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HomeMy WebLinkAboutEX_06_RS_Geotechnical_Report_220812_v1Geotechnical Engineering Services Longacres Field Entitlement Renton, Washington for Unico Properties, LLC June 23, 2022 RECEIVED 10/12/2022 JDing PLANNING DIVISION DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 Geotechnical Engineering Services Longacres Field Entitlement Renton, Washington for Unico Properties, LLC June 23, 2022 17425 NE Union Hill Road, Suite 250 Redmond, Washington 98052 425.861.6000 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 Geotechnical Engineering Services Longacres Field Entitlement Renton, Washington File No. 9061-019-00 June 23, 2022 Prepared for: Unico Properties, LLC 1215 4th Avenue, Suite 600 Seattle, Washington 98161 Attention: Julia Reeve, Development Manager Prepared by: GeoEngineers, Inc. 17425 NE Union Hill Road, Suite 250 Redmond, Washington 98052 425.860.6000 Yen Nhi Amy Nguyen, EIT Staff Geotechnical Engineer Matthew W. Smith, PE Senior Principal YNAN:MWS:tjh Disclaimer: Any electronic form, facsimile or hard copy of the original document (email, text, table, and/or figure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page i File No. 9061-019-00 Table of Contents 1.0 INTRODUCTION ............................................................................................................................................... 1  2.0 SCOPES OF SERVICES .................................................................................................................................... 1  3.0 PROJECT DESCRIPTION .................................................................................................................................. 1  4.0 PREVIOUS SITE EVALUATIONS ....................................................................................................................... 1  5.0 SITE CONDITIONS ............................................................................................................................................ 1  5.1. Surface Conditions...................................................................................................................................... 1  5.2. Subsurface Conditions ............................................................................................................................... 2  5.2.1. Soil Conditions ............................................................................................................................ 2  5.2.2. Groundwater Conditions ............................................................................................................. 2  6.0 CONCLUSIONS AND RECOMMENDATIONS ................................................................................................... 3  6.1. Summary of Key Geotechnical Issues ....................................................................................................... 3  6.2. Earthquake Engineering ............................................................................................................................. 3  6.2.1. Ground Shaking .......................................................................................................................... 3  6.2.2. Seismic Hazards ......................................................................................................................... 4  6.3. Site Preparation and Earthwork ................................................................................................................. 5  6.3.1. Clearing and Site Preparation .................................................................................................... 6  6.3.2. Sedimentation and Erosion Control ........................................................................................... 6  6.3.3. Settlement ................................................................................................................................... 7  6.3.4. Subgrade Preparation................................................................................................................. 7  6.3.5. Structural Fill ............................................................................................................................... 7  6.4. Excavations and Permanent Slopes ....................................................................................................... 10  6.4.1. Temporary Cut Slopes ............................................................................................................. 10  6.4.2. Permanent Cut and Fill Slopes ................................................................................................ 11  6.5. Utility Trenches ......................................................................................................................................... 11  6.6. Pavement Recommendations ................................................................................................................. 11  6.6.1. Subgrade Preparation.............................................................................................................. 11  6.6.2. New Hot Mix Asphalt Pavement .............................................................................................. 11  6.6.3. Portland Cement Concrete Pavement .................................................................................... 12  6.7. Recommended Additional Geotechnical Services ................................................................................. 12  7.0 LIMITATIONS ................................................................................................................................................ 13  8.0 REFERENCES ............................................................................................................................................... 13 LIST OF FIGURES Figure 1. Vicinity Map Figure 2. Conceptual Site Plan Figure 3. Exploration Site Plan APPENDICES Appendix A. Boring Logs from Previous Explorations Appendix B. Report Limitations and Guidelines for Use DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page 1 File No. 9061-019-00 1.0 INTRODUCTION This report presents the results of our geotechnical engineering services for the entitlement of the fields for the Seattle Sounders training facility in Renton, Washington. The site is shown relative to surrounding physical features in Figure 1, Vicinity Map, Figure 2, Site Plan and Figure 3, Exploration Site Plan. The purpose of this report is to provide preliminary geotechnical engineering recommendations that satisfies the City of Renton Conditional Use Permit (CUP) requirements. The subject property is approximately 19.36 acres and consists of five King County Parcels (numbers 088670-0110, 088670-0120, 088670-0130, 088670-0370 and 088670-0140). Our services were performed in general accordance with our proposal dated February 22, 2022. Signed authorization to proceed with our services was provided by the Unico Properties, LLC on March 1, 2022. 2.0 SCOPES OF SERVICES GeoEngineers’ scope of services includes: ■ Review available reports and studies for the subject property and surrounding area available from our files; ■ Providing preliminary earthwork recommendations for site grading including recommendations for imported fill, compaction criteria, subgrade preparation, utility trench backfill, site drainage and wet weather construction considerations; and ■ Preparing this report. 3.0 PROJECT DESCRIPTION We understand that the planned improvements include constructing five new training fields with both natural grass and artificial turf at the Longacres site (1901 Oaksdale Avenue SW) in Renton, Washington. The planned training fields are anticipated to require some fill to raise site grades. 4.0 PREVIOUS SITE EVALUATIONS The logs of selected explorations from previous site evaluations in the project vicinity were reviewed and are presented in Appendix A, Exploration Logs from Previous Studies. The approximate locations of these explorations are shown on Figure 2. 5.0 SITE CONDITIONS 5.1. Surface Conditions The proposed training fields are bounded by landscaping and a wetland to the north and west, and the Boeing BCAG Headquarter Building 25-20 and associated surface parking to the east, and private property to the south. Based on conceptual plans provided by Unico and a survey by NV5 dated April 6, 2021, the soccer field’s proposed layout is located on Lots 11 through 14 and a portion of Tract B. The site is currently DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page 2 File No. 9061-019-00 occupied by a surface parking lot, landscaping and wetland areas. Existing site grades slope gently down from west to east from approximately Elevation 17 to 10 feet. Buried utilities consisting of sanitary sewer, storm drain, gas, water, electric, and telecommunications fiber are anticipated within the rights-of-way adjacent to the site and through the surface parking lot. 5.2. Subsurface Conditions 5.2.1. Soil Conditions GeoEngineers’ understanding of subsurface conditions is based on review of existing geotechnical information in the vicinity of the project site. The approximate locations of the previous explorations are presented in Figure 2. The soils encountered in the site vicinity consist of shallow fill overlying alluvial deposits, beach deposits and glacially consolidated soils. The fill generally consists of very soft to stiff silt and to medium silty sand with varying amounts of gravel. Fill in the vicinity of the site ranged to approximately 6 feet thick. The alluvial deposits were encountered at the existing ground surface or beneath the fill. The alluvial soil generally consists of loose to medium dense sands and gravels with varying amounts of silt and very soft to medium stiff silt. The sand and silty sand deposits were generally interbedded with lenses of soft to medium stiff organic silt. The alluvial deposits in the vicinity of the site range up to approximately 45 feet deep. Beach deposits are present below the alluvial deposits and consist of medium dense to very dense sand and gravel with variable silt content. The glacially consolidated soils were encountered below the beach deposits and extended to the depths explored in the borings and cone penetration tests (CPT). The glacially consolidated soils consist of medium dense to very dense sands with varying amounts of silt and gravel. Although not encountered in previous explorations, occasional cobbles and boulders are typical of glacially consolidated soils and may be present at the site and have been encountered in nearby construction projects. 