of work outlined in the report and Contract for Professional Services between Client and Materials Testing and inspection, Zne. ("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 whatever, known or unknown to Client or Consultant. Neither Client nor Consultant shall have liability to, or indemnifies or holds harmless third parties for losses incurred by actual or purported use or misuse of this report. No other warranties are implied or expressed. General: Revisions in plans and or drawings for the proposed structures from those enumerated in this report should be brought to the attention of the soils engineer to determine if changes in foundation reconunendations are required. Deviations firom noted subsurface conditions, if encountered during construction, should also be brought to the attention of the soils engineer. 7446 W. Lernhi St., Boise, ID 837�8 2Q8 376�4748 Fax 208 322-6�15 E-Mail mti@mti-id.com www.rnti-id.com MATGRIALS 'reSTING & M N S P rECT10111 �1�Iarch 7, 2003 Page # 7 of 30 ❑ Environmental Services J Geotechnicai Engineering ❑ Construction Materials Testing ❑ Special inspections 1lrnt10% rl Y%O reportst2003 reportslOQO-l99\b3Q084g1h30084gentech.doc I}E0C1%xPTZO11NT l�I+' SITE SYte Access: Access to the site may be gained via Interstate 84 to Exit 46 tEagle Road Exit}. Proceed south on Eagle Road approximately 3 miles to Lake Hazel Road. Tura east on Lake Hazel Road and continue for approximately Yz mile to the proposed site. The parcel is located on the south side of Lake Hazel Road and is bounded by Ten Mile Creek on the west and Boise Ranch Golf Course on the east. Presently the site exists as undeveloped agricultural land. The location is depicted in site map plates included in the Appendix. Genexal Geology ()f Area: The subject site is located within the Boise Valley which is directly underlain by a thick sequence of alluvial sands and gravels typically deposited on basalt formations. These sediments are loosely named the Boise River Gravels and were deposited as river i'loodplain and stream outwash from the Boise River. These gravel deposits tend to have imbricated well- rounded clasts, poor sorting and crude stratification. Beds of gravel and lenses of crass -bedded sands/silts suggest deposition in braided channels. The Boise River Gravels consist of unconsolidated clay, silt, sand, gravel, and cobbles. The vast majority of #his material has been derived from Idaho Batholithic granitic rocks. These are relatively recent materials of Quaternary age (<l.d million years). The site is adjacent to Ten Mile Creek, and has been mapped as Sandy Alluvium of Side - Stream Valleys and Gulches. These sediments line or mantle these drainages and locally inter -finger with sands and gravels of the Boise Terrace gravels. These sediments commonly consist of medium to coarse sand interbedded with silty fine sand and silt, Of note are minor pedogenic clays and calcium carbonate cementation. Site Topagrapliy, Drainage ,A.nd Vegetation: he proposed developzxient consists of a relatively flat, triangular -shaped lot. Ten Mile Creek is unlined and runs along the western boundary of the site. The creek was dry at the tune of this investigation. .Regional drainage is west toward Ten Mile Creek and north to the Boise River. Stormwater drainage for the site is achieved by percolation through surficial soils. No stormwater drainage facilities are located in the vicinity. 'Vegetation throughout the area consists primarily of grasses and remnants of agricultural activities. 7446 W. Lamhi St., Boise, li? 83709 E-Mail mtiC�mti-id.com ...._ .._.__._Cepyright_Q2.QQ3_Materials�e�ting &inspection, lnc. 208 376-4748 Fax 208 322-6515 www.mti-id.com MATERIALS reSTING & NSPrECTION ❑ Environmental Services ❑ Geotechnical Site Climatology And Geochemistry: Cl Construction Matonals T'esun March 77 2003 Wage # 8 of 30 ❑ SCIP.[:iAl In ilmtJaW V%erlreports12a03 reports100a-1991b300$4rvIU 84geatcch.doc Average precipitation for the region is an the order of 10 to 12 inches per year. Annual average temperature range from 20' F to 9 V F with extremes ranging from -4° F to 102" F. Average wind speed range to 11 miles per hour in spring with a prevailing direction from the southeast. Soil in the area is primarily derived from siliceous materials and exhibits low eleetro-chemical potential for corrosion of metals or concretes, Local aggregates are generally appropriate for Portland Cement and Lime Cement mixtures. The State Transportation Department has adopted anionic asphalt cements. The pH of surface water, groundwater, and soil in the region typically range from 7 to 9. No indication of abnormal geochem.ical conditions was noted on -site. Nominal frost penetration is typically on the order of b inches, with extremes ranging to 3 feet. Geoseismic Setting: Soils on -site are