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Home My WebLink AboutSt. Luke's Surgery Center - Stormwater Management On-site Disposal Report (2)St. Luke's Surgery Center STORMWATER MANAGEMENT ON-SITE DISPOSAL REPORT JOB # 842-1211 December 2012 PREPARED BY: HORROCKS ENGINEERS Pleasant Grove, UT r u i TABLE OF CONTENTS INTRODUCTION y EXISTING CONDITIONS HYDROLOGIC ANALYSIS EXISTING SITE CONDITIONS ' POST -DEVELOPMENT HYDROLOGIC ANALYSIS i PROPOSED SITE CONDITIONS i RUNOFF VOLUME Z Storm Duration Rainfall Intensity 4 STORMWATER MANAGEMENT SYSTEM y CONVEYANCE WATER QUALITY INFILTRATION ' SYSTEM MAINTENANCE a SUMMARY LIST OF TABLES ` Table 1 - Drainage Areas d Table 2 - Sand Filters n Table 3 - Infiltration Trenches Table 4 - Infiltration Time LIST OF EXHIBITS A. VICINITY MAP B. GEOTECHNICAL INVESTIGATION C. PRE -DEVELOPMENT DRAINAGE AREAS MAP D. POST -DEVELOPMENT DRAINAGE AREAS MAP t E. RATIONAL METHOD RUNOFF C -COEFFICIENTS 4 F. REGIONAL RAINFALL CURVE CHART a G. IMPERVIOUS AREA CALCULATIONS 1 1 1 2 2 2 2 2 3 3 3 4 5 5 3 4 4 5 INTRODUCTION This report addresses the hydrologic analysis of the stormwater runoff generated by the proposed on-site private improvements within the St. Luke's Meridian Medical Center development, located in Meridian, Idaho. The analysis includes the design of the required water quality and retention/percolation facilities in compliance with the engineering standards set forth by the Ada County Highway District (ACHD) Policy Manual Section 8000. Please refer to the submitted Construction Drawing set of plans for this project for design configuration of the stormwater system. EXISTING CONDITIONS HYDROLOGIC ANALYSIS The proposed development is located on in section 16, Township 3N, Range 1 E, south of E St Luke's Road and east of S Eagle Road. Please see the attached Vicinity map. There is an existing stormwater conveyance and infiltration system in the St. Luke's Medical Center development. The proposed development will remove existing infiltration beds and add new infiltration beds matching the volume that was removed. EXISTING SITE CONDITIONS The site currently consists of two main parts. The eastern portion is an existing asphalt parking lot with landscaped islands. The western portion is a landscaped area primarily covered with sod. The site is bounded by St. Luke's Road to the north and Eagle Road to the west. A two way private drive aisle separates the two portions of the site and the site is connected by other interior drive aisles. A Geotechnical Investigation (Exhibit B), prepared by Materials Testing & Inspection dated December 5, 2012, is attached, describing the existing soils for the building area. (Please refer to the provided copy of the Geotechnical Report for complete surface and subsurface soil analysis and hydraulic conductivity.) The runoff from existing parking lots, buildings and other impervious areas is contained within an underground storm system. All surface runoff is routed or directed to this system where the stormwater is absorbed into the ground. POST -DEVELOPMENT HYDROLOGIC ANALYSIS PROPOSED SITE CONDITIONS The proposed project watershed consists of two (2) basin areas totaling 1.7 acres. These areas consist entirely of the private parcel. The total imperious area for all of these areas combined totals 1.3 acres (or 76%) of the total basin area (see Impervious Area Calculations and Post Development Drainage Area Map.) Approximately 19,000 sqft of impervious area that is now asphalt parking lot will be replaced with rooftop from the proposed building. RUNOFF VOLUME To determine the conveyance and storage requirements, the runoff volumes were calculated based on the storm duration and intensities, in accordance with ACHD Policy Manual Section 8000 requirements. The Policy Manual indicates that the Rational Method is to be used for calculating peak flow rates for areas smaller than 100 -acres. The following equation is the Rational Method with variable descriptions. Q = C I A where: Q = peak flow rate (cfs) C = Non -dimensional runoff coefficient I = Average rainfall intensity (in/hr) A = Size of the contributing area (ac) The Policy Manual was referenced to determine the ACHD recommended runoff coefficient for use in the Rational equation. Exhibit A indicates that for Streets, Asphalt and Concrete surfaces a coefficient of 0.95 should be used. Storm Duration Section 8006.1.1 of the Policy Manual indicates that a storm duration of 1 hour is to be used when using the Rational Method for calculating peak discharge. Rainfall Intensity Exhibit B of Section 8000 includes an Intensity -Duration -Frequency Curve. With the storm duration and a return period of 25 years, for primary conveyance systems (Policy Manual, Section 8000, Table 1), the rainfall intensity for design was determined to be approximately 0.76 in/hr. Likewise, for secondary conveyance systems the return period used is 100 years, and the subsequent intensity is 1.06 in/hr. 2 I Table 1 — Drainage Areas Table 1 shows the total runoff expected during the 100 -yr event and the size of the drainage area. The actual areas were calculated as opposed to using the "Thompson's Rule" for more accurate results. STORMWATER MANAGEMENT SYSTEM CONVEYANCE The Policy Manual indicates that primary conveyance systems should convey the design storm with maximum treatment and minimum impact or inconvenience to the public. To determine the maximum hydraulic conveyance capacity of the street gutters, Izzard's Manning Equation was used (ACHD Policy Manual 8008.1). Q = 0.56 Z d8/3 S'/2 n where: Q = Discharge (cfs) Z= US, SX = Pavement cross slope N d = depth of water at face of curb (ft) S = Longitudinal grade of street (%) n = Manning's roughness coefficient WATER QUALITY A permanent water quality facility must be constructed to reduce contaminants that enter the storm system. Consequently, a grease/sand trap is proposed upstream of the new infiltration basin, in accordance with Idaho Standards for Public Works Construction Standard Drawing SD -624. 3 100 -yr Event Event Runoff Peak Runoff Infiltration Area Size Event Duration Volume Volume Flow Rate Trench DA -1 17,700 sf 1.06 in / hr 1 hr 1,563 cf 1,485 cf 0.41 cfs 1 DA -2 Existing System Table 1 shows the total runoff expected during the 100 -yr event and the size of the drainage area. The actual areas were calculated as opposed to using the "Thompson's Rule" for more accurate results. STORMWATER MANAGEMENT SYSTEM CONVEYANCE The Policy Manual indicates that primary conveyance systems should convey the design storm with maximum treatment and minimum impact or inconvenience to the public. To determine the maximum hydraulic conveyance capacity of the street gutters, Izzard's Manning Equation was used (ACHD Policy Manual 8008.1). Q = 0.56 Z d8/3 S'/2 n where: Q = Discharge (cfs) Z= US, SX = Pavement cross slope N d = depth of water at face of curb (ft) S = Longitudinal grade of street (%) n = Manning's roughness coefficient WATER QUALITY A permanent water quality facility must be constructed to reduce contaminants that enter the storm system. Consequently, a grease/sand trap is proposed upstream of the new infiltration basin, in accordance with Idaho Standards for Public Works Construction Standard Drawing SD -624. 3 The sand trap has a capacity of 1,500 gallons. It consists of a dual chamber structure with two cleanout lids. The interior of the structure will have two baffle walls. Table 2 - Grease / Sand Traps Assume negligible velocity Q = C I A i The drainage area where the new building will be located is currently an asphalt t parking lot. Approximately 19,000 sqft of this area will be replaced with building 1 rooftop. This will serve to increase the water quality of the existing system. Currently, sand and grease collect in the parking area and are washed into the existing storm system. The roof area that is proposed will greatly reduce the sand and grease entering i into the storm system, as rooftops are much less likely to accumulate these pollutants. r INFILTRATION When the on-site improvements are constructed, the increased impervious areas will c contribute to the greater flows from stormwater surface runoff. This volume of water will be contained and re -introduced to the groundwater system through the design and implementation of on-site infiltration beds. Table 3 shows the infiltration trench lengths required to provide the needed volume to accommodate the 100 -yr event. The void ratios for the rock and sand media are taken from Section 8000. Table 3 - Infiltration Trenches GREASE / SAND TRAPS Sand 25 -yr Event Event Filter Throat Maximum Event Peak Peak Trap Event Duration Volume Width Width Flow Rate" Flow Rate" Throat Velocity 1 0.76 in/hr 1hr 1,485 cf 4ft 11 in 0.41cf/sec: 0.41cfIsec 0.13ft/sec Assume negligible velocity Q = C I A i The drainage area where the new building