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Home My WebLink AboutSoils Report 02.19.20207 CTL I THOMPSON GEOTECHNICAL ENGINEERING INVESTIGATION AUGUST TEAGUE RESIDENCE LOT 24, CORYELL RANCH GARFIELD COUNTY, COLORADO Prepared For: HARRY TEAGUE ARCHITECTS 129 Emma Road, Unit A Basalt, CO 81621 Attention: Galen Hoover Architect Project No. GS06445.000-120 February 19, 2020 TABLE OF CONTENTS SCOPE 1 SUMMARY OF CONCLUSIONS 1 SITE CONDITIONS 2 PROPOSED CONSTRUCTION 3 SITE GEOLOGY 3 GEOLOGIC HAZARDS 4 SUBSURFACE CONDITIONS 4 SITE EARTHWORK 6 Subexcavation and Structural Fill 6 Foundation Wall Backfill 7 FOUNDATION 7 SLABS -ON -GRADE 8 STRUCTURALLY -SUPPORTED FLOORS 9 FOUNDATION WALLS 10 SUBSURFACE DRAINAGE 11 SURFACE DRAINAGE 11 CONCRETE 12 CONSTRUCTION OBSERVATIONS 13 STRUCTURAL ENGINEERING SERVICES 13 GEOTECHNICAL RISK 13 LIMITATIONS 14 FIGURE 1 — VICINITY MAP FIGURE 2 — AERIAL PHOTOGRAPH FIGURE 3 — PROPOSED BUILDING FOOTPRINT FIGURE 4 — SUMMARY LOGS OF EXPLORATORY PITS FIGURES 5 AND 6 — GRADATION TEST RESULTS FIGURES 7 AND 8 — FOUNDATION WALL DRAIN CONCEPTS TABLE I — SUMMARY OF LABORATORY TESTING HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 C:IUsers1acraig1Box1ProJects1Glenwood Springs - ProJects1GS06445.000-August Teague ResIdence112012. Reports\GS06445.000 120 R1.docx SCOPE This report presents the results of our geotechnical engineering investiga- tion for the August Teague Residence proposed on Lot 24, Coryell Ranch in Gar- field County, Colorado. We conducted this investigation to evaluate subsurface conditions at the site and provide geotechnical engineering recommendations for the planned residence. Our report was prepared from data developed from our field exploration, laboratory testing, engineering analysis, and our experience with similar conditions. This report includes a description of the subsurface con- ditions observed in our exploratory pits and presents geotechnical engineering recommendations for design and construction of foundations, floor systems, be- low -grade walls, and details influenced by the subsoils. A summary of our con- clusions is presented below. SUMMARY OF CONCLUSIONS 1. Subsoils encountered in our exploratory pits were about 6 inches of topsoil over 2.5 to 4.5 feet of sandy clay underlain by slightly silty gravel with cobbles and boulders to the maximum explored depth of 10 feet. Groundwater was not found in our exploratory pits during our subsurface investigation. Our exploratory pits indicate the silty gravel and cobble soil, which has good foundation support properties, is near the ground surface in the area of the proposed residence. We recommend construct- ing the building on a footing foundation supported by the undis- turbed, silty gravel and cobble soil. Where clay soils are found at planned footing elevations, the clay should be subexcavated to ex- pose the underlying gravel and cobble soil. Foundation elevations can be re -attained with densely -compacted, granular structural fill. Design and construction criteria for footing foundations are pro- vided in the report. 3. Floors in basement and garage areas are planned as slabs -on - grade. The sandy clay soil at the site possesses relatively poor slab support characteristics as compared to the silty gravel and cobble. We recommend removal of clay soils below the building floor slabs to a depth of at least 2 feet and replacement with HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000.120 1 densely -compacted, granular structural fill. Additional discussion is in the report. 4. A perimeter foundation drain should be constructed around below - grade areas in the residence. Site grading should be designed and constructed to convey surface water away from the building. SITE CONDITIONS The August Teague Residence is proposed on Lot 24, Coryell Ranch in Garfield County, Colorado. A vicinity map with the location of the site is shown on Figure 1. The lot is an approximately 2 -acre parcel bordered by Coryell Ranch Road at the northwest and Spirit Mountain Drive at the north and east. Vacant residential lots are adjacent to the property on all sides. An aerial photo- graph of the site is included as Figure 2. A rock -lined irrigation ditch borders the property at the west. No structures are present on the subject lot. Ground