classed as Site Class D in accordance with Chapter 1 � of the 2000 edition of the IBC. The mapped spectral acceleration at short periods (Ss) should be taken as 35, with the spectral acceleration at a I. second period (SI) taken as 10. Building structures on this project should be designed as per the IBC requirement for such a seismic classification. Our investigation did not reveal characteristics particularly susceptible to seismic hazards. Incidence and anticipated acceleration of seismic activity in the area is low, SC)ILS E�P�ORATICIN Exploration And Sampling Procedures: The field exploration to determine engineering characteristics of subsurface ma#erials included a reconnaissance of the project site and investigation by test pit. Test pit sites were located in the field by means of normal taping procedures from on -site features or known locations and are presumed to be accurate to within a few feet, Capon completion of investigation each test pit was backfilled in with loose excavated materials. These loose areas need to be re -excavated and compacted prior to constructing structures over them. Samples were obtained from representative soil stra#a encountered in test pits. Samples obtained have been visually classified in the field by an engineer yr geologist, identified according to test pit number and depth, placed in sealed containers and transported to our laboratory for additional testing. These materials have been further desc�7bed in detail on logs provided in the Appendix. Results of field and laboratory tests are also presented on these logs. It is recommended that these logs not be used for estimating quantities because of highly interpretive results. ?446 W, Lemhi St., Boise, 1D 83709 208 376-4748 Fax 20$ 322-0515 E-Mail mti Q mti-id.com www.mti-id.com MATERIALS TESTING & I NISPECTI ON ❑ Environmental Services ❑ Geotechnical Laboratory 'besting Program: ❑ Construction Materials Test March 7, 2003 Page # 9 of 30 ❑ Special inspections `lmtiserverireports12003 reports1000-I99\b30084r w30084geotech.doc Along with the field investigation, a supplemental laboratory testing program was conducted to determine additional pertinent engineering characteristics of subsurface materials necessary in analyzing the behavior of the proposed structures. Laboratory tests were conducted according to 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 designation D 431$, and Grain Size Analysis - ASTM designation C 117, C 136. Soil And Sediment Profile. Test pits were advanced to depths of 4.Q to 6.5 feet across the site. Groundwater was encountered in all test pits. Because of the areal extent of the studied parcel, the developed soil profile represents only a generalized case. The following soils were not encountered in each test pit, but instead represent a hypothesized profile as compiled from observations in each of the six test pits advanced: Surficial Sandy Lean Clay PLOW ZONE (CL-PLO'VV ZONT�} -This sail was encountered at the ground surface in all six test pits, consisting of dark brown, slightly moist to moist, soft to stiff, sandy lean clay with excessive organic content in the upper 6 inches. Plow zones extended to depths ranging from 0.8 to 1.5 feet across the site. Sandy Lean Clay (CX,) —Underlying the surficial plow zone is undisturbed sandy lean clay. The clay sails were found to be dark brown, slightly moist to moist, stiff, and extended to depths 1.3 to 3.6 feet below existing grades. Poorly Graded Gravel (GP) - Poorly graded gravels were encountered below the clay soils. The gravel sediments were light brown to brown, moist to saturated, medium dense, and consisted of 4-inch minus cobbles and coarse grained sand. Poorly graded gravels extended through termination depths within the test Walls of each test pits were stable with the exception of those through the saturated gravels. Excavations through fill and granular soils, particularly after penetrating the water table, will. have a propensity for sloughing or caving. Soils Survey Review. A review of the United States Department of Agriculture, Soil Conservation Service, Soil Survey of Ada County Area, Xdaho, 19$0, indicated the site can be characterized as Aerie Hapalaquepts soil type. Flooding is a hazard within these soils in years of unusually high precipitation. Depth to the water table ranges from 18 to 36 inches in summer. Runoff is very slow, and the hazard of erosion is slight. 