will be located is currently an asphalt t parking lot. Approximately 19,000 sqft of this area will be replaced with building 1 rooftop. This will serve to increase the water quality of the existing system. Currently, sand and grease collect in the parking area and are washed into the existing storm system. The roof area that is proposed will greatly reduce the sand and grease entering i into the storm system, as rooftops are much less likely to accumulate these pollutants. r INFILTRATION When the on-site improvements are constructed, the increased impervious areas will c contribute to the greater flows from stormwater surface runoff. This volume of water will be contained and re -introduced to the groundwater system through the design and implementation of on-site infiltration beds. Table 3 shows the infiltration trench lengths required to provide the needed volume to accommodate the 100 -yr event. The void ratios for the rock and sand media are taken from Section 8000. Table 3 - Infiltration Trenches 4 INFILTRATION Rock Rock Sand Total Pipe Pipe Pipe Pipe Trench Volume Width Depth Voids Depth Storage Length Diameter Area Volume Lencith 1 2,520 of 8 ft 7 ft 40% 3 ft 22.4 cf / Ift 45 ft 12 in 0.79 sf 35.6 cf 45 ft 2 5,250 cf 15 ft 7 ft 40% 3 ft 42.0 cf I Ift 50 ft 12 In 0.79 sf 39.5 cf 50 ft 3 5,320 cf 8 ft 7 ft 40% 3 ft 22.4 cf / Ift 82 ft 12 in 0.79 sf 75.1 cf 95 ft 4 In order to determine if the infiltration trenches are adequately sized for the 100 -yr storm event within the 24 -hours required by the Policy Manual, the individual infiltration rates and subsequent infiltration times were calculated for each of the trenches. By using the observed infiltration rates presented in the Geotechnical Investigation (original report and subsequent percolation test results,) and the 100 -yr event volumes, the infiltration time required was calculated, as shown in Table 4. Table 4 - Infiltration Time The resulting infiltration times presented in Table 4 indicate that all of the proposed trenches operate satisfactorily, discharging 90% of the accumulated volume in less than 20 hours. SYSTEM MAINTENANCE A system maintenance agreement will be prepared and submitted to Meridian City for approval, under a separate cover. SUMMARY In conclusion, the stormwater facilities proposed are designed to meet the ACHD requirements for the 25 -yr and 100 -yr storm events in conveyance and volume capacities, where applicable. Design of the stormwater management facilities are in compliance with the ACHD Standards as set forth in Section 8000. 5 INFILTRATION TIME Infiltration Observed Reduction Available Wall Wall Infiltration Required Infiltration Trench Infiltration Factor Rate Area Usage Rate Discharge Time 1 3.95 in I hr 50% 1.98 in / hr 1,060 sf 67% 117 cf / hr 90% 13.35 hr 2 3.95 in 1 hr 50% 1.98 in / hr 1,300 sf 67% 143 cf I hr 90% Exist 3 3.95 in / hr 50% 1.98 in / hr 2,060 sf 67% 227 cf / hr 90% Exist The resulting infiltration times presented in Table 4 indicate that all of the proposed trenches operate satisfactorily, discharging 90% of the accumulated volume in less than 20 hours. SYSTEM MAINTENANCE A system maintenance agreement will be prepared and submitted to Meridian City for approval, under a separate cover. SUMMARY In conclusion, the stormwater facilities proposed are designed to meet the ACHD requirements for the 25 -yr and 100 -yr storm events in conveyance and volume capacities, where applicable. Design of the stormwater management facilities are in compliance with the ACHD Standards as set forth in Section 8000. 5 EXHIBITS ,.W Aiuro4-Dr,'� i t�'ek ee ci of - W 5 H k _ _ ri I w'= �' ei EtSla ~.,'�W: r^, r E•Plne Avs •.. •' Pine St _. `,{ ., it t �Dn � ,.♦ oaWt. E'Commerclel Ct4 E Kin St n •' W _ Z p __ w:+ - nE•Franl in'R"" r WFoe�illin d L FSp r9vmvn 0.Wi W `�. � �� 1 1"� •• h Autumn W aY 411 u � W Cemas z,.. D aE•Ovurlanld'Rd<W-Overland•Rcl _ ism � a "• c i rt E'Girr nneyrv�" B. GEOTECHNICAL INVESTIGATION MATERIALS TESTING is INSPECTION ❑ Environmental Services U Prepared for: Gardner Company 3277 East Louise Drive, Suite 375 Meridian, ID 83642 U '.i ,U ❑F. UPDATE LETTER for St. Lukes Surgery Center 520 S Eagle Road Meridian, ID MTI File Number B121203g 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mti®mti-id.com • www.mti-id.com 4 MATERIALS ( TESTING & INSPECTION 5 December 2012 Page # 1 of 2 h121203g_letter ❑ Environmental Services O Geotechnical Engineering I] Construction Materials Testing 0 Special Inspections Mr. Tom Ahlquist Gardner Company 3277 East Louise Drive, Suite 375 Meridian, ID 83642 (208) 246-8909 Re: Update Letter ( St. Luke's Surgery Center 520 S Eagle Road Meridian, ID c Dear Mr. Ahlquist: a In compliance with your instructions, this report updates the original Geotechnical Engineering Report (MTI 'i file number B30733g) and provides additional information needed for the design of the above referenced development. Unless otherwise noted in this report, all initial recommendations, limitations, and warranties expressed in the previous report must be adhered to. All references to the 2000 International Building Code (IBC) in the original report should be changed to the 2009 edition of the IBC. This letter report is based on existing available information from adjacent sites. Confirmation of the conditions outlined in this report is required, at the time of construction. The proposed structure will be a steel -framed, two-story building with no basement and shallow spread foundations. Geoseismic Setting Soils on site are classed as Site Class C in accordance with Chapter 16 of the 2009 edition of the IBC. The site class has been based on the soils encountered in several borings advanced within approximately 1/2 mile of the project site. 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. Foundation Recommendations The original recommendations for bearing on the cemented silt soils with an allowable bearing capacity of 3,000 pounds per square foot (psf) are still applicable. To achieve a higher bearing capacity footings must bear on the native poorly graded sandy gravel sediments at depths varying between 5 and 8 feet. An allowable soils bearing capacity for the poorly graded sandy gravels is 5,000 psf. Allowable bearing pressures are for spread footing sizes up to 10 feet, and total settlements up to 1 inch. For frost protection, the bottom of external footings should be 30 inches below finished grade. Confirmation of bearing conditions, at the time of construction is required. MTI's engineer must inspect the exposed bearing surfaces to confirm they are in accordance with the conditions outlined in this report. At that time, further over -excavation and/or modifications may be required. Copyright 0 2012 Materials "resting & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mtiOn ti-id.com • www.mti-id.com MATERIALS TESTING & INSPECTION 5 December 2012 Page # 2 of 2 b121203g_lener ❑ Environmental Services ❑ Geolechnical Engineering O Construction Materials Testing O Special Inspections Construction Recommendations MTI must be onsite to confirm the recommendations provided in the original report are suitable for the conditions observed during construction. Specifically the following items must be addressed: • Floor slab -on -grade - It is anticipated that shallow expansive clay soils may be encountered throughout the site. These soils must be removed from below the floor slabs. Current data suggests 1.5 to 2 feet of clayey material could be present. At present, it is not known how much of the clay material may have been removed in preparation of the existing parking lot. • Pavement - The pavement designs provided in the original report are based on the presence of clay soils. It is possible the clay soils below the existing pavements may be soft or unstable, as a result of water infiltration. This will need to be assessed at the time of initial excavation, to determine the need for further excavation or other remedial measures. It is recommended that the original pavement recommendations (from B30733g report) be implemented for this project. • Infiltration Facilities - It is MTI's understanding that two existing seepage beds are located below a portion of the proposed building. The seepage beds must be completely removed, along with any saturated soils surrounding the bed. The extent of the excavation required must be determined during construction. Resulting excavation must be backfilled with imported granular structural fill, placed in maximum 12 inch thick loose lifts and compacted per the original report. Structural fill and compaction requirements can be found in the original report (1330733g). New infiltration facilities must extend through the upper cemented silt soils and into the native free - draining sand and gravel sediments. An excavation depth of approximately 8 feet should be anticipated. General Comments All recommendations outlined in the original report (1330733g) shall be adhered, except as modified in this letter. Further, onsite observations as outlined in this letter shall be performed to confirm same or similar conditions to the those encountered in the original report. Alternate conditions may require additional recommendations and associated construction activities. 