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PZ - GeoTech Report MATERIALS TESTING 8 INSPECTION AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GEOTECHNICAL ENGINEERING REPORT of Midgrove Plaza Subdivision 1450 East Franklin Road Meridian, ID Prepared for: Rodney Evans + Partners 1014 South La Pointe Street, Suite 3 Boise, ID 8370G MTI File Number 13200127g 2791 S Victory View Way•Boise, ID 83709•(208)376-4748• Fax(208)322-6515 www.mti-id.com •mti(aDmti-id.com MATERIALS 13 February 2020 TESTING & Page# 1 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections Mr. Ben Semple Rodney Evans +Partners 1014 South La Pointe Street, Suite 3 Boise, ID 83706 208-514-3300 Re: Geotechnical Engineering Report Midgrove Plaza Subdivision 1450 East Franklin Road Meridian,ID Dear Mr. Semple: In compliance with your instructions, MTI has conducted a soils exploration and foundation evaluation for the above referenced development. Fieldwork for this investigation was conducted on 4 and 7 February 2020. Data have been analyzed to evaluate pertinent geotechnical conditions. Results of this investigation, together with our recommendations, are to be found in the following report. We have provided a PDF copy for your review and distribution. Often, questions arise concerning soil conditions because of design and construction details that occur on a project. MTI would be pleased to continue our role as geotechnical engineers during project implementation. Additionally, MTI can provide materials testing and special inspection services during construction of this project. If you will advise us of the appropriate time to discuss these engineering services, we will meet with you at your convenience. MTI appreciates this opportunity to 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 (k LN*6 r� Nick Stevens, G.I.T. Reviewed by: Elizabeth Brown, P.E. Staff Geologist Geotechnical Services Manager 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 2 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections TABLE OF CONTENTS INTRODUCTION......................................................................................................................................................3 ProjectDescription.........................................................................................................................................3 Authorization..................................................................................................................................................3 Purpose...........................................................................................................................................................3 Scopeof Investigation....................................................................................................................................3 SITEDESCRIPTION.................................................................................................................................................4 SiteAccess.....................................................................................................................................................4 RegionalGeology...........................................................................................................................................4 GeneralSite Characteristics...........................................................................................................................4 Regional Site Climatology and Geochemistry...............................................................................................5 SEISMICSITE EVALUATION...................................................................................................................................5 GeoseismicSetting.........................................................................................................................................5 Seismic Design Parameter Values..................................................................................................................5 SOILSEXPLORATION.............................................................................................................................................6 Explorationand Sampling Procedures...........................................................................................................6 LaboratoryTesting Program..........................................................................................................................6 Soiland Sediment Profile...............................................................................................................................6 VolatileOrganic Scan....................................................................................................................................7 SITEHYDROLOGY..................................................................................................................................................7 Groundwater...................................................................................................................................................8 SoilInfiltration Rates.....................................................................................................................................8 FOUNDATION AND PAVEMENT DISCUSSION AND RECOMMENDATIONS................................................................9 Foundation Design Recommendations...........................................................................................................9 Recommended Pavement Sections.................................................................................................................9 FlexiblePavement Sections............................................................................................................................9 Pavement Subgrade Preparation...................................................................................................................10 Common Pavement Section Construction Issues.........................................................................................10 CONSTRUCTION CONSIDERATIONS......................................................................................................................11 Earthwork.....................................................................................................................................................11 DryWeather.................................................................................................................................................12 WetWeather.................................................................................................................................................12 SoftSubgrade Soils......................................................................................................................................12 FrozenSubgrade Soils..................................................................................................................................13 StructuralFill...............................................................................................................................................13 Backfillof Walls..........................................................................................................................................14 Excavations..................................................................................................................................................14 GroundwaterControl....................................................................................................................................15 GENERALCOMMENTS .........................................................................................................................................15 REFERENCES........................................................................................................................................................16 APPENDICES ........................................................................................................................................................17 Warranty and Limiting Conditions...............................................................................................................17 Plate1:Vicinity Map...................................................................................................................................19 Plate2: Site Map..........................................................................................................................................20 Geotechnical Investigation Test Pit Log......................................................................................................21 GeotechnicalGeneral Notes.........................................................................................................................26 AASHTO Pavement Thickness Design Procedures.....................................................................................27 Important Information About This Geotechnical Engineering Report.........................................................29 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 3 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections INTRODUCTION This report presents results of a geotechnical investigation and analysis in support of data utilized in design of structures as defined in the 2015 International Building Code (IBC). 