sur- face is gently sloping to the northwest at grades Tess than 5 percent. Vegetation consists of grass and weeds. A photograph of the site at the time of our subsur- face investigation is below. Looking south across the site HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 2 PROPOSED CONSTRUCTION We were provided with progress architectural plans for the August Teague Residence by Harry Teague Architects. The proposed building footprint is shown on Figure 3. The plans indicate the residence will be a one and two-story, wood - framed building with an attached garage. Basement and crawl space areas are planned below the main level in living areas. Slab -on -grade floors are proposed for basement and garage areas. Maximum excavation depths in basement areas will likely be about 8 to 10 feet. We expect foundation loads along perimeter walls to be between 1,000 and 3,000 pounds per linear foot. Maximum interior column Toads of about 30 kips are anticipated. We should be provided with con- struction plans, as they are developed so that we can provide geotechnical/geo- structural engineering input. SITE GEOLOGY As part of our geotechnical engineering investigation, we reviewed the ge- ologic map by the Colorado Geology Survey (CGS), titled, "Geologic Map of the Carbondale Quadrangle, Garfield County, Colorado", by Kirkham and Widmann (dated 2008). The overburden soils at the site are mapped as younger terrace alluvium deposits of the late Pleistocene Epoch. The deposits are described as mostly poorly -sorted, clast-supported, locally bouldery, pebble and cobble gravel in a sand and silt matrix deposited as glacial outwash. The gravel and cobble soil found in our exploratory pits is consistent with the geologic description. The soils are underlain at depth by bedrock of the Eagle Valley Evaporite formation. The surface of the bedrock is typically irregular and contorted and not representative of the relatively flat ground surface at the site. The geologic map shows numerous surficial features of sinkholes located near the subject site. HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 3 GEOLOGIC HAZARDS We also reviewed the CGS map "Collapsible Soils and Evaporite Karst Haz- ard Map of the Roaring Fork Valley, Garfield, Pitkin and Eagle Counties", by Jon- athan L. White (dated 2002). CGS has mapped sinkhole, subsidence, and soil collapse features within Coryell Ranch near the subject property. Surface subsidence in the geologic environment in the area of the site is usually due to solution cavities that form in the underlying Eagle Valley Evaporite bedrock. The Evaporite minerals in the bedrock formation are dissolved and re- moved by circulating ground water. Most of the flow in the area of this site is subflow tributary to the Roaring Fork River and Crystal River. The ground water circulates through the permeable alluvial terrace gravel, forming solution cavities in the Eagle Valley Evaporite. Overburden soils collapse into the solution cavities. When caving propagates to the ground surface, ground subsidence and/or sink- holes occur. Formation of sinkholes is random and can occur anywhere and at any time in the geologic environment at this site and cannot be predicted. The degree of risk related to sinkholes cannot reasonably be quantified. We did not observe ob- vious visual evidence of sinkhole/subsidence formations on or immediately adja- cent to the subject property. We are not aware of buildings in Coryell Ranch in the immediate vicinity of the subject site that have experienced recent subsidence - related damage. We rate the potential risk of sinkhole development at the site as low to moderate. We judge that the risk of subsidence and/or sinkholes is similar to and no greater than the risk at other Tots in Coryell Ranch. SUBSURFACE CONDITIONS Subsurface conditions at the site were investigated by directing the exca- vation of three exploratory pits (TP -1 through TP -3) at the approximate locations HARRY TEAGUE ARCHITECTS 4 AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 shown on Figures 2 and 3. Subsurface conditions observed in the pits were logged by our representative who obtained samples of the soils. Subsoils found in our exploratory pits were about 6 inches of topsoil and 2.5 to 4.5 feet of sandy clay