The URL can be used to link to this page

Home My WebLink AboutGEO2019-00069 for BLD2019-00835 - GEO Geological Review - 7/31/2019 �Eo 266 -DX&9 Fob SHANNON 6WILSON GEOTECHNICAL AND ENVIRONMENTAL CONSULTANTS PLANNING RECEIVED July 25, 2019 JUL 31 2019 Mr. Ray Nelson 615 W. Alder Street Watermark Estate Management Services, LLC 10230 NE Points Drive, Suite 200 Kirkland, WA 98033 RE: GEOTECHNICAL ENGINEERING DESIGN OF GUEST LODGE PROJECT, UNION, WASHINGTON, RESIDENCES, UNION, WASHINGTON Dear Mr. Nelson: This letter presents the results of our geotechnical explorations, laboratory testing, and our design recommendations for the Guest Lodge Project. The project is located in Union, Washington, as shown in Figure 1. The project involves renovation and remodel of the former Maintenance Building and its surrounding paved areas including parking, driveways, and a sports court to serve as a Guest Lodge. The arrangement of the current site is shown in the Site and Exploration Plan, Figure 2. Dalby Creek flows south to north through the West Parcel and roughly parallel to the west side of the proposed Guest Lodge site. The distance to Dalby Creek from the proposed Guest Lodge varies from about 50 to 80 feet, as shown in Figure 2. The Guest Lodge site is located on relatively flat ground and is surrounded by landscaping and paved areas at approximate elevation 35 feet. There is a sports court located approximately 50 feet north of the proposed Guest Lodge. There is a 4- to 5-foot-high landscaped slope between the sports court and the paved parking area on the north side of the proposed Guest Lodge. The conceptual plans and site layout by James Davison Architects shows the renovated building as having the same footprint as the existing building. We understand that some relatively low retaining walls will be needed to construct the proposed landscaping areas around the west side of the Guest Lodge. We understand that the remodel will include some new interior footings and other structural improvements to bring the building up to current building codes. 400 North 34th Street ■ Suite 100 ■ PO Box 300303 ■ Seattle, Washington 98103■ 206 632-8020 ■ Fax 206 695-6777 ■ www.shannonwilson.com ■ Mr. Ray Nelson 011SHMNON EMLSON Watermark Estate Management Services, LLC July 25, 2019 Page 2 of 9 GEOTECHNICAL EXPLORATIONS Geotechnical subsurface explorations,designated borings SW-7 and SW-8,were conducted at two locations near the proposed Guest Lodge to evaluate the subsurface and groundwater conditions. The locations of the explorations are shown in Figure 2. The soil borings were drilled by Gregory Drilling in September 2017. These borings were advanced to depths of to 21.5 feet below ground surface. Groundwater observation wells were installed in boring SW-5. The locations of these explorations are shown in Figure 2. The boring logs are presented in Appendix A as Figures A-2 and A-3. Figure A-1 presents a key to our classification of the soils summarized in the boring logs. Laboratory tests were performed on three selected soil samples retrieved from each of the two borings. The laboratory testing natural moisture content and grain size distribution. Classification and index laboratory tests included visual classification and tests to determine natural water content and grain size distribution. The results from the laboratory tests are included in Appendix A. SUBSURFACE CONDITIONS The geology and subsurface conditions at the project site were inferred from soil samples and information obtained from borings and test pits, data gathered from prior reports by Shannon&Wilson, and geologic maps of the area. The following is a summary of the general geology and the subsurface soil and groundwater conditions encountered at the project site. Site Geologic Conditions The sediments encountered in boring SW-8 at the Guest Lodge site consist of a surficial layer of fill approximately 2 foot-thick underlain by alluvium(Ha)consisting of medium dense to dense, gravel with sand and silt(poorly graded gravel with silt and sand). Cobbles are also present in the gravel layer encountered at SW-7. Groundwater was observed in the soil boring SW-7 at depths of 7.5 to 4.3 feet(approximate elevations ranging from 21.5 feet to 24.7 feet). Groundwater levels were measured in the soil boring SW-8 at depths of 11.5 to 7.5 feet(approximate elevations ranging from 21.5 feet to 24.7 feet). Groundwater levels are highest during the winter months following heavy rainfall. � , 21-1-22423-001 Mr. Ray Nelson 'III SHANNON6\MLSON Watermark Estate Management Services, LLC July 25, 2019 Page 3 of 9 CONCLUSIONS AND RECOMMENDATIONS Foundations The boring explorations indicated that competent bearing soils consisting of medium dense to very dense alluvial soils are present at the proposed Guest Lodge site. Based on the results of our subsurface explorations and engineering studies,we recommend the Lodge be supported on spread footings bearing on undisturbed,sandy gravel deposits.An allowable bearing pressure of 4 kips per square foot(ksf) is recommended for design. The minimum depth of building foundations should be 18 inches below the lowest adjacent grade. The allowable bearing value may be increased by one-third for short-term seismic loading. Note that our soil boring was located approximately 30 feet west of the Lodge building. The base of all footing excavations should be evaluated by a geotechnical engineer's representative from our firm to confirm that competent soils are present below the existing building footprint where new footings will be located. Assuming a foundation loading of approximately 4 ksf or less on the native soils,we estimate that the total settlement of the proposed foundations would be less than 1/2 inch, with maximum differential settlement, amounting to less than half the value of the total settlement. These settlements would occur as the foundation is loaded during construction. Earth Pressures Lateral forces for the proposed retaining walls west of the building would be resisted by passive earth pressure against the buried portions of the structures and friction against the bottom of spread footings. Active lateral earth pressures should be estimated using an equivalent fluid density of 35 pounds per cubic feet(pcO. In our opinion,passive earth pressures developed from compacted granular fill could be estimated using an equivalent fluid density of 350 pcf. This value is based on the assumption that the structures extend at least 1.5 feet below the lowest adjacent exterior grade and are properly drained, and that the backfill around the structure is compacted to a dense and unyielding condition. The above equivalent fluid density values include a factor of safety(FS) of 1.5 to limit lateral deflection. We understand that surcharge loading on the walls will not be present. We recommend that a coefficient of friction of 0.35 be used between foundation cast-in-place concrete and compacted native soil. This value includes a FS of 1.5. 