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. Revisions in plans or drawings for the proposed development from those enumerated in this report should be brought to the attention of the soils engineer to determine whether changes in the provided recommendations are required. Deviations from noted subsurface conditions, if encountered during construction, should also be brought to the attention of the soils engineer. Project Description The proposed development is in the central portion of the City of Meridian, Ada County, ID, and occupies a portion of the SE'/4SE'/4 of Section 7, Township 3 North, Range 1 East, Boise Meridian. This project will consist of construction of an unknown number of commercial/industrial structures on 6 lots ranging from 1.67 to 2.29 acres in size. The site to be developed is roughly 12.839 acres. Assumptions have been made for traffic loading of pavements. Retaining walls are not anticipated as part of the project. MTI has not been informed of the proposed grading plan. Authorization Authorization to perform this exploration and analysis was given in the form of a written authorization to proceed from Mr. Ben Semple of Rodney Evans + Partners to Monica Saculles of Materials Testing and Inspection (MTI), on 21 January 2020. Said authorization is subject to terms, conditions, and limitations described in the Professional Services Contract entered into between Rodney Evans + Partners and MTI. Our scope of services for the proposed development has been provided in our proposal dated 21 January 2020 and repeated below. Purpose The purpose of this Geotechnical Engineering Report is to determine various soil profile components and their engineering characteristics for use by either design engineers or architects in: • Preparing or verifying suitability of foundation design and placement • Preparing site drainage designs • Indicating issues pertaining to earthwork construction • Preparing light and heavy duty pavement section design requirements Scope of Investigation The scope of this investigation included review of geologic literature and existing available geotechnical studies of the area, visual site reconnaissance of the immediate site, subsurface exploration of the site, field and laboratory testing of materials collected, and engineering analysis and evaluation of foundation materials. The scope of work did not include design recommendations specific to individual commercial/industrial structures. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page#4 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections SITE DESCRIPTION Site Access Access to the site may be gained via Interstate 84 to the Meridian Road exit. Proceed north on Meridian Road approximately 0.75 mile to its intersection with Franklin Road. From this intersection, proceed east 0.95 mile to Locust Grove Road. The site occupies the northwest corner of this intersection. Presently the site exists as an undeveloped lot with a series of fill stockpiles. It is currently used to graze horses. The location is depicted on site map plates included in the Appendix. Regional Geology The project site is located within the western Snake River Plain of southwestern Idaho and eastern Oregon. The plain is a northwest trending rift basin, about 45 miles wide and 200 miles long,that developed about 14 million years ago(Ma)and has since been occupied sporadically by large inland lakes. Geologic materials found within and along the plain's margins reflect volcanic and fluvial/lacustrine sedimentary processes that have led to an accumulation of approximately 1 to 2 km of interbedded volcanic and sedimentary deposits within the plain. Along the margins of the plain, streams that drained the highlands to the north and south provided coarse to fine-grained sediments eroded from granitic and volcanic rocks,respectively. About 2 million years ago the last of the lakes was drained and since that time fluvial erosion and deposition has dominated the evolution of the landscape. The project site is underlain by "Sandy Alluvium of Side-Stream Valleys and Gulches" as mapped by Othberg and Stanford (1993). Locally, these deposits are composed of medium to coarse sand interbedded with silty fine sand and silt and are mostly derived from weathered granite and reworked Tertiary sediments of the Boise Foothills. The thickness of this unit is variable. Because of the relative youthfulness of these deposits they contain only minor pedogenic clay and calcium carbonate. General Site Characteristics The site to be developed is approximately 12.839 acres in size. The land is currently undeveloped and the central portion of the site was being utilized for horse grazing during the field exploration. Multiple stockpiles of varying fill materials are scattered throughout the site, but mostly occupy the northern half. Fivemile Creek runs roughly southwest to northwest through the southern portion of the property. An open spur ditch from Fivemile Creek used for irrigation runs along the north perimeter of the site then turns south, running along the eastern half of the site before it goes underground at Locust Grove Road. During the field investigation,ponded surface water was noted throughout much of the southeast portion of the site. Multiple metal gates allow access to the project site along the southern and eastern boundary; however, only one vehicle access point was noted from Locus Grove Road. This access consists of an ungated gravel driveway that leads to the Basalite property to the west of the site. The site is generally located in an industrial/commercial area, with some residential structures located to the south of Franklin Road. Vegetation on the site consists primarily of mature trees, woody shrubs, volunteer growth, and pasture grasses throughout the site. A majority of the mature trees and wood bushes are present along the creek banks and in the southwest corner of the site. The site is relatively flat and level. However, a slight drop in elevation occurs from south to north. Additionally, slopes along Fivemile Creek range from roughly 7 feet horizontal to 1 foot vertical (7:1) to 10:1. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 5 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections Regional drainage is north and west toward the Boise River. Stormwater drainage for the site is achieved by percolation through surficial soils. From the north, west, and east, intermittent off-site stormwater may drain onto the project site. Stormwater drainage collection and retention systems are not in place on the project site, but currently exist as curb, gutter, and drop inlet along adjacent roadways. Regional Site Climatology and Geochemistry According to the Western Regional Climate Center, the average precipitation for the Treasure Valley is on the order of 10 to 12 inches per year, with an annual snowfall of approximately 20 inches and a range from 3 to 49 inches. The monthly mean daily temperatures range from 21°F to 95°F, with daily extremes ranging from - 25°F to I I I'F. Winds are generally from the northwest or southeast with an annual average wind speed of approximately 9 miles per hour(mph)and a maximum of 62 mph. Soils and sediments in the area are primarily derived from siliceous materials and exhibit low electro-chemical potential for corrosion of metals or concretes. Local aggregates are generally appropriate for Portland cement and lime cement mixtures. Surface water, groundwater, and soils in the region typically have pH levels ranging from 7.2 to 8.2. SEISMIC SITE EVALUATION Geoseismic Setting Soils on site are classed as Site Class D in accordance with Chapter 20 of the American Society of Civil Engineers (ASCE)publication ASCE/SEI 7-10. Structures constructed on this site should be designed per IBC requirements for such a seismic classification. Our investigation did not reveal hazards resulting from potential earthquake motions including: slope instability, liquefaction, and surface rupture caused by faulting or lateral spreading. Incidence and anticipated acceleration of seismic activity in the area is low. Seismic Design Parameter Values The United States Geological Survey National Seismic Hazard Maps (2008), includes a peak ground acceleration map. The map for 2% probability of exceedance in 50 years in the Western United States in standard gravity (g) indicates that a peak ground acceleration of 0.180 is appropriate for the project site based on a Site Class D. The following section provides an assessment of the earthquake-induced earthquake loads for the site based on the Risk-Targeted Maximum Considered Earthquake (MCER). The MCER spectral response acceleration for short periods, Sacs, and at I-second period, Sari, are adjusted for site class effects as required by the 2015 IBC. Design spectral response acceleration parameters as presented in the 2015 IBC are defined as a 5% damped design spectral response acceleration at short periods, SDs, and at I-second period, SDI. The USGS National Seismic Hazards Mapping Project includes a program that provides values for ground motion at a selected site based on the same data that were used to prepare the USGS ground motion maps. The maps were developed using attenuation relationships for soft rock sites; the source model, assumptions, and empirical relationships used in preparation of the maps are described in Petersen and others (1996). 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 6 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections Seismic Desi n Values Seismic Design Parameter Design Value Site Class D "Stiff Soil" SS 0.292 ( ) Si 0.102 (g) Fa 1.566 Fv 2.390 SMs 0.457 SMi 0.245 SDs 0.305 SDI 0.163 SOILS EXPLORATION Exploration and Sampling Procedures Field exploration conducted to determine engineering characteristics of subsurface materials included a reconnaissance of the project site and investigation by test pit. Test pit sites were located in the field by means of a Global Positioning System (GPS) device and are reportedly accurate to within ten feet. Upon completion of investigation, each test pit was backfilled with loose excavated materials. Re-excavation and compaction of these test pit areas are required prior to construction of overlying structures. In addition, samples were obtained from representative soil strata encountered. Samples obtained have been visually classified in the field by professional staff, identified according to test pit number and depth,placed in sealed containers, and transported to our laboratory for additional testing. Subsurface materials have been described in detail on logs provided in the Appendix. Results of field and laboratory tests are also presented in the Appendix. MTI recommends that these logs not be used to estimate fill material quantities. Laboratory Testing Program Along with our field investigation, a supplemental laboratory testing program was conducted to determine additional pertinent engineering characteristics of subsurface materials necessary in an analysis of anticipated behavior of the proposed structures. Laboratory tests were conducted in accordance with current applicable American Society for Testing and Materials (ASTM) specifications, and results of these tests are to be found on the accompanying logs located in the Appendix. The laboratory testing program for this report included: Atterberg Limits Testing—ASTM D4318 and Grain Size Analysis—ASTM C117/C136. Soil and Sediment Profile The profile below represents a generalized interpretation for the project site. Note that on site soils strata, encountered between test pit locations, may vary from the individual soil profiles presented in the logs, which can be found in the Appendix. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cDmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 7 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections The materials encountered during exploration were quite typical for the geologic area mapped as Sandy Alluvium of Side-Stream Valleys and Gulches. Test pit 4 was advanced into an existing stockpile near the central portion of the site. Fill materials encountered in the stockpile consisted of varying clay, silt, sand and gravel mixtures. These materials were light brown to brown, dry to slightly moist, and medium to stiff/medium dense, with fine to medium-grained sand, fine to coarse gravel, 6-inch minus cobbles, and intermittent trash debris. Near the termination of test pit 4 and at ground surface in the remaining 4 test pits, clay, sand, and gravel fill mixtures were encountered. These materials were brown, slightly moist to wet, and medium dense to dense,with fine to coarse-grained sand, fine to coarse gravel, and 12-inch minus cobbles. Organic materials were measured to depths of roughly 0.9 foot where encountered. Sandy fat/lean clay fill materials were encountered beneath surficial fills in test pits 1 through 3. Clay fills were gray to gray brown, slightly moist to moist, and stiff to very stiff, with fine to coarse-grained sand and intermittent 12-inch minus cobbles. A decomposing organic odor was noted in portions of these fills. Sandy silts and sandy lean clays were observed beneath fill materials in test pits 1, 2, 3, and 5. These fine-grained soils were gray brown and light brown to brown, dry to slightly moist, and stiff to very stiff,with fine to coarse- grained sand. At depth excluding test pit 4, clayey gravel with sand and clayey sand with gravel sediments were exposed. Clayey gravels and sands were noted in color as red-brown, orange-brown, and brown. Moisture contents ranged from slightly moist to saturated. Relative densities were medium dense to very dense. These sediments consisted of fine to coarse-grained sand, fine to coarse-gravel, and 12-inch minus cobbles. During excavation, test pit sidewalls were generally stable. However, moisture contents will affect wall competency with saturated soils having a tendency to readily slough when under load and unsupported. Volatile Organic Scan No environmental concerns were identified prior to commencement of the investigation. Therefore, soils obtained during on-site activities were not assessed for volatile organic compounds by portable photoionization detector. Samples obtained during our exploration activities exhibited no odors or discoloration typically associated with this type of contamination. Groundwater encountered did not exhibit obvious signs of contamination. SITE HYDROLOGY Existing surface drainage conditions are defined in the General Site Characteristics section. Information provided in this section is limited to observations made at the time of the investigation. Either regional or local ordinances may require information beyond the scope of this report. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 8 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections Groundwater During this field investigation, groundwater was originally encountered in test pit 1 at a depth of 15.6 feet bgs. On 7 February 2020 a delayed groundwater reading was taken in the piezometers onsite and revealed groundwater depths ranging from 13.2 to 13.4 feet bgs. Water seepage was also encountered in test pit 2 and 3 at depths of 2.8 and 3.2 feet bgs,respectively. This shallow water seepage is likely related to the ponded surface water noted in the vicinity of test pit 2 and 3, possibly caused by shallow fat clay fill materials inhibiting drainage of surface waters. Soil moistures in the test pits were generally dry to moist within surficial fills and soils. Clayey sands and clayey gravels graded from moist to saturated as the water table was approached and penetrated. In the vicinity of the project site, groundwater levels are controlled in large part by residential and commercial irrigation activity and by the stage and flow of the Five Mile Creek. Maximum groundwater elevations likely occur during late spring to early summer runoff season and continue during the later portion of the irrigation season. The project site is located in a local topographic low with Fivemile Creek bisecting through the southwest portion of the project site. Clayey gravel sediments on site typically have a low hydraulic conductivity and prevent consistent flow of groundwater. When inundated by groundwater seepage from canals or creeks, these sediments have an increased moisture content that limits drainage characteristics significantly. It should be expected for shallow groundwater seepage from Fivemile Creek to saturate these sediments during peak irrigation season with a very slow decrease in moisture content throughout the year. Based on relative moisture contents and shallow seepage encountered during projects within approximately 0.1 mile to the north of the site in April 2009 and January 2018, shallow seepage can be expected at depths as shallow as approximately 4.5 feet bgs. During previous investigations performed in May 2009 and October 2011 within approximately '/4-mile to the east and northeast of the project site, groundwater was encountered within numerous test pits at depths ranging from 10.5 to 11.9 feet bgs. Based on evidence of this investigation and background knowledge of the area,MTI estimates groundwater depths to remain greater than approximately 10 feet bgs throughout the year. This depth should be confirmed through long-term groundwater monitoring_ Soil Infiltration Rates Soil permeability,which is a measure of the ability of a soil to transmit a fluid,was not tested in the field. Given the absence of direct measurements, for this report an estimation of infiltration is presented using generally recognized values for each soil type and gradation. Of soils comprising the generalized soil profile for this study, sandy lean clay and sandy silt soils have typical hydraulic infiltration rates of less than 2 inches to 4 inches per hour. Clayey sand and clayey gravel sediments typically have infiltration rates ranging from 2 to 6 inches per hour. The presence of shallow groundwater seepage and clayey sediments will limit drainage; therefore, MTI recommends that infiltration testing be conducted to determine site specific infiltration rates. However, for preliminary design purposes, an infiltration rate of 0.5 inch per hour can be assumed. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 9 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections FOUNDATION AND PAVEMENT DISCUSSION AND RECOMMENDATIONS Various foundation types have been considered for support of the proposed structures. Two requirements must be met in the design of foundations. First, the applied bearing stress must be less than the ultimate bearing capacity of foundation soils to maintain stability. Second, total and differential settlement must not exceed an amount that will produce an adverse behavior of the superstructure. Allowable settlement is usually exceeded before bearing capacity considerations become important; thus, allowable bearing pressure is normally controlled by settlement considerations. Foundation Design Recommendations Because of the variable fill zone,which contains various types of debris, settlement of the structures is likely to occur and could be on the order of multiple inches. At this time,the actual amount of settlement is indeterminate because of the nature and condition of the uncontrolled fill. Depending on proposed construction and building loading parameters, multiple foundation design recommendations may be provided. These could include: complete removal of existing fill materials, deep foundation system, or partial removal of fill materials and replacement with structural fill with geogrid reinforcement. Once the nature of the individual structures are known, MTI can provide lot specific foundation and floor slab-on-grade design recommendations. Recommended Pavement Sections MTI has made assumptions for traffic loading variables based on the character of the proposed construction. The Client shall review and understand 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 California Bearing Ratio (CBR) value of 4 has been assumed for near-surface fill materials on site. The following are minimum thickness requirements for assured pavement function. Depending on site conditions, additional work, e.g. soil preparation, may be required to support construction equipment. These have been listed within the Soft Subgrade Soils section. Flexible Pavement Sections The American Association of State Highway and Transportation Officials (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 ISPWC Standard Specification for Highway Construction. Construction of the pavement section should be in accordance with these specifications and should adhere to guidelines recommended in the section on Construction Considerations. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 10 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections AASHTO Flexible Pavement S ecifications Pavement Section Component' Driveways and Parking Driveways and Parking Light Duty Heavy Duty Asphaltic Concrete 2.5 Inches 3.0 Inches Crushed Aggregate Base 4.0 Inches 4.0 Inches Structural Subbase 8.0 Inches 12.0 Inches Compacted Subgrade See Pavement Subgrade See Pavement Subgrade Preparation Section Preparation Section 1It will be required for MTI personnel to verify subgrade competency at the time of construction. Asphaltic Concrete: Asphalt mix design shall meet the requirements of ISPWC, Section 810 Class III plant mix. Materials shall be placed in accordance with ISPWC Standard Specifications for Highway Construction. Aggregate Base: Material complying with ISPWC Standards for Crushed Aggregate Materials. Structural Subbase: Granular structural fill material complying with the requirements detailed in the Structural Fill section of this report except that the maximum material diameter is no more than 2/3 the component thickness. Gradation and suitability requirements shall be per ISPWC Section 801, Table 1. Debris-containing uncontrolled fill materials were encountered throughout the site and will remain below the improved 21/2 foot zone (See Pavement Subgrade Preparation Section). Changes in moisture conditions within these fill materials may cause settlement or vertical movement of pavements overtime. This risk must be recognized and accepted by the project owner. If the scope of the project changes with ,grade changes from existing conditions, alternative pavement recommendations can be provided. Pavement Subgrade Preparation Uncontrolled fill, which contained debris, was encountered in portions of the site. MTI recommends that these fill materials be removed to a depth of at least 2'/2 feet below existing grade. If fill materials remain after excavation, the exposed subgrade must be compacted to at least 95 percent of the maximum dry density as determined by ASTM D698 for flexible pavements. The excavated fill materials can be replaced in accordance with the Structural Fill section provided that all organic material and/or debris is completely removed. Once final grades have been determined, MTI is available to provide additional recommendations. 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 using a heavy rubber-tired, fully loaded,tandem-axle dump truck or equivalent. Verification of subgrade competence by MTI personnel at the time of construction is required. Fill materials on the site must demonstrate the indicated compaction prior to placing material in support of the pavement section. MTI anticipated that pavement areas will be subjected to moderate traffic. Subgrade claw and silty soils near and above optimum moisture contents may_pump during compaction. Pumping or soft areas must be removed and replaced with structural fill. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 11 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections Fill material and aggregates in support of the pavement section must be compacted to no less than 95 percent of the maximum dry density as determined by ASTM D698 for flexible pavements and by ASTM D1557 for rigid pavements. If a material placed as a pavement section component cannot be tested by usual compaction testing methods, then compaction of that material must be approved by observed proof rolling. Minor deflections from proof rolling for flexible pavements are allowable. Deflections from proof rolling of rigid pavement support courses should not be visually detectable. MTI recommends that rigid concrete pavement be provided for heavy garbage receptacles. This will eliminate damage caused by the considerable loading transferred through the small steel wheels onto asphaltic concrete. Rigid concrete pavement should consist of Portland Cement Concrete Pavement (PCCP) generally adhering to ITD specifications for Urban Concrete. PCCP should be 6 inches thick on a 4-inch drainage fill course and should be reinforced with welded wire fabric. Control joints must be on 12-foot centers or less. CONSTRUCTION CONSIDERATIONS Earthwork Excessively organic soils,deleterious materials,or disturbed soils generally undergo high volume changes when subjected to loads, which is detrimental to subgrade behavior in the area of pavements, floor slabs, structural fills, and foundations. Mature trees, brush, and thick grasses with associated root systems were noted at the time of our investigation. It is recommended that organic or disturbed soils, if encountered, be removed to depths of I foot (minimum), and wasted or stockpiled for later use. However, in areas where trees are/were present, deeper excavation depths should be anticipated. Stripping depths should be adjusted in the field to assure that the entire root zone or disturbed zone or topsoil are removed prior to placement and compaction of structural fill materials. Exact removal depths should be determined during grading operations by MTI personnel, and should be based upon subgrade soil type, composition, and firmness or soil stability. If underground storage tanks, underground utilities, wells, or septic systems are discovered during construction activities, they must be decommissioned then removed or abandoned in accordance with governing Federal, State,and local agencies. Excavations developed as the result of such removal must be backfilled with structural fill materials as defined in the Structural Fill section. MTI should oversee subgrade conditions (i.e., moisture content) as well as placement and compaction of new fill (if required) after native soils are excavated to design grade. Recommendations for structural fill presented in this report can be used to minimize volume changes and differential settlements that are detrimental to the behavior of footings, pavements, and floor slabs. Sufficient density tests should be performed to properly monitor compaction. For structural fill beneath building structures, one in-place density test per lift for every 5,000 square feet is recommended. In parking and driveway areas, this can be decreased to one test per lift for every 10,000 square feet. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 12 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections Dry Weather If construction is to be conducted during dry seasonal conditions,many problems associated with soft soils may be avoided. However,some rutting of subgrade soils may be induced by shallow groundwater conditions related to springtime runoff or irrigation activities during late summer through early fall. Solutions to problems associated with soft subgrade soils are outlined in the Soft Subgrade Soils section. Problems may also arise because of lack of moisture in native and fill soils at time of placement. This will require the addition of water to achieve near-optimum moisture levels. Low-cohesion soils exposed in excavations may become friable, increasing chances of sloughing or caving. Measures to control excessive dust should be considered as part of the overall health and safety management plan. Wet Weather If construction is to be conducted during wet seasonal conditions (commonly from mid-November through May),problems associated with soft soils must be considered as part of the construction plan. During this time of year, fine-grained soils such as silts and clays will become unstable with increased moisture content, and eventually deform or rut. Additionally, constant low temperatures reduce the possibility of drying soils to near optimum conditions. Soft Subgrade Soils Shallow fine-grained subgrade soils that are high in moisture content should be expected to pump and rut under construction traffic. During periods of wet weather, construction may become very difficult if not impossible. The following recommendations and options have been included for dealing with soft subgrade conditions: • Track-mounted vehicles should be used to strip the subgrade of root matter and other deleterious debris and to perform any other necessary excavations. Heavy rubber-tired equipment should be prohibited from operating directly on the native subgrade and areas in which structural fill materials have been placed. Construction traffic should be restricted to designated roadways that do not cross, or cross on a limited basis,proposed roadway or parking areas. • Soft areas can be over-excavated and replaced with granular structural fill. • Construction roadways on soft subgrade soils should consist of a minimum 2-foot thickness of large cobbles of 4 to 6 inches in diameter with sufficient sand and fines to fill voids. Construction entrances should consist of a 6-inch thickness of clean, 2-inch minimum, angular drain-rock and must be a minimum of 10 feet wide and 30 to 50 feet long. During the construction process, top dressing of the entrance may be required for maintenance. • Scarification and aeration of subgrade soils can be employed to reduce the moisture content of wet subgrade soils. After stripping is complete,the exposed subgrade should be ripped or disked to a depth of 11/2 feet and allowed to air dry for 2 to 4 weeks. Further disking should be performed on a weekly basis to aid the aeration process. • Alternative soil stabilization methods include use of geotextiles, lime, and cement stabilization. MTI is available to provide recommendations and guidelines at your request. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 13 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections Frozen Subgrade Soils Prior to placement of structural fill materials or foundation elements, frozen subgrade soils must either be allowed to thaw or be stripped to depths that expose non-frozen soils and wasted or stockpiled for later use. Stockpiled materials must be allowed to thaw and return to near-optimal conditions prior to use as structural fill. The onsite, shallow clayey and silty soils are susceptible to frost heave during freezing temperatures. For exterior flatwork and other structural elements, adequate drainage away from subgrades is critical. Compaction and use of structural fill will also help to mitigate the potential for frost heave. Complete removal of frost susceptible soils for the full frost depth, followed by replacement with a non-frost susceptible structural fill, can also be used to mitigate the potential for frost heave. MTI is available to provide further guidance/assistance upon request. Structural Fill Soils recommended for use as structural fill are those classified as GW, GP, SW, and SP in accordance with the Unified Soil Classification System(USCS) (ASTM D2487). Use of silty soils (USCS designation of GM, SM, and ML) as structural fill may be acceptable. However, use of silty soils (GM, SM, and ML) as structural fill below footings is prohibited. These materials require very high moisture contents for compaction and require a long time to dry out if natural moisture contents are too high and may also be susceptible to frost heave under certain conditions. Therefore, these materials can be quite difficult to work with as moisture content, lift thickness, and compactive effort becomes difficult to control. If silty soil is used for structural fill, lift thicknesses should not exceed 6 inches (loose), and fill material moisture must be closely monitored at both the working elevation and the elevations of materials already placed. Following placement, silty soils must be protected from degradation resulting from construction traffic or subsequent construction. Recommended granular structural fill materials, those classified as GW, GP, SW, and SP, should consist of a 6-inch minus select, clean, granular soil with no more than 50 percent oversize (greater than 3/4-inch) material and no more than 12 percent fines (passing No. 200 sieve). These fill materials should be placed in layers not to exceed 12 inches in loose thickness. Prior to placement of structural fill materials, surfaces must be prepared as outlined in the Construction Considerations section. Structural fill material should be moisture-conditioned to achieve optimum moisture content prior to compaction. For structural fill below footings,areas of compacted backfill must extend outside the perimeter of the footings for a distance equal to the thickness of fill between the bottom of foundation and underlying soils, or 5 feet,whichever is less. All fill materials must be monitored during placement and tested to confirm compaction requirements, outlined below, have been achieved. Each layer of structural fill must be compacted, as outlined below: • Below Structures and Rigid Pavements: A minimum of 95 percent of the maximum dry density as determined by ASTM D1557. • Below Flexible Pavements: A minimum of 92 percent of the maximum dry density as determined by ASTM D1557 or 95 percent of the maximum dry density as determined by ASTM D698. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cDmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 14 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections The ASTM D 15 57 test method must be used for samples containing up to 40 percent oversize (greater than 3/4- inch)particles. If material contains more than 40 percent but less than 50 percent oversize particles, compaction of fill must be confirmed by proof rolling each lift with a 10-ton vibratory roller (or equivalent) until the maximum density has been achieved. Density testing must be performed after each proof rolling pass until the in-place density test results indicate a drop (or no increase) in the dry density, defined as maximum density or "break over"point. The number of required passes should be used as the requirements on the remainder of fill placement. Material should contain sufficient fines to fill void spaces, and must not contain more than 50 percent oversize particles. Backfill of Walls Backfill materials must conform to the requirements of structural fill, as defined in this report. For wall heights greater than 2.5 feet, the maximum material size should not exceed 4 inches in diameter. Placing oversized material against rigid surfaces interferes with proper compaction,and can induce excessive point loads on walls. Backfill shall not commence until the wall has gained sufficient strength to resist placement and compaction forces. Further, retaining walls above 2.5 feet in height shall be backfilled in a manner that will limit the potential for damage from compaction methods and/or equipment. It is recommended that only small hand- operated compaction equipment be used for compaction of backfill within a horizontal distance equal to the height of the wall, measured from the back face of the wall. Backfill should be compacted in accordance with the specifications for structural fill, except in those areas where it is determined that future settlement is not a concern, such as planter areas. In nonstructural areas, backfill must be compacted to a firm and unyielding condition. Excavations Shallow excavations that do not exceed 4 feet in depth may be constructed with side slopes approaching vertical. Below this depth, it is recommended that slopes be constructed in accordance with Occupational Safety and Health Administration(OSHA)regulations, Section 1926, Subpart P. Based on these regulations, on-site soils are classified as type"C" soil, and as such, excavations within these soils should be constructed at a maximum slope of 1'/2 feet horizontal to 1 foot vertical (1'/2:1) for excavations up to 20 feet in height. Excavations in excess of 20 feet will require additional analysis. Note that these slope angles are considered stable for short- term conditions only, and will not be stable for long-term conditions. During the subsurface exploration, test pit sidewalls generally exhibited little indication of collapse; however, sloughing of fill materials and native granular sediments from test pit sidewalls was observed,particularly after penetration of the water table. For deep excavations, native granular sediments cannot be expected to remain in position. These materials are prone to failure and may collapse,thereby undermining upper soil layers. This is especially true when excavations approach depths near the water table. Care must be taken to ensure that excavations are properly backfilled in accordance with procedures outlined in this report. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 15 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections Groundwater Control Groundwater was encountered during the investigation but is anticipated to be below the depth of most construction. Excavations below the water table will require a dewatering program. Dewatering will be required prior to placement of fill materials. Placement of concrete can be accomplished through water by the use of a treme. It may be possible to discharge dewatering effluent to remote portions of the site, to a sump, or to a 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, MTI should be contacted to provide more detailed groundwater control measures. Special precautions may be required for control of surface runoff and subsurface seepage. It is recommended that runoff be directed away from open excavations. Silty and clayey soils may become soft and pump if subjected to excessive traffic during time of surface runoff. Ponded water in construction areas should be drained through methods such as trenching, sloping,crowning grades,nightly smooth drum rolling,or installing a French drain system. Additionally, temporary or permanent driveway sections should be constructed if extended wet weather is forecasted. GENERAL COMMENTS Based on the subsurface conditions encountered during this investigation and available information regarding the proposed development,the site is adequate for the planned construction. When plans and specifications are complete, and if significant changes are made in the character or location of the proposed structure, consultation with MTI must be arranged as supplementary recommendations may be required. Suitability of subgrade soils and compaction of structural fill materials must be verified by MTI personnel prior to placement of structural elements. Additionally, monitoring and testing should be performed to verify that suitable materials are used for structural fill and that proper placement and compaction techniques are utilized. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cDmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 16 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections REFERENCES American Association of State Highway and Transportation Officials(AASHTO) (1993). AASHTO Guide for Design 1 of Pavement Structures 1993. Washington D.C.: AASHTO. American Society of Civil Engineers (ASCE) (2013). Minimum Design Loads for Buildings and Other Structures: ASCE/SEI 7-10. Reston,VA: ASCE. American Society for Testing and Materials(ASTM) (2017). Standard Test Method for Materials Finer than 75-µNo. 200) Sieve in Mineral Aggregatesy Washing: ASTM C117. West Conshohocken,PA: ASTM. American Society for Testing and Materials(ASTM)(2014). Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates: ASTM C136.West Conshohocken,PA: ASTM. American Society for Testing and Materials (ASTM) (2012). Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort: ASTM D698. West Conshohocken,PA: ASTM. American Society for Testing and Materials (ASTM) (2012). Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort: ASTM D1557. West Conshohocken,PA: ASTM. American Society for Testing and Materials(ASTM)(2017). Standard Practice for Classification of Soils for Engineering Purposes Unified Soil Classification System): ASTM D2487.West Conshohocken,PA: ASTM. American Society for Testing and Materials(ASTM) (2017). Standard Test Methods for Liquid Limit,Plastic Limit, and Plasticity Index of Soils: ASTM D4318. West Conshohocken,PA: ASTM. Desert Research Institute.Western Regional Climate Center. [Online] Available: <http://www.wrcc.dri.edu/>(2020). International Building Code Council(2015). International Building Code, 2015. Country Club Hills,IL: Author. Local Highway Technical Assistance Council (LHTAC) (2017). Idaho Standards for Public Works Construction, 2017. Boise,ID: Author. Othberg, K. L. and Stanford, L. A., Idaho Geologic Society (1993). Geologic Map of the Boise Valley and Adjoining Area,Western Snake River Plain,Idaho. (scale 1:100,000).Boise, ID: Joslyn and Morris. U.S. Department of Labor, Occupational Safety and Health Administration. CFR 29, Part 1926, Subpart P: Safety and Health Regulations for Construction,Excavations(1986). [Online] Available: <www.osha.gov>(2020). U.S. Geological Survey (2020). National Water Information System: Web Interface. [Online] Available: <http://waterdata.usgs.gov/nwis>(2020). U.S. Geological Survey. (2011). U.S. Seismic Design Maps: Web Interface. [Online] Available: <https://earthquake.usgs.gov/designmaps/us/application.php>(2020). 