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. Elizabeth Brown, P.E. Geotechnical Engineer Attachment: Geotechnical Engineering Report (830733) Reviewed by: David O. Cram, P.E. General Manager Copyright © 2012 Materials Testing & Inspection, Inc. 2791 South Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 mtMmti-id.com • www.mti-id.com CpMATERIALS TESTING & INSPECTION Q Environmental Services U Geotechnical Engineering ❑ Constructi0n Materials Testing ❑ Special Inspections GEOTECHNICAL ENGINEERING REPORT of MontvuE Medical Building Franklin Road and EaglE Road BoisE, Idaho PrEparEd for: Engineered Structures, Inc. 12400 WEst OvErland Road BoisE, Idaho 83709 MTI FilE NumbEr B3O733g 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti•id.com t MATERIALS i TESTING & INSPECTION August 15, 2003 Page # I of 27 7 Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections \\mtiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doc Mr. Neil Nelson Engineered Structures, Inc. 12400 West Overland Road Boise, Idaho 83709 (208) 362-3040 Re: Geotechnical Engineering Report Proposed Commercial Development Montvue Medical Building Boise, Idaho Mr. Nelson: In compliance with your instructions, we have conducted a soils exploration and foundation evaluation for the above mentioned development. Field work for this investigation was conducted on 1 August 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 and construction details that occur on a project, questions arise concerning soil conditions. We would be pleased to continue our role as geotechnical engineers during project implementation. MTI 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 to working with you in the future. If you have questions please call us at (208) 376-4748. Respectfully Submitted, c�ONALFN r<, Materials Testing Inspectio a Fd iM c aeodworth, P.E. e �T9�/ Tt, e e Schroeder, P.G. y EO�,a,. Geotechnical Engineer t'F� -. - echnical Services Manager Copyright © 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www inti-id,com cpMATERIALS TESTING & NSPECTION August 15, 2003 Page # 2 of 27 ❑ Environmental Seivices ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections \\mtiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doe TABLE OF CONTENTS PREAMBLE............................................................................................................................1 EXECUTIVESUMMARY.........................................................................................................3 INTRODUCTION.....................................................................................................................4 Project Description...............................................................................................4 Authorization........................................................................................................4 Purpose..................................................................................................................4 Scope......................................................................................................................4 Warranty And Limiting Conditions....................................................................5 General..................................................................................................................5 DESCRIPTIONOF SITE.........................................................................................................6 SiteAccess.............................................................................................................6 General Geology Of Area .... -................................................................................6 Site Topography, Drainage And Vegetation......................................................6 Site Climatology And Geochemistry....................................................................7 SOILSEXPLORATION...........................................................................................................7 Exploration and Sampling Procedures...............................................................7 Laboratory Testing Program...............................................................................7 Soil And Sediment Profile ............................................ --.... ............................... 8 Electrical, pH, and Water Soluble Sulfate Analysis.........................................8 SoilsSurvey Review..............................................................................................8 VolatileOrganic Scan...........................................................................................8 SITEHYDROLOGY................................................................................................................9 GeneralNotes.........................................................................................................9 Groundwater.........................................................................................................9 HydraulicConductivity ........................................................................................9 LATERAL EARTH PRESSURES..............................................................................................10 FOUNDATION, SLAB AND PAVEMENT DISCUSSION AND RECOMMENDATIONS .................. 11 GeneralNotes........................................................................................................1l Foundation Design Recommendations................................................................11 FloorSlab-On-Grade...........................................................................................12 Recommended Pavement Sections.......................................................................13 CONSTRUCTIONCONSIDERATIONS..................................................................................... 14 Earthwork.............................................................................................................14 DryWeather.. ........... ......................................................................... .................. 15 WetWeather.........................................................................................................15 FrozenSubgrade Soils..........................................................................................15 StructuralFill........................................................................................................16 Backfill...................................................................................................................16 Excavations............................................................................. Groundwater Control............................................................. GENERAL COMMENTS........................................................................... REFERENCES..................................................................................... APPENDIXLIST.................................................................................. Geotechnical General Notes .............................................. Unified Soil Classification ................................................. TestPit Logs....................................................................... Pavement Thickness Design .............................................. 7446 W. Lemhi St., Boise, ID 83709 E -Mail Int! @mti-id.wm 16 17 .................17 .................18 .............................20 ................................ 21 ................................22 ................................ 