2 1-1-22423-00 1 Mr. Ray Nelson 011SHMNON 6WILSON Watermark Estate Management Services, LLC July 25, 2019 Page 4 of 9 Temporary and Permanent Slopes All excavations should be made in accordance with the safety requirements of the Washington State Department of Labor and Industries. According to these standards, temporary excavation slopes are to be no steeper than 1 Horizontal to 1 Vertical(1H:1V)for the dense granular soils and 1.5H:1 V for loose soils. All slope cuts of temporary unsupported excavations should be the responsibility of the Contractor, as should the safety of the people working in or near the excavation slopes. Permanent cut slopes could be used in combination with permanent retaining walls to achieve site grading. We recommend that permanent slopes be cut no steeper than 2.5H:1V in the alluvial soils. Flatter slopes may be required if clean granular soils and/or groundwater is encountered. Seismic Design Considerations The project is located in a moderately active seismic region. While the region has historically experienced moderate to large earthquakes(i.e.,April 13, 1949,magnitude 7.1 Olympia Earthquake;April 29, 1965,magnitude 6.5 Seattle-Tacoma Earthquake;and February 28,2001, magnitude 6.8 Nisqually Earthquake),geologic evidence suggests that larger earthquakes have occurred in the prehistoric past and will occur in the future(e.g., magnitude 8.5 to 9.0 Cascadia Subduction Zone Interplate events,magnitude 7.5 Seattle Fault events). We understand that the proposed Guest Lodge will be designed in accordance with the International Building Code(IBC)2015(International Code Council,Inc. [ICC],20141). For the IBC 2015, the seismological inputs are: ■ Short-period spectral acceleration,Ss • Spectral acceleration at the 1-second period, S1 The coefficients, Ss and S1, are for a maximum considered earthquake,which corresponds to a ground motion with a 2 percent probability of exceedance in 50 years, or a 2,475-year return period (with a deterministic maximum cap in some regions). For our geotechnical engineering analyses, we also considered the peak ground acceleration of the maximum I International Code Council(ICC),2014,International Conference of Building Officials,International Building Code(IBC):Country Club Hills,Ill. 21-1-22423-001 Mr. Ray Nelson 0111111SF MWAIMLSM Watermark Estate Management Services, LLC July 25, 2019 Page 5 of 9 considered earthquake. The coefficients are based on regional probabilistic ground motion studies completed in 2008 by the U.S. Geological Survey. The spectral response acceleration values are scaled by site soil response factors to account for site amplification/damping effects. The site classification determines the site soil response factors. Based on the soil conditions encountered in the borings, a Site Class D would adequately characterize the site subsurface conditions. Seismic design parameters for a Site Class D are presented in Table 1. Table 1: International Building Code 2015 Parameters for Seismic Design of Structures ResponseSpectral PeriodCoeff icients Acceleration (PGA) Short . Period Mapped SRAO,2)(Site Class B) PGA=0.69 Ss=1.43 S1=0.59 Site Coefficients(Site Class C)(2) N/A(3) Fa= 1.00 Fv=1.50 Design SRAO,2) SDPga=0.38 SDs=0.95 SD1 =0.59 NOTES: 1 Mapped SRA and Design SRA values are in units of gravity. 2 The Mapped SRA values are based on regional probabilistic ground motion studies conducted by the U.S.Geological Survey (USGS)and determined using the USGS Java ground motion parameter calculator. 3 International Building Code(IBC)2015 does not explicitly include PGA as a design parameter. We calculated the design SDP9a by following IBC 2015 procedures for constructing the design response spectrum. N/A=not applicable We have also evaluated potential seismically induced geologic hazards(i.e., ground rupture, liquefaction, and slope instability) and have found these to be negligible at the site Drainage and Infiltration We recommend installing a 4-inch-diameter perforated drainage pipe along the base of retaining walls to prevent the buildup of standing water against the foundation. The drainage should connect into a tightline and be conveyed to a suitable stormwater discharge location. The perimeter footing drain should consist of a perforated, 4-inch-diameter plastic pipe, sloped to drain, and bedded in 3/8-inch to No. 8 size washed pea gravel or 5/s-inch minus crushed gravel. Cleanouts should be provided at convenient locations. While we use a different(Unified Soil Classification System) soil classification system than Mason County, it is possible to estimate Septic Soil Types based on the gravel and sand content from grain size distributions. Mason County uses Chapter 246-272A Washington Administrative Code, Rules and Regulations of the State Board of Health for On-Site Sewage Systems. This code identifies Septic Soil type based on seven categories ranging 21-1-22423-001 Mr. Ray Nelson =111SHANNON 6\AALSON Watermark Estate Management Services, LLC July 25, 2019 Page 6 of 9 from Type 1-gravelly and very gravelly, coarse sands to Type 7-sandy clay,silty clay. Types 3 through 6 are for relatively fine-grained soils. Types 1 and 2 pertain to relatively free-draining,coarse-grained soils. Based on the gravel content of the soils in boring SW-8, we recommend that you assume soils are Septic Soil Type 1 for the Guest Lodge location. Structural Backfill and Compaction Any fill placed beneath load-bearing structures or fill relied on for lateral resistance should consist of compacted structural fill. Structural fill should consist of relatively well-graded sand or sand and gravel having a maximum particle size of about 3 inches. It should contain less than 20 percent fines(material passing the No.200 sieve,based on the 3/4-inch minus fraction) and, during wet weather or wet conditions, it should contain no more than 5 percent fines. Structural fill should not contain organics or deleterious material. It should be placed in horizontal lifts and compacted to at least 95 percent of its Modified Proctor maximum density(ASTM D1557), and should be verified to be in a dense and unyielding condition. The thickness of loose lifts should not exceed 8 inches for heavy equipment compactors and 6 inches for hand-operated compactors. In our opinion, the gravel with sand(Ha)present at the site will be suitable for use as structural fill and backfill provided it is free of organics and it can be kept dry so that the moisture content does not exceed the optimum for compaction. Topsoil and fill containing organics and debris at the site will not be suitable for use as structural fill but may be used for landscaping areas. Wet-Weather Earthwork Earthwork would most easily be accomplished during the normally drier months of June through mid-October. It is our opinion that earthwork performed during the wet-weather months will prove more costly. The condition of exposed very dense and hard sand and silt will deteriorate rapidly when exposed to moisture and construction activity. This could lead to deeper footing excavations than anticipated. The following recommendations are applicable if earthwork is to be accomplished in wet weather or in wet conditions: ■ Earthwork should be accomplished in small sections to minimize exposure to wet weather. If there is to be traffic over the exposed subgrade,the undisturbed subgrade should be protected with a compacted layer of clean sand and gravel,crushed rock, or a 2-to 3-inch-thick lean concrete pad. This should be done as needed to protect the foundation soils and act as a working surface. An overexcavation may be needed to ,J,. . 