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HomeMy WebLinkAboutSubsoil Studyffi CTL I THOMPSON æ CTLITHOMP$ON YgARS F0{"tf-{$H'Ð $N TgVf GEOTECHNIGAL ENGINEERING INVESTIGATION 565 FARANHYLL RANCH ROAD (A.K.A. PARCEL #4, FARANHYLL RANCH) GARFIELD COUNTY, GOLORADO Prepared For: GREEN LINE ARCHITECTS 65 N.4th Street, Suite 5 Carbondale, CO 81623 Project No. GS06 572.000-120 234 Center Drive I Glenwood Springs, Colorado 81601 Telephone: 970-S45-2809 Fax: 970-945-7411 J trrrnJtrTTTNrlrrrlItrXXII July 1 ,2021 ffi TABLE OF CONTENTS scoPE......... SUMMARY OF CONCLUSIONS SITE CONDITIONS PROPOSED CONSTRUCTION ......,.. GEOLOGY AND GEOLOGIC HAZARDS............. SUBSURFACE CONDITIONS.......... SITÊ EARTHWORK..... Excavations Subexcavation and Structural Fill...-.....,..... Foundation Wall Backfi11.,................ FOUNDATrONS.............. SLAB-ON.GRADE CONSTRUCTION ........... CRAWL SPACE CONSTRUCTION..,....,,...... FOUNDATION WALLS SUBSURFACE DRAINAGE,.,.. SURFACE DRAINAGE CONCRETE CONSTRUCTION OBSERVATIONS ...... STRUCTURAL ENGIN EERING SERVICES . GEOTECHNICAL RISK LtMITATtONS ....,........... FIGURE 1-VICINITYMAP FIGURE 2 _AERIAL PHOTOGRAPH FIGURE 3 - PROPOSED CONSTRUCTION FIGURE 4 - SUMMARY LOGS OF EXPLORATORY BORINGS AND PITS FIGURE 5 - SWELL-CONSOLIDATION TEST RESULTS' FIGURE 6 - GRADATION TEST RESULTS FIGURE 7 AND 8 _ FOUNDATION WALL DRAIN CONCEPTS TABLE I _ SUMMARY OF LABORATORY TESTING GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJECT NO. GS06572.000-.1 20 1 1 2 3 3 4 6 6 6 7 I I 10 10 11 12 13 13 14 14 ...., 15 ffi SCOPE CTL I Thompson, lnc. has completed a geotechnical engineering investiga- tion for the property at 565 Faranhyll Ranch Road (a.k.a. Parcel #4, Faranhyll Ranch) in Garfield County, Colorado. We conducted this investígatÍon to evatuate subsurface conditions at the site and provide geotechnical engineering recom- mendations for the proposed construction. The scope of our investigation was set forth in our Proposal No. GS 21-0186. Our report was prepared from data devel- oped from our field exploration, laboratory testing, engineering analysis, and our experience with similar conditions. The report includes a description of subsurface conditions encountered in our exploratory boring and pits and provides geotech- nical engineering recommendations for design and construction of the building foundations, floor systems, below-grade walls, subsurface drainage systems, and details influenced by the subsoils. A summary of our conclusíons is below. SUII/IMARY OF CONGLUSIONS subsurface conditions encountered in our exploratory boring and pits consísted of about I inches of topsoil and 4.5 to 5.5 feet of sandy clay, underlain by clayey gravel, cobbles, and boulders. Groundwater was not found in our exploratory boring and pits at the time of our subsurface investigation. Based on geologic mapping and our engineering experience, the sandy clay and clayey gravel have potential for moderate to high amounts of consolidation when wetted under building loads. We judge the residence and ADUlgarage can be constructed on footing foundations, provided the soils below footings are sub-excavated to a depth of at least 3 feet and replaced as densely-compacted, struc- tural fill. To enhance potential performance of floor slabs in buildings at the site, we recommend subexcavation of the soils below slabs to a depth of at least 3 feet and replacement with densely-compacted, structuralfill. 4.A foundation wall drain should be constructed around the perimeter of below-grade areas of the buildings to mitigate surface water that infiltrates backfill soils adjacent to the foundations. Site grading GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJECT NO. GS06572.000-120 1 2. 3 1 ffi should be designed and constructed to rapidly convey surface water away from the buildings. SITE COND¡TIONS The site is located at 565 Faranhyll Ranch Road (a.k.a. Parcel #4, Faranhyll Ranch) in Garfield County, Colorado. A vicinity map with the site locatíon is includ- ed as Figure 1. The property is at the base of the east flank of the Grand Hogback. The lot is an approximately 35-acre parcel that is predominantly west of Faranhyll Ranch Road. The new buildings are proposed in the west part of the property, south of an existing residence. An aerial photograph of the west part of the parcel, including the existing residence is shown on Figure 