26 Copyright © 2003 Materials Testing & Inspection, Inc. 208 37C-4748 Fax 206 322.6515 www.mti-id.com orMATERIALS TESTING & INSPECTION August 15, 2003 Page # 3 of 27 ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections \\mtiserver2\reports12003 reports\600-7991b30733g\b30733geotech.doc EXECUTIVE SUMMARY 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: Four test pits were advanced to depths of 5.7 to 18.1 feet across the site. surficial moderately to highly plastic clay (CL -CH) was encountered at the ground surface in all test pits, consisting of brown, dry to moist, very stiff, clay. Limited wood and organic debris was encountered throughout the clay. Clay soils were encountered to depths of 1.2 to 2.6 feet within the test pits. Underlying the surficial clay soil is cemented silt. This soil was noted to be light brown, slightly moist, hard, strongly cemented silt. Cemented silt soil was noted to extend to depths of 4.8 to 7.9 feet. Redddish-brown, slightly moist, very dense, gravel sediments with medium to coarse grained sand was observed underlying cemented sandy silt soils. Gravel sediments extended beyond the termination depths of the test pits advanced. Building Foundations: On the basis of data obtained from the site and test results from various laboratory tests performed, MTI recommends following guidelines be used for the net allowable soils bearing capacity. Building Floor Slabs: Moderately to highly plastic clay soils are present to depths of up to approximately 2'/ feet, depending on location. These soils will be subjected to volume changes with changes in moisture content. Considering- this, removal and replacement of the clay soil is recommended to prevent movement of any ground supported slabs. Basement slabs, if present are anticipated to extend through surficial clay soils. The presence of a qualified soils technician is recommended to identify clay soils in the field. Prior to placement of concrete slabs or placement of slab supporting fill, organic, loose or obviously compressive materials must be removed. In addition, 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 backfilled 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. Fill materials must be compacted to a minimum 95% of maximum density as determined by ASTM D 1557. Copyright O 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com ASTM D 1557 Net Allowable Soils Footing Depth Subgrade Com action Bearing Capacity 2 feet and greater bearing on competent, native, Not Required for cemented silt soils or compacted structural fill. Cemented Soil 3,000 lbs/ft' Existing- lean clay and sandy fat clay soils mast be 95% for Structural Fill completely removed from below all foundation elements. Building Floor Slabs: Moderately to highly plastic clay soils are present to depths of up to approximately 2'/ feet, depending on location. These soils will be subjected to volume changes with changes in moisture content. Considering- this, removal and replacement of the clay soil is recommended to prevent movement of any ground supported slabs. Basement slabs, if present are anticipated to extend through surficial clay soils. The presence of a qualified soils technician is recommended to identify clay soils in the field. Prior to placement of concrete slabs or placement of slab supporting fill, organic, loose or obviously compressive materials must be removed. In addition, 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 backfilled 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. Fill materials must be compacted to a minimum 95% of maximum density as determined by ASTM D 1557. Copyright O 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com cpMATERIALS TESTING & INSPECTION August 15, 2003 Page # 4 of 27 ❑ Environmental Services ❑ Geotechnical Engineering ❑ Conshuction Materials Testing ❑ Special Inspections \\mtiscNer2\reports\2003 reports\600-799\b30733g\b30733geotech.doe INTRODUCTION This report presents results of a geotechnical investigation and analysis in support of data utilized in design of structures as defined in the 2000 International Building Code (IBC). Information in support of groundwater and stonnwater 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 Description: The proposed development is west of the City of Boise, Ada County, Idaho, and occupies a portion of the NW'/4NWV4 of Section 16, Township 3 North, Range 1 East, Boise Meridian. The project will consist of construction of a 2 -story, 12,000 to 15,000 square foot commercial structure with possible basement. Total settlements are limited to 1 inch. Loads of up to 3,000 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. Authorization: i Authorization to perform this exploration and analysis was given in the form of a verbal authorization to proceed from Mr. Neil Nelson of Engineered Structures, Inc. to Kevin L. Schroeder of Materials Testing and Inspection, hrc. (MTI), on 1 August 2003. Said authorization is subject to terms, conditions, and limitations 4 described in the Professional Services Contract entered into between Engineered Strictures, Inc. and MTI. J Our scope of services for the proposed development has been provided in our proposal dated 20 June 2003, and again below. Purpose: The purpose of this Geotechnical Engineering Report is to determine various soil profile components and their engineering characteristics for use by design engineers and/or architects in: • Preparing or verifying suitability of foundation design and placement, • Preparing light and heavy duty pavement sections, • Providing lateral earth pressures, • Indicating issues pertaining to earthwork construction. 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. Copyright © 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mf@mti-id.com www.mti-id.com CVMATERIALS TESTING & INSPECTION August 15, 2003 Page # 5 of 27 ❑ Environmental Services O Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections \\mtisemr2\reports\2003 reports\600-799\b30733g\b30733geotech.doe Warranty And Limiting Conditions: Field 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 site investigation. This report was prepared for the exclusive use of Engineered Structures, Inc. and their retained design consultants ("Client"). Conclusions and recommendations presented in this report are based upon agreed-upon scope of work outlined in the report and Contract for Professional Services between 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 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 structure from those enumerated in this report should be brought to the attention of the soils engineer to determine if 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. Copyright 0 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www,mti-id.com crMATERIALS TESTING & INSPECTION August 15, 2003 Page # 6 of 27 ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections \\mtiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doe DESCRIPTION OF SITE Site Access: Access to the site may be gained via Interstate 84 to Eagle Road off ramp (Exit #46). Travel north on Eagle Road 0.25 miles to West Montvue Drive. The parcel is located on the east side of West Momvue Drive and is approximately 1 acre. Presently the site exists as a site that was previously a private residential dwelling. The location is depicted in site map plates included in the Appendix. General Geology Of 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 floodplain 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 cross -bedded sands/silts suggest deposition in braided channels. The Boise River Gravels consist of unconsolidated clay, silt, sand, gravel, and cobbles. The Boise River Gravels have been subdivided into smaller units based on their age and are exposed as distinct alluvial terraces. Five of these teiTaces are well exposed in the Boise area and range in age from Middle Pleistocene to Holocene (<1 million years ago). The site is situated on the Sunrise Terrace, the third terrace above the flood plain. The Sunrise Terrace generally consists of sandy pebble and cobble gravels with a mantling of 3 to 7 feet of loess. The entire thickness is approximately 44 feet. Underlying these soils are poorly graded free draining washed sands and sandy gravels. Geologic data published for the area indicate that bedrock may not be encountered at depths less than 500 feet beneath the soil surface (Othberg and Stanford, 1992). Site Topography, Drainage And Vegetation: The proposed development consists of approximately 1 acre of flat terrain with a small irrigation ditch along the southern property line. A previously occupied residential dwelling with a partial basement has been demolished. Also identified is a small shed is located on the eastern portion of the property. Stormwater drainage for the site is achieved by percolation through surficial soils and drop inlets located along West Montvue Drive. The area does not receive any off-site drainage. Vegetation throughout the area consists primarily of mature trees and grass. Copyright © 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mf-id.com 4 MATERIALS v cp TESTING & INSPECTION August 15, 2003 Page # 7 of 27 ❑ Environmental Service:: ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections \\mtismer2\reports\2003 reports\600-799\b30733g\b30733geotech.doc Site Climatology And Geochemistry: Average precipitation for the region is on the order of 10 to 12 inches per year. Annual average temperature range from 20° F to 910 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 electro -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 geochemical conditions was noted on-site. Nominal frost penetration is typically on the order of 6 inches, with extremes ranging to 3 feet. SOILS EXPLORATION Exploration And Sampling Procedures: The field exploration 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 normal taping procedures 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 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 strata encountered in test pits. Samples obtained have been visually classified in the field by an engineer, 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 described 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. Laboratory Testing Program: 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 4318, and Grain Size Analysis - ASTM designation C 117, C 136. Copyright© 2003 Materials Testing. & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376.4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com 6 MATERIALS TESTING & INSPECTION August 15, 2003 Page # 8 of 27 ❑ Environmental Services ❑ .