2 1-1-22423-00 1 Mr. Ray Nelson =IIISFMNON F\MLSON Watermark Estate Management Services, LLC July 25, 2019 Page 7 of 9 accommodate this protective layer. The size or type of equipment used in the excavation may have to be limited to prevent soil disturbance. ■ Fill material should consist of clean,granular soil,of which not more than 5 percent by dry weight passes the No. 200 mesh sieve,based on wet-sieving the fraction passing the 3/4-inch sieve. The fines should be nonplastic. Such soil would need to be imported to the site. The identification of suitable wet-weather backfilling material should be made by a geotechnical engineer from our firm experienced in wet-weather construction. ■ The ground surface in the construction area should be sloped and sealed with a smooth drum,vibratory roller,or equivalent to promote the rapid runoff of precipitation,to prevent surface water from flowing into excavations,and to prevent ponding of water. Soils that become too wet for compaction should be removed and replaced with clean granular soil. ■ Excavation and placement of structural fill material should be observed on a full-time basis by a geotechnical engineer or technician experienced in wet-weather earthwork to determine that all unsuitable materials are removed and suitable compaction and site drainage is achieved. ■ Covering work areas, soil stockpiles,or slopes with plastic;sloping, ditching,sumps, dewatering, and other measures should be employed as necessary to permit proper completion of the work. Bales of straw and/or geotextile silt fences should be strategically located to control soil movement and erosion. The above recommendations for wet-weather earthwork should be incorporated into the contract specifications. Review of Plans and Construction Monitoring We recommend that our firm be retained to review those portions of the plans and specifications that pertain to the geotechnical aspects of the project to determine if they are consistent with our recommendations. We also recommend that we be retained to monitor excavations and earthwork, footing and floor slab subgrade preparation, drainage installation,fill placement and compaction, and other geotechnically related work. We recommend that we be retained to monitor the geotechnical aspects of construction activities at the site,including the preparation of footing subgrades for the structure and compaction of structural fill or backfill. .,I-": ;t.F 21-1-22423-001 Mr. Ray Nelson MUSHMNON 6WILSON Watermark Estate Management Services, LLC July 25, 2019 Page 8 of 9 LIMITATIONS This letter was prepared for the exclusive use of the Watermark Estate Management Services,LLC and members of the design team for specific application to the design of the currently proposed Guest Lodge at this site. Subsurface information and test results should be provided to prospective contractors for information on factual data only. The information and discussion of subsurface conditions should not be interpreted as a warranty of subsurface conditions,such as may be interpreted from boring logs. The analyses,conclusions, and recommendations contained in this letter are based on current site conditions. We assume that explorations conducted for this project are representative of the subsurface conditions throughout the site,i.e., the subsurface conditions between explorations are not significantly different from those encountered at exploration locations. If conditions different from those described in this letter are observed or appear to be present during construction, we should be advised at once so that we can review the conditions and reconsider our recommendations,where necessary. If there is a substantial lapse of time between the submission of this letter and the start of construction, or if conditions have changed due to natural causes or construction operations at or near the site,we should review this report to determine the applicability of our conclusions and recommendations considering the changed conditions and time lapse. Within the limitations of scope, schedule, and budget, the analyses, conclusions, and recommendations presented in this letter were prepared in accordance with generally accepted professional geotechnical engineering principles and practice in this area at the time this letter was prepared. We make no warranty,either express or implied. Unanticipated soil conditions are commonly encountered and cannot be fully determined by merely taking soil samples or conducting subsurface explorations. Such unexpected conditions frequently require that additional expenditures be made to attain a properly constructed project. Therefore, some contingency fund is recommended to accommodate such potential extra costs. The scope of our services for letter report did not include any environmental assessment or evaluation regarding the presence or absence of wetlands or hazardous or toxic materials in the soil, surface water,groundwater, or air on,below, or around the site. 21-1-22423-001 Mr. Ray Nelson =111SHANNON6WILSON Watermark Estate Management Services, LLC July 25, 2019 Page 9 of 9 Shannon &Wilson has prepared the enclosed, "Important Information About Your Geotechnical/Environmental Report," to assist you and others in understanding the use and limitations of our reports. Sincerely, SHANNON & WILSON 'SINwj k! A 2 sh 9 'gyp 3030�8 p ,c`',� / NAL� Martin W.Page,PE,LEG Vice President Geotechnical Engineer MWP/mwp Enc. Figure 1—Vicinity Map Figure 2—Site and Exploration Plan Appendix A—Laboratory Test Results Important Information About Your Geotechnical/Environmental Report 1-1-22423-001-L2.00c ri. 21-1-22423-001 / on Y L * 6REMENTON attle roje f 1 � 1 Y -� •fir. UN N y 0 +44 +►' I th , . a r-1� '1 a • r y SHELTON OMAN AM LCHE • " •i- , Goo • . i Union Residences Gu- •..