744fi W. Lemhi St., Boise, ID 837n9 208 376-4748 I;ax 208 322-6515 E-Mail mti@mti-id.com �Nww.mti-id.com MATeRIALS reSTING & NSPIECTION March 7, 2003 Page # 10 of 30 Environmental Services ❑ Ceotechnical Engineering ❑ Construction Materials lesting ❑ Special Inspections 1\mtiserver\reportsreports\000-199\b30034g\b300$4geotech.doc V©lathe Qirga>aic 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 photoxonization detector. Samples obtained during our exploration activities exhibited no odors or discoloration typically associated with this type contamination. SITE �YD�.t)LOGY General Dotes: existing surface drainage conditions are defined in the Description of Site. Zx�.formation provided in this section is limited to observations made at the time of the investigation. Regional and/or local ordinances may require information beyond the scope of this report. The site is bordered to the west by Tenmile Creek. This section of the creek carries primarily runoff from irrigation activities upstream and groundwater. Water coming into this section of the creek is controlled by a small earthen dam at the southern end of the subject property. The dam appears to allow for collection of water for irrigation purposes. Discussions with neighbors revealed that excessive irrigation runoff water into the dammed area has caused isolated flooding at the southern end of the subject property. This situation can be corrected by increasing the height of the canal 1 dam embankments. Groundwater: Groundwater was encountered within all test pits advanced during the field investigation. Sail moistures in the test pets were generally slightly moist to saturated within the upper 3 feet and very moist to saturated as the water table was encountered. Groundwater was encountered at depths ranging from approximately 3.5 to 4.5 feet below the ground surface. The estimation of the extent to which groundwater levels fluctuate under seasonal influences is problematic without regular monitoring. Groundwater levels in the site vicinity are controlled ix� large part by residential, commercial, and agricultural irrigation activity and canal leakage in the local area, and are likely at their maximum elevations during the irrigation season. Based on the evidence of this investigation, and background knowledge of the area, groundwater will likely be encountered at depths as shallow as 18 inches below the ground surface during the irrigation season. MTI has installed piezometers in the southern and northern portions of the site to monitor fluctuations of the water table. MTI will continue to monitor water table levels throughout the year. ._.______ �_ _ �__..� �'opyxighLQ2I143..a'1�aterials.Testing &inspection, Inc. 7446 W. l.emhi St., Boise, !D 837Q9 2�8 376-4748 Fax 2d8 322-6515 E-Mail mti @ mti-id.corn www.mti-id.com MATERIALS reSTINC & NSPECTION March 7, 2003 Page # 11 of 30 O Environmental Services U GeotechnicaE Engineering U Construction [Materials lesting ❑ Special Inspections 1lmtiserverlrelivit 003 reports1000-I991b30084g1b30084geotech.doc FZUUdllil6: A review of the Federal Emergency Management Agency's (FEMA) Flood Insurance Rate Maps {FhZM) revealed that the site is not within the one percent flood area (or hundred year flood). A majority of the site is identified as being outside the 0.2 percent annual chance floodplain, per FIRM number 16001 CO265 (revised February 19, 2003). However, the Tenmile Creek area is identified as being subject to inundation by the 1 percent annual chance flood event. Construction within this area would require structural fill placement and special permitting, as is therefore not recommended. See Appendix for FIRM information. Far site development, several items will need to be implemented as part of construction: 1. All below grade structures more than 2 feet in depth will require either a de -watering system and/or waterproofing membrane. 2. Onsite septic system(s) may require elevation of the drain field. Long4errn monitoring of the groundwater fluctuations will determine the actual need for this recommendation. 3. Permanent drainage of the site can be achieved by installing gravel drains across the site. Drains would consist of trenches at least 4 feet in depth and 2 feet wide, sloping from east to west to Tenmile Creek. The drains could be backfilled with free draining materials as specified in the structural fill section of this report. 4. Foundation drains are required around the exterior of all foundation systems. The drains shall consist of 4 inch diameter perforated PVC pipe placed adjacent to the bottom of the spread footings. The pipe must be encased in 3 inches of 2" minus drain rock and wrapped in filter fabric (6 ounce per square yard). All drains must be sloped at least 1.5% to ensure proper drainage. S. The above recommendations are preliminary in nature and will require further consultation and possible revisions once long-term groundwater fluctuations and design requirements are established. Depending on groundwater data, elevation of the building structures may warranted. Hydraulic Conductivity: Soil permeability is a measure of the ability of a liquid to move through a soil and was not tested in the field. Xx� this report this parameter is approximated by soil type and gradation. of soils comprising the generalized soil profile for this study, sandy lean clay soils generally offer little permeability, with typical hydraulic conductivity values ranging from less than 2 to 4 inches per hour. Poorly graded gravel with sand soils typically exhibit hydraulic conductivity values in excess of 24 inches per hour. 7446 W. Lemhi St., i3aise, Id $3709 E-Mai! mti@mti-id.com r-.._____�-_,_,..