� 'utechnical Engineering O Construction Materials Testing ❑ Special Inspections \\mtiserver2\reports\2003 reports\600-7991b30733g\b30733geotech.doc Soil And Sediment Profile: Test pits were advanced to depths of 5.7 to 18.1 feet across the site. No groundwater was encountered at the time of our investigation. The following soils were not encountered in each test pit, but instead represent a hypothesized profile as compiled from observations in each of the four test pits advanced: ti Surficial Moderately to Highly Plastic Clay (CL -CH) — This soil was encountered at the ground surface in all test pits, consisting of brown, dry to moist, very stiff, clay. Limited wood and organic debris was encountered throughout the clay. Clay soils were encountered to depths of 1.2 to 2.6 feet within the test pits. Cemented Silt (ML) — Underlying the surficial clay soil is a cemented silt. This soil was noted to be light ( brown, slightly moist, hard, strongly cemented silt. Cemented silt soil was noted to extend to depths of 4.8 to ( 7.9 feet. Poorly Graded Sandy Gravel (GP) — Poorly graded gravel was encountered below the cemented silt. This soil was noted to be red brown, slightly moist, very dense, with medium to coarse grained sand. Gravel soils 1 were generally found to exhibit calcium carbonate cementation within the upper 3 to 4 feet. Gravel sediments t extended beyond the termination depths of the test pits advanced. f Electrical Resistivity, pH, and Water Soluble Sulfate Analysis: A grab sample of native sandy lean clay was collected on 1 August 2003 at a depth of 1.0 to 2.0 feet in the vicinity of test pit 4. This location is illustrated on the included site drawing. Analysis results as determined ( by Alchem Laboratories, Inc. in Boise are given in the following table. Results of laboratory analysis, will be ( forwarded in the form of an addendum letter upon receiving the results. Soils Survey Review: A review of the United States Department of Agriculture, Soil Conservation Service, Soil Survey of Ada County Area, Idaho, 1980, indicated the site can be characterized as Tindahay fine sandy loam. This soil is excessively drained, with moderately rapid permeability, slow runoff, and erosion hazard is slight. Septic tank absorption fields can work well in this soil. Digging and trenching may be hampered by unstable cutbanks. This soil is well suited for structures with basements. 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 photoicnization detector. Samples obtained during our exploration activities exhibited no odors or discoloration typically associated with this type contamination. No groundwater was encountered. _ _ _ _Copyright @ 2003 Materials Testing & Inspection, Inc. 7446 K Lemhi St., Boise, ID 83709 ^ 208 376-4748 Fax 208 322-6515 E -Mail mti0mti-id.com www.mti-id.com CPMATERIALS TESTING & INSPECTION August 15, 2003 Page # 9 of 27 ❑ i -r..s- ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections \\mtisetver2\reports\2003 reports\600-799\b30733g\b30733geotech.doc SITE HYDROLOGY General Notes: Existing surface drainage conditions are defined in the Description of Site. Information 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. Groundwater: Groundwater was not encountered within the depths explored during the field investigation. Soil moistures in the test pits were generally dry within the surficial fill and slightly moist below. The estimation of the extent to which groundwater levels fluctuate under seasonal influences is problematic without regular monitoring. However, during previous explorations performed in June 2003 at the site immediately to the east no evidence of groundwater was noted within numerous borings to depths of 20 feet. The relatively deep groundwater in the vicinity of the site is likely related to the proximity of the site to the norther edge of the Sunrise Terrace. Groundwater levels in the site vicinity are controlled in large part by residential and commercial 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, it is unlikely that groundwater will be encountered during construction and is anticipated to remain at depths of greater than 18 feet below the ground surface throughout the year. 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. In this report this parameter is approximated by soil type and gradation. Of soils comprising the generalized soil profile for this study, clay and silt soils generally offer little permeability, with typical hydraulic conductivity values less than 2 inches per hour. Calcium carbonate cementation may have hydraulic conductivity values near zero. Non-cemented poorly graded sandy gravel soils typically exhibit hydraulic conductivity values in excess of 24 inches per hour. Copyright @ 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com CPMATERIALS TESTING & INSPECTION August 15, 2003 Page # 10 of 27 ❑ Environmur ni _, „_- ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections \\mtiserver2\rcports\2003 reports\600-799\b30733g\b30733geotech.doc LATERAL EARTH PRESSURES Retaining and/or below grade and basement walls are proposed as part of the development and 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 defined by the surface of the wall and a plane inclined 35° from vertical passing through the base of the wall. The following recommendations should be used in dealing with lateral earth pressures. The following lateral earth pressures are presented as Rankine's states of plastic equilibrium. For lateral forces on a gravity block, a sliding frictional coefficient of 0.45 is appropriate considering granular structural fill or native gravel soils (GP) under typical conditions. A state of plastic equilibrium is one in which the subject material is considered to be 1) homogeneous and unbounded and 2) at the point of incipient instability. This state is evaluated based 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 are considered for use, MTI must be contacted to provide revised lateral pressure information. Fu thermore, changes in natural soil moisture, such as can be imposed by site stormwater systems, can change the values listed below. Below grade restrained walls, such as basement walls, should be designed with at -rest pressures. Active pressures are used for 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 0.001 times the height of the wall will be necessary for the "active" pressure condition for imported or on-site SP/GP structural backfill. MTI perceives that the soils of interest for lateral earth pressures will be the poorly graded sandy gravel soils encountered below depths of 5 to 8 feet in the test pits. For these soils the following values are applicable: Soil Type: Compacted Sandy Gravel Dry Unit Weight: 128 pcf Internal Friction Angle: 35 Bouyam Unit Weight: 83 pcf Natural Void Ratio: 0.4 Natural Moisture: At rest lateral earth pressure: 57 pounds per cubic foot Active lateral earth pressure: 36 pounds per cubic foot Passive lateral earth pressure: 496 pounds per cubic foot 5% K"= 0.4 Ka= 0.3 K"= 3.7 Values listed above are for non -surcharged, drained conditions. Should another material be used in for backfill, MTI should be consulted for correct lateral earth pressure values. Granular structural fill should consist of 4 inch minus select, clean, granular soil with no more than 30% oversize (greater than 3/4") material and no more than 12% fines (less than #200). Copyright © 2003 Materials Testing & Inspection, Inc. 7446 W. Lemht St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mtiOrnti-id.com www.mti-id.com CPMATERIALS TESTING & INSPECTION August 15, 2003 Page # 11 of 27 0 Environmental Services 0 Geotechnical Engineering 0 Construction Materials Testing 0 Special Inspections \\mtiserver2\reports\2003 reports\600-799\b30733g\b30733geotecb.doc 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 for structures with remarkable perimeter landscaping, a soils engineer should be retained as part of the design team in developing appropriate project design parameters and construction specifications. MTI recommends that the retained/restrained soil mass be drained. This can be accomplished by installing wall and toe drains in each soil -supporting wall. In areas where there is potential for significantly high soil moistures in the supported soil mass, installation of drains in the soil mass is recommended. Particular consideration of roof drain effluent and irrigation water must be made. Further, these drainage systems must be soarate from other retaining wall/forutdation systems. 