2. Ground surface in the areas of the proposed buildings generally slopes down to the northeast at grades visually estimated at about 10 percent. The subject area of the site is an irrigated hayfield. A photograph of the proposed building site at the time of our subsurface investiga- tion is below. GREEN LINE ARCHNECTS 565 FARANHYLL RANCH ROAD PROJECT NO. GS06572,000-120 2 Looking east across proposed building site ffi PROPOSED CONSTRUCTION Architectural plans for a proposed single-family residence and an ADU/garage building were being developed at the time of our geotechnical engi- neering investigation. The residence is anticipated as a one and two-story building We understand that garage and storage space in the uphill (west) side of the resi- dence will have a slab-on-grade main level floor with no below-grade areas. The downhill (east) side of the residence will have a structurally-supported floor with a crawl space below. Preliminary plans indicate the main level of the ADU/garage building will be a slab-on-grade. The uphill (west) side of the building will retain earth. We expect maximum foundation excavation depths of about I to 10 feet. Foundations loads are likely to be on the order of 1,000 to 3,000 pounds per linear foot of foundation wall with maximum interior column loads of tess than 75 kips. We should be provided with architectural plans, as they are further developed, so we can províde geotechnical/geo-structural engineering input. GEOLOGY AND GEOLOGIC HAZARDS we reviewed the geologic map by the colorado Geology survey (cGS), ti- tled, "Geologic Map of the Cattle Creek Quadrangle, Garfield County, Colorado", by Kirkham, Streufert, Hemborg, and Stelling (dated 2014). The area of the subject property is mapped as intermediate debris flow deposits of the Holocene and Pleistocene Epochs. The sandy clay and clayey gravel soils found in our explora- tory boring and pits are consistent with the description of the debris flow deposits. Due to the depositional method, the debrís flow deposits have not been subject to significant geologic loads. These soils are prone to consolidation when wetted un- der building loads. We judge the debris flow deposits have potential for moderate to high amounts of consolidation when wetted under building loads. We also reviewed the CGS map "Collapsible Soils and Evaporite Karst Hazard Map of the Roaring Fork Valley, Garfield, Pitkin and Eagle Counties", by GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJECT NO. GS06572.000-120 3 ffi Jonathan L. White (dated 2002). The surficial soils at the site are mapped as un- consolidated, which possess potentialfor hydrocompaction when wetted, especial- ly under building loads. CGS has mapped the approximate location of a historical occurrence soil settlement on Four Mile Road about 1 mile southeast of the sub- ject site. Formation of sinkholes is random and can CIccur anywhere and at any time in the geologic environment at this site and cannot be predícted. The degree of risk related to sinkholes cannot reasonably be quantified. We did not observe obvious visual evidence of sinkhole/subsidence formations on or immediately ad- jacent to the subject property. We are not aware of buildings in the immediate vi- cinity of the property that have experienced recent subsidence-related damage, We rate the potential risk of sinkhole development at the site as low. SUBSURFACE CONDITIONS Subsurface conditions were investigated by directing drilling of one explora- tory boring (TH-1) and observing the excavation of two exploratory pits (TP-1 and TP-2) at the site. The approximate location of the boring and pits are shown on Figures 2 and 3. Our boring was drilled on May 6,2A21 with soild-stem auger and a track-mounted drill rig. The pits were excavated on May 21,2021with a track- hoe. Exploratory drilling and excavation operations were directed by our engineer, who logged the soils encountered in the boring and pits and obtaíned representa- tive samples. Graphic logs of the soils encountered in our exploratory boring and exploratory pits are shown on Figure 4. Subsurface conditions encountered in our exploratory boring and pits con, sisted of about I inches of topsoil and 4.5 to 5.5 feet of sandy clay, underlain by clayey gravet, cobbles, and boulders. Groundwater was not found in our explorato- ry boring and pits at the time of our subsurface investigation. PVC