�..Copyright©_20.O�.Materialsl'esting &inspection, Inc. 20$ 376-474$ fax 208 322-6$i 5 www.mti-id.com MAT6RIALS TESTING & INSPECTION march 7, 2003 Page # 12 of 30 ❑ Environmental Services t j Geotechnical Engineering ❑ Construction Materials Testing ❑ Special inspections 1lmtiserverlreports12QQ3 repo6% 30084geotech.doc FOUNDATIONS �7I,AB A,l`'D A.VFIVIEN'J, DISCUSSION AIYD RECOMIVMNDATIONS General Notes: Various foundation Types have been considered for support of the proposed building structures, Two requirements must be fulfilled in the design of foundations. First, the load must be less than the ultimate bearing capacity of foundation soils to maintain stability; and secondly, total and differential settlement must not exceed an amount that will produce 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 if the following design and construction recommendations are observed. Foundation DesYgn Recommendations: 4n the basis of data obtained from the site and test results from various laboratory tests performed, MTl recommends following guidelines be used for the net allowable soils bearing capacity, Footing Depth AST1Vf D 1557 Subgrade Compaction Net Allowable Soils Bearing Capacity Footings should bear on compacted structural fill extending to competent, native, poorly graded Not required for native 21,500 lbs/ft� sand or poorly graded sandy gravel soils. All clay soil soils must be removed to expose sand and gravel soils below all footings. Excavation depths of 1 to 4 feet below existing grades should be anticipated. Depending on time of construction, dewatering of foundation excavations should be anticipated. Because of hiphl�y variable soxl.conditions across the site, ve�r�ficatxoia of bearing soils for each structure must be ed by a qualified nxeal engineer 7446 W. Lemhi St., Boise, 1D 837Q9 2Q8 376-4748 fax 2Q8 322-6515 E-Mail mti®mti-id.com www.mti-id.com (MATERIALS TESTING & INSPECTION ❑ Environmental Services ❑ Geotechnical Engineers ❑ Construction Materials Tests March 7, 2003 Page # 13 of 30 ons \lmtis%al Vko reports12443 reports�060-199\b30484g1b3Qq$q.geotech.dac Footings should be proportioned to ro.eet the stated bearing capacity and/or fihe 200Q IBC minimum requirements. Total settlement should be limited to about 1 inch with differential settlement of approximately 1/2 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 in seasonal moisture content, MTI recommends continuous footings be suitably reinforced to make them as rigid as possible. For frost protection, the bottom of external footin sg should be 3Q inches below finished grade. Floor Slab -On -Grade: Because of the relatively shallow groundwater levels in the vicinity of the site, surf�cial clay soils are likely to be relatively soft and moist, particularly during the irrigation season. Prior to placement of structural fill below floor slabs, the subgrade must be stripped and proof rolled, with any organic, loose, or obviously compressive materials completely removed. The remaining subgrade should be treated in accordance with Earthwork guidelines and other Construction Considerations presented later in this report. Areas of excessive yielding should be excavated and backfrlled with structural fill. Fill used to increase the elevation of the floor slab should meet requirements for structural fill. Refer to the section on Structural Fill for these requirements. A free draining granular m.at (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 generally complying with ASTM D 1241 Type 1 Gradation A aggregate. No less than 90°10 of this aggregate shall pass the 3/4 inch screen and no more than 10% of the aggregate shall pass the #200 screen. Maximum nominal aggregate size shall be 3/4 inches. A vapor barrier should be placed beneath floor slabs to minimize potential ground moisture effects on floor coverings. The granular mat shall be compacted to no less than 95% of maximum density as determined by ASTM D 1557. Recommended Pavement Sections: MTl has made assumptions for traffic loading variables based on the character of the proposed construction. The Client should review these assumptions to make sure they reflect intended use and loading ofpavements both now and in the future. Based on experience with soils in the region, a subgrade C.B.R. (California Bearing Ratio) value of 4 has been assigned for the site. The following thicknesses are MINWUM THICKNESSES for assured pavement function. Depending on site conditions, additional work may be required to support construction equipment. These have been listed within the section on Soft Subgrade Soils. 