underlain by slightly silty gravel with cobbles and boulders to the total exca- vated depth of 10 feet. Groundwater was not found in our pits at the time of ex- cavation. Pits were backfilled immediately after completion of our field investiga- tion. Graphic logs of the soils observed in the exploratory pits are shown on Fig- ure 4. A photograph of soils exposed in TP -2 below. Soils excavated from TP -2 Samples of the soils obtained from our exploratory pits were returned to our laboratory for pertinent laboratory testing. Three samples of the silty gravel soil selected for gradation analysis contained 57 to 65 percent gravel, 31 to 36 percent sand, and 4 to 11 percent silt and clay (passing the No. 299 sieve). A Targe fraction of the soils at this site are comprised of cobbles and boulders. Gra- dation test results are not inclusive of gravel and cobbles larger than 5 inches. Gradation test results are shown on Figures 5 and 6. Laboratory testing is sum- marized on Table I. HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000.120 5 SITE EARTHWORK We anticipate maximum foundation excavation depths of about 10 feet in basement areas. Excavations in the soils at the site can likely be made with a conventional heavy-duty trackhoe. Sides of excavations need to be sloped to meet local, state, and federal safety regulations. The on-site clay and gravel soils will likely classify as Type B and Type C soils, respectively, based on OSHA criteria. Sides of excavation in Type B soils and Type C soils should be sloped no steeper than 1 to 1 horizontal to vertical and 1.5 to 1, respectively. Contrac- tors are responsible for site safety and providing and maintaining safe and stable excavations. Contractors should identify the soils encountered and ensure that OSHA standards are met. Free groundwater was not encountered in our exploratory pits. We do not expect that excavations for the proposed construction will penetrate the free groundwater table. We suggest excavations be sloped to a gravity discharge or to a temporary sump where water from precipitation and runoff can be removed by pumping. Subexcavation and Structural Fill Our exploratory pits indicate the silty gravel and cobble soil, which has good building support properties, is near the ground surface in the area of the proposed residence. Where clay soils are found at planned footing elevations, the clay should be subexcavated to expose the underlying gravel and cobble soil. We recommend removal of clay soils below the building floor slabs to a depth of at least 2 feet. the subexcavated clay should be replaced with densely -com- pacted, granular structural fill. We recommend that structural fill consist of a CDOT aggregate base course or similar soil. HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 6 Structural fill should be placed in loose lifts of 10 inches thick or Tess and moisture -conditioned to within 2 percent of optimum moisture content. Structural fill should be compacted to 98 percent of standard Proctor (ASTM D 698) maxi- mum dry density. Moisture content and density of structural fill should be checked by a representative of our firm during placement. Observation of the compaction procedure is necessary. Foundation Wall Backfill Proper placement and compaction of foundation backfill is important to re- duce infiltration of surface water and settlement of backfill. This is especially im- portant for backfill areas that will support concrete slabs, such as driveways and patios. The excavated soils free of rocks larger than 4 inches in diameter, organ- ics and debris can be reused as backfill adjacent to foundation wall exteriors. Backfill should be placed in loose lifts of approximately 10 inches thick or less, moisture -conditioned to within 2 percent of optimum moisture content and compacted to at least 95 percent of maximum standard Proctor dry density (ASTM D 698). Our representative should test moisture content and density of the backfill during placement. FOUNDATION Our exploratory pits indicate the silty gravel and cobble soil, which has good foundation support properties, is near the ground surface in the area of the proposed residence. We recommend constructing the residence on a footing foundation supported by the undisturbed, silty gravel and cobble