- Project • • • VICINITY MAP July 2019 11 " i I — i I I � I I i I o — — tiREA F VVOR i / I o 1 O I 1 / C -- N slDmo R SETS - - - -, - - o -_ SW-7 / Ii CL 4 SEE S s04 FQA', NXI N ° VVHEEL _ H04SE _ _ O 0 O Co N Union Washington Residences N LEGEND: Union, Washington N -appl mtg o Boring Location, 2017 )avison O N SW-7 PROPOSED GUEST LODGE a 9 O Boring Location, 2005 of current, SITE AND EXPLORATION PLAN B-4 aj July 2019 21-1-22423-001 Cu E _ �"�SIIANNON 8V1hLSOf�ING DlOTlCMYIC•L.YD lDYIYOYYlYi.l C0!lYLT.l,! FIG. 2 LL PARTICLE SIZE DEFINITIONS DESCRIPTION SIEVE NUMBER AND/OR APPROXIMATE SIZE Shannon& Wilson, Inc. (S&W), uses a soil identification system modified from the Unified FINES <#200(0.075 mm=0.003 in.) Soil Classification System(USCS). Elements of the USCS and other definitions are provided on SAND this and the following pages. Soil descriptions Fine #200 to#40(0.075 to 0.4 mm; 0.003 to 0.02 in.) are based on visual-manual procedures(ASTM Medium #40 to#10(0.4 to 2 mm; 0.02 to 0.08 in.) D2488) and laboratory testing procedures Coarse #10 to#4(2 to 4.75 mm; 0.08 to 0.187 in.) (ASTM D2487), if performed. GRAVEL Fine #4 to 3/4 in. (4.75 to 19 mm; 0.187 to 0.75 in.) S&W INORGANIC SOIL CONSTITUENT DEFINITIONS Coarse 3/4 to 3 in.(19 to 76 mm) FINE-GRAINED SOILS COARSE-GRAINED CONSTITUENT (50%or more fines)' SOILS COBBLES 3 to 12 in.(76 to 305 mm) less than 50/o fines Silt,Lean Clay, BOULDERS > 12 in. (305 mm) Major Elastic Silt or Sand or Grave l° Fat Clay3 RELATIVE DENSITY/CONSISTENCY Modifying 30%or more More than 12% COHESIONLESS SOILS COHESIVE SOILS (Secondary) coarse-grained: fine-grained: Precedes major Sandy or Gravelly Silty or Clayey3 N, SPT, RELATIVE N, SPT, RELATIVE constituent BLOWS/FT. DENSITY BLOWS/FT. CONSISTENCY 15%to 30% 5%to 12% <4 Very loose <2 Very soft coarse-grained: fine-grained: with Sand or with Silt or 4-10 Loose 2-4 Soft Follows major with Gravel°_ __ with Cla�r3__ 10-30 Medium dense 4-8 Medium stiff constituent 30/o or more total 30-50 Dense 8- 15 Stiff coarse-grained and 15%or more of a >50 Very dense 15-30 Very stiff lesser coarse- second coarse- >30 Hard grained constituent grained constituent: is 15%or more: with Sand or WELL AND BACKFILL SYMBOLS with Sand or with Gravels with Gravels Bentonite Surface Cement All percentages are by weight of total specimen passing a 3-inch sieve. ® Cement Grout s�^.y Seal ZThe order of terms is:Modifying Major with Minor. 4Determined based on behavior. ® Bentonite Grout Asphalt or Cap Determined based on which constituent comprises a larger percentage. 'Whichever is the lesser constituent. Bentonite Chips Slough MOISTURE CONTENT TERMS Silica Sand Inclinometer or Dry Absence of moisture,dusty,dry Non-perforated Casing to the touch Perforated or Screened Casing m Vibrating Wire Moist Damp but no visible water Piezometer Wet Visible free water, from below PERCENTAGES TERMS''s water table Trace <5% Few 5 to 10% STANDARD PENETRATION TEST(SPT) Little 15 to 25% SPECIFICATIONS Some 30 to 45% Hammer: 140 pounds with a 30-inch free fall. Mostly 50 to 100% Rope on 6-to 10-inch-diam.cathead 2-1/4 rope turns, > 100 rpm 'Gravel,sand,and fines estimated by mass. Other constituents,such as NOTE: If automatic hammers are organics,cobbles,and boulders,estimated by volume. used, blow counts shown on boring ZReprinted,with permission,from ASTM D2488-09a Standard Practice for N logs should be adjusted to account for Description and Identification of Soils(Visual-Manual Procedure),copyright efficiency of hammer. ASTM International,100 Barr Harbor Drive,West Conshohocken,PA 19428. q A copy of the complete standard may be obtained from ASTM International, Sampler: 10 to 30 inches long www.astm.org. Shoe I.D. = 1.375 inches Barrel I.D. = 1.5 inches Union, Washington, Residences Barrel O.D. =2 inches Proposed Guest Lodge a N-Value: Sum blow counts for second and third Union,Washington 6-inch increments. N Refusal: 50 blows for 6 inches or N less; loblows for o inches. SOIL DESCRIPTION CL W NOTE:Penetration resistances(N-values)shown on AND LOG KEY Y boring logs are as recorded in the field and have not been corrected for hammer July 2019 21-1-22423-001 efficiency, overburden, or other factors. FSHANNON &WILSON, INC. FIG. A-1 0 Geot!hnical and Environmental Consultants Sheet 1 Of 3 UNIFIED SOIL CLASSIFICATION SYSTEM(USCS) (Modified From USACE Tech Memo 3-357,ASTM D2487,and ASTM D2488) MAJOR DIVISIONS GROUP/GRAPHIC SYMBOL TYPICAL IDENTIFICATIONS GW .'• Well-Graded Gravel;Well-Graded Gravel with Sand Gravel (less than 5% Gravels fines) GP o Q° Poorly Graded Gravel;Poorly Graded (more than 50% o p Gravel with Sand of coarse fraction retained on No.4 sieve) GM ' SiltyGravel;SiltyGravel with Sand Silty or Gr Clayey avel COARSE- (more than 12% Clayey Gravel;Clayey Gravel with GRAINED fines) GC Sand SOILS (more than 50% retained on No. SW Well-Graded Sand;Well-Graded Sand 200 sieve) Sand with Gravel (less than 5% fines) Poorly Graded Sand;Poorly Graded Sands SP Sand with Gravel (50%or more of coarse fraction passesi the)No. 4 Silty or SM Silty Sand;Silty Sand with Gravel Clayey Sand (more than 12% fines) SC Clayey Sand;Clayey Sand with Gravel ML Silt;Silt with Sand or Gravel;Sandy or Gravelly Silt Inorganic Silts and Clays Lean Clay;Lean Clay with Sand or (liquid limit less CL Gravel;Sandy or Gravelly Lean Clay than 50) FINE-GRAINED Organic Silt or Clay;Organic Silt or SOILS Organic OL — — Clay with Sand or Gravel;Sandy or Gravelly Organic Silt or Clay (50%or more — — passes the Elastic Silt;Elastic Silt with Sand or 200 sieve)) MH Gravel;Sandy or Gravelly Elastic Silt Silts and Clays Inorganic Fat Clay;Fat Clay with Sand or Gravel; (liquid limit 50 or CH more) Sandy or Gravelly Fat Clay Organic Silt or Clay;Organic Silt or Organic OH Clay with Sand or Gravel;Sandy or Gravelly Organic Silt or Clay HIGHLY- ORGANIC Primarily organic matter,dark in PT Peat or other highly organic soils(see SOILS color,and organic odor ASTM D4427) NOTE: No.4 size=4.75 mm=0.187 in.; No.200 size=0.075 mm=0.003 in. m N r H J NOTES Union, Washington, Residences co Proposed Guest Lodge 1.Dual symbols(symbols separated by a hyphen,i.e., SP-SM,Sand Union, Washington N with Silt)are used for soils with between 5%and 12%fines or when the liquid limit and plasticity index values plot in the CL-ML area of ry the plasticity chart. Graphics shown on the logs for these soil types SOIL DESCRIPTION LD are a combination of the two graphic symbols(e.g., SP and SM). AND LOG KEY Y 2. Borderline symbols(symbols separated by a slash,i.e., CL/ML, U) lean Clay to Silt;SP-SM/SM, Sand with Silt to Silty Sand)indicate July 2019 21-1-22423-001 g that the soil properties are close to the defining boundary between two groups. SHANNON&WILSON, INC. I FIG. A-1 p Geotechnical and Environmental Consultants Sheet 2 of 3 GRADATION TERMS ACRONYMS AND ABBREVIATIONS Poorly Graded Narrow