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 17 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections APPENDICES WARRANTY AND LIMITING CONDITIONS MTI warrants that findings and conclusions contained herein have been formulated in accordance with generally accepted professional engineering practice in the fields of foundation engineering, soil mechanics, and engineering geology only for the site and proj ect described in this report. These engineering methods have been developed to provide the client with information regarding apparent or potential engineering conditions relating to the site within the scope cited above and are necessarily limited to conditions observed at the time of the site visit and research. Field observations and research reported herein are considered sufficient in detail and scope to form a reasonable basis for the purposes cited above. Limitations Due to existing heavy vegetation and limited equipment access from Franklin Road,test pits were not advanced to the west of Fivemile Creek. Exclusive Use This report was prepared for exclusive use of the property owner(s), at the time of the report, and their retained design consultants ("Client"). Conclusions and recommendations presented in this report are based on the agreed-upon scope of work outlined in this report together with the Contract for Professional Services between the Client and Materials Testing and Inspection("Consultant"). Use or misuse of this report,or reliance upon findings hereof, by parties other than the Client is at their own risk. Neither Client nor Consultant make representation of warranty to such other parties as to accuracy or completeness of this report or suitability of its use by such other parties for purposes whatsoever, known or unknown, to Client or Consultant. Neither Client nor Consultant shall have liability to indemnify or hold harmless third parties for losses incurred by actual or purported use or misuse of this report. No other warranties are implied or expressed. Report Recommendations are Limited and Subiect to Misinterpretation There is a distinct possibility that conditions may exist that could not be identified within the scope of the investigation or that were not apparent during our site investigation. Findings of this report are limited to data collected from noted explorations advanced and do not account for unidentified fill zones,unsuitable soil types or conditions,and variability in soil moisture and groundwater conditions. To avoid possible misinterpretations of findings, conclusions, and implications of this report, MTI should be retained to explain the report contents to other design professionals as well as construction professionals. Since actual subsurface conditions on the site can only be verified by earthwork, note that construction recommendations are based on general assumptions from selective observations and selective field exploratory sampling. Upon commencement of construction, such conditions may be identified that require corrective actions, and these required corrective actions may impact the project budget. Therefore, construction recommendations in this report should be considered preliminary, and MTI should be retained to observe actual subsurface conditions during earthwork construction activities to provide additional construction recommendations as needed. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 18 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections Since geotechnical reports are subject to misinterpretation, do not separate the soil logs from the report. Rather, provide a copy of, or authorize for their use, the complete report to other design professionals or contractors. Locations of exploratory sites referenced within this report should be considered approximate locations only. For more accurate locations, services of a professional land surveyor are recommended. This report is also limited to information available at the time it was prepared. In the event additional information is provided to MTI following publication of our report, it will be forwarded to the client for evaluation in the form received. Environmental Concerns Comments in this report concerning either onsite conditions or observations, including soil appearances and odors, are provided as general information. These comments are not intended to describe, quantify, or evaluate environmental concerns or situations. Since personnel, skills, procedures, standards, and equipment differ, a geotechnical investigation report is not intended to substitute for a geoenvironmental investigation or a Phase II/III Environmental Site Assessment. If environmental services are needed, MTI can provide, via a separate contract, those personnel who are trained to investigate and delineate soil and water contamination. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cDmti-id.com Copyright© Maters Testingg&Inspection Vicinity Map Plate 1 MAP NOTES: MWOW •Delorme Street Atlas •Not to Scale T arLEGEND 3T_ W US CK RD E VSTIC-K RDFOL E USTICK RID Approximate Site F Ln Location m-< Z; mLL � 5�r Y KC,HEFtRY L1V f- FAIRVIEW AVE 5R 55'}iV SR 5� WY � Ff�IR1�iE'JV AVE r Meridian o N �.....__,.. .. ,..... _....�. d W FRANKLIN F{D E FRr41NKLI NKLIN u - Zn r 7V Site Location a Q Mid rove Plaza Subdivision 1450 East Franklin Road . 55 30 Meridian,ID EVERLAD RQ 'r' Modified from DeLorme by:CCW 5 February 2020 M m Drawing:B200127g 59 m MATERIALS TESTING & INSPECTION E VICMR,Y RD 2791 S.Victory View Way Phone: 208 376-4748 Boise,ID 83709-2835 Fax: 208 322-6515 FcnT E-mail: mti@mti-id.com Site Map Plate 2 W Q m a LOCUST GROVE ROAD]" K e �� ,46'V5Z pLU9Z m, 6,52 .4E'£5£ W _ M„[ .I .FPS W W —�__—_______� ______ ____�---_____ /¢ ----� — ___ __:--___ ______��__ _Q ____ _ �__—ti—--_��___ E'9pI O Q TP-1 W — S53M g v W P3lIYf6 0 2 � � g ® �� __ wN J LL�7 LLB W pMa Z - � caI d z ;F¢�z— a �� x x `.M¢�z �¢�z 4 D �NO l p�wD�� i2 I-oN0 a H :0 ��W I N o f v Jp dNrN _j N �•�vim 10 9 �n Vim. ❑ rCd r. TP-5 D a o • B F I f l oayy `z - 0 y o a4 p SZ dab"9 i1T9t4 3.. ,Be.00x s •� —� SS _ ^� 9V'!!L' ,6Efi°L T, No Out � •. TP-4 ---__. s / o �7 AWIMS A sW U Z •mow I H W LL `0 8 �¢fn cai aNw - SS� 61� w0 Hoop 0 CM N J"°' ' I NO 24 i 1.6sm.00N V p NOTES: LEGEND Mid rove Plaza Subdivision MATERIALS •Not to Scale Approximate Site Approximate MTI Test ® 1450 East Franklin Road TESTING & Boundary Pit Location with Meridian,ID INSPECTION Piezometer Modified by:CCW ez Approximate MTI Test O 2791 S.Victory View Way Phone: 208376-4748 Pit Location 8 5 February 2020 Boise,ID 83709-2835 Fax: 208 322-6515 Drawing:B200127g E-mail: mti@mti-id.com MATERIALS 13 February 2020 TESTING & Page# 21 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-1 Date Advanced: 4 Feb 2020 Logged by: Clint Wyllie, G.I.T. Excavated by: Creighton Contracting, LLC Location: See Site Map Plates Latitude: 43.607580 Longitude: -116.375032 Depth to Water Table: 15.6 Feet bgs (Initial Reading) Total Depth: 16.3 Feet bgs 13.4 Feet bgs (Delayed Reading) Notes: Piezometer installed to 16.3 feet bgs. Depth Field Description and USCS Soil and Sample Sample Depth Lab (Feet bgs) Sediment Classification T (Feet bgs) Qp Test ID Clayey Gravel with Sand Fill (GC-FILL): Brown, slightly moist, medium dense, with 0.0-3.6 fine to coarse-grained sand, fine to coarse gravel, and 6-inch-minus cobbles. --Organics noted to 0.9 foot bgs. --Clay content increased with depth. Fat Clay Fill (CH-FILL): Gray to gray- brown, slightly moist, very stiff, with fine- 3.6-5.2 grained sand. --Decomposing organic odor noted throughout. Sandy Silt (ML): Brown, slightly moist, stiff 5.2-7.3 to very stiff, with fine to medium-grained sand. Clayey Gravel with Sand (GC): Brown to red-brown, slightly moist to moist, dense to 7.3-14.7 very dense, with fine to coarse-grained sand, fine to coarse gravel, and 12-inch-minus cobbles. Clayey Sand with Gravel (SC): Brown to orange-brown, moist to saturated, medium 14.7-16.3 dense to dense, with fine to coarse-grained sand,fine to coarse gravel, and 6-inch-minus cobbles. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 22 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-2 Date Advanced: 4 Feb 2020 Logged by: Clint Wyllie, G.I.T. Excavated by: Creighton Contracting, LLC Location: See Site Map Plates Latitude: 43.605253 Longitude: -116.375119 Depth to Water Table: 13.2 Feet bgs (Delayed Reading) Total Depth: 15.6 Feet bgs Water seepage at 2.8 feet bgs Notes: Piezometer installed to 15.6 feet bgs. Depth Field Description and USCS Soil and Sample Sample Depth Lab (Feet bgs) Sediment Classification T (Feet bgs) Qp Test ID Clayey Gravel with Sand Fill (GC-FILL): Brown, slightly moist to wet, medium dense, 0.0-2.8 with fine to coarse-grained sand, fine to coarse gravel, and 8-inch-minus cobbles. --Water seepage encountered at 2.8 feet bgs. Sandy Fat Clay Fill (CH-FILL): Gray to gray-brown, slightly moist to moist, stiff to 2 8-6 7 very stiff, with fine to coarse-grained sand and intermittent 6-inch-minus cobbles. --Decomposing organic odor noted throughout. Clayey Gravel with Sand (GC): Brown, 6.7-15.6 slightly moist to moist, dense to very dense, with fine to coarse-grained sand, fine to coarse gravel, and 12-inch-minus cobbles. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 23 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-3 Date Advanced: 4 Feb 2020 Logged by: Clint Wyllie, G.I.T. Excavated by: Creighton Contracting, LLC Location: See Site Map Plates Latitude: 43.606196 Longitude: -116.375552 Depth to Water Table: Water seepage at 3.2 feet bgs Total Depth: 11.7 Feet bgs Depth Field Description and USCS Soil and Sample Sample Depth V Lab Feet bgs) Sediment Classification Type Feet bgs) Qp Test ID Clayey Gravel with Sand Fill (GC-FILL): Brown, slightly moist to wet, medium dense, 0.0-3.2 with fine to coarse-grained sand, fine to coarse gravel, and 10-inch-minus cobbles. --Water seepage encountered at 3.2 feet bgs. Sandy Fat Clay Fill (CH-FILL): Gray to gray-brown, slightly moist, very stiff, with 3.2-4.4 fine to coarse-grained sand and intermittent 12-inch-minus cobbles. --Decomposing organic odor noted throughout. Sandy Lean Clay (CL): Gray-brown to 4.4-7.2 brown, slightly moist, very stiff, with fine to GS 4.5-5.0 A medium-grained sand. Clayey Gravel with Sand (GC): Brown, 7.2-11.7 slightly moist, dense, with fine to coarse- grained sand, fine to coarse gravel, and 8- inch-minus cobbles. Lab Test ID M LL PI Sieve Analysis % passing) % - - AU44 #10 #40 #100 #200 A 16.0 31 15 100 99 82 62 57.2 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 24 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-4 Date Advanced: 4 Feb 2020 Logged by: Clint Wyllie, G.I.T. Excavated by: Creighton Contracting, LLC Location: See Site Map Plates Latitude: 43.606537 Longitude: -116.375817 Depth to Water Table: Not Encountered Total Depth: 9.2 Feet bgs Depth Field Description and USCS Soil and Sample Sample Depth Lab Feet b s Sediment Classification Type Feet b s Qp Test ID Sandy Lean Clay Fill (CL-FILL): Brown, 0.0-1.4 slightly moist, medium stiff to stiff, with fine- 1.0-1.5 grained sand. Silty Sand with Gravel Fill(SM-FILL):Light brown, dry, medium dense, with fine to 1.4-2.8 medium-grained sand,fine to coarse gravel, and 6-inch-minus cobbles. --Intermittent trash debris noted throughout. --Some clay content noted throughout. Lean Clay with Sand Fill(CL-FILL):Brown, 2.8-6.4 dry to slightly moist, stiff, with fine-grained sand. --Intermittent trash debris noted throughout. Clayey Gravel with Sand Fill (GC-FILL): 6.4-9.2 Brown, slightly moist, dense, with fine to coarse-grained sand, fine to coarse gravel, and 12-inch-minus cobbles. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 25 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-5 Date Advanced: 4 Feb 2020 Logged by: Clint Wyllie, G.I.T. Excavated by: Creighton Contracting, LLC Location: See Site Map Plates Latitude: 43.607330 Longitude: -116.375628 Depth to Water Table: Not Encountered Total Depth: 12.2 Feet bgs Depth Field Description and USCS Soil and Sample Sample Depth V Lab Feet bgs) Sediment Classification Type Feet bgs) Qp Test ID Clayey Sand with Gravel Fill (SC-FILL): Brown, slightly moist, medium dense, with 0.0-1.9 fine to coarse-grained sand, fine to coarse gravel, and 4-inch-minus cobbles. --Organics noted to 0.7 foot bgs. Sandy Lean Clay (CL): Brown, slightly 1.9-4.6 moist, stiff, with fine to medium-grained sand. Sandy Silt (ML): Brown, slightly moist, stiff 4.6-6.5 to very stiff, with fine to medium-grained sand. Clayey Gravel with Sand (GC): Brown, 6.5-12.2 slightly moist, dense to very dense, with fine to coarse-grained sand,fine to coarse gravel, and 12-inch-minus cobbles. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 26 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GEOTECHNICAL GENERAL NOTES NIFIED SOIL CLASSIFICATION SYSTEM Ma'or Divisions Symbol Soil Descriptions Gravel&Gravelly GW Well-graded gravels; ravel/sand mixtures with little or no fines Soils<50% GP Poorly-graded ravels; ravel/sand mixtures with little or no fines Coarse-Grained coarse fraction GM Silty gravels;poorly-graded ravel/sand/silt mixtures Soils<50% passes No.4 sieve GC Clayey gravels;poorly-graded gravel/sand/clay mixtures passes No.200 Sand&Sandy SW Well-graded sands;gravelly sands with little or no fines sieve Soils>50% SP Poorly-graded sands;gravelly sands with little or no fines coarse fraction SM Silty sands;poorly-graded sand/gravel/silt mixtures passes No.4 sieve SC Clayey sands;poorly-graded sand/gravel/clay mixtures ML Inorganic silts; sandy,gravelly or clayey silts Silts&Clays Lean clays; inorganic, gravelly, sandy, or silty, low to medium-plasticity Fine-Grained LL<50 CL clays Soils>50% OL Organic,low-plasticity clays and silts passes No.200 MH Inorganic,elastic silts; sandy,gravelly or clayey elastic silts sieve Silts&Clays LL>50 CH Fat clays;high-plasticity,inorganic clays OH Organic,medium to high-plasticity clays and silts Highly Organic Soils PT Peat,humus,hydric soils with high organic content RELATIVE ENSITY AND CONSIST MOISTURE CONTENT AND EMENTATION CLASSIFICATION 1 CLASSIFICATION Coarse-Grained Soils SPT Blow Counts N) Description Field Test Very Loose: <4 Dry Absence of moisture,dusty,dry to touch Loose: 4-10 Slightly Moist Damp,but not visible moisture Medium Dense: 10-30 Moist Visible moisture Dense: 30-50 Wet Visible free water Very Dense: >50 Saturated Soil is usually below water table Fine-Grained Soils SPT Blow Counts Description Field Test Very Soft: <2 Weak Crumbles or breaks with handling or slight Soft: 2-4 finger pressure Medium Stiff: 4-8 Moderate Crumbles or breaks with considerable finger Stiff. 8-15 pressure Very Stiff. 15-30 Strong Will not crumble or break with finger pressure Hard: >30 PARTICLE SIZE K ACRONYM LIST Boulders: > 12 in. GS grab sample Cobbles: 12 to 3 in. LL Liquid Limit Gravel: 3 in.to 5 mm M moisture content Coarse-Grained Sand: 5 to 0.6 mm NP non-plastic Medium-Grained Sand: 0.6 to 0.2 mm PI PlasticityIndex Fine-Grained Sand: 0.2 to 0.075 mm Qp penetrometer value, unconfined compressive strength, Silts: 0.075 to 0.005 mm tsf Clays: <0.005 mm V vane value,ultimate shearing strength,tsf 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 27 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections AASHTO PAVEMENT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: Midgrove Plaza Subdivision,Light Duty Average Daily Traffic Count: 100 All Lanes&Both Directions Design Life: 20 Years Percent of Traffic in Design Lane: 50% 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 ESALs Passenger Cars: 42 2.0% 0.0008 298 Buses: 0 2.0% 0.6806 0 Panel&Pickup Trucks: 5 2.0% 0.0122 541 2-Axle,6-Tire Trucks: 2 2.0% 0.1890 3,352 Emergency Vehicles: 1.0 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 Trailer Trucks 0 2.0% 2.3187 0 Heavy Tractor Trailer Combo Trucks: 0 2.0% 2.9760 0 Average Daily Traffic in Design Lane: 50 Total Design Life 18-kip ESALs: 43,922 Actual Log(ESALs): 4.643 Trial SN: 2.41 Trial Log(ESALs): 4.653 Pavement Section Design SN: 2.41 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 n/a Crushed Aggregate Base: 4.00 0.14 1.0 Subbase: 8.00 0.10 1.0 Special Aggregate Subgrade: 0.00 0.09 0.9 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection MATERIALS 13 February 2020 TESTING & Page# 28 of 30 INSPECTION b200127g_geotech AN ATLAS COMPANY ❑Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections AASHTO PAVEMENT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: Midgrove Plaza Subdivision,Heavy Duty Average Daily Traffic Count: 100 All Lanes&Both Directions Design Life: 20 Years Percent of Traffic in Design Lane: 50% 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 ESALs Passenger Cars: 5 2.0% 0.0008 35 Buses: 0 2.0% 0.6806 0 Panel&Pickup Trucks: 20 2.0% 0.0122 2,164 2-Axle,6-Tire Trucks: 20 2.0% 0.1890 33,523 Emergency Vehicles: 1.0 2.0% 4.4800 39,731 Dump Trucks: 0 2.0% 3.6300 0 Tractor Semi Trailer Trucks: 2 2.0% 2.3719 42,071 Double Trailer Trucks 2 2.0% 2.3187 41,127 Heavy Tractor Trailer Combo Trucks: 0 2.0% 2.9760 0 Average Daily Traffic in Design Lane: 50 Total Design Life 18-kip ESALs: 158,651 Actual Log(ESALs): 5.200 Trial SN: 3.02 Trial Log(ESALs): 5.243 Pavement Section Design SN: 3.02 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: 4.00 0.14 1.0 Subbase: 12.00 0.10 1.0 Special Aggregate Subgrade: 0.00 0.09 0.9 2791 S Victory View Way•Boise,ID 83709•(208)376-4748•Fax(208)322-6515 www.mti-id.com•mti(cbmti-id.com Copyright© Maters Testingg&Inspection IMPOPIOnt InfOPM81100 Rhout ■ GeolechnicalmEngineeping Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes. While you cannot eliminate all such risks, you can manage them. The following information is provided to help. The Geoprofessional Business Association (GBA) will not likely meet the needs of a civil-works constructor or even a has prepared this advisory to help you—assumedly different civil engineer.Because each geotechnical-engineering study a client representative—interpret and apply this is unique,each geotechnical-engineering report is unique,prepared geotechnical-engineering report as effectively as solely for the client. possible. In that way, you can benefit from a lowered Likewise,geotechnical-engineering services are performed for a specific exposure to problems associated with subsurface project and purpose.For example,it is unlikely that a geotechnical- conditions at project sites and development of engineering study for a refrigerated warehouse will be the same as them that,for decades, have been a principal cause one prepared for a parking garage;and a few borings drilled during of construction delays, cost overruns, claims, a preliminary study to evaluate site feasibility will not be adequate to and disputes. If you have questions or want more develop geotechnical design recommendations for the project. information about any of the issues discussed herein, contact your GBA-member geotechnical engineer. Do not rely on this report if your geotechnical engineer prepared it: Active engagement in GBA exposes geotechnical • for a different client; engineers to a wide array of risk-confrontation • for a different project or purpose; techniques that can be of genuine benefit for • for a different site(that may or may not include all or a portion of everyone involved with a construction project. the original site);or before important events occurred at the site or adjacent to it; e.g.,man-made events like construction or environmental Understand the Geotechnical-Engineering Services remediation,or natural events like floods,droughts,earthquakes, Provided for this Report or groundwater fluctuations. Geotechnical-engineering services typically include the planning, collection,interpretation,and analysis of exploratory data from Note,too,the reliability of a geotechnical-engineering report can widely spaced borings and/or test pits.Field data are combined be affected by the passage of time,because of factors like changed with results from laboratory tests of soil and rock samples obtained subsurface conditions;new