5.2.2. Groundwater Conditions The ground water levels in the vicinity of the site will fluctuate as a function of season, precipitation and water levels in the Green River. Based on our review of the available subsurface information, the regional groundwater table in the project vicinity varies seasonally at the site and is near the ground surface elevation during extended periods of wet weather. DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page 3 File No. 9061-019-00 6.0 CONCLUSIONS AND RECOMMENDATIONS 6.1. Summary of Key Geotechnical Issues Based on our review of available subsurface information and experience on other projects within the area, we conclude that the planned field improvements can be constructed satisfactorily as planned with respect to geotechnical elements. The key geotechnical issues for the project include: ■ The site is designated as seismic Site Class F per the 2018 International Building Code (IBC) (IBC 2018), due to the presence of potentially liquefiable soils. Site-response analysis is required for Site Class F sites; however, an exception is made for structures that have fundamental periods of vibration less than 0.5 second (sec). Based on our conversation with the structural engineer, we understand that the fundamental period of vibration of the proposed structure will be less than 0.5 sec and therefore this exception applies. Because of this, the response spectrum for Site Class E can be assumed for preliminary design based on the standard penetration test (SPT) blow counts obtained in nearby previous borings. ■ The existing fill and alluvial deposits encountered in the explorations contain a high percentage of fines and are highly moisture sensitive. We expect that operation of equipment on these soils will be difficult during the wet season (typically October through May) and in wet weather conditions. ■ On-site soils free of organics and organic silt may be used as structural fill during dry weather conditions (typically June through September) provided the material is properly moisture conditioned (likely need to be dried) to achieve proper compaction. Organic soils and organic silt should be removed from the site, if encountered during grading. Site preparation and earthwork should be completed during the drier months to reduce costs associated with these activities. Imported gravel borrow should be used as structural fill during wet weather conditions and during the wet season (typically October through May). ■ Design of the fields should consider estimated site settlement because of the underlying fill and alluvial deposits. In addition to being susceptible to liquefaction, the alluvial soils are compressible and are expected to settle under new/increased loading conditions. Static settlements will depend on the thickness of new fill placed. These geotechnical issues and other considerations are discussed further and recommendations pertaining to geotechnical aspects of the project are presented in the following sections. 6.2. Earthquake Engineering 6.2.1. Ground Shaking There is a risk of earthquake induced ground shaking at the site, as with all sites in the Puget Sound region, and the intensity of the ground shaking could be severe. The severity of ground shaking will be mostly a function of the earthquake magnitude and proximity to the site. We recommend that the seismic ground shaking at the site be evaluated in accordance with the 2018 International Building Code (IBC). 6.2.1.1. 2018 IBC Seismic Design Information The 2018 IBC references ASCE 7-16 for the Site Class determination and the development of seismic design parameters. The loose to medium dense granular soils below the water have moderate to high liquefaction potential. Accordingly, the site is Site Class F per ASCE 7-16 Section 20.3.1. Site response DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page 4 File No. 9061-019-00 analysis is required for Site Class F sites per Section 11.4.8. However, Section 20.3.1 provides an exception for structures that have a fundamental period of vibration equal to or less than 0.5 seconds, whereby the Site Class may be determined in accordance with Section 20.3 and the corresponding site coefficients determined per Section 11.4.4 to derive prescriptive seismic design parameters. The seismic design parameters presented in Table 1 below assume that the proposed structures will have a fundamental period of vibration equal to or less than 0.5 seconds, based on conversations we have had with the structural engineer. Accordingly, based on the subsurface data from the borings completed in the project vicinity, the response spectrum for Site Class E can be used for preliminary design for the purpose of developing seismic design parameters. Further, per ASCE 7-16 Supplement 3 Section 11.4.8, a site-specific ground motion hazard analysis and/or ground response analysis is required to determine design ground motions for structures on Site Class E sites with SS ≥1.0 or S1≥0.2. The mapped SS and S1 values for this site are 1.45 and 0.49, respectively; therefore, these provisions apply. Alternative to performing a site-specific evaluation, the parameters listed in Table 1 below may be used provided Exceptions 1 and 2 of ASCE 7-16 Supplement 3 Section 11.4.8 are used. Refer to ASCE 7-16 Supplement 3 Section 11.4.8 for further details. We recommend the use of the following 2018 IBC parameters for short period spectral response acceleration (SS), 1-second period spectral response acceleration (S1) and seismic coefficients (FA and FV) for the project site. TABLE 1. 2018 IBC DESIGN PARAMETERS 2018 IBC Parameter1 Recommended Values Site Class E Short Period Spectral Response Acceleration, SS (g) 1.448 1-Second Period Spectral Response Acceleration, S1 (g) 0.493 Seismic Coefficient, FA 1.202 Seismic Coefficient, FV 2.213 Peak Ground Acceleration (g) 0.616 Site Amplification Factor for PGA, FPGA 1.1 TS (seconds) 0.63 Notes: 1 Parameters developed based on latitude 47.4622 and longitude -122.2343 using the Applied Technology Council (ATC) Hazards online tool (https://hazards.atcouncile.org/). 2 Per ASCE 7-16 Supplement 3 Section 11.4.8 Table 11.4-1. 3 For calculating TS, determination of Seismic Design Category, linear interpolation for intermediate values of S1, and when taking the exceptions under Items 1 and 2 of ASCE 7-16 Supplement 3 for the calculation of SD1. 6.2.2. Seismic Hazards 6.2.2.1. Liquefaction Potential Liquefaction is a phenomenon where strong vibration or ground shaking, usually from earthquakes, results in development of excess pore pressures in loose, saturated soils and subsequent loss of strength in the soil deposits so affected. DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page 5 File No. 9061-019-00 Ground settlement, lateral spreading and/or sand boils may result from soil liquefaction. Structures supported on liquefied soils could suffer foundation settlement or lateral movement that could be severely damaging to the structures. Conditions favorable for liquefaction occur in loose to medium dense, clean to moderately silty sand that is below the groundwater level. Based on our evaluation of the subsurface conditions encountered in the explorations completed at the site, it is our opinion that potentially liquefiable soils are present below the proposed fields. We evaluated the liquefaction triggering potential (Youd and Idriss 2001; Idriss and Boulanger 2014) for the soils at the site using the simplified method. Our analysis indicates that the loose to medium dense sand which underlies the site has a moderate to high risk of liquefying. Structures such as utilities or walkways which are supported on-grade will likely experience liquefaction-induced and differential settlement during a design seismic event. The amount of settlement is difficult to estimate because of the complexity of conditions that cause liquefaction. Some cracking and/or structural damage may be experienced by structures supported on-grade as a result of liquefaction induced settlement. Structures should be designed per the IBC/ASCE 7-16 criteria for differential settlement, lateral spreading and bearing capacity. In the event that structures supported on shallow foundations do not meet the code criteria for differential settlement, lateral spreading and bearing capacity, deep foundations or ground improvement may be required to mitigate the liquefaction hazard. Additional explorations in the vicinity of planned structures are recommended during the design phase to assess the liquefaction hazard further and to meet the code criteria. 