range of grain sizes present or,within ATD At Time of Drilling the range of grain sizes present, one or more Diam. Diameter sizes are missing(Gap Graded). Meets Elev. Elevation criteria in ASTM D2487, if tested. Well-Graded Full range and even distribution of grain sizes ft. Feet present. Meets criteria in ASTM D2487, if FeO Iron Oxide tested. gal. Gallons CEMENTATION TERMS' Horiz. Horizontal HSA Hollow Stem Auger Weak Crumbles or breaks with handling or slight I.D. Inside Diameter finger pressure. Moderate Crumbles or breaks with considerable finger in. Inches pressure. lbs. Pounds Strong Will not crumble or break with finger MgO Magnesium Oxide pressure. mm Millimeter PLASTICITYZ MnO Manganese Oxide APPROX. NA Not Applicable or Not Available PLASITICITY NP Nonplastic DESCRIPTION VISUAL-MANUAL CRITERIA INDEX RANGE O.D. Outside Diameter Nonplastic A 1/8-in.thread cannot be rolled <4 OW Observation Well at any water content. pcf Pounds per Cubic Foot Low A thread can barely be rolled and 4 to 10 a lump cannot be formed when PID Photo-Ionization Detector drier than the plastic limit. PMT Pressuremeter Test Medium A thread is easy to roll and not 10 to 20 ppm Parts per Million much time is required to reach the plastic limit. The thread psi Pounds per Square Inch cannot be rerolled after reaching PVC Polyvinyl Chloride the plastic limit. A lump rpm Rotations per Minute crumbles when drier than the plastic limit. SPT Standard Penetration Test High It takes considerable time rolling >20 USCS Unified Soil Classification System and kneading to reach the plastic q� Unconfined Compressive Strength limit. A thread can be rerolled several times after reaching the VWP Vibrating Wire Piezometer plastic limit. A lump can be Vert. Vertical formed without crumbling when WOH Weight of Hammer drier than the plastic limit. WOR Weight of Rods ADDITIONAL TERMS Wt. Weight Mottled Irregular patches of different colors. Bioturbated Soil disturbance or mixing by plants or STRUCTURE TERMS' animals. Interbedded Alternating layers of varying material or color with layers at least 1/4-inch thick; Diamict Nonsorted sediment; sand and gravel in silt singular: bed. and/or clay matrix. Laminated Alternating layers of varying material or color with layers less than 1/4-inch thick; Cuttings Material brought to surface by drilling. singular: lamination. Fissured Breaks along definite planes or fractures Slough Material that caved from sides of borehole. with little resistance. Slickensided Fracture planes appear polished or Sheared Disturbed texture, mix of strengths. glossy; sometimes striated. Blocky Cohesive soil that can be broken down PARTICLE ANGULARITY AND SHAPE TERMS' into small angular lumps that resist further breakdown. Angular Sharp edges and unpolished planar surfaces. Lensed Inclusion of small pockets of different soils, such as small lenses of sand N Subangular Similar to angular, but with rounded edges. scattered through a mass of clay. Homogeneous Same color and appearance throughout. Subrounded Nearly planar sides with well-rounded edges. J Rounded Smoothly curved sides with no edges. Flat Width/thickness ratio>3. Union, Washington, Residences Cn Proposed Guest Lodge 0 Elongated Length/width ratio>3. Union,Washington c6 N V N (V Reprinted,with permission,from ASTM D2488-09a Standard Practice for Description and M Identification of Soils(Visual-Manual Procedure),copyright ASTM International,100 Ban SOIL DESCRIPTION a Harbor Drive,West Conshohocken,PA 19428. A copy of the complete standard may be AND LOG KEY w obtained from ASTM International,www.astm.org. Y U) 2Adapted,with permission,from ASTM D2488-09a Standard Practice for Description and July 2019 21-1-22423-001 En a Identification of Soils(Visual-Manual Procedure),copyright ASTM International,100 Ban A J Harbor Drive,West Conshohocken,PA 19428. A copy of the complete standard may be SHANNON&WIL A SON, INC. FIG. _1 p obtained from ASTM International,www.astm.org. Geotechnical and Environmental Consultants N Sheet 3 of 3 Total Depth: 21.5 ft. Northing: Drilling Method: Hollow Stem Auger Hole Diam.: Top Elevation: -29 ft. Easting: Drilling Company: Gregory Drilling Rod Diam.: Vert. Datum: Station: Drill Rig Equipment: Mini Track HSA Hammer Type: Automatic Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION a m -o ct� PENETRATION RESISTANCE (blows/foot) Refer to the report text for a proper understanding of the r a = w t A Hammer Wt. &Drop: 140 Ibs/30 inches subsurface materials and drilling methods. The stratification L E E o to a lines indicated below represent the approximate boundaries U) cn between material types,and the transition may be gradual. 0 20 40 60 Medium dense to dense, brown, Well-graded • • ' • • • • • : : : • • ' • • • • ' • Gravel with Silt and Sand(GP); moist to wet at ° 7 feet;few cobbles. (3 (Ha) 0 O - Water encountered at 4.3 feet on ° 5 . . . . . . . . . . .\. . . . . . . . . . . . . 11/22/2017. o . . . . . . . . . . . . . . . . . . . . . . . . . . : . : ................... ......... ......... .................:. o .:.:.:.:.:. .:.:.:.:.:.:.:.:.:. N ° O 10 oQC 31 H O Q O O ° 15 O O � 20 °21.5 � e BOTTOM OF BORING COMPLETED 9/18/2017 ................... ................... ...... Y n 25 ................... ...:.:.:.:.:.:.:.:. .: o; 3 ................... .:.:.:.:.:.:.: 0 J LEGEND Sample Not Recovered = Well Screen and Sand Fitter 0 % Fines(<0.075mm) I 2.0"O.D.Split Spoon Sample ® Bentonite-Cement Grout • % Water Content ® Bentonite Chips/Pellets ® Bentonite Grout t Ground Water Level in Well Union, Washington, Residences Proposed Guest Lodge v NOTES Union, Washington CL �i 1.Refer to KEY for explanation of symbols,codes,abbreviations and definitions. 2.Groundwater level,if indicated above,is for the date specified and may vary. 3.USCS designation is based on visual-manual classification and selected lab testing. LOG OF BORING SW-7 N W July 2019 21-1-22423-001 LU SHANNON&WILSON, INC. FIG.A-2 ¢ Geotechnical and Environmental Consultants f REV 3 -Approved for Submittal Total Depth: 21.5 ft. Northing: Drilling Method: Hollow Stem Auqer Hole Diam.: 6 in. Top Elevation: —35 ft. Easting: Drilling Company: Gregory Drilling Rod Diam.: Vert.Datum: Station: Drill Rig Equipment: Mini-Track 309 Hammer Type: Automatic Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION o a zt� PENETRATION RESISTANCE (blowstfoot) Refer to the report text for a proper understanding of the z n :D t ♦ Hammer Wt. 8 Drop: 140 Ibs/30 inches subsurface materials and drilling methods. The stratification i E E o n lines indicated below represent the approximate boundaries 0 U cn (D 3 between material types,and the transition may be gradual. 