7446 W. Lemhi St., Boise, !C3 83749 2fl8 376-4748 Fax 208 322-65'15 E-Mail mti @ mti-id.com www.mti-id.com MAT6RiALS reSTING & I NSPECTION O Environmental Services t� Geotechnlcal En Flexible Pavement Sections 0 Construction Materials March 7, 2003 Page # 14 of 30 ons tlmtiserverlreports12003 reports1000A 91b300"r.630084geotech.doc The AASIIT(� design xnelhod has been used to calculate the following pavement sections. Calculation sheets provided in the Appendix indicate the soils constant, traffic loading, traffic projections acid material constants used to calculate the pavement sections. MTI recommends that materials used in the construction of Asphaltic Concrete Pavements meet requirements of the State of Idaho Transportation Department (ITD) 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. man kM Asphaltic Concrete - Inches - s t - s• `• • • T 1 4 t Structural Sub�Base `9121VIVO Isla! Compacted Subgrade Not Required Not e quired iDepending on timing of construction and prevailing soil moistures, increasing of Granular Borrow section and/or use of stabilization fabric such as Amoco 2006/2016 may be required. Aggregate Base Material complying with ITD Standard Specifications for highway Construction sections 303 and 703 for aggregates. Structural Subbase Material complying with the requirement for granular structural fill in the Soils Report Bh%YCEPT that maximum material diameter is no more than 2/3 of the component thicleness. Common Pavement Section Construction Yssues The subgrade upon which above pavement sections are to be constructed must be properly stripped, inspected and proof rolled. Proof Trolling of subgrade soils should be accomplished with a heavy rubber -tired fully loaded tandem axle dump truck or equivalent. MTI anticipates that pavement areas will be subject to moderate traffic. Pumping or soft areas must be removed and replaced with structural fill. Fill material and compacted native subgrade soils (if required} in support of the pavement section as well as aggregates comprising the pavement section must be compacted to not less than 95% of maximum dry density indicated by ASTM D 698 for flexible pavements and by ASTM D 1557 for rigid pavements. If a material placed as a pavement section component cannot be tested by usual compaction testing methods, compaction of that material shall 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 receptacle parking. This will eliminate damage caused by the considerable load of containers transferred onto the small steel wheels and subsequently onto the asphaltic concrete. Rigid concrete pavement should consist of Portland Cement Concrete Pavement (PCCP) generally adhering to ITD specifications for Urban Concrete. PCCP shall be 6 inches thick on a 4 inch drainage fill course (see Floor Slab"on-Grade section), should be reinforced with welded wire fabric, and control joints shall be on 12 foot centers or less. C4pyrighE_&200.3_iYlatQriabLTesting & Inspection, Inc. 7446 W. Lemhi St., Boise, !D 83709 208 378-4748 Fax 208 322-6515 E-Mallmti@mtlmld.com www.mti-id.com MATGRIALS Tr=STI NG & INSPECTION March 7, 2003 Page # 15 of 30 ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing 0 Special Inspections 1lmi10%01 V%6 reports12003 reparts1000-1991b30084g1b3a084geotech.doc C kill JV AV V %W TION C ONSIDERATIONS Earthwork: Recommendations in this report are based upon structural elements of the project being founded on competent native clay silt�sand mixtures or compacted structural fill. Structural areas should be stripped to an elevation that exposes these soil types. Excessively organic soils, deleterious materials, and/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. Grasses with associated root systems were noted at the time of our investigation. It is recommended that organic and/or disturbed soils, if encountered, be removed to depths of I foot (minimum), and wasted or stockpiled for later use. Stripping depths should be adjusted in the field to assure that the entire root zone and/or disturbed zone (plow depths), has been removed prior to placement and compaction of structural fill materials. In addition, prior to placement of structural fill material, the existing subgrade must demonstrate stability. Therefore proof rolling with heavy equipment will be required to verify stable soil conditions. Exact removal depths should be determined during grading operations by a qualified geotechnical representative, and shall be based upon subgrade soil type, composition, and firmness or soil stability. It should be noted that relativelysoft, moist, clay soils are present at the ground surface. Depending