6.2.2.2. Lateral Spreading Lateral spreading is associated with liquefaction and involves lateral displacements of large volumes of liquefied soil. It can occur on near-level ground as blocks of surface soils displace relative to adjacent blocks. It also occurs as blocks of surface soils are displaced toward a nearby slope or free-face by movement of the underlying liquefied soil. Site specific explorations should be completed during the design phase to further assess the lateral spreading hazard and to determine if additional measures will be required to meet the IBC/ASCE 7-16 code criteria for planned buildings. 6.2.2.3. Other Seismic hazards Due to the location of the site and the site’s topography, the risk of adverse impacts resulting from seismically induced slope instability, differential settlement, or surface displacement due to faulting is considered to be low. 6.3. Site Preparation and Earthwork Based on the subsurface soil conditions encountered in the explorations, we expect that the soils at the site may be excavated using conventional heavy duty construction equipment. The materials anticipated to be encountered in planned excavations include very soft to stiff and loose to medium dense fill and loose to medium dense alluvial deposits. The on-site fill and alluvial soils contain significant fines (particles passing the U.S. Standard No. 200 sieve) and are highly moisture-sensitive and susceptible to disturbance, especially when wet. Ideally, earthwork should be undertaken during extended periods of dry weather (June through September) when the surficial soils will be less susceptible to disturbance and provide better support for construction equipment. DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page 6 File No. 9061-019-00 Dry weather construction will help reduce earthwork costs and increase the potential for reusing the existing fill and native soils as structural fill. Trafficability on the site is not expected to be difficult during dry weather conditions. However, the fill and native soils will be susceptible to disturbance from construction equipment during wet weather conditions and pumping and rutting of the exposed soils under equipment loads may occur. 6.3.1. Clearing and Site Preparation Construction of the proposed improvements will require clearing and stripping. We expect that there will be relatively minor site demolition of existing hardscape and utilities. Concrete and asphalt material should be removed from the site along with other construction debris. Areas to be developed or graded should be cleared of surface and subsurface deleterious matter including debris, shrubs, trees and associated stumps and roots. Graded areas should be stripped of organic materials and topsoil. Based on previous explorations and site observations, we estimate that stripping depths will be on the order of 2 to 6 inches to remove topsoil within existing field and lawn areas. The stripped organic soils can be stockpiled and used later for landscaping purposes. Materials that cannot be used for landscaping should be removed from the project site. 6.3.2. Sedimentation and Erosion Control Construction activities including stripping and grading will expose soils to the erosional effects of wind and water. The amount and potential impacts of erosion are partly related to the time of year that construction actually occurs. Wet weather construction will increase the amount and extent of erosion and potential sedimentation. Effective methods of erosion control at construction sites include efficient surface water management, minimization of the size of disturbed areas, and erosion resistant slope covers. Erosion and sedimentation control measures should include proper channeling of surface water runoff into lined diversion ditches that incorporate energy dissipaters, and use of straw bales and geotextile silt fences, as appropriate. Surface water must not be directed toward the top of slopes or onto slopes. Management of surface water runoff during construction is the responsibility of the contractor. Grading must be completed in a manner that avoids concentrated runoff onto fill areas, cut or fill slopes, natural slopes, or other erosion-sensitive areas. Erosion and sedimentation control measures may be implemented by using a combination of interceptor swales, straw bale barriers, silt fences and straw mulch for temporary erosion protection of exposed soils. Disturbed areas should be finish graded and seeded as soon as practicable to reduce the risk of erosion. Erosion and sedimentation control measures should be installed and maintained in accordance with the requirements of the approved project plans and specifications. 6.3.2.1. Erosion Control To reduce potential erosion and to help establish permanent vegetation on existing and newly created slopes, we recommend that erosion protection of the slopes include hydroseeding in conjunction with installation of an erosion control blanket. We recommend that the erosion control blanket be staked to DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page 7 File No. 9061-019-00 disturbed slopes to help reduce the risk of erosion during wet work periods and after the work is completed. We recommend that the erosion control blanket consist of Curlex 1, manufactured by American Excelsior Company, or SC150, manufactured by North American Green. We recommend that the erosion control blanket be installed in accordance with the manufacturer's recommendations and that the installation and stapling methods be observed during construction. Hydroseeding and installation of the erosion control blanket should occur as soon as possible and prior to the wet winter months. Hydroseeding should occur to allow proper germination before the winter. We also recommend that the hydroseed mix include a tackifier to increase adhesion between the hydroseed mixture and the fine grained native soils. 6.3.3. Settlement The site is underlain by compressible silts and organics silts that vary up to approximately 8 feet in thickness. Placement of fill over the silt and organic silt deposits will result in long term ground settlement as the silts consolidate. The amount of settlement will depend on factors such as the thickness of the fill, thickness of the silt and organic silt layers, and groundwater levels at the time fill is placed. We anticipate that most of the settlement will occur within a period of 1 to 2 months after fill placement. 6.3.4. Subgrade Preparation Prior to placing new fills, pavement or synthetic turf field base course materials subgrade areas should be evaluated by proof rolling or probing to locate zones of soft or pumping soils. Prior to proof rolling, unsuitable soils should be removed from below planned field areas. Proof rolling can be completed using a piece of heavy tire-mounted equipment such as a loaded dump truck. During wet weather, the exposed subgrade areas should be probed to determine the extent of soft soils. If zones of soft or pumping soils are identified, they should be removed and replaced with structural fill. Once approved, the subgrade areas should be recompacted to a firm condition, if possible. The degree of compaction that can be achieved will depend on when construction is performed. If the work is performed during dry weather conditions, we recommend that subgrade areas be recompacted to at least 95 percent of the maximum dry density (MDD) obtained using the American Society for Testing and Materials (ASTM) D 1557 test procedure (modified Proctor). If the work is performed during wet weather conditions, it may not be possible to recompact the subgrade to 95 percent of the MDD. In this case, we recommend that the subgrade be compacted to the extent possible without causing undue weaving or pumping of the subgrade soils. Subgrade disturbance or deterioration could occur if the subgrade is wet and cannot be dried. If the subgrade deteriorates during compaction or while being subjected to construction traffic, it may become necessary to modify the compaction criteria or methods. 6.3.5. Structural Fill New fill, whether on-site or imported fill for support of the fields, pavement areas and as backfill for utility trenches should meet the criteria for structural fill presented below. Structural fill soils should be free of organic matter, debris, man-made contaminants and other deleterious materials, with no individual DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page 8 File No. 9061-019-00 particles larger than 4 inches in greatest dimension. The suitability of soil for use as structural fill depends on its gradation and moisture content. 