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 AND PAVEMENT DISCUSSION AND RECOMMENDATIONS General Notes: Various foundation types have been considered for support of the proposed building structure. 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 Design Recommendations: On the basis of data obtained from the site and test results from various laboratory tests performed, MTI recommends following guidelines be used for the net allowable soils bearing capacity. l;opyngnty zuue matenais testing ae tnspecnon, mc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mt!@mti-id.com www.mti-id.com ASTM D 1557 Net Allowable Soils Footing Depth Sub rade Compaction Bearing Ca acity 2 feet and greater bearing on competent, native, cemented silt soils or compacted structural fill. Not Required for Cemented Soil 3,000 lbs/ft2 Existing lean clay and sandy fat clay soils must be 95% for Structural Fill completely removed from below all foundation elements. l;opyngnty zuue matenais testing ae tnspecnon, mc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mt!@mti-id.com www.mti-id.com s CPMATERIALS TESTING & INSPECTION August 15, 2003 Page # 12 of 27 ❑ Environmental Services ❑ ;entechnical Engineering ❑ Construction Materials Testing U Special InspeciLo \lmtiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doc Footings should be proportioned to meet the stated bearing capacity and/or the 2000 IBC minimum requirements. Total settlement should be limited to about I 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 footings should be 30 inches below finished grade. Floor Slab -On -Grade: As previously discussed, moderately to highly plastic clay soils are present to depths of up to approximately ,1 21/2 feet, depending on location. These soils will be subjected to volume changes with changes in moisture content. Considering this removal and replacement of the clay soil is recommended to prevent movement of g any ground supported slabs. Basement slabs, if present are anticipated to extend through surficial clay soils. Q The presence of a qualified soils technician is recommended to identify clay soils in the field. Recommendations are as follows: 9 1. Strip vegetation and excavate the upper clay soils to sufficient depths to expose weakly to moderately indurated clayey sand. Excavation depths will be highly variable, with no excavation required in the l northern portion of the lot, and excavation depths of up to 2'/2 feet are likely to be required in the d southeastern portion of the lot. t 2. Place and compact granular structural fill to achieve finished subgrade elevation. Granular structural E fill must be placed and compacted in accordance with recommendations presented in the Earthwork a section. Prior to placement of concrete slabs or placement of slab supporting fill, organic, loose or obviously compressive materials must be removed. In addition, 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 backfilled with structural fill. Fill used to increase the elevation of the floor slab should meet requirements for structural fill. Refer to the section on 'i Structural Fill for these requirements. Fill materials must be compacted to a minimum 95% of maximum density as determined by ASTM D 1557. 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 generally complying with ASTM D 1241 Type 1 Gradation A aggregate. No less than 90% of this aggregate shall pass the '/4 inch screen and no more than 10% of the aggregate shall pass the 4200 screen. Maximum nominal aggregate size shall be 3/4 inches. A moisture retarder should be placed beneath floor slabs to minimize potential ground moisture effects on floor coverings. The granular mat shall be compacted J to no less than 95% of maximum density as determined by ASTM D 1557. t Copyright © 2003 Materials Testing & Inspection, Inc. 1 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com d CrMATERIALS TESTING & INSPECTION August 15, 2003 Page 4 13 of 27 Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections \\mtiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doc Recommended Pavement Sections: 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 they reflect intended use and loading of pavements 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 MINIMUM THICKNESSES for assured pavement function. Flexible Pavement Sections The AASHTO design method has been used to calculate the following pavement sections. 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 requirements of the Idaho Specifications for Public Works Construction (ISPWC). Construction of the pavement section should be in accordance with these specifications and should adhere to guidelines recommended in the section on Construction Considerations. Pavement Section Component Driveways and Parking, Truck Access Driveways and Parkin , No Truck Access Asphaltic Concrete 3.0 Inches 2.5 Inches Crushed Aggregate Base 6.0 Inches 4.0 Inches Structural Sub -Base 12.0 Inches 8.0 Inches Compacted Subgraile ** 95 % of ASTM D-698 ** 95 % of ASTM D-698 ** Because of the expansive nature of the near surface clay soils, clay soils below the parking lot and roadway sections must be compacted to between 92% and 95% of the maximum dry density as determined by ASTM D-698 and should have moisture contents +1 to +4% above optimum. Aggregate Base Material complying with ISPWC Standards for Crushed Aggregate Materials. Structural Sub -base Material complying with the requirement 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, compacted (if indicated), inspected and proof rolled. Proof rolling of subgrade soils should be accomplished with a heavy rubber -tired fully loaded tandem axle dump truck or equivalent. Existing identified fill on-site must demonstrate the indicated compaction prior to placing material in support of the pavement section. MTI anticipates that pavement areas will be subject to moderate traffic. MTI does not anticipate pumping material to become evident during compaction, but clays and silts near to and above optimum moisture contents, may tend to pump. Pumping or soft areas must be removed and replaced with structural fill. Copyright @ 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376.4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com CVMATERIALS TESTING & INSPECTION August 15, 2003 Page # 14 of 27 U Environmental Seivicc- _J ;,1 1 a 1 pi :_I i - U Construction Materials Testing U Special Inspections \\mtiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doc 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. CONSTRUCTION CONSIDERATIONS Earthwork: Recommendations in this report are based upon structural elements of the project being founded on competent native cemented silt 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. Mature trees and grass 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 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 and disturbed zone is removed, prior to placement and compaction of structural fill materials. 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. Underground storage tanks (UST), below surface utilities, wells, or septic systems must be decommissioned, removed or abandoned as deemed necessary by governing Federal, State, and local agencies. Excavations developed as the result of such removal must be backfilled with structural fill materials as defined below, and in the above section on Floor Slab -On -Grade. Copyright © 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mtl-id.com CPMATERIALS TeSTING & INSPECTION August 15, 2003 Page # 15 of 27 ❑ Environmental Services ❑ Geotechnical Engineering O Construction Materials Testing ❑ Special Inspections \\mtiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doc 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 required) 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. Dry Weather: If construction is to be conducted during what is considered "Dryseasonal 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. 