on time of year of construction, these soils will be difficult, if not impossible to work with. Therefore, if hif h soil WIN moistures are prevalent at the time of construction, areas of siggificant cuts or fills or structural areas will likely require removal of these soils, and subsequent replacement with structural fill. Considering this, strip.uindepths of up to 4 feet may e required in areas of the site. See Soft Sublrade Soils section of this report for specific recommendations for dealing with soft souls. However, it should be noted, that depending on time of vear of construction and presence of irrigation water, complete removal of silty soils may not be required. After existing subgrade soils are excavated to design grade, proper control of subgrade conditions (i.e., moisture content} and placement and compaction of new fill (if requited} should be overseen by a representative of the soils engineer (MTI). Recommendations for structural fill presented within 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. 7446 W. L.emhi St., Boise, ID $3709 E-Mail mti C�J mti-id.com Cc�pyzight_Q.200�Materials�sting 3c Inspection, Inc. 20$ 376-4748 Fax 2a8 322-6815 www.mti-id.com i% ATEP1ALS reSTING & NSPECTION March 7, 2003 Page # lb of 30 ❑ Environmental Services ❑ Geotechnical Engineering ❑Construction Materials Testing ❑ Special inspections 1lmt10%01V%* reperts12003 reports61b300$46;;VM%; .UOC Dry 'VVVeather0 if construction is to be conducted during what is considered "L)ry�' seasonal conditions, problems associated with soft soils may be avoided. However, shallow groundwater conditions, related to springtime runoff and/or late summer/early fall irrigation, may induce rutting subgrade soils. Solutions to problems associated with soft subgrade soils are outlined below. Problems may also arise because of lack of moisture in native and fill soils at time of placement. This will require addition of water to achieve near optimum moisture levels. Low cohesive 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 m anagernent plan. V'�et ,Weather: zf construction is to be conducted during what is considered "Wet" seasonal conditions (commonly from mid -November to April), 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 5ubgrade Sails: Shallow fine grained subgrade soils that are high in moisture content can be expected to pump and rut under construction traffic. The following recommendations and/or options have been included for dealing with anticipated subgrade conditions. • Track -mounted vehicles should be used to strip subgrade of root matter and other deleterious debris. :Heavy rubber -tired equipment should be prohibited from operating directly on native subgrades, and in structural areas such as roadways and foundations. Construction traffic can be restricted to designated imited basis, proposed roadway or parking subgrades. roadways that do not cross, or cross on a l • During periods of wet weather, construction on -site may become very difficult if not impossible. To ensure constructability, access/haul roads should be constructed with a minimum of 2 feet of structural fill material. Fill material should consist of relatively large cobble (4 to b inch in diameter) with sufficient fines to fill voids. • Instead of structural fill placement, scan cation and aeration of subgrade soils can be employed to reduce the moisture content. After stripping is complete, the exposed subgrade should be ripped and/or disked to a depth of 1.5 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. « Alternate recommendations can be provided involving lime or cement stabilization and use of geotextiles, upon request. 7446 W. Lemhi St., Boise, 1D 83709 208 376-4748 fax 208 322-6515 E-Mail mti � mti-id.com www. mti-id.com M ATE R I,ALS TESTING & 1 NSPGCTION C% Environmental Services Frozen Subgrade Soils: O Geotechnical Enainee O Construction Materials Testin 1VZarch 7, 2003 Page # 17 of 30 ns \lmtiseiverlrLevu rts12003 reports1000-1991b30d84g1b30084geotech.doe Frozen subgrade soils must be allowed to thaw, ar may be stripped prior to placement of structural fill materials or foundation elements. Frozen soils must be removed to depths that expose non -frozen soils and wasted or stockpiled for later use. These soils must be allowed to thaw and return to near optimum conditions prior to use as structural fill. Structural FiIY: Soils suitable for use as structural fill_ are those classified as GVi1, GP, GNS, SW, SP, S1V1, and 1VIf., in accordance with the Unified Soil Classification System (USCS) (ASTM D 2487). Granular structural fill (USCS designation GW, GP, SW, SP) should consist of a 6 inch minus select, clean, granular soil with no more than 30% oversize (greater than Y4 inch) material and no more than 12% fines (less than #200) and placed in layers not to exceed 9 inches in thickness. Prior to placement of structural fill materials, surfaces must be prepared as outlined in the Construction. Considerations section. Each layer of structural fill should be compacted to a minimum density of 95% of maximum dry density as determined by ASTM D 1557 (for rigid structures) or D 698 (for flexible pavements). 