6.3.5.1. Fill Criteria Materials used under the planned fields, new pavement areas, used to construct embankments, or to backfill utility trenches are classified as structural fill for the purpose of this report. Recommended structural fill material quality varies depending upon its use as described below: ■ Structural fill placed in the planned fields, parking lot, sidewalk areas, and in utility trenches should consists of Gravel Borrow as described in Section 9-03.14(1) of the 2022 Washington State Department of Transportation (WSDOT) Standard Specifications, with the additional restriction that the fines content be limited to no more than 5 percent, especially if the work occurs in wet weather or during the wet season (October through May). However, if earthwork occurs during the normally dry months (June through September) on-site soils that are properly moisture conditioned (dried) and that can be properly compacted may be used as structural fill in these areas. ■ Crushed surfacing base course below pavements should conform Section 9-03.9 (3) of the 2022 WSDOT Standard Specifications. ■ Utility pipe bedding should conform to Section 9-03.12(3) of the 2022 WSDOT Standard Specifications unless required otherwise by the civil engineer. We recommend that the suitability of structural fill soil from proposed borrow sources be evaluated by a representative of our firm before the earthwork contractor begins transporting the soil to the site. 6.3.5.2. Reuse of On-site Soils The existing fill and native soils contain a high percentage of fines and will be sensitive to changes in moisture content and difficult to handle and compact during wet weather. On-site soils are expected to be suitable for structural fill, provided the work is completed during the normally dry season (June through September) and that the soil can be properly moisture conditioned. On-site soils with significant debris, large particles (greater than 4 inches in largest dimension) or organic matter, including organic silt soils, should not be used as structural fill. It may be necessary to import Gravel Borrow to achieve adequate compaction during wet weather construction. Imported structural fill consisting of Gravel Borrow should be planned for this project unless the earthwork takes place during the normally dry season. The contractor should plan to cover and maintain all fill stockpiles with plastic sheeting if they will be used as structural fill. The reuse of on-site soils is highly dependent on the skill of the contractor and schedule, and we will work with the design team and contractor to maximize the reuse of on-site soils during the wet and dry seasons. 6.3.5.3. Fill Placement and Compaction Criteria Structural fill should be mechanically compacted to a firm, non-yielding condition. Structural fill should be placed in loose lifts not exceeding 12 inches in thickness if using heavy compactors and 6 inches if using hand operated compaction equipment. The actual lift thickness will be dependent on the structural fill material used and the type and size of compaction equipment. Each lift should be conditioned to the proper DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page 9 File No. 9061-019-00 moisture content and compacted to the specified density before placing subsequent lifts. Structural fill should be compacted to the following criteria: ■ All fill placed under the proposed field area should be placed as structural fill compacted to at least 95 percent of the MDD estimated using the ASTM D 1557 test method, unless otherwise required by the project civil engineer. ■ Structural fill to form permanent fill slopes should be compacted to at least 90 percent of the MDD. ■ Structural fill in new pavement and hardscape areas, including utility trench backfill, should be compacted to at least 90 percent of the MDD, except that the upper 2 feet of fill below final subgrade should be compacted to at least 95 percent of the MDD. ■ Structural fill placed as crushed surfacing base course below pavements and the synthetic turf fields should be compacted to 95 percent of the MDD. ■ Non-structural fill, such as fill placed in landscape areas, should be compacted to at least 90 percent of the MDD. An adequate number of in-place moisture and density tests should be performed during the placement and compaction of structural fill to evaluate whether the specified degree of compaction is being achieved. 6.3.5.4. Weather Considerations Disturbance of near surface soils should be expected, especially if earthwork is completed during periods of wet weather. During dry weather, the soils will: (1) be less susceptible to disturbance; (2) provide better support for construction equipment; and (3) be more likely to meet the required compaction criteria. The wet weather season generally begins in October and continues through May in western Washington; however, periods of wet weather may occur during any month of the year. For earthwork activities during wet weather, we recommend that the following steps be taken: ■ The ground surface in and around the work area should be sloped so that surface water is directed away from the work area. The ground surface should be graded so that areas of ponded water do not develop. Measures should be taken by the contractor to prevent surface water from collecting in excavations and trenches. Measures should be implemented to remove surface water from the work area. Surface water must not be directed towards slopes and we recommend that storm water drainage ditches be constructed where needed along the crest of slopes to prevent uncontrolled surface water runoff. ■ Earthwork activities should not take place during periods of moderate to heavy precipitation. ■ Slopes with exposed soils should be covered with plastic sheeting. ■ The contractor should take necessary measures to prevent on-site soils and soils to be used as fill from becoming wet or unstable. These measures may include the use of plastic sheeting, sumps with pumps, and grading. The site soils should not be left uncompacted and exposed to moisture. Sealing the surficial soils by rolling with a smooth-drum roller prior to periods of precipitation will help reduce the extent that these soils become wet or unstable. ■ The contractor should cover all soil stockpiles that will be used as structural fill with plastic sheeting. DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page 10 File No. 9061-019-00 ■ Construction activities should be scheduled so that the length of time that soils are left exposed to moisture is reduced to the extent practical. 6.4. Excavations and Permanent Slopes The stability of open cut slopes is a function of soil type, groundwater seepage, slope inclination, slope height and nearby surface loads. The use of inadequately designed open cuts could impact the stability of adjacent work areas and existing utilities, and endanger personnel. The contractor performing the work has the primary responsibility for protection of workers and adjacent improvements. In our opinion, the contractor will be in the best position to observe subsurface conditions continuously throughout the construction process and to respond to variable soil and groundwater conditions. Therefore, the contractor should have the primary responsibility for deciding whether or not to use open cut slopes for much of the excavations rather than some form of temporary excavation support, and for establishing the safe inclination of the cut slope. Acceptable slope inclinations for utilities and ancillary excavations should be determined during construction. Because of the diversity of construction techniques and available shoring systems, the design of temporary shoring is most appropriately left up to the contractor proposing to complete the installation. Temporary cut slopes and shoring must comply with the provisions of Title 296, Washington Administrative Code (WAC), Part N, “Excavation, Trenching and Shoring.” Because the contractor has control of the construction operations, the contractor should be made responsible for the stability of cut slopes, as well as the safety of the excavations. The contractor should take all necessary steps to ensure the safety of the workers near the slopes. 6.4.1. Temporary Cut Slopes For planning purposes, temporary unsupported cut slopes more than 4 feet high may be inclined at 1.5H:1V in the fill and alluvial soils. These inclinations may need to be flattened by the contractor if significant caving/sloughing or groundwater seepage occurs. For open cuts at the site, we recommend that: ■ No traffic, construction equipment, stockpiles, or building supplies be allowed at the top of cut slopes within a distance of at least 5 feet from the top of the cut. ■ The excavation does not encroach on a 1H:1V influence line projected down from the edges of nearby or planned foundation elements. ■ Exposed soil along the slope be protected from surface erosion using waterproof tarps or plastic sheeting. ■ Construction activities be scheduled so that the length of time the temporary cut is left open is reduced to the extent practicable. ■ Erosion control measures be implemented as appropriate such that runoff from the site is reduced to the extent practicable. ■ Surface water be diverted away from the excavation. ■ The general condition of the slopes be observed periodically by GeoEngineers to confirm adequate stability. DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page 11 File No. 9061-019-00 6.4.2. Permanent Cut and Fill Slopes Permanent slopes may be constructed at inclinations of 2H:1V or flatter. Fill to create permanent slopes should be compacted to at least 90 percent of the MDD. To achieve uniform compaction, we recommend that fill slopes be slightly overbuilt (2 to 3 feet) and cut back to expose well-compacted fill. To reduce erosion, newly constructed slopes and disturbed existing slopes should be planted or hydroseeded shortly after completion of grading. Until the vegetation is established, some sloughing and raveling of the slopes should be expected. This may necessitate localized repairs and reseeding. Temporary covering, such as clear heavy plastic sheeting, or erosion control blankets (such as American Excelsior Curlex 1 or North American Green SC150) could be used to protect the slopes during periods of rainfall. 