pipe was in- stalled in our boring and pits, prior to backfilling, to facilitate subsequent checks of groundwater. A photograph of conditions exposed in TP-1 is below. GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJÊCT NO. GS06572.000-120 4 ffi Conditions exposed in TP-1 Samples of the soíls obtained from our exploratory boring and pits were re- turned to our laboratory for pertinent testing. One sample of sandy clay selected for one-dimensional, swell-consolidation testing exhibited 0.3 percent swellwhen wetted under a load of 1,000 psf. Swell-consolidation test results are shown on Figure 5. One sample of the clayey gravel selected for gradation analysis con- tained 29 percent gravel, 32 percent sand, and 39 percent silt and clay (passing the No. 200 sieve). Gradation test results are not inclusive of rocks larger than 5 inches, whích are present in the in-situ clayey gravel. Gradation test results are shown on Figure 6. One sample of the sandy clay tested had a water-soluble sul- fate content of 0.00 percent. Laboratory testing is summarized on Table L GREEN LINË ARCHITECTS 565 FARANHYLL RANCH ROAD PROJECT NO. c506572.000-120 5 ffi SITE EARTHWORK Excavations Based on our subsurface investigation, we expect excavations for the pro- posed construction at this síte can be accomplished using conventional, heavy- duty excavating equipment. Excavations deeper than 5 feet must be braced or sloped to meet local, state, and federal safety regutations. The sandy clay soílwill likely classify as Type B soil and the clayey gravel likely classifies as a Type C soil pursuant to OSHA standards governing excavations. Temporary excavations should be no steeper than 1 to 1 (horizontal to vertical) in Type B soils and 1,5 to 1 in Type C soils. Contractors are responsible for site safety and providing and maintaining safe and stable excavations. Contractors should identify the soils en- countered in excavations and ensure that osHA standards are met. Free groundwater was not encountered in our exploratory boring and pits at the time of our subsurface investígation. We do not anticipate excavations to con- struct the proposed buildings will penetrate a free groundwater table. To mitigate water from precipitation, excavations should be sloped to gravity discharges or be directed to temporary surnps where water can be removed by pumping. Subexcavation d Structural Fill Based on our field and laboratory data from the site, and our engineering experience, the sandy clay and clayey gravel (i.e., debris flow deposits) at the site have potential for moderate to high amounts of consolidation when wetted under building loads. We judge the residence can be constructed on a footing foundation with slab-on-grade floors, provided the soils below footings and floor slabs are sub-excavated to a depth of at least 3 feet and replaced as densely-compacted, structuralfill. The subexcavation process should extend at least 1 foot beyond the perimeter of the building footprint. CTL should be called to observe conditions in GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJECT NO. GS06572.000-120 6 ffi the foundation excavations, príor to placement of structural fill. The subexcavated soils should be replaced with densely-compaeted, granular, structuralfill. The soils excavated from the site can be reused as struc- tural fill, provided they are free of rocks larger than 3 inches in diameter, organic matter, and debris. lmported structural fill should consist of an aggregate base course or pit run with a maximum rock size of 3 inches. A sample of desired import soil should be submitted to our office for approval. The subexcavated soils, free of organic matter, debris and rocks larger than 3 inches in diameter can be re-used as structuralfill. The structuralfill soils should be placed in loose lifts of B inches thick or less and moisture-conditioned to within 2 percent of optimum moisture content. Structural fill should be compacted to at least 98 percent of standard Proctor (ASTM D 698) maximum dry density, Mois- ture content and density should be checked by a representatíve 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 backfíll. 