0 20 40 60 Loose, brown, Poorly Graded Gravel with Silt and Sand(GP-GM); dry. Fill (Hf) 2.0 Medium dense to dense, brown, Poorly ° Graded Gravel with Silt and Sand(GP); moist O ................... ................... ................... to wet at 11 feet. °Q 5 (Ha) °Q .:.:.:.:.:.:.:. .:.:.:.:.:......... ................... . . . . . . . . . . . . . . . . . . . . . . . . . . - Water encountered at 7.5 feet on O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11/22/2017. Q 10 021 O n O p ................. O . °Q 15 Q 3I O Q °Q .:.:.:... O Q 20 o Q 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . BOTTOM OF BORING 21.5 COMPLETED 9/18/2017 ................... .. Y 25 ................... ................... ................... Q, ................... .................:. .. ............... 3 ................... ............ . 0 J 0 20 40 60 LEGEND 0 % Fines(<0.075mm) Sample Not Recovered (� Well Screen and Sand Fitter I 2.0"O.D.Split Spoon Sample ® Bentonite-Cement Grout % Water Content N ® Bentonite Chips/Pellets ® Bentonite Grout t Ground Water Level in Well Union, Washington, Residences Proposed Guest Lodge NOTES Union, Washington 1.Refer to KEY for explanation of symbols,codes,abbreviations and definitions. M 2.Groundwater level,if indicated above,is for the date specified and may vary. N 3.USCS designation is based on visual-manual classification and selected lab testing. LOG OF BORING SW-8 N W July 2019 21-1-22423-001 Of N SHANNON&WILSON, INC. FIG.A•3 Q Geotechnical and Environmental Consultants REV 3 -Approved for Submittal MIISHANNON 6WILSON Appendix A Laboratory Test Results 21-1-22423-001 SHANNON 6WILSON,INC. APPENDIX GEOTECHNICAL LABORATORY TESTING 21-1-22423-001 SHANNON MWILSON,INC. APPENDIX GEOTECHNICAL LABORATORY TESTING TABLE OF CONTENTS Page 1 VISUAL CLASSIFICATION .............................................................................................1 2 WATER CONTENT DETERMINATION..........................................................................1 3 GRAIN SIZE DISTRIBUTION ANALYSIS......................................................................1 3.1 Sieve Analysis.......................................................................................................2 4 CONSIDERATIONS...........................................................................................................2 5 REFERENCES ....................................................................................................................2 TABLES Laboratory Terms Sample Types Laboratory Test Summary TESTS Grain Size Distribution Plot, Boring SW-7 Grain Size Distribution Plot, Boring SW-8 21-1-22423-001-R1-A 21-1-22423-001 1 SHANNON 6WILSON,INC. APPENDIX GEOTECHNICAL LABORATORY TESTING We performed geotechnical laboratory testing on selected soil samples retrieved from the two borings completed for the Union, Washington, Residences Guest Lodge Project. The laboratory testing program included tests to classify the soil and provide data for engineering studies. We performed visual classification on all retrieved samples. Our laboratory testing program included water content determinations, and grain size distribution analyses. The following sections describe the laboratory test procedures. 1 VISUAL CLASSIFICATION We visually classified soil samples retrieved from the borings using a system based on ASTM International (ASTM) D2487-11, Standard Test Method for Classification of Soil for Engineering Purposes, and ASTM D2488-09a, Standard Recommended Practice for Description of Soils (Visual-Manual Procedure). We summarize our classification system in Appendix A. We assigned a Unified Soil Classification System (USCS) group name and symbol,based on our visual classification of particles finer than 76.2 millimeters (3 inches). We revised visual classifications using results of the index tests discussed below. 2 WATER CONTENT DETERMINATION We tested the water content of selected samples in accordance with ASTM D2216-10 Standard P , Method for Laboratory Determination of Water(Moisture) Content of Soil, Rock, and Soil- Aggregate Mixtures. Comparison of the water content of a soil with its index properties can be useful in characterizing soil unit weight, consistency, compressibility, and strength. We present water content test results in the Laboratory Test Summary table in this appendix, and graphically on Appendix A exploration logs. 3 GRAIN SIZE DISTRIBUTION ANALYSIS Grain size distribution analyses separate soil particles through mechanical or sedimentation processes. Grain size distributions are used to classify the granular component of soils and can correlate with soil properties, including frost susceptibility, permeability, shear strength, liquefaction potential, capillary action, and sensitivity to moisture. We plot grain size distribution analysis results in this appendix. Grain size distribution plots provide tabular information about each specimen, including: USCS group symbol and group name; water 21-1-22423-001-R 1-A 21-1-22423-001 1 SHANNON WLSON.INC. content; constituent (i.e., cobble, gravel, sand, and fines) percentages; coefficients of uniformity and curvature, if applicable; personnel initials; ASTM standard designation; and testing remarks. Constituent percentages are presented in the Lab Summary Table in this appendix and fines contents are plotted as data points on Appendix A exploration logs. 3.1 Sieve Analysis We performed mechanical sieve analyses on selected soil specimens to determine the grain size distribution of coarse-grained soil particles, in accordance with ASTM C 136/C 136M- 14, Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates. 4 CONSIDERATIONS Drilling and sampling methodologies may affect the outcome of prescribed geotechnical laboratory tests. Refer to the field exploration discussion in this report for a discussion of these potential effects. Instances of limited recovery may have resulted in test samples not meeting specified minimum mass requirements, per ASTM standards. Test plots show which samples do not meet ASTM specified minimum mass requirements. 