6.5. Utility Trenches Trench excavation, pipe bedding, and trench backfilling should be completed using the general procedures described in the 2022 WSDOT Standard Specifications, City of Renton requirements, or other suitable procedures specified by the project civil engineer. The fill soils and alluvial deposits encountered at the site are generally of low corrosivity based on our experience in the Puget Sound area. Utility trench backfill should consist of structural fill and should be placed in lifts of 12 inches or less (loose thickness) when using heavy compaction equipment, and 6 inches or less when using hand compaction equipment, such that adequate compaction can be achieved throughout the lift. Each lift must be compacted prior to placing the subsequent lift. Prior to compaction, the backfill should be moisture conditioned to within 2 percent of the optimum moisture content. The backfill should be compacted in accordance with the criteria discussed above. 6.6. Pavement Recommendations 6.6.1. Subgrade Preparation We recommend the subgrade soils in new pavement areas be prepared and evaluated as described in the “Site Preparation and Earthwork” section of this report. All new pavement and hardscape areas should be supported on subgrade soils that have been proof rolled or probed as described in the Site Preparation section of this report. If the exposed subgrade soils are loose or soft, it may be necessary to excavate localized areas and replace them with structural fill or gravel base course. Pavement subgrade conditions should be observed during construction and prior to placing the subbase materials in order to evaluate the presence of zones of unsuitable subgrade soils and the need for over-excavation and replacement of these zones. 6.6.2. New Hot Mix Asphalt Pavement In light-duty pavement areas (e.g., automobile parking or trails), we recommend a pavement section consisting of at least a 2-inch thickness of ½-inch HMA (PG 58-22) per WSDOT Sections 5-04 and 9-03, over a 4-inch thickness of densely compacted crushed surfacing base course per WSDOT Section 9-03.9(3). In heavy-duty pavement areas, we recommend a pavement section consisting of at least a 3-inch thickness of ½-inch HMA (PG 58-22) over a 6-inch thickness of densely compacted crushed surfacing base course. The base course should be compacted to at least 95 percent of the MDD obtained using ASTM D 1557. We recommend that proof rolling of the subgrade and compacted base course be observed by a DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page 12 File No. 9061-019-00 representative from our firm prior to paving. Soft or yielding zones observed during proof rolling may require over-excavation and replacement with compacted structural fill. The pavement sections recommended above are based on our experience. Thicker asphalt sections may be needed based on the actual traffic data, bus or truck loads and intended use. All paved and landscaped areas should be graded so that surface drainage is directed to appropriate catch basins. 6.6.3. Portland Cement Concrete Pavement Portland cement concrete (PCC) sections may be considered for areas where concentrated heavy loads may occur. We recommend that these pavements consist of at least 6 inches of PCC over 6 inches of crushed surfacing base course. A thicker concrete section may be needed based on the actual load data for use of the area. If the concrete pavement will have doweled joints, we recommend that the concrete thickness be increased by an amount equal to the diameter of the dowels. The base course should be compacted to at least 95 percent of the MDD. We recommend PCC pavements incorporate construction joints and/or crack control joints spaced at maximum distances of 12 feet apart, center-to-center, in both the longitudinal and transverse directions. Crack control joints may be created by placing an insert or groove into the fresh concrete surface during finishing, or by saw cutting the concrete after it has initially set-up. We recommend the depth of the crack control joints be approximately one fourth the thickness of the concrete; or about 1½ inches deep for the recommended concrete thickness of 6 inches. We also recommend the crack control joints be sealed with an appropriate sealant to help restrict water infiltration into the joints. 6.7. Recommended Additional Geotechnical Services Throughout this report, recommendations are provided where we consider additional geotechnical services to be appropriate. These additional services are summarized below: ■ GeoEngineers will complete a design-level engineering report for the project during the design phase of the project. Additional subsurface borings and cone penetration tests are required to better characterize the subsurface soils for field design and settlement analysis during the design phase. GeoEngineers should also be retained to review the project plans and specifications when complete to confirm that our design recommendations have been implemented as intended, as required by the City of Renton. ■ During construction, GeoEngineers should observe stripping and grading, observe and evaluate any playfield subgrades, evaluate temporary and permanent slope conditions, observe and test structural backfill, observe installation of subsurface drainage measures, evaluate the suitability of pavement subgrades and other appurtenant structures, and provide a summary letter of our construction observation services. The purposes of GeoEngineers’ construction phase services are to confirm that the subsurface conditions are consistent with those observed in the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, to evaluate whether or not earthwork and foundation installation activities are completed in accordance with our recommendations, and other reasons described in Appendix B, Report Limitations and Guidelines for Use. DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page 13 File No. 9061-019-00 7.0 LIMITATIONS We have prepared this report for use by the Unico Properties, LLC and other members of the project team for the Longacres Field Entitlement project. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the field of geotechnical engineering in this area at the time this report was prepared. No warranty or other conditions, express or implied, should be understood. Any electronic form, facsimile or hard copy of the original document (email, text, table, and/or figure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. Please refer to Appendix B, titled Report Limitations and Guidelines for Use, for additional information pertaining to use of this report. 8.0 REFERENCES ASCE (2016) “SEI/ASCE 7-16, Minimum Design Loads for Buildings and Other Structures,” American Society of Civil Engineers. GeoEngineers, 1991. “Geotechnical Engineering Services, Boeing Longacres Park, Renton, Washington, For Boeing Support Services.” GeoEngineers, 1997. “Geotechnical Engineering Services, Boeing BCAG, Headquarters Building 25-20, Boeing Longacres Park, Renton, Washington.” Idriss, I.M., and R.W. Boulanger 2014. “Soil Liquefaction during Earthquakes.” Earthquake Engineering Research Institute MNO-12. International Code Council, 2018, “International Building Code.” Landau Associates, 2008, “Report, Phase II Environmental Site Assessment, Boeing Longacres, Renton, Washington.” Landau Associates, 2021, “Report, Phase II Environmental Site Assessment, Boeing Longacres Park, Renton, Washington.” Washington State Department of Transportation, 2022, “Standard Specifications for Road, Bridge, and Municipal Construction.” Youd, T.L. and Idriss, I.M., 2001. “Liquefaction resistance of soils: summary report from the 1996 NCEER and 1998 NCEER/NSF workshops on evaluation of liquefaction resistance of soils,” Journal of Geotechnical and Geoenvironmental Engineering, 127(4), pp. 297-313. DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 FIGURES DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 57thAveS56thAveSMacadamRdS58thAveSI -5Rest r i ct edLnWestfield Southcenter T u k w i l a SouthcenterPkwy181 ShattuckAveSShattuckAveSPowellAveSWS W 7 t h S t 65t hAveSS W 1 9 t h S t SW 3rd Pl S W 1 2 t h S t S W 1 6 t h S t Rai ni erAveSOakesdal e AveSWS W S u n s etBlvd ValleyFwyBoeing Longacr es Indus trial P ark Family Fun Centers Blac k Riv er Forest Fort Dent Park TalbotRdSS W 34t h S t AndoverParkWS t r a n d e r B l v d S W 4 1 s t S t S W 2 7 t h S t AndoverParkES W 39th St EValleyRdOakesdaleAveSWWValleyHwyValleyFwyOr il l i a TalbotRdSS 5t h S t S 4 t h S t S 3 r d S t TalbotRdSBensonDrSTalbotRdSS E C a rrRdµ SITE Vicinity Map Figure 1 Longacres Field Renovation Renton, Washington 3 Alpine Lakes Wildernes s Kent Tacoma Seattle 2,000 2,0000 Feet Data Source: ESRI Notes: 1. The locations of all features shown are approximate. 2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. Projection: NAD 1983 UTM Zone 10N P:\9\9061019\GIS\9061019_Project\9061019_Project.aprx\906101900_F01_VicinityMap Date Exported: 03/09/22 by glohrmeyerDocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 Figure 2 Longacres Field Renovation Renton, Wshington Conceptual Site Plan P:\9\9061019\CAD\00\Geotech\906101900_F02_Conceptual Site Plan.dwg TAB:F02 Date Exported: 06/22/22 - 11:08 by cdiasWENSFeet 080 80 Notes: 1.The locations of all features shown are approximate. 