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, organics 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. Thickness of lifts will need to be about 6 inches if there are small, con- fined areas of backfill, which limit the size and weight of compaction equipment. We recommend backfíll soils be compacted to 95 percent of standard Proctor (ASTM D 698) maximum dry density. Moisture content and density of the backfill GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJECT NO. GSo6572.000-120 7 ffi should be checked during placement by a representative of our firm. Observation of the compactíon procedure is necessary. FOUNDATIONS Based on geologic mapping and our engineering experience, the sandy clay and clayey gravel have potential for moderate to high amounts of consolida- tion when wetted under building loads. We judge the residence and ADU/garage can be constructed on footing foundations, provided the soils below footings are sub-excavated to a depth of at least 3 feet and replaced as densely-compacted, structuralfill. The structural fill should be in accordance with recommendations in the Subexcavation and Structural Fill section. Recommended design and construction criteria for footings are below. These criteria were developed based on our analysis of field and laboratory data, as well as our engineering experience. The residence and ADU/garage can be constructed on footing foun- dations that are supported by an at least 3-feet thickness of densely- compacted, structural fill. The structuralfill should be in accordance with recommendations in the subexcavation and structural Fill sec- tion. Footings supported by the densely-compacted, structural fill can be designed for a maximum net allowable soil bearing pressure of 3,000 psf. The weight of backfill soils above the footings can be neglected for bearing pressure calculation. A friction factor of 0.40 can be used to calculate resistance to slidÍng between concrete footings and the structuralfill. Continuous wall footings should have a minimum wídth of at least 1G inches. Foundations for isolated columns should have minimum di- mensions of 24 inches by 24 inches. Larger sizes may be required, depending upon foundation loads. GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJÊCT NO. cS06572.000-120 1 2 3 4 I ffi Grade beams and foundation walls should be well reinforced to span undisclosed loose or soft soil pockets. we recommend reinforcement sufficient to span an unsupported distance of at least 12 feet. 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 for frost protection The Garfield County building department should be consulted re- garding required frost protection depth. SLAB-ON.G RADE CONSTRUCTION Slab-on-grade floors are planned in parts of the residence and ADU/garage, To enhance potential performance of floor slabs, we recommend subexcavation of the soils befow slabs to a depth of at least 3 feet and replacement with densely- compacted, structuralfill. The structural fill should be in accordance with recom- mendations in the Subexcavation and Structural Fill section. Based on our analysis of field and laboratory data, as well as our engineer- ing experience, we recommend the following precautions for slab-on-grade con- struction at this site. Slabs should be separated from footings and columns pads with slip joints which allow free vertical movement of the slabs. ïhe use of underslab plumbing should be minimized. Underslab plumbíng should be pressure tested for leaks 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. Exterior patio slabs should be isolated from the building. These slabs should be well-reinforced to function as independent units. Frequent controf joints should be provided, in accordance with Amer- ican Concrete lnstitute (ACl) recommendations, to reduce problems associated with shrinkage and curling. 5 6 1 2 3. 4. GREEN LINE ARCHITECTS 565 FARANHYLL RÁ,NCH ROAD PROJECT NO. GS06572.000-120 9 ffi CRAWL SPACE CONSTRUCTION The main level floor in the downhill (east) part of the residence is proposed as structurally-supported by the foundatíon walls with a crawl space below the floor. Buílding codes normally require a clear space of at least '18 inches between ex- posed earth and untreated wood floor components. For non-organic systems, we recommend a minimum clear space of 12 inches, This minimum clear space should be maintained between 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 connec- tions to appliances on structural floors should be capable of absorbing some deflec- tion of the floor. Plumbing that passes through the floor