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 management plan. Wet Weather: If 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. Frozen Subgrade Soils: Frozen subgrade soils must be allowed to thaw, or 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. Copyright @ 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376.4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com CpMATERIALS TESTING & INSPECTION August 15, 2003 Page # 16 of 27 ❑ Environmental ServiceJ ;_-_.'technical Engineering O Construction Materials Testing ❑ Special Inspections \\mtiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doc Structural Fill: Soils suitable for use as structural fill are those classified as GW, GP, GM, SW, SP, SM, and ML 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 3/4 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, SM, and ML) as fill is acceptable but not recommended. However, use of these soils as fill below footings is not acceptable. These materials require very high moisture contents for compaction and require a long time to dry out if natural moisture contents are too high. This makes moisture content, lift thickness, and compactive effort difficult to control. If silty soil is used for structural fill, lift thicknesses should not exceed 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 from degradation resulting from construction traffic or subsequent construction. Backfill: Backfill materials shall ascribe to the requirements of structural fill except that the maximum material size shall be 4 inches. In 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, 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 not exceed I foot vertical to 1 foot horizontal. Shallow, cemented fine grained soils (caliche), encountered through much of the site, may cause difficulties during foundation development and utility placement. These soils typically extended through depths of 4.8 to 7.9 feet. 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. _ Copyright @ 2003 Materials Testing & inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com I& MATERIALS TESTING & INSPECTION August 15, 2003 Page # 17 of 27 ❑ Environmental Services ❑ ,�olechnical Engineering i] Cunstruction Materials Testing ❑ Special Inspections \\mtiserver2\reports\2003 report"00-799\b30733g\b30733geotech.doe 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 backfilled 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: Groundwater was not encountered during the field investigation, and is anticipated to remain below the depth of construction. However, special precautions may be required for control of surface runoff and subsurface seepage in general. It 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 COMMENTS 4. When plans and specifications are complete, or if significant changes are made in the character or location of 6 the proposed structure, consultation should be arranged as supplementary recommendations may 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 4 requirements. Monitoring and testing should also be performed to verify that suitable materials are used for 4 structural fill and that proper placement and compaction is performed. Copyright© 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti®mti-id.com www.mti-id.com CrMATERIALS TESTING & INSPECTION August 15, 2003 Page # 18 of 27 ❑ Environmental Services ❑ Geotechnical Eiglneenng ❑ Construction Materials Testing ❑ Special Inspections \\mtiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doc REFERENCES American Society for Testing Materials, 1999, Standard Test Method for Materials Finer than 75-µm (No. 200) Sieve in Mineral Aggregates by Washing: C 117 - 95, 3 p. American Society for Testing Materials, 1999, Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates: C 136 - 96a, 5 p. American Society for Testing Materials, 1999, Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils, ASTM Designation: D 4318 - 86, 11 p. Collett, R.A., 1980, Soil Survey of Ada County Area, Idaho: US Department of Agriculture, Soil Conservation Service, 327 p. Othberg, K.L. and Stanford, L.A., 1992, Geologic Map of the Boise Valley and adjoining area, Ada and Canyon Counties, Idaho: Idaho Geologic Map Series, scale 1:100,000. _ Copyright O 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail roti@mti-id.com www.mti-id.com erMATERIALS TESTING & INSPECTION August 15, 2003 Page # 19 of 27 ❑ Environmental Services i7 Geotechnical Engineering ❑ Constiuciien Materials Testing ❑ Special Inspectieil,:. \\nrtiserver2\reperts\2003 reports\600-799\b30733g\b30733geotech.doc APPENDIX GEOTECHNICAL GENERAL NOTES UNIFIED SOIL CLASSIFICATION SYSTEM GEOTECHNICAL TEST PIT LOGS AASHTO PAVEMENT THICKNESS DESIGN SHEETS SITE MAP PLATES Copyright(D 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com MATERIALS August 15, 2003 r Page# 200£27 TESTING & INSPECTION ❑ Environmental Services 0 Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections \\mtiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doe GEOTECHNICAL GENERAL NOTES SOIL PROPERTY SYMBOLS N: Standard "N" penetration: Blows per foot of a 140 pound hammer falling 30" on a 2" O.D. SS. Qu: Unconfined compressive strength, tons/ft2 Qp: Penetrometer value, unconfined compressive strength, tons/ft2 Qe: Cone Penetrometer value, unconfined compressive strength, pounds/in2 V: Vane value, ultimate shearing strength, tons/ft2 M: Water content, % LL: Liquid Limit PI: Plasticity Index NP: Non -Plastic D: Natural dry density, lbs/ft3 WT: Apparent groundwater level (at time noted after completion). DRILLING AND SAMPLING SYMBOLS SS: Split -Spoon - 13/8" I.D., 2" O.D., except where noted. ST: Shelby Tube - 3" O.D., except where noted. AU: Auger Sample. DB: Diamond Bit. CB: Carbide Bit. GS: Grab Sample. RELATIVE DENSITY AND CONSISTENCY CLASSIFICATION Non -Cohesive Soils Standard Penetration Resistance Cohesive Soils Standard Penetration Resistance Very Loose <4 Very Soft <2 Loose 4-10 Soft 2-4 Medium Dense 10-30 Firm Medium Stiff) 4-8 Dense 30-50 Stiff 8-15 Very Dense >50 Very Stiff 15-30 Hard >30 PARTICLE SIZE Boulders 12 in. + Coarse Sand Cobbles 12 in. to 3 in. Medium Sand Gravel 3 in. to 5 mm Fine Sand 7446 W. Lemhi St., Boise, ID 83709 E -Mail mti@mti-id.com 5 mm to 0.6 mm Silts 0.074 mm to 0.005 nun 0.6 tum to 0.2 nun Clays 0.005 stun & Smaller 0.2 mm to 0.074 mm Copyright © 2003 Materials Testing & Inspection, Inc. 208 376-4748 Fax 208 322-6515 www.mti-id.com 6 MATERIALS TESTING & INSPECTION August 15, 2003 Page # 21 of 27 :1 Environmental Services ❑ Geotechnical Engineering O Construction Materials Testing ❑ Special Inspections \\mtiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doc Unified Soil Classification System Major Symbol Soil Descriptions Divisions Well -graded gravels, gravel -sand mixtures, little or no fines Gravel GW Poorly -graded gravels, gravel -sand mixtures, little or no fines and Gravelly GP Soils Silty gravels, Poorly -graded gravel -sand -silt mixtures <50% GM coarse fraction Clayey gravels, Poorly -graded gravel -sand -clay mixtures passes #4 sieve GC Coarse Well -graded sands, gravelly sands, little or no fines Grained Sand SW Soils and Poorly -graded sands, gravelly sands, little or no fines <50% Sandy SP Silty sands, Poorly -graded sand -gravel -silt mixtures passes Soils #200 sieve >50% SM Clayey sands, Poorly -graded sand -gravel -clay mixtures coarse fraction passes #4 sieve SC Inorganic silts & very fine sands, silty or clayey fine sands, clayey Silts ML silts Inorganic clays of low to medium plasticity, gravelly clays, sandy and Clays CL clays, silty clays, lean clays Organic silts and organic silt -clays of low plasticity Fine LL < 50 Grained OL Soils Inorganic silts, micaceous or diatomaceous fine sand or silt >50% Silts MH Inorganic clays of high plasticity, fat clays passes and #200 sieve Clays CH Organic silts and clays of medium -to -high plasticity LL > 50 OH Highly Organic Soils Peat, humus, hydric soils with high organic content PT Copyright Q 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376.4748 Fax 208 322-6515 E -Mail mti®mtl-id.com www.mti-id.com MATERIALS August 15, 2003 Page # 22 of 27 Cr TESTING & INSPECTION Environmental Services ❑ Geotechnical Engineering r] Construction Materials Testing O Special Inspections 6mtiserve0reports\2003 reports\600-799\b30733g\b30733geotech.doc GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP -1 Date Advanced: 8/8/2003 Logged By: Brandon Wright, E.I.T. Excavated By: Ira -Mac Backhoe Service Location: See Later Site Map Plates Depth to Water Table: Not Encountered Depth to Bottom Of Hole: 5.7 Feet Depth Field Description, w/USCS Soil Sample Sample Depth Qp Lab Test (Feet) and Sediment Classification Type From -To) ID Lean Clay (CL): Brown, Diy to 0.0-1.7 Moist, Very Stiff, with organic debris GS 0.5-1.0 3.0-4.0 A in the upper 10 inches. Cemented Silt (ML): Light Brown, 1.7-4.8 D,y to Slightly Moist, Hard, Strongly Cemented Silt. Poorly Graded Sandy Gravel 4.8-5.7 (GP): Red Brown, Slightly Moist, Very Dense with Medium to Coarse Grained Sand. Lab Test ID M LL