soil. Where clay soils are found at planned footing elevations, the clay should be subexcavated to expose the underlying gravel and cobble soil. Footing elevations can be re -at- tained with densely -compacted, granular structural fill. The structural fill should HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 7 be in accordance with recommendations in the Subexcavation and Structural Fill section. The residence can be constructed on a footing foundation sup- ported by the undisturbed gravel and cobble soil or densely -com- pacted, granular structural fill. 2. Footings on the gravel and cobble soil can be sized using a maxi- mum allowable bearing pressure of 4,000 psf. Continuous wall footings should have a minimum width of at least 16 inches. Foundations for isolated columns should have minimum dimensions of 24 inches by 24 inches. Larger sizes may be re- quired, depending upon foundation loads. 4. Grade beams and foundation walls should be well reinforced, top and bottom, to span undisclosed loose or soft soil pockets. We rec- ommend reinforcement sufficient to span an unsupported distance of at least 12 feet. 5. The soils under exterior footings should be protected from freezing. We recommend the bottom of footings be constructed at a depth of at least 36 inches below finished exterior grades. The Garfield County building department should be consulted regarding required depth. SLABS -ON -GRADE Plans indicated floors in basement and garage areas will be slabs -on - grade. The sandy clay soil at the site possesses relatively poor slab support characteristics as compared to the silty gravel and cobble. We recommend re- moval of clay soils below the building floor slabs to a depth of at least 2 feet and replacement with densely -compacted, granular structural fill. Structural fill below slabs should be placed in accordance with recommendations in the Structural Fill section. We recommend the following precautions for slab -on -grade construction at this site. HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 8 Floor slabs should be separated from exterior walls and interior bearing members with slip joints which allow free vertical move- ment of the slabs. 2. The use of underslab plumbing should be minimized. Underslab plumbing should be pressure tested for Teaks before the slabs are constructed. Plumbing and utilities which pass through slabs should be isolated from the slabs with sleeves and provided with flexible couplings to slab supported appliances. 3. Exterior concrete flatwork should be isolated from the building. These slabs should be well -reinforced to function as independent units. Frequent control joints should be provided, in accordance with American Concrete Institute (ACI) recommendations, to reduce problems associated with shrinkage and curling. STRUCTURALLY -SUPPORTED FLOORS Main level floors in parts of the residence are proposed as structurally - supported with crawl spaces below. The required air space in crawl spaces de- pends on the materials used to construct the floor and the potential expansion of the underlying soils. Building codes normally require a clear space of at least 18 inches between exposed earth and untreated wood floor components. We rec- ommend increasing the clear space to at least 24 inches to allow for heave of the ground under the floor. For non-organic systems, we recommend a minimum clear space of 12 inches. This minimum clear space should be maintained be- tween any point on the underside of the floor system (including beams, plumbing pipes and floor drain traps) and the soils. Utility connections, including water, gas, air duct, and exhaust stack con- nections to appliances on structural floors should be capable of absorbing some deflection of the floor. Plumbing that passes through the floor should ideally be hung from the underside of the structural floor and not laid on the bottom of the excavation. It is prudent to maintain the minimum clear space below all plumbing HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 9 lines. If trenching below the lines is necessary, we recommend sloping these trenches, so they discharge to the foundation drain. Control of humidity in crawl spaces is important for indoor air quality and performance of wood floor systems. We believe the