2.This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. Data Source: Background from D.A. Hogan & Associates, Inc., dated 5/23/2022. Projection: WA State Plane, North Zone, NAD83, US Foot DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 CPT-1 CPT-5 CPT-2 CPT-4 CPT-6 CPT-3 B-8CPT-7 TP15 TP14 TP13 TP12 TP11 TP10 TP9 TP8 TP5 TP4 LAI-13 LAI-18 LAI-14 LAI-10 LAI-17 LAI-15 Oakesdale Ave SW LAI-16 TP-6 B-20 TP-5 TP-7 TP-16 TP-15 TP-8 B-21 TP-4 TP-10 TP-9 TP-3 TP-12 TP-14 TP-17 TP-11 Bldg 25-20 Figure 3 Longacres Field Renovation Renton, Wshington Exploration Site Plan P:\9\9061019\CAD\00\Geotech\906101900_F03_Exploration Site Plan.dwg TAB:F03 Date Exported: 06/22/22 - 11:05 by cdiasWENSFeet 0150 150 B-20 Boring by GeoEngineers, 1997 CPT-1 Cone Penetration Test Pit by GeoEngineers, 1997 TP-3 Test Pit by GeoEngineers, 1997 B-5 Boring by GeoEngineers, 1991 TP1 Test Pit Landau Associates, 2008 LAI-10 Test Pit Landau Associates, 2020 Notes: 1.The locations of all features shown are approximate. 2.This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. Data Source: Aerial from King County Imap dated 2019. Projection: WA State Plane, North Zone, NAD83, US Foot Legend Site Boundary DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 APPENDICES DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 APPENDIX A Boring Logs from Previous Explorations DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page A-1 File No. 9061-019-00 APPENDIX A BORINGS LOGS FROM PREVIOUS EXPLORATIONS Included in this section are logs from previous studies completed in the immediate vicinity of the project site. ■ The log of one boring completed be GeoEngineers, in 1991 for Boeing Longacres Park; ■ The log of two borings, 14 test pits and seven cone penetration tests completed by GeoEngineers, in 1997 for the Boeing BCAG Headquarters Building 25-20; ■ The log of 10 test pits by Landau Associates, in 2008 for the Boeing Longacres Property Park Phase II Environmental Site Assessment; and ■ The log of seven direct push borings by Landau Associates, in 2021 for the Boeing Longacres Property Park Phase II Environmental Site Assessment. DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 TP-3 (4-6) Boring Completed 01/07/08 Total Depth of Boring = 7.0 ft. SW SM Log of Boring TP-3 Light brown, fine to medium SAND with interbedded gray silt and trace organics, (medium dense, moist), (no odor, no sheen) d Light brown, fine to medium SAND with silt and gravel, (medium dense, moist), (no odor, no sheen) Dark brown, fine to medium SAND with trace silt, (medium dense, wet), (no odor, no sheen) SW SM Dark brown, fine to medium SAND with organics, (medium dense, moist), (no odor, no sheen) A-20 SAMPLE DATA Sampler TypeNotes: SOIL PROFILE Depth (ft)Drilling Method: 1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols.PID (ppm)Figure25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGBoeing Longacres Renton, WashingtonSample Number& IntervalUSCS SymbolGroundwater not encountered. GROUNDWATER TP-3 0 2 4 6 8 10 Blows/FootRubber-tired Backhoe Ground Elevation (ft):25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGGraphic SymbolDocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 0 2 4 6 8 10 Dark brown, fine to medium SAND with organics, (loose, moist), (no odor, no sheen) d Log of Boring TP-4 SW ML ML/ CL SM TP-4 (0-6) Boring Completed 01/07/08 Total Depth of Boring = 8.5 ft. A-21 Gray/brown, sandy SILT wtih organics, (medium stiff, low plasticity), (no odor, no sheen) SAMPLE DATA GROUNDWATER Sampler TypeNotes: SOIL PROFILE Depth (ft)Drilling Method: 1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols.PID (ppm)Figure25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGBoeing Longacres Renton, WashingtonSample Number& IntervalUSCS SymbolLight brown, clayey SILT with organics, (stiff, low plasticity), (no odor, no sheen) -Becomes gray Dark brown, fine to medium SAND with silt, (dense, wet), (no odor, no sheen) Groundwater not encountered. TP-4 Rubber-tired Backhoe Ground Elevation (ft):25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGGraphic SymbolBlows/FootDocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 Log of Boring TP-7 Boring Completed 01/07/08 Total Depth of Boring = 7.0 ft. Brown, sandy GRAVEL with concrete and organics, (loose, moist), (no odor, no sheen) Light brown, fine to medium SAND with silt, (medium dense, moist), (no odor, no sheen) GP SM SM Dark brown, medium SAND with silt and trace organics, (medium dense, wet), (no odor, no sheen) 0 2 4 6 8 10 Notes: SOIL PROFILE Depth (ft)Sample Number& IntervalSampler TypeA-24 GROUNDWATER Figure25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGBoeing Longacres Renton, Washington 1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols.Graphic SymbolBlows/FootUSCS SymbolRubber-tired Backhoe Ground Elevation (ft):25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGGroundwater not encountered. TP-7 Drilling Method:PID (ppm)SAMPLE DATA DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 TP-8 (6-7) Boring Completed 01/07/08 Total Depth of Boring = 7.0 ft. SM Log of Boring TP-8 Gray, SILT with fine SAND, (stiff, low plasticity), (no odor, no sheen) d Dark brown, medium SAND with gravel, (dense, moist), (no odor, no sheen) Brown, fine to medium SAND with silt, (medium dense, moist), (no odor, no sheen) SW ML GROUNDWATER Notes: SOIL PROFILE Depth (ft)Sample Number& Interval0 2 4 6 8 10 A-25 SAMPLE DATA Figure25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGBoeing Longacres Renton, Washington 1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. Rubber-tired Backhoe Groundwater not encountered.Blows/FootSampler TypeUSCS SymbolPID (ppm)Ground Elevation (ft):25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGGraphic SymbolTP-8 Drilling Method: DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 Boring Completed 01/07/08 Total Depth of Boring = 5.0 ft. Log of Boring TP-10 0 2 4 6 8 10 Groundwater not encountered. TP-10 (3-5) SM Brown, fine to medium SAND with silt, (medium dense, moist), (no odor, no sheen) d Blows/FootDepth (ft)Sample Number& Interval1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. Notes: SOIL PROFILE Figure25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGBoeing Longacres Renton, Washington A-2725185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGUSCS SymbolRubber-tired Backhoe Ground Elevation (ft):Graphic SymbolTP-10 Drilling Method:PID (ppm)SAMPLE DATA GROUNDWATER Sampler TypeDocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 TP-11 (4-5) Boring Completed 01/07/08 Total Depth of Boring = 6.0 ft. SM Log of Boring TP-11 Brown, sandy SILT, (stiff, low plasticity), (no odor, no sheen) d Light brown, fine to medium SAND with trace silt and organics, (medium dense, moist), (no odor, no sheen) Black to dark brown, fine to medium SAND with silt, (medium dense, moist), (no odor, no sheen) SW ML GROUNDWATER Notes: SOIL PROFILE Depth (ft)Sample Number& Interval0 2 4 6 8 10 A-28 SAMPLE DATA Figure25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGBoeing Longacres Renton, Washington 1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. Rubber-tired Backhoe Groundwater not encountered.Blows/FootSampler TypeUSCS SymbolPID (ppm)Ground Elevation (ft):25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGGraphic SymbolTP-11 Drilling Method: DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 Log of Boring TP-12 0 2 4 6 8 10 Brown, fine to medium SAND with silt, (medium dense, moist), (no odor, no sheen) d Boring Completed 01/08/08 Total Depth of Boring = 6.0 ft. -Geotextile fabric SM TP-12 (5-6) Groundwater not encountered.Blows/FootDepth (ft)Sample Number& Interval1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. Notes: SOIL PROFILE Figure25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGBoeing Longacres Renton, Washington A-2925185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGUSCS SymbolRubber-tired Backhoe Ground Elevation (ft):Sampler TypeGraphic SymbolTP-12 Drilling Method:PID (ppm)SAMPLE DATA GROUNDWATER DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 SOIL PROFILE Depth (ft)Sample Number& Interval1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. A-30 Figure GROUNDWATER 25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGBoeing Longacres Renton, Washington Log of Boring TP-13 Slight 0 2 4 6 8 10 Blows/FootWater LevelUSCS SymbolNotes: Ground Elevation (ft):Sampler Type25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGGraphic SymbolTP-13 Drilling Method:PID (ppm)SAMPLE DATA Rubber-tired Backhoe ML TP-13 (2-3) TP-13 (4-5) Boring Completed 01/08/08 Total Depth of Boring = 8.0 ft. d SM d Brown, fine to medium SAND with silt and trace organics, (medium dense, moist), (no odor, no sheen) -Mottled color and trace organic material Gray/black, sandy SILT with fine sand and trace gravel, (stiff, low plasticity), (no odor, no sheen) -Traces of concrete and brick debris DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 Boring Completed 01/08/08 Total Depth of Boring = 5.5 ft. Log of Boring TP-14 0 2 4 6 8 10 Blows/FootTP-14 (3-5) SW -Becomes wet, test pit caving Brown, fine to medium SAND with trace silt, (loose, moist), (no odor, no sheen) d SOIL PROFILE Boeing Longacres Renton, Washington25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGFigure A-31 1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols.Sample Number& IntervalDepth (ft)Graphic SymbolUSCS SymbolRubber-tired Backhoe Ground Elevation (ft):25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGNotes: TP-14 Drilling Method:PID (ppm)SAMPLE DATA GROUNDWATER Sampler TypeDocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 Blows/FootGroundwater not encountered. 