PI Sieve Anal sis % #4 1 #10 1 #40 1 #100 1 #200 A 1 L 1 43 27 99 1 99 1 97 1 89 77.8 Copyright © 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376.4748 Fax 208 322.6515 E -Mail mti®mti-id.com www.mti-id.com CPMATERIALS TESTING & INSPECTION August 15, 2003 Page # 23 of 27 0 Environmental Services ❑ 11 .I I t �iins-cnny ❑ Construction Materials Testing ❑ tipee; III I" , ;tinII, \\mtiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doc GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP -2 Date Advanced: 8/8/2003 Logged By: Brandon Wright, E.I.T. Excavated By: Ira -Mac Backhoe Service Location: See Later Site Map Plates Depth to Water Table: Not Encountered Depth to Bottom Of Hole: 6.8 Feet Depth Field Description, w/USCS Soil Sample Sample Depth Qp Lab Test (Feet) and Sediment Classification Type From -To) ID Lean Clay (CL): Brown, Diy to 0.0-1.3 Moist, Very Stiff, with organic debris in the upper 12 inches. Cemented Silt (ML)- Light Brown, 1.3-5.7 Dry to Slightly Moist, Hard Strongly Cemented Silt. Poorly Graded Sandy Gravel 5.7-6.8 (GP): Red Brown, Slightly Moist, Very Dense with N(edhan to Coarse Grained Sand. opyright © 2003 Materials Testing S Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@rnti-id.com www.mti-id.com CrMATERIALS TESTING & INSPECTION August 15, 2003 Page # 24 of 27 U En njunn-i ntal D-arvices J Engineering D Construction Matenals roslino D Special Inspections \\mtismer2\reports\2003 reports\600-799\b3W33g\b30733geotech.doc GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP -3 Date Advanced: 8/8/2003 Logged By: Brandon Wright, E.I.T. Excavated By: Ira -Mac Backhoe Service Location: See Later Site Map Plates Depth to Water Table: Not Encountered Depth to Bottom Of Hole: 8.6 Feet Depth Field Description, w/USCS Soil Sample Sample Depth Qp Lab Test (Feet) and Sediment Classification Type (From -To) ID Lean Clay (CL): Brown, Dry to 0.0-1.2 Moist, Very Stiff, with organic debris in the upper IO inches. Cemented Silt (ML,): Light Brown, 1.2-7.9 Dry to Slightly Moist, Hard, Strongly Cemented Silt. Poorly Graded Sandy Gravel 7.9-8.6 (GP): Red Brown, Slightly Moist, Very Dense with Medium to Coarse Grained Sand. Copyright O 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com MATERIALS August 15, 2003 Page # 25 of 27 6 TESTING & INSPECTION ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections Vrntiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doc GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP -4 Date Advanced: 8/8/2003 Logged By: Brandon Wright, E.I.T. Excavated By: Ira -Mac Backhoe Service Location: See Later Site Map Plates Depth to Water Table: Not Encountered Depth to Bottom Of Hole: 18.1 Feet Depth Field Description, w/USCS Soil Sample Sample Depth QP Lab Test (Feet) and Sediment Classification Type (From -To) ID Sandy Fat Clay (CH): Brown, Dry 0.0-2.6 to Moist, Very Stiff, with organic GS 1.0-2.0 3.0-4.0 B debris in the upper 12 inches. Cemented Silt (ML): Light Brown, 2.6-5.7 Dry to Slightly Moist, Hard, Strongly Cemented Silt. Poorly Graded Sandy Gravel 5.7-18.1 (GP): Red Brown, Slightly Moist, Very Dense with Medium to Coarse Grained Sand. Lab Test ID M LL PI Sieve Anal sis % - - #4 1 #10 1 #40 #100 1 #200 B 6.7 53 32 99 1 99 1 94 __IL_i 63.4 Copyril�ht Q_2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com coMATERIALS TESTING 6 INSPECTION August 15, 2003 Page # 26 of 27 ❑ Environmental Services Q Geotechnical Engineering ❑ Construction Macrials Testing ❑ Special Inspections \\mtiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doe AASHTO PAVEMENT THICKNESS DESIGN PROCEDURES Copyright © 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com Pavement Section Design Location: Proposed Montvue Medical Building, No Truck Access Average Daily Traffic Count: 100 All Lanes & Both Directions Design Life: 20 Years of TraITte in Design Lane: 100% Terminal Seviceability Index (Pt): 2.5 Level of Reliability: 95 Subgrade CBR Value: 4 Subgrade Me: 6,000 Calculation of Design 18 kipESALs Daily Growth Load Design Traffic Rate Factors ESAL's Passenger Cars: 84 2.0% 0.0008 596 Buses: 0 2.0% 0.6806 0 Panel & Pickup Trucks: t5 2.0% 0.0122 1,623 2 Axle, 6 Tire Trucks: 0 2.0% 0.1890 0 Concrete Trucks: LO 2.0% 4.4800 39,731 Dump Trucks: 0 2.0% 3.6300 0 Tractor Semi Trailer Trucks: 0 2.0% 2.3719 0 Double Trai ler Trucks 0 2.0% 2.3187 0 heavy Tractor Trailer Combo Trucks: 0 2.0% 2.9760 0 Average Daily Traffic in Design lane: 100 Total Design Life IS kip ESAL's: 41,950 Actual Log (ESAL's): 4.623 Trial SN: 2.40 Trial Log (ESAL's): 4.643 This must be equal to or greater than the Actual Lag (ESAL's) Pavement Section Design SN: 2.41 This Number must be equal to or greater than the trial SN Design Depth Structural Drainage Inches Coefficient Coefficient ..Asphaltic Concrete: 2.50 0.42 n/a Asphalt Treated Base: 0.00 0.25 n/a Cement Treated Base: 0.00 0,17 u/a Crushed Aggregate Base: 4.00 0.14 1.0 Pit Run Aggregate Subgrade: 8.00 0.10 1.0 Special Aggregate Subgrade: 0.00 0.09 0,9 Copyright © 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com erMATERIALS TESTING & INSPECTION August 15, 2003 Page # 27 of 27 ❑ Environmental Services ❑ Geotechnical Engineering U Construction Materials Testing U Special Inspections \\rmiserver2\reports\2003 reports\600-799\b30733g\b30733geotech.doc AASHTO PAVEMENT THICKNESS DESIGN PROCEDURES Copyright* 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 - 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com Pavement Section Design Location: Proposed Montvue Medical Building, Truck Access Areas Average Daily Traffic Count: 200 All Lanes & Both Directions Design Life: 20 Years %, of Traffic in Design Lane: 100% Terminal Seviceability Index (Pt): 2.5 Level of Reliability: 95 Subgrade CBR Value: 4 Subgrade Mr: 6,000 Calculation of Design 18 kip ESALs Daily Growth Load Design Traffic Rate Factors ESAL's Passenger Cars: 150 2.0% 0.0008 1,064 Buses: 10 2.0% 0.6806 60,359 Panel & Pickup Trucks: 25 2.0% O.O122 2,705 2 Axle, 6 Tire Trucks: 9 2.0% 0.1890 15,085 Concrete Trucks: 2 2.0% 4.4800 79,462 Dump Trucks: 0 2.0% 3.6300 0 Tractor Semi Trailer Trucks: 4 2.0% 2.3719 84,141 Double Trailer Trucks 0 2.0% 2.3187 0 Fleavy Tractor Trailer Combo Trucks: 0 2.0% 2.9760 0 Average Daily Traffic in Design Lane: 200 Total Design Life 18 kip ESAL's: 242,817 Actual Log (ESAL's): 5.385 Trial SN: 3.25 Trial Log (ESAL's): 5.436 This must be equal to or greater than the Actual Log (ESAL's) Pavement Section Design SN: 3.30 This Number must be equal to or greater than the mel SN Design Depth Structural Drainage Inches Coefficient Coefficient Asphaltic Concrete: 3.00 0.42 n/a Asphalt Treated Base: 0.00 0.25 n/a Cement Treated Base: 0.00 0.17 n/a Crushed Aggregate Base: 6.00 0.14 1.0 Pit Run Aggregate Subgrade: 12.00 0.10 CO Coarse Aggregate Base: 0.00 0.12 0.9 Copyright* 2003 Materials Testing & Inspection, Inc. 7446 W. Lemhi St., Boise, ID 83709 - 208 376-4748 Fax 208 322-6515 E -Mail mti@mti-id.com www.mti-id.com Montvue Medical Building: Topographic Map Materials Testing & Inspection 7446 W. Lemhi St. 208 376-4748 Boise, 10 83709-2835 Fax: 208 3226515 M&U-id.cnm Montvue Medical Building Eagle Road & Franklin Road Boise, Idaho Modified from USGS by; BKW August 11, 2003 DRAWING* 330733g Plate 1 NOTES LEGEND Boise, Idaho = Interstate 841184 N 10 Foot Contour Interval — Pdmary Highway NW114 NW114 Sec. 16, T3N, R1E - Secondary Highway Photoredsed 1979 Light -Duty Road NOT TO SCALE C. PRE -DEVELOPMENT DRAINAGE AREAS MAP DTy ._ - ,.__• 9DI' Ar D _rel: -- �� i E. RATIONAL METHOD RUNOFF C -COEFFICIENTS Categorized by surface Forested 0.059-0.2 Asphalt 0.7-0.95 s Brick 0.7-0.85 Concrete 0.8-0.95 Shingle roof 0.75-0.95 f Lawns, well -drained (sandy soil) 0.2-0.35 ! up to 2% slope 0.05-0.1 2% to 7% slope 0.10-0.15 over 7% slope 0.15-0.2 Lawns, poorly drained (clay soil) 0.7-0.95 up to 2% slope 0.13-0.17 2% to 7% slope 0.18-0.22 over 7% slope 0.25-0.35 Driveways, walkways 0.75-0.85 Categorized by use Farmland 0.05-0.3 Pasture 0.05-0.3 Unimproved 0.1-0.3 Parks 0.1-0.25 Cemeteries 0.1-0.25 Railroad yards 0.2-0.35 Playgrounds (except asphalt or concrete) 0.2-0.35 Business districts Neighborhood 0.5-0.7 City (downtown) 0.7-0.95 Residential Single family 0.3-0.5 Multiplexes, detached 0.4-0.6 Multiplexes, attached 0.6-0.75 Suburban 0.25-0.4 Apartments, condominiums 0.5-0.7 Industrial Light 0.5-0.8 Heavy 0.6-0.9 F. REGIONAL RAINFALL CURVE CHART Exibit `B' 4.0 U 2 2.0 W 0- w w = 1.0 U Z 0.8 Z 0.6 N 0.4 Z W z 0.2 J J zZ �.0 8 .0 6 .0 4 .0 2 . 10 15 20 30 40 5060 2 3 4 8 6 8 10 12 18 24 MINUTES HOURS DURATION �.�n1 ©I■11■� oil 0 INN �■■n11��11■11■� .0 2 . 10 15 20 30 40 5060 2 3 4 8 6 8 10 12 18 24 MINUTES HOURS DURATION G. IMPERVIOUS AREA CALCULATIONS TOTAL Area Impervious Area Total Area Impervious DA -1 DA -2 10,160 sf 46,465 sf 17,500 sf 56,677 sf 58% 82% Total 56,625 sf 74,177 sf 76%