best current practices to control humidity involve the use of a vapor retarder or vapor barrier (10 mil mini- mum) placed on the soils below accessible subfloor areas. The vapor re- tarder/barrier should be sealed at joints and attached to concrete foundation ele- ments. FOUNDATION WALLS Foundation walls which extend below -grade should be designed for lateral earth pressures where backfill is not present to about the same extent on both sides of the wall, such as in crawl spaces. Many factors affect the values of the design lateral earth pressure. These factors include, but are not limited to, the type, compaction, slope, and drainage of the backfill, and the rigidity of the wall against rotation and deflection. For a very rigid wall where negligible or very little deflection will occur, an "at -rest" lateral earth pressure should be used in design. For walls that can de- flect or rotate 0.5 to 1 percent of wall height (depending upon the backfill types), design for a lower "active" lateral earth pressure may be appropriate. Our experi- ence indicates typical below -grade walls in residences deflect or rotate slightly under normal design loads, and that this deflection results in satisfactory wall performance. Thus, the earth pressures on the walls will likely be between the "active" and "at -rest" conditions. HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 10 For backfill consisting of the soils excavated from the site, that are not sat- urated, we recommend design of below -grade walls at this site using an equiva- lent fluid density of at least 40 pcf. This value assumes deflection; some minor cracking of walls may occur. If very little wall deflection is desired, a higher de- sign value for the at -rest condition using an equivalent fluid pressure of 50 pcf is recommended. SUBSURFACE DRAINAGE Water from precipitation and surface irrigation of lawns and landscaping frequently flows through relatively permeable backfill placed adjacent to a resi- dence, and collects on the surface of less permeable soils at the bottom of foun- dation excavations. This process can cause wet or moist conditions in below - grade areas, such as basements and crawl spaces, after construction. To reduce the likelihood water pressure will develop outside foundation walls and the risk of accumulation of water in below -grade areas, we recommend provision of a foun- dation drain adjacent to the perimeter of basement and crawl space areas in the building. The drain should consist of a 4 -inch diameter, slotted pipe encased in free -draining gravel. The drain should lead to a positive gravity outlet or to a sump where water can be removed by pumping. The foundation drain concept is shown on Figures 7 and 8. SURFACE DRAINAGE Surface drainage is critical to the performance of foundations, floor slabs, and concrete flatwork. Surface drainage should be designed to provide rapid runoff of surface water away from the residence. Proper surface drainage and ir- rigation practices can help control the amount of surface water that penetrates to foundation levels and contributes to settlement or heave of soils and bedrock that HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-720 11 support foundations and slabs -on -grade. Positive drainage away from the foun- dation and avoidance of irrigation near the foundation also help to avoid exces- sive wetting of backfill soils, which can lead to increased backfill settlement and possibly to higher lateral earth pressures, due to increased weight and reduced strength of the backfill. We recommend the following precautions. The ground surface surrounding the exterior of the residence should be sloped to drain away from the building in all directions. We recommend a minimum constructed slope of at least 12 inches in the first 10 feet (10 percent) in landscaped areas around the resi- dence, where practical. Roof downspouts and drains should discharge well beyond the lim- its of all backfill. Splash blocks and/or extensions should be pro- vided at all downspouts so water discharges onto the ground be- yond the backfill. Landscaping should be carefully designed and maintained to mini- mize irrigation. Plants placed close to foundation walls should be limited to those with low moisture requirements. Sprinklers should not