0 2 4 6 8 10 USCS SymbolHand Implements Boring Completed 01/08/08 Total Depth of Boring = 2.0 ft. SM Brown, fine to medium SAND with silt, (medium dense, moist), (no odor, no sheen) SOIL PROFILE Boeing Longacres Renton, Washington25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGFigure A-32 1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols.Sample Number& IntervalDepth (ft)Log of Boring TP-15 Notes:Sampler TypeGROUNDWATERSAMPLE DATA PID (ppm)Drilling Method: TP-15 Graphic Symbol25185.02 1/30/08 \\EDMDATA\GINT\GINT7\PROJECTS\025185.GPJ SOIL BORING LOGGround Elevation (ft): DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 d3 AC SP ML SM Flush-mounted monument with silicone cap Concrete Seal Hydrated Bentonite Grout 1/4" Tubing (Teflon) Dry Granular Bentonite 2/12 Silica Sand Stainless Steel Vapor implant Bentonite chips Boring Completed 11/04/20 Total Depth of Boring = 5.0 ft. Soil Gas Well Completed 11/04/20 Total Depth of Soil Gas Well = 4.5 ft. (ASPHALT) Brown, gravelly, fine to coarse SAND with trace silt; no odor, no sheen (loose, damp) (FILL) Gray, sandy SILT with organics; no odor, no sheen (medium stiff to stiff, damp) (ALLUVIUM) Brown, silty, fine SAND with trace organics; no odor, no sheen (medium dense to dense, damp) 0 2 4 6 8 10 12 14 16 Groundwater not encountered.Not Determined Water LevelDepth (ft)Sample Number& IntervalUSCS SymbolGeoprobeTM SAMPLE DATA LAI-10 SOIL PROFILE 2.25 inGround Elevation (ft): GROUNDWATER Blows/FootSampler TypePID (ppm)Drilling Method:Graphic Symbol1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. Notes: Soil Gas Well Detail (DOE#: BMY199) B-11Log of Soil Gas Well LAI-10 Figure0025227.170.171 4/2/21 N:\PROJECTS\0025227.170.GPJ WELL LOGLongacres Phase II ESA Renton, Washington DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 0 0 0d3 SM ML Flush-mounted monument with silicone cap Concrete Seal Hydrated Bentonite Grout 1/4" Tubing (Teflon) Dry Granular Bentonite 2/12 Silica Sand Stainless Steel Vapor implant Bentonite chips Boring Completed 11/04/20 Total Depth of Boring = 5.0 ft. Soil Gas Well Completed 11/04/20 Total Depth of Soil Gas Well = 4.5 ft. Brown, silty, fine SAND with organics; no odor, no sheen (loose, damp) (ALLUVIUM) Brown, rust-mottled, sandy SILT with trace organics; no odor, no sheen (medium stiff to stiff, damp) 0 2 4 6 8 10 12 14 16 Groundwater not encountered.Not Determined Water LevelDepth (ft)Sample Number& IntervalUSCS SymbolGeoprobeTM SAMPLE DATA LAI-13 SOIL PROFILE 2.25 inGround Elevation (ft): GROUNDWATER Blows/FootSampler TypePID (ppm)Drilling Method:Graphic Symbol1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. Notes: Soil Gas Well Detail (DOE#: BMY198) B-12Log of Soil Gas Well LAI-13 Figure0025227.170.171 4/2/21 N:\PROJECTS\0025227.170.GPJ WELL LOGLongacres Phase II ESA Renton, Washington DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 0d3 AC GP SP SM Flush-mounted monument with silicone cap Concrete Seal Hydrated Bentonite Grout 1/4" Tubing (Teflon) Dry Granular Bentonite 2/12 Silica Sand Stainless Steel Vapor implant Boring Completed 11/05/20 Total Depth of Boring = 5.0 ft. Soil Gas Well Completed 11/05/20 Total Depth of Soil Gas Well = 4.5 ft. (ASPHALT) Gray and brown GRAVEL with sand and trace silt; no odor, no sheen (loose, damp) (FILL) Brown, gravelly, fine to medium SAND with trace silt; no odor, no sheen (loose, damp) Gray, silty, fine SAND; no odor, no sheen (medium dense, damp) (ALLUVIUM) 0 2 4 6 8 10 12 14 16 Groundwater not encountered.Not Determined Water LevelDepth (ft)Sample Number& IntervalUSCS SymbolGeoprobeTM SAMPLE DATA LAI-14 SOIL PROFILE 2.25 inGround Elevation (ft): GROUNDWATER Blows/FootSampler TypePID (ppm)Drilling Method:Graphic Symbol1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. Notes: Soil Gas Well Detail (DOE#: BMY202) B-13Log of Soil Gas Well LAI-14 Figure0025227.170.171 4/2/21 N:\PROJECTS\0025227.170.GPJ WELL LOGLongacres Phase II ESA Renton, Washington DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 0 0 0 0 0 0 d3 d3 d3 SM ML SP- SM ATD BOL- LAI-15- S(1-3) BOL- LAI-15- S(10-11) Flush-mounted monument with silicone cap Concrete Seal 1/4" Tubing (Teflon) Hydrated Bentonite Grout Dry Granular Bentonite 2/12 Silica Sand Stainless Steel Vapor implant Bentonite chips Native Slough Boring Completed 11/06/20 Total Depth of Boring = 15.0 ft. Soil Gas Well Completed 11/06/20 Total Depth of Soil Gas Well = 4.5 ft. Brown, silty, fine SAND with organics and trace medium and coarse sand; no odor, no sheen (loose, damp) (ALLUVIUM) Soil Sample: BOL-LAI-15-S(1-3) Brown, rust-mottled, sandy SILT with organics; no odor, no sheen (medium stiff, damp) Brown, fine to medium SAND with silt and trace organics (medium dense, damp) Soil Sample: BOL-LAI-15-S(10-11) -becomes wet at 11 ft. -turns a dark gray, almost black, color at 11.2 ft. 0 2 4 6 8 10 12 14 16 Not Determined Water LevelDepth (ft)Sample Number& IntervalUSCS SymbolGeoprobeTM SAMPLE DATA LAI-15 SOIL PROFILE 2.25 inGround Elevation (ft): GROUNDWATER Blows/FootSampler TypePID (ppm)Drilling Method:Graphic Symbol1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. Notes: Soil Gas Well Detail (DOE#: BMY206) B-14Log of Soil Gas Well LAI-15 Figure0025227.170.171 4/2/21 N:\PROJECTS\0025227.170.GPJ WELL LOGLongacres Phase II ESA Renton, Washington DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 0 0 0 0 d3 d3 SP- SM ML SM SP- SM ATD BOL- LAI-16- S(1-3) BOL- LAI-16- S(7-9) Flush-mounted monument with silicone cap Concrete Seal Hydrated Bentonite Grout 1/4" Tubing (Teflon) Dry Granular Bentonite 2/12 Silica Sand Stainless Steel Vapor implant Bentonite chips Native Slough Boring Completed 11/06/20 Total Depth of Boring = 10.0 ft. Soil Gas Well Completed 11/06/20 Total Depth of Soil Gas Well = 4.5 ft. Gray and black, gravelly, fine to medium SAND with silt and organics; no odor, no sheen (loose, moist) (ALLUVIUM) Gray, sandy SILT; no door, no sheen (medium stiff, damp) Soil Sample: BOL-LAI-16-S(1-3) Gray, silty fine SAND (medium dense, damp) -turns a brown color with rust-mottling at 4.8 ft. -silt lense from 5 ft to 5.4 ft Brown, fine to medium SAND with silt; no odor, no sheen (medium dense, damp to moist) Soil Sample: BOL-LAI-16-S(7-9) 0 2 4 6 8 10 12 14 16 Not Determined Water LevelDepth (ft)Sample Number& IntervalUSCS SymbolGeoprobeTM SAMPLE DATA LAI-16 SOIL PROFILE 2.25 inGround Elevation (ft): GROUNDWATER Blows/FootSampler TypePID (ppm)Drilling Method:Graphic Symbol1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. Notes: Soil Gas Well Detail (DOE#: BMY207) B-15Log of Soil Gas Well LAI-16 Figure0025227.170.171 4/2/21 N:\PROJECTS\0025227.170.GPJ WELL LOGLongacres Phase II ESA Renton, Washington DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 0 0 0d3 AC SP ML SM Flush-mounted monument with silicone cap Concrete Seal Hydrated Bentonite Grout 1/4" Tubing (Teflon) Dry Granular Bentonite 2/12 Silica Sand Stainless Steel Vapor implant Boring Completed 11/05/20 Total Depth of Boring = 5.0 ft. Soil Gas Well Completed 11/05/20 Total Depth of Soil Gas Well = 4.5 ft. (ASPHALT) Brown, gravelly, fine to medium SAND with silt (loose, dry) (FILL) Gray SILT with sand (medium stiff, dry) (ALLUVIUM) -turns a brown color with rust-mottling at 1.1 ft. Brown, rust-mottled, silty, fine SAND (medium dense, damp) 0 2 4 6 8 10 12 14 16 Groundwater not encountered.Not Determined Water LevelDepth (ft)Sample Number& IntervalUSCS SymbolGeoprobeTM SAMPLE DATA LAI-17 SOIL PROFILE 2.25 inGround Elevation (ft): GROUNDWATER Blows/FootSampler TypePID (ppm)Drilling Method:Graphic Symbol1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. Notes: Soil Gas Well Detail (DOE#: BMY201) B-16Log of Soil Gas Well LAI-17 Figure0025227.170.171 4/2/21 N:\PROJECTS\0025227.170.GPJ WELL LOGLongacres Phase II ESA Renton, Washington DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 0 0 0 0 0 0 0 d3 d3 d3 AC GM GP ATD BOL- LAI-18- S(1-3) Flush-mounted monument with silicone cap Concrete Seal 1/4" Tubing (Teflon) Hydrated Bentonite Grout Dry Granular Bentonite 2/12 Silica Sand Stainless Steel Vapor implant Bentonite chips Native Slough Boring Completed 11/05/20 Total Depth of Boring = 15.0 ft. Soil Gas Well Completed 11/05/20 Total Depth of Soil Gas Well = 4.5 ft. (ASPHALT) Brown, sandy GRAVEL with trace silt; no odor, no sheen (loose, dry) (FILL) Soil Sample: BOL-LAI-18-S(1-3) Brown and rust-mottled GRAVEL with sand; no odor, no sheen (loose, moist to wet) -rust-mottling dissipates at 10 ft Groundwater Sample: BOL-LAI-18-GW collected from temporary screen installed from 4 to 14 ft bgs 0 2 4 6 8 10 12 14 16 Not Determined Water LevelDepth (ft)Sample Number& IntervalUSCS SymbolGeoprobeTM SAMPLE DATA LAI-18 SOIL PROFILE 2.25 inGround Elevation (ft): GROUNDWATER Blows/FootSampler TypePID (ppm)Drilling Method:Graphic Symbol1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. Notes: Soil Gas Well Detail (DOE#: BMY200) B-17Log of Soil Gas Well LAI-18 Figure0025227.170.171 4/2/21 