5 REFERENCES ASTM International, 2011, Standard practice for classification of soils for engineering purposes (unified soil classification system), D2487-11: West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.08, soil and rock (I): D420 - D5876, 12 p., available: www.astm.org. ASTM International, 2010, Standard test methods for laboratory determination of water (moisture) content of soil and rock by mass, D2216-10: West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.08, soil and rock (I): D420 - D5876, 7 p., available: www.astm.org. ASTM International, 2014, Standard test method for sieve analysis of fine and coarse aggregates, C136-14: West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.02, concrete and aggregates, 5 p., available: www.astm.org. 21-1-22423-001-R I-A 21-1-22423-001 2 SHANNON 8WILSON,INC. LABORATORY TERMS Abbreviations, Symbols,and Terms T Descriptions % Percent * Sample specimen weight did not meet required minimum mass for the test method Inch Test not performed by Shannon&Wilson,Inc. laboratory ASTM Std. ASTM International Standard C, Coefficient of curvature Clay-size Soil particles finer than 0.002 mm cm Centimeter cm Square centimeter Coarse-grained Soil particles coarser than 0.075 mm(cobble-, ravel-and sand-sized articles) Cobbles Soil articles finer than 305 mm and coarser than 76.2 mm C Coefficient of uniformity CU Consolidated-Undrained E Axial strain Fine-grained Soil particles finer than 0.075 mm(silt-and clay-sized articles) ft Feet ym Wet unit weight Gravel Soil particles finer than 76.2 mm and coarser than 4.75 mm G, Specific gravity of soil solids Ho Initial height AH Change in height AHload End of load increment deformation in Inch in Cubic inch LL Liquid Limit min Minute mm Millimeter µm Micrometer MC Moisture content MPa Mega-Pascal NP Non-plastic OC Organic content Total stress Effective stress Pa Pascal cf Pounds per cubic foot PI Plasticity Index PL Plastic Limit sf Pounds per square foot psi Pounds per square inch Deviatoric stress Sand Soil particles finer than 4.75 mm and coarser than 0.075 nun sec Second Silt Soil particles finer than 0.075 mm and coarser than 0.002 mm t. Time to n%primary consolidation tload Duration of load increment tsf Short tons per square foot USCS Unified Soil Classification System LIU Unconsolidated-Undrained WC Water content 21-1-22423-001-R1-A-Table 21-1-22423-001 SHANNON&WILSON,INC. SAMPLE TYPES Abbreviations, Symbols, and Terms Descriptions 2SS 2.5-inch Outside Diameter Split-Spoon Sample 2ST 2-inch Outside Diameter Thin-Walled Tube 3HSA 3-inch CME Hollow-stem Auger Sampler 3SS 3-inch Outside Diameter Split-Spoon Sample 4SS 4-inch Inside Diameter Spht-Spoon Sample 6SS 6-inch Inside Diameter Split-Spoon Sample CA MC Modified California Sampler CA SPT Standard Penetration Test SPT CORE Rock Core DM +3.25 inch Outside Diameter Split-Spoon Sample DMR 3.25-inch Sampler with Internal Rings GRAB Grab Sample GUS 3-inch Outside Diameter Gregory Undisturbed Sampler(GUS)Sample OSTER 3-inch Outside Diameter Osterberg Sample PITCHER 3-inch Outside Diameter Pitcher Sample PMT Pressuremeter Test f=failed PO Porter Penetration Test Sample PT 2.5-inch Outside Diameter Thin-Walled Tube ROCK Rock Core Sample SCORE Soil Core as in Sonic Core Borings) SH 1 1-inch Plastic Sheath SH2 2-inch Plastic Sheath with Soil Recovery SH3 2-inch Plastic Sheath with no Soil Recovery SPT 2-inch Outside Diameter Split-Spoon Sample SS S lit-S oon ST 3-inch Outside Diameter Thin-Walled Tube STW 3-inch Outside Diameter Thin-Walled Tube TEST Sample Test Interval TW Thin Wall Sample UNDIST Undisturbed Sample VANE Vane Shear WATER Water Sample for Probe Logs XCORE Core Sample 21-1-22423-001-RI-A-Table 21-1-22423-001 > q. cl � C7 b b b -d -d d C7 C7 �7 3 a � o v �n `.r M M /•� iE iF dF V] SaUTA F ° °° W Pugs % o a 0 0 M O 00 \�O 3 `n 4 4 juno3 Moig cCl V M 00 N N (71 �C adSl ajdures a a a a a a .iagmnN aidtugS M cis rig v� v� v� v� (13) q;dad dos, d H H C I— [— l— 00 00 00 Q '0 333333 s LnV) V) CA � N a N N N -III SHANNON 6WILSON,INC. GRAIN SIZE DISTRIBUTION PLOT Union,Washington, Residences Guest Lodge BORING SW-7 Union,Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay-Size Mesh Opening in Inches Mesh Openings per Inch,U.S.Standard Grain Size in Millimeters ^dry a ry o O O O O 00 O° o`O �' 00 O^' O^cP O° ^� ry ^ ^ •7 ^� 4 ^ ry P ro ^ w O' O' O' O' O'O' O' O' O' O' O 100 0 95 5 90 10 85 15 80 20 75 25 70 30 65 35 Vl 0) (Np 60 40 � a 55 45 0 O C 50 50 N I.L (p C 45 55 V U 40 60 d y 35 65 to 30 70 25 75 20 80 15 85 10 90 5 95 0 100 ^ry 00 PO 00 ^O ^O 0 0 w P '7 •4 ^O O O O O O' O^y o o O� Ory O g0 g0 g0 g~ g O' O' ' O' Grain Size(MITI) O' O" O w Sample Depth GrSouS USCS Gravel Sand Fines <20pm <2Nm WC Tested Review ASTM Identification (ft) Sy oup Group Name %, % % % % % By By Std. SW-7,S-3 10.0 GW-GM Well-Graded Gravel with Silt and Sand 48 45 6.5 10.5 JJM AKV C136 r Test specimen did not meet minimum mass recommendations. i o c� >J_> >I Z N 7 a c� N N N N Z Q QI y U' Q 0 4 M O N SHANNON&WILSON,INC. 400 NORTH 34TH STREET SUITE 100 SEATTLE,WASHINGTON 98103 MAIN(206)632-8020 FAX(206)695-6777 ' 11 SHANNON 6WILSON,INC. GRAIN SIZE DISTRIBUTION PLOT Union,Washington, Residences Guest Lodge BORING SW-8 Union,Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay-Size Mesh Opening in Inches Mesh Openings per Inch,U.S.Standard Grain Size in Millimeters "ry b' N O O O O O 00 00 00 CY 00 O^• O CP O 00 Oo 00 00 ^� IV ^i b ^ �1. b 0 1. O' Cr O' O' O'O' O' O' O' O' O' 100 0 95 5 90 10 85 15 80 20 75 25 70 30 65 35 N 60 40 55 45 0 O C 50 50 N lL N C 45 55 Q U 0) 40 60 0- to 35 65 1n 30 70 25 75 20 80 15 85 10 90 5 95 0 100 ^O•y 00 b0 �O ry0 ^O 0 •o W O O O O O O' p4j O O O� O O 80 80 Sp 8� Sry O' O' O' O' O' O' O Grain Size(mm) Sample Depth USCS USCS Gravel Sand Fines <20pm <2pm WC Tested Review ASTM GrpIdentification (ft) Symd Group Name % % % % % % By By Std. SW-8,S-2 10.0 SP-SM Poorly Graded Sand with Silt and Gravel 28 63 8.4 11.0 JJM AKV C136 N ■SW-8,S-3 15.0 GP-GM Poorly Graded Gravel with Silt and Sand 47 46 7.1 10.8 JJM AKV C136 rn o Test specimen did not meet minimum mass recommendations. J Z Q x ai N N N N Z Q Q� 0 6 0 4 M N N N N SHANNON&WILSON,INC. 400 NORTH 34TH STREET SUITE 100 • SEATTLE,WASHINGTON 98103 MAIN(206)632-8020 FAX(206)695-6777 11 I SHAN NON 8W LSO N Attachment to and part of Report: 21-1-22423-001 GEOTECHNICAL AND ENVIRONMENTAL CONSULTANTS Date: July 25,2019 To: Mr.Ray Nelson Watermark Estate Management Services,LLC Important Information About Your Geotechnical/Environmental Report CONSULTING SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND FOR SPECIFIC CLIENTS. Consultants prepare reports to meet the specific needs of specific individuals. A report prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer. Unless indicated otherwise,your consultant prepared your report expressly for you and expressly for the purposes you indicated. No one other than you should apply this report for its intended purpose without first conferring with the consultant. No party should apply this report for any purpose other than that originally contemplated without first conferring with the consultant. THE CONSULTANT'S REPORT IS BASED ON PROJECT-SPECIFIC FACTORS. A eotechnical/environmental report is based on a subsurface exploration plan designed to consider a unique set g p P P Sn q of project-specific factors. Depending on the project,these may include the general nature of the structure and property involved;its size and configuration,its historical use and practice,the location of the structure on the site and its orientation,other improvements such as access roads,parking lots,and underground utilities;and the additional risk created by