discharge within 5 feet of foundations. Plastic sheeting should not be placed beneath landscaped areas adjacent to foundation walls or grade beams. Geotextile fabric will inhibit weed growth yet still allow natural evaporation to occur. CONCRETE Concrete in contact with soil can be subject to sulfate attack. We meas- ured a soluble sulfate concentration of 0.01 percent in a sample of the soil from this site. For this level of sulfate concentration, ACI 332-08 Code Requirements for Residential Concrete indicates there are no special requirements for sulfate resistance. In our experience, superficial damage may occur to the exposed surfaces of highly permeable concrete. To control this risk and to resist freeze thaw deteri- oration, the water-to-cementitious materials ratio should not exceed 0.50 for con- crete in contact with soils that are likely to stay moist due to surface drainage or HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 12 high-water tables. Concrete should have a total air content of 6% +/-1.5%. We recommend all foundation walls and grade beams in contact with the subsoils (in- cluding the inside and outside faces of garage and crawl spaces) be damp - proofed. CONSTRUCTION OBSERVATIONS We recommend that CTL 1 Thompson, Inc. be retained to provide con- struction observation and materials testing services for the project. This would allow us the opportunity to verify whether soil conditions are consistent with those found during this investigation. If others perform these observations, they must accept responsibility to judge whether the recommendations in this report remain appropriate. It is also beneficial to projects, from economic and practical stand- points, when there is continuity between engineering consultation and the con- struction observation and materials testing phases. STRUCTURAL ENGINEERING SERVICES CTL 1 Thompson, Inc. is a full-service geotechnical, structural, materials, and environmental engineering firm. Our services include preparation of struc- tural framing and foundation plans. We can also design earth retention systems. Based on our experience, CTL 1 Thompson, Inc. typically provides value to pro- jects from schedule and economic standpoints, due to our combined expertise and experience with geotechnical, structural, and materials engineering. We would like the opportunity to provide proposals for structural engineering services on your future projects. GEOTECHNICAL RISK The concept of risk is an important aspect of any geotechnical evaluation. The primary reason for this is that the analytical methods used to develop ge- otechnical recommendations do not comprise an exact science. The analytical HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 13 tools which geotechnical engineers use are generally empirical and must be tem- pered by engineering judgment and experience. Therefore, the solutions or rec- ommendations presented in any geotechnical evaluation should not be consid- ered risk-free and, more importantly, are not a guarantee that the interaction be- tween the soils and that the proposed structure will perform as desired or in- tended. What the engineering recommendations presented in the preceding sec- tions do constitute is our estimate, based on the information generated during this and previous evaluations and our experience in working with these condi- tions, of those measures that are necessary to help the building perform satisfac- torily. This report has been prepared for the exclusive use of the client for the purpose of providing geotechnical design and construction criteria for the pro- posed project. The information, conclusions, and recommendations presented herein are based upon consideration of many factors including, but not limited to, the type of structures proposed, the geologic setting, and the subsurface condi- tions encountered. The conclusions and recommendations contained in the re- port are not valid for use by others. Standards of practice continuously change in the area of geotechnical engineering. The recommendations provided in this re- port are appropriate for three years. If the proposed project is not constructed within three years, we should be contacted to determine if we should update this report. LIMITATIONS Our exploratory pits were