N:\PROJECTS\0025227.170.GPJ WELL LOGLongacres Phase II ESA Renton, Washington DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 APPENDIX B Report Limitations and Guidelines for Use DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page B-1 File No. 9061-019-00 APPENDIX B REPORT LIMITATIONS AND GUIDELINES FOR USE1 This appendix provides information to help you manage your risks with respect to the use of this report. Geotechnical Services Are Performed For Specific Purposes, Persons And Projects This report has been prepared for use by Unico Properties, LLC and other members of the project team for the entitlement of the soccer fields for the Seattle Sounders training facility. This report may be made available to prospective contractors for bidding or estimating purposes; but our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. This report is not intended for use by others, and the information contained herein is not applicable to other sites. GeoEngineers structures our services to meet the specific needs of our clients. For example, a geotechnical or geologic study conducted for a civil engineer or architect may not fulfill the needs of a construction contractor or even another civil engineer or architect that are involved in the same project. Because each geotechnical or geologic study is unique, each geotechnical engineering or geologic report is unique, prepared solely for the specific client and project site. No one except Unico Properties, LLC and other members of the design team should rely on this report without first conferring with GeoEngineers. This report should not be applied for any purpose or project except the one originally contemplated. A Geotechnical Engineering Or Geologic Report Is Based On A Unique Set Of Project-Specific Factors This report has been prepared for the entitlement of the soccer fields for the Seattle Sounders training facility in Renton, Washington. GeoEngineers considered a number of unique, project-specific factors when establishing the scope of services for this project and report. Unless GeoEngineers specifically indicates otherwise, do not rely on this report if it was: ■ not prepared for you; ■ not prepared for your project; ■ not prepared for the specific site explored; or ■ completed before important project changes were made. For example, changes that can affect the applicability of this report include those that affect: ■ the function of the proposed structure; ■ elevation, configuration, location, orientation or weight of the proposed structure; ■ composition of the design team; or ■ project ownership. 1 Developed based on material provided by ASFE, Professional Firms Practicing in the Geosciences; www.asfe.org . DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page B-2 File No. 9061-01-00 If important changes are made after the date of this report, GeoEngineers should be given the opportunity to review our interpretations and recommendations and provide written modifications or confirmation, as appropriate. Subsurface Conditions Can Change This geotechnical or geologic report is based on conditions that existed at the time the study was performed. The findings and conclusions of this report may be affected by the passage of time, by manmade events such as construction on or adjacent to the site, or by natural events such as floods, earthquakes, slope instability or groundwater fluctuations. Always contact GeoEngineers before applying a report to determine if it remains applicable. Most Geotechnical and Geologic Findings are Professional Opinions Our interpretations of subsurface conditions are based on field observations from widely spaced sampling locations at the site. Site exploration identifies subsurface conditions only at those points where subsurface tests are conducted or samples are taken. GeoEngineers reviewed field and laboratory data and then applied our professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface conditions may differ, sometimes significantly, from those indicated in this report. Our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. Geotechnical Engineering Report Recommendations are Not Final Do not over-rely on the preliminary construction recommendations included in this report. These recommendations are not final, because they were developed principally from GeoEngineers’ professional judgment and opinion. GeoEngineers’ recommendations can be finalized only by observing actual subsurface conditions revealed during construction. GeoEngineers cannot assume responsibility or liability for this report's recommendations if we do not perform construction observation. Sufficient monitoring, testing and consultation by GeoEngineers should be provided during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork activities are completed in accordance with our recommendations. Retaining GeoEngineers for construction observation for this project is the most effective method of managing the risks associated with unanticipated conditions. A Geotechnical Engineering or Geologic Report Could Be Subject to Misinterpretation Misinterpretation of this report by other design team members can result in costly problems. You could lower that risk by having GeoEngineers confer with appropriate members of the design team after submitting the report. Also retain GeoEngineers to review pertinent elements of the design team's plans and specifications. Contractors can also misinterpret a geotechnical engineering or geologic report. Reduce that risk by having GeoEngineers participate in pre-bid and preconstruction conferences, and by providing construction observation. Do Not Redraw the Exploration Logs Geotechnical engineers and geologists prepare final boring and testing logs based upon their interpretation of field logs and laboratory data. To prevent errors or omissions, the logs included in a geotechnical engineering or geologic report should never be redrawn for inclusion in architectural or other design DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 June 23, 2022 | Page B-3 File No. 9061-019-00 drawings. Only photographic or electronic reproduction is acceptable, but recognize that separating logs from the report can elevate risk. Give Contractors a Complete Report and Guidance Some owners and design professionals believe they can make contractors liable for unanticipated subsurface conditions by limiting what they provide for bid preparation. To help prevent costly problems, give contractors the complete geotechnical engineering or geologic report, but preface it with a clearly written letter of transmittal. In that letter, advise contractors that the report was not prepared for purposes of bid development and that the report's accuracy is limited; encourage them to confer with GeoEngineers and/or to conduct additional study to obtain the specific types of information they need or prefer. A pre-bid conference can also be valuable. Be sure contractors have sufficient time to perform additional study. Only then might an owner be in a position to give contractors the best information available, while requiring them to at least share the financial responsibilities stemming from unanticipated conditions. Further, a contingency for unanticipated conditions should be included in your project budget and schedule. Contractors Are Responsible For Site Safety on Their Own Construction Projects Our geotechnical recommendations are not intended to direct the contractor’s procedures, methods, schedule or management of the work site. The contractor is solely responsible for job site safety and for managing construction operations to minimize risks to on-site personnel and to adjacent properties. Read These Provisions Closely Some clients, design professionals and contractors may not recognize that the geoscience practices (geotechnical engineering or geology) are far less exact than other engineering and natural science disciplines. This lack of understanding can create unrealistic expectations that could lead to disappointments, claims and disputes. GeoEngineers includes these explanatory “limitations” provisions in our reports to help reduce such risks. Please confer with GeoEngineers if you are unclear how these “Report Limitations and Guidelines for Use” apply to your project or site. Geotechnical, Geologic and Environmental Reports Should Not Be Interchanged The equipment, techniques and personnel used to perform an environmental study differ significantly from those used to perform a geotechnical or geologic study and vice versa. For that reason, a geotechnical engineering or geologic report does not usually relate any environmental findings, conclusions or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Similarly, environmental reports are not used to address geotechnical or geologic concerns regarding a specific project. Biological Pollutants GeoEngineers’ Scope of Work specifically excludes the investigation, detection, or assessment of the presence of Biological Compounds which are Pollutants in or around any structure. Accordingly, this report includes no interpretations, recommendations, findings, or conclusions for the purpose of detecting, assessing, or abating Biological Pollutants. The term “Biological Pollutants” includes, but is not limited to, molds, fungi, spores, bacteria, and viruses, and/or any of their byproducts. DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521 DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521