scope-of-service limitations imposed by the client. To help avoid costly problems,ask the consultant to evaluate how any factors that change subsequent to the date of the report may affect the recommendations. Unless your consultant indicates otherwise,your report should not be used(1)when the nature of the proposed project is changed(for example,if an office building will be erected instead of a parking garage,or if a refrigerated warehouse will be built instead of an unrefrigerated one,or chemicals are discovered on or near the site);(2)when the size,elevation,or configuration of the proposed project is altered;(3)when the location or orientation of the proposed project is modified;(4)when there is a change of ownership;or(5)for application to an adjacent site. Consultants cannot accept responsibility for problems that may occur if they are not consulted after factors that were considered in the development of the report have changed. SUBSURFACE CONDITIONS CAN CHANGE. Subsurface conditions may be affected as a result of natural processes or human activity. Because a geotechnical/environmental report is based on conditions that existed at the time of subsurface exploration, construction decisions should not be based on a report whose adequacy may have been affected by time. Ask the consultant to advise if additional tests are desirable before construction starts;for example,groundwater conditions commonly vary seasonally. Construction operations at or adjacent to the site and natural events such as floods,earthquakes,or groundwater fluctuations may also affect subsurface conditions and,thus,the continuing adequacy of a geotechnical/environmental report. The consultant should be kept apprised of any such events and should be consulted to determine if additional tests are necessary. MOST RECOMMENDATIONS ARE PROFESSIONAL JUDGMENTS. Site exploration and testing identifies actual surface and subsurface conditions only at those points where samples are taken. The data were extrapolated by your consultant,who then applied judgment to render an opinion about overall subsurface conditions. The actual interface between materials may be far more gradual or abrupt than your report indicates. Actual conditions in areas not sampled may differ from those predicted in your report. While nothing can be done to prevent such situations,you and your consultant can work together to help reduce their impacts. Retaining your consultant to observe subsurface construction operations can be particularly beneficial in this respect. Page 1 of 2 1/2019 011SHANNON MMM A REPORT'S CONCLUSIONS ARE PRELIMINARY. The conclusions contained in your consultant's report are preliminary,because they must be based on the assumption that conditions revealed through selective exploratory sampling are indicative of actual conditions throughout a site. Actual subsurface conditions can be discerned only during earthwork;therefore,you should retain your consultant to observe actual conditions and to provide conclusions. Only the consultant who prepared the report is fully familiar with the background information needed to determine whether or not the report's recommendations based on those conclusions are valid and whether or not the contractor is abiding by applicable recommendations. The consultant who developed your report cannot assume responsibility or liability for the adequacy of the report's recommendations if another party is retained to observe construction. THE CONSULTANT'S REPORT IS SUBJECT TO MISINTERPRETATION. Costly problems can occur when other design professionals develop their plans based on misinterpretation of a geotechnical/environmental report. To help avoid these problems,the consultant should be retained to work with other project design professionals to explain relevant geotechnical,geological,hydrogeological,and environmental findings,and to review the adequacy of their plans and specifications relative to these issues. BORING LOGS AND/OR MONITORING WELL DATA SHOULD NOT BE SEPARATED FROM THE REPORT. Final boring logs developed by the consultant are based upon interpretation of field logs(assembled by site personnel),field test results,and laboratory and/or office evaluation of field samples and data. Only final boring logs and data are customarily included in geotechnical/environmental reports. These final logs should not,under any circumstances,be redrawn for inclusion in architectural or other design drawings,because drafters may commit errors or omissions in the transfer process. To reduce the likelihood of boring log or monitoring well misinterpretation,contractors should be given ready access to the complete geotechnical engineering/environmental report prepared or authorized for their use. If access is provided only to the report prepared for you,you should advise contractors of the report's limitations, assuming that a contractor was not one of the specific persons for whom the report was prepared,and that developing construction cost estimates was not one of the specific purposes for which it was prepared. While a contractor may gain important knowledge from a report prepared for another party,the contractor should discuss the report with your consultant and perform the additional or alternative work believed necessary to obtain the data specifically appropriate for construction cost estimating purposes. Some clients hold the mistaken impression that simply disclaiming responsibility for the accuracy of subsurface information always insulates them from attendant liability. Providing the best available information to contractors helps prevent costly construction problems and the adversarial attitudes that aggravate them to a disproportionate scale. READ RESPONSIBILITY CLAUSES CLOSELY. Because geotechnical/environmental engineering is based extensively on judgment and opinion,it is far less exact than other design disciplines. This situation has resulted in wholly unwarranted claims being lodged against consultants. To help prevent this problem,consultants have developed a number of clauses for use in their contracts,reports,and other documents. These responsibility clauses are not exculpatory clauses designed to transfer the consultant's liabilities to other parties;rather,they are definitive clauses that identify where the consultant's responsibilities begin and end. Their use helps all parties involved recognize their individual responsibilities and take appropriate action. Some of these definitive clauses are likely to appear in your report, and you are encouraged to read them closely. Your consultant will be pleased to give full and frank answers to your questions. The preceding paragraphs are based on information provided by the ASFE/Association of Engineering Firms Practicing in the Geosciences,Silver Spring,Maryland Page 2 of 2 1/2019