or modified codes,standards,or from field exploration(if applicable),observations made during site regulations;or new techniques or tools.If you are the least bit uncertain reconnaissance,and historical information to form one or more models about the continued reliability of this report,contact your geotechnical of the expected subsurface conditions beneath the site.Local geology engineer before applying the recommendations in it.A minor amount and alterations of the site surface and subsurface by previous and of additional testing or analysis after the passage of time-if any is proposed construction are also important considerations.Geotechnical required at all-could prevent major problems. engineers apply their engineering training,experience,and judgment to adapt the requirements of the prospective project to the subsurface Read this Report in Full model(s). Estimates are made of the subsurface conditions that Costly problems have occurred because those relying on a geotechnical- will likely be exposed during construction as well as the expected engineering report did not read the report in its entirety.Do not rely on performance of foundations and other structures being planned and/or an executive summary.Do not read selective elements only.Read and affected by construction activities. refer to the report in full. The culmination of these geotechnical-engineering services is typically a You Need to Inform Your Geotechnical Engineer geotechnical-engineering report providing the data obtained,a discussion About Change of the subsurface model(s),the engineering and geologic engineering Your geotechnical engineer considered unique,project-specific factors assessments and analyses made,and the recommendations developed when developing the scope of study behind this report and developing to satisfy the given requirements of the project.These reports may be the confirmation-dependent recommendations the report conveys. titled investigations,explorations,studies,assessments,or evaluations. Typical changes that could erode the reliability of this report include Regardless of the title used,the geotechnical-engineering report is an those that affect: engineering interpretation of the subsurface conditions within the context . the site's size or shape; of the project and does not represent a close examination,systematic . the elevation,configuration,location,orientation, inquiry,or thorough investigation of all site and subsurface conditions. function or weight of the proposed structure and Geotechnical-Engineering Services are Performed the desired performance criteria; the composition of the design team;or for Specific Purposes, Persons, and Projects, . project ownership. and At Specific Times Geotechnical engineers structure their services to meet the specific As a general rule,always inform your geotechnical engineer of project needs,goals,and risk management preferences of their clients.A or site changes-even minor ones-and request an assessment of their geotechnical-engineering study conducted for a given civil engineer impact.The geotechnical engineer who prepared this report cannot accept responsibility or liability for problems that arise because the geotechnical conspicuously that you've included the material for information purposes engineer was not informed about developments the engineer otherwise only.To avoid misunderstanding,you may also want to note that would have considered. "informational purposes"means constructors have no right to rely on the interpretations,opinions,conclusions,or recommendations in the Most Of the "Findings" Related in This Report report.Be certain that constructors know they may learn about specific Are Professional Opinions project requirements,including options selected from the report,only Before construction begins,geotechnical engineers explore a site's from the design drawings and specifications.Remind constructors subsurface using various sampling and testing procedures.Geotechnical that they may perform their own studies if they want to,and be sure to engineers can observe actual subsurface conditions only at those specific allow enough time to permit them to do so.Only then might you be in locations where sampling and testing is performed.The data derived from a position to give constructors the information available to you,while that sampling and testing were reviewed by your geotechnical engineer, requiring them to at least share some of the financial responsibilities who then applied professional judgement to form opinions about stemming from unanticipated conditions.Conducting prebid and subsurface conditions throughout the site.Actual sitewide-subsurface preconstruction conferences can also be valuable in this respect. conditions may differ-maybe significantly-from those indicated in this report.Confront that risk by retaining your geotechnical engineer Read Responsibility Provisions Closely to serve on the design team through project completion to obtain Some client representatives,design professionals,and constructors do informed guidance quickly,whenever needed. not realize that geotechnical engineering is far less exact than other engineering disciplines.This happens in part because soil and rock on This Report's Recommendations Are project sites are typically heterogeneous and not manufactured materials Confirmation-Dependent with well-defined engineering properties like steel and concrete.That The recommendations included in this report-including any options or lack of understanding has nurtured unrealistic expectations that have alternatives-are confirmation-dependent.In other words,they are not resulted in disappointments,delays,cost overruns,claims,and disputes. final,because the geotechnical engineer who developed them relied heavily TO confront that risk,geotechnical engineers commonly include on judgement and opinion to do so.Your geotechnical engineer can finalize explanatory provisions in their reports.Sometimes labeled"limitations,' the recommendations only after observing actual subsurface conditions many of these provisions indicate where geotechnical engineers' exposed during construction.If through observation your geotechnical responsibilities begin and end,to help others recognize their own engineer confirms that the conditions assumed to exist actually do exist, responsibilities and risks.Read these provisions closely.Ask questions. the recommendations can be relied upon,assuming no other changes have Your geotechnical engineer should respond fully and frankly. occurred.The geotechnical engineer who prepared this report cannot assume responsibility or liabilityfor confirmation-dependent recommendations fyou Geoenvironmental Concerns Are Not Covered fail to retain that engineer to perform construction observation. The personnel,equipment,and techniques used to perform an environmental study-e.g.,a"phase-one"or"phase-two"enviromnental This Report Could Be Misinterpreted site assessment-differ significantly from those used to perform a Other design professionals'misinterpretation of geotechnical- geotechnical-engineering study.For that reason,a geotechnical-engineering engineering reports has resulted in costly problems.Confront that risk report does not usually provide environmental findings,conclusions,or by having your geotechnical engineer serve as a continuing member of recommendations;e.g.,about the likelihood of encountering underground the design team,to: storage tanks or regulated contaminants.Unanticipated subsurface • confer with other design-team members; environmental problems have led to project failures.If you have not • help develop specifications; obtained your own environmental information about the project site, review pertinent elements of other design professionals'plans and ask your geotechnical consultant for a recommendation on how to find specifications;and environmental risk-management guidance. • be available whenever geotechnical-engineering guidance is needed. Obtain Professional Assistance to Deal with You should also confront the risk of constructors misinterpreting this Moisture Infiltration and Mold report.Do so by retaining your geotechnical engineer to participate in While your geotechnical engineer may have addressed groundwater, prebid and preconstruction conferences and to perform construction- water infiltration,or similar issues in this report,the engineer's phase observations. services were not designed,conducted,or intended to prevent migration of moisture-including water vapor-from the soil Give Constructors a Complete Report and Guidance through building slabs and walls and into the building interior,where Some owners and design professionals mistakenly believe they can shift it can cause mold growth and material-performance deficiencies. unanticipated-subsurface-conditions liability to constructors by limiting Accordingly,proper implementation of the geotechnical engineer's the information they provide for bid preparation.To help prevent recommendations will not of itself be sufficient to prevent the costly,contentious problems this practice has caused,include the moisture infiltration.Confront the risk of moisture infiltration by complete geotechnical-engineering report,along with any attachments including building-envelope or mold specialists on the design team. or appendices,with your contract documents,but be certain to note Geotechnical engineers are not building-envelope or mold specialists. GEOPROFESSIONAL BUSINESS SEA ASSOCIATION Telephone:301/565-2733 e-mail:info@geoprofessional.org www.geoprofessional.org Copyright 2019 by Geoprofessional Business Association(GBA).Duplication,reproduction,or copying of this document,in whole or in part,by any means whatsoever,is strictly prohibited,except with GBAs specific written permission.Excerpting,quoting,or otherwise extracting wording from this document is permitted only with the express written permission of GBA,and only for purposes of scholarly research or book review.Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind. Any other firm,individual,or other entity that so uses this document without being a GBA member could be committing negligent or intentional(fraudulent)misrepresentation.