located to provide a reasonably accurate picture of subsurface conditions. Variations in the subsurface conditions not indicated by the pits will occur. This investigation was conducted in a manner consistent with that level of care and skill ordinarily exercised by geotechnical engineers currently practicing HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 14 under similar conditions in the locality of this project. No warranty, express or im- plied, is made. If we can be of further service in discussing the contents of this report, please call. CTL 1 THOMPSON, INC. Reviewed By: Ryan R. Barbone, E.I.T. Staff Engineer RRB:JDK:ac HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 ,? 1 ••!I u -Y� P ames D. Kellogg;' . 19 c ivision Manager `.�voaP,A �a. 15 I 0 1000 2000 NOTE: IMAGE FROM GOOGLE EARTH SCALE: 1' . 2000' Harry Teague Architects August Teague Residence Project No. GS06445.000-120 Vicinity Map FIO. 1 LEGEND: TP -1 APPROXIMATE LOCATION OF II EXPLORATORY PIT APPROXIMATE PROPERTY BOUNDARY 0 50 100 NOTE: IMAGE FROM GOOGLE EARTH SCALE: 1' = 100' Harry Teague Architects August Teague Residence Project No. GS06445.000-125 Aerial Photograph FIg. 2 50 100 SCALE 1 a loo' LEGEND: TP -1 APPROXIMATE LOCATION OF • EXPLORATORY PIT NOTE: BASE DRAWING FROM HARRY TEAGUE ARCHITECTS Harry Teague Architects August Teague Residence Project No. GS06445.000-120 Proposed Building Footprint Fl®. 3 TP -1 TP -2 TP -3 EL. 6082 EL. 6086 EL. 6086 —6,090 6,090 6,085 Tr - w 6,080 Z- °al o ▪ - .4 er —6,075 ?•0 6,085 6,080 6,075 6,070 6,070 HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE CTLIT PROJECT NO. GS06445.000-120 i LEGEND: 1 —7 w w LL SANDY CLAY "TOPSOIL", MOIST, DARK BROWN CLAY, SANDY, GRAVEL, MEDIUM STIFF, MOIST, DARK BROWN. (CL) GRAVEL, SLIGHTLY SILTY, COBBLES AND BOULDERS, MEDIUM DENSE, MOIST, BROWN, GRAY. (GP, GP -GM) INDICATES BULK SAMPLE FROM EXCAVATED SOILS. Z w NOTES: 1. EXPLORATORY PITS WERE EXCAVATED WITH A TRACKHOE ON FEBRUARY 5, 2020. PITS WERE BACKFILLED IMMEDIATELY AFTER EXPLORATORY EXCAVATION OPERATIONS WERE COMPLETED. 2. FREE GOUNDWATER WAS NOT FOUND IN OUR EXPLORATORY PITS AT THE TIME OF EXCAVATION. 3. LOCATIONS OF EXPLORATORY PITS ARE APPROXIMATE. ELEVATIONS WERE ESTIMATED FROM GROUND SURFACE ELEVATION CONTOURS ON FIGURE 3. 4. THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS AS CONTAINED IN THIS REPORT. Summary Logs of Exploratory Pits FIG. 4 Sample of GRAVEL, SLIGHTLY SILTY (GP -GM) From TP -1 AT 6 - 7 FEET GRAVEL 57 % SAND SILT & CLAY 1.1 % LIQUID LIMIT PLASTICITY INDEX 32 % 1 HYDROMETER ANALYSIS 1 SIEVE ANALYSIS 25 HR. 7 HR. TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 '100 50 '40 '30 '16 '10 '8 '4 3/6" 3/4" 1W 3" 5"8" ft" inn N nPERCrT PASSING 0 0 0 0 0 0 0 o i ZERCCNT P&SSINQC 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 PERCENT RETAINED 10 20 1. T 30 Et z '"—' 40 1-- 50 50 w V ix 60 0. 70 80 r 90 x.001 0 002 .005 .009 .019 .037 .074 ' .149 .2970.42590 j'1 19 2.0 2.38 4 76 9 52 19.1 36.1 76.2 127 DIAMETER OF PARTICLE IN MILLIMETERS CLAY TO SILT (NON SANDS GRAVEL (PLASTIC) -PLASTIC) FINE I MEDIUM 1 COARS FINE I COARSE rCOBBLES T-,- Sample of GRAVEL, SLIGHTLY SILTY (GP -GM) From TP -1 AT 6 - 7 FEET GRAVEL 57 % SAND SILT & CLAY 1.1 % LIQUID LIMIT PLASTICITY INDEX 32 % Sample of GRAVEL, CLEAN (GP) From TP -2 AT 7 - 8 FEET HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 GRAVEL 60 % SAND SILT & CLAY 4 % LIQUID LIMIT PLASTICITY INDEX Gradation Test Results 36 % FIG. 5 1 HYDROMETER ANALYSIS 1 SIEVE ANALYSIS I 25 HR. 7 HR TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 '100 '50 '40 '30 '16 '10 '8 '4 3/8" 3/4" 1W 3" 5"6" 8' inn 0 ZERCCNT P&SSINQC 0 0 0 0 00 0 0 0 0 0 10 20 1. T 30 Et z '"—' 40 1-- 50 50 w V ix 60 0. 70 80 90 T-,- 0 002 005.009 . . .019 .037 .074 s .149 DIAMETER .2970.42 OF PARTICLE .590 . w 1 IN MILLIMETERS 19 2 0 2.36 4 76 9 52 19.1 36.1 76.2 12152200 100 CLAY TO SILT SANDS GRAVEL (PLASTIC) (NON -PLASTIC) FINE I MEDIUM I COARS FINE I COARSE I COBBLES Sample of GRAVEL, CLEAN (GP) From TP -2 AT 7 - 8 FEET HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 GRAVEL 60 % SAND SILT & CLAY 4 % LIQUID LIMIT PLASTICITY INDEX Gradation Test Results 36 % FIG. 5 Sample of GRAVEL, CLEAN (GP) From TP -3 AT 9 - 10 FEET GRAVEL 65 % SAND SILT & CLAY 4 % LIQUID LIMIT PLASTICITY INDEX 31 % 1 HYDROMETER ANALYSfS 1 SIEVE ANALYSIS 1 25 HR. 7 HR. TIME READINGS U.S STANDARD SERIES CLEAR SQUARE OPENINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 900 50 '40 '30 96 90 '8 •4 3/8" 3/4" 1W 3" 5"6" 8' inn n 25 HR. 7 HR. TIME READINGS U S. STANDARD SERIES CLEAR SQUARE OPENINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 '100 50 40 '30 '16 '10 '8 '4 3/8" 3/4" 1W 3" 5"6" 8" inn PERCENT PASSING I 0 0 0 Co 0 0 0 0 0 1 D 0 0 0 0 0 0 0 0 0 PERCENT RETAINED 0 o 0 0 0 PERCENT RETAINED ... . ,,,. . . ...a .... . -.001 0 002 .005 .009 .019 .037 .074 ' .149 297 .590 1 19 2 0 2.38 4 76 9 52 19.1 36.1 76.2 127 0.42 DIAMETER OF PARTICLE IN MILLIMETERS CLAY (PLASTIC) TO SILT (NON GRAVEL -PLASTIC) iSANDS FINE I MEDIUM I COARS FINE I COARSE I COBBLES `yy -.001 0 002 .005 .009 .019 .037 .074 .149 .297 •.590 1 19 2 0 2.38 4 76 9 52 19.1 36.1 76.2' 12152200 0.42 DIAMETER OF PARTICLE IN MILLIMETERS CLAY (PLASTIC) TO SILT (NON -PLASTIC) SANDS GRAVEL FINE I MEDIUM 1 COARS FINE 1 COARSE f COBBLES Sample of GRAVEL, CLEAN (GP) From TP -3 AT 9 - 10 FEET GRAVEL 65 % SAND SILT & CLAY 4 % LIQUID LIMIT PLASTICITY INDEX 31 % Sample of From HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 GRAVEL SILT & CLAY PLASTICITY INDEX % SAND % LIQUID LIMIT Gradation Test Results FIG. 6 % OA 1 HYDROMETER ANALYSIS 1 SIEVE ANALYSIS 25 HR. 7 HR. TIME READINGS U.S STANDARD SERIES CLEAR SQUARE OPENINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 900 50 '40 '30 96 90 '8 •4 3/8" 3/4" 1W 3" 5"6" 8' inn n XERCCNT PPSSINCQ 0 0 0 0 0 0 0 0 0 D 0 0 0 0 0 0 0 0 0 PERCENT RETAINED ... . ,,,. . . ...a .... . -.001 0 002 .005 .009 .019 .037 .074 ' .149 297 .590 1 19 2 0 2.38 4 76 9 52 19.1 36.1 76.2 127 0.42 DIAMETER OF PARTICLE IN MILLIMETERS CLAY (PLASTIC) TO SILT (NON GRAVEL -PLASTIC) iSANDS FINE I MEDIUM I COARS FINE I COARSE I COBBLES Sample of From HARRY TEAGUE ARCHITECTS AUGUST TEAGUE RESIDENCE PROJECT NO. GS06445.000-120 GRAVEL SILT & CLAY PLASTICITY INDEX % SAND % LIQUID LIMIT Gradation Test Results FIG. 6 % OA SLOPE PER OSHA COVER ENTIRE WIDTH OF GRAVEL WITH NON -WOVEN GEOTExTILE FABRIC MIRAFl 140N OR EQUIVALENT). SLOPE PER REPORT E3ACKFILL PREFABRICATED DRAINAGE COMPOSITE (MIRADRAIN 6000 OR EQUIVALENT) BELOW -GRADE WALL ATTACH PLASTIC SHEETING TO FOUNDATION WALL SUP JOINT ....:;5LA8-ON-GRW7E .............. Tu owurr I 2" MINIMUM 8" MINIMUM t OR BEYOND 1:1 SLOPE FROM BOTTOM OF FOOTING (WHICHEVER IS GREATER) 4—INCH DIAMETER PERFORATED RIGID DRAIN PIPE. THE PIPE SHOULD BE PLACED IN A TRENCH WITH A SLOPE OF AT LEAST 1/8 -INCH DROP PER FOOT OF DRAIN. ENCASE PIPE IN 1/2" TO 1-1/2" WASHED GRAVEL. EXTEND GRAVEL LATERALLY TO FOOTING AND AT LEAST 1/2 HEIGHT OF FOOTING. FILL ENTIRE TRENCH WITH GRAVEL. �— FOOTING OR PAD NOTE THE BOTTOM OF THE DRAIN SHOULD BE AT LEAST 2 INCHES BELOW BOTTOM OF FOOTING AT THE HIGHEST POINT AND SLOPE DOWNWARD TO A POSITIVE GRAVITY OUTLET OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING. Harry Teague Architects August Teague RU kionce Foundation Wall Drain C`nnt•anf NOTE: DRAIN SHOULD BE AT LEAST 2 INCHES BELOW BOTTOM OF FOOTING AT THE HIGHEST POINT AND SLOPE DOWNWARD TO A POSITIVE GRAVITY OUTLET OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING. STRUCTURAL FLOOR SLOPE PER REPORT MIRADRAIN G200N OR EQUIVALENT ATTACH PLASTIC SHEETING SLOPE TO FOUNDATION WALL PER OSHA COVER ENTIRE WIDTH OF GRAVEL WITH NON -WOVEN GEOTEX11LE FABRIC (MIRAFI 140N OR EQUIVALENT). 2" MINIMUM 8" MINIMUM - OR BEYOND 1:1 SLOPE FROM BOTTOM OF FOOTING (WHICHEVER IS GREATER) 4 --INCH DIAMETER PERFORATED DRAIN PIPE. THE PIPE SHOULD BE PLACED IN A TRENCH WITH A SLOPE OF AT LEAST 1/8 -INCH DROP PER FOOT OF DRAIN. Harry Teague Architects Auguot Teague Residence PrnlAf"f Me i_'CAC.A A= AAA 4 nn r- CRAWL SPACE --� FOOTING OR PAD "MUD SLAB" OR VAPOR. BARRIER Foundation Wall Drain Concept TABLE 1 SUMMARY OF LABORATORY TESTING PROJECT NO. GS06445.000-120 EXPLORATORY DEPTH BORING (FEET) TP -1 MOISTURE CONTENT (%) DRY DENSITY (PCF) ATTERBERG LIMITS LIQUID LIMIT (%) PLASTICITY INDEX (%) SOLUBLE SULFATES (%) PERCENT GRAVEL (%) PERCENT SAND (%) PASSING NO. 200 SIEVE (%) DESCRIPTION 3-4 30 TP -1 TP -2 TP -3 6-7 7-8 14 0.010 57 32 60 36 71 11 4 CLAY, SANDY (CL) GRAVEL, SLIGHTLY SILTY (GP -GM) GRAVEL, CLEAN (GP) 9-10 65 31 4 GRAVEL, CLEAN (GP) Page 1 of 1