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. The use of silty soils (USCS designation of GM, S1V1, and ML) as structural fill is acceptable but not recommended. These materials require very high moisture contents for compaction and require a long time if natural moisture contents are too high. 'Phis makes moisture content, lift thickness, and to dry out lty soil is used for structural fill, lift thicknesses should not exceed compactioe effort difficult to control. if si 6 inches (loose), and fill material moisture should be closely monitored at both the working elevation and the elevation of material already placed. After placement, silty soils must be protected horn degradation resulting from construction traffic or subsequent construction. B aclrfiIl: Backfill materials shall ascribe to the requirements of structural fill except that the maximum material size shall be 4 inches. � no case shall material greater than 2 inches in diameter bear directly on structural elements. Placing oversized material against rigid surfaces interferes with proper compaction. Backfill should be compacted in accordance with 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, backf ll must be compacted to a firm and unyielding condition. 7446 W. �emhi St., Boise, ID $37g9 208 376-4748 Fax 20$ 322-651 � E-Mail mti@mti-id.com www.mti-id.com MATERIALS reSTINS & iNSPIECTION Environmentai Services +excavations: to Geotechnica{ E. nsering ❑ Construction Matenais ie March 7, 2003 Page # 18 of 30 ❑ Special ins i\mtise1verlrepartsLfl03 reports\000-199\b3OO84g\b30084geotech,doc 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 not exceed 1 foot vertical to 1 foot horizontal. Shallow groundwater encountered across the site, may cause difficulties during foundation development and utility placement. For deep excavations, native granular soils 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 working at depths near the water table. Proper care must be taken to protect personnel and equipment. During our subsurface exploration, test pit sidewalls generally exhibited little indication of collapse. However, some caving of granular soils occurred, especially after penetration of the water table. Care must be taken so that excavations are properly backftlled in accordance with procedures outlined in this report. Water and loose debris should be removed from these excavations, prior to placement of fill soils or concrete. Groundwater Control: +Groundr7uater was encountered in the investigation and is likely to impede construction. Excavations below the water table will require a dewatering program. It may be possible to discharge dewatering effluent to remote portions of the site or to a strategically located sump or pit. This will essentially recycle effluent, thus eliminating the need to enter into agreements with local drainage authorities. Should the scope of the proposed project change,lVITI should be contacted to provide more detailed groundwater control measures. Special precautions may be required for control of surface runoff and subsurface seepage in general. rt is recommended that runoff caused by wet weather be directed away from open excavations. On- site silty or clayey soils can be expected to become soft and pump if subjected to excessive traffic following periods of wet weather. Ponded surface water areas should be drained to allow construction to take place through methods such as trenching, sloping, crowning grades, nightly smooth drum rolling, or installation of a French -drain system. Additionally, temporary or permanent driveway sections may be constructed should wet weather be forecast. GENERAL COIYIIYIENTS When plans and specifications are complete, or if significant changes are xnade in the character or location of the proposed structures, consultation should be arranged as supplementary recommendations xnay be required. It is recommended that the service of a qualified geotechnical engineering firm be engaged to test and evaluate soils in footing excavations before placement of concrete to determine if soils meet compaction requirements. Monitoring and testing should also be performed to verify that suitable materials are used for structural fill and that proper placement and compaction is performed. ..._. .We .,._.__._�..-._._....._.__,,,..__..._....,.,..___._._Cop.Yright..Q.20U3..Ivlaterials_T.pAzting &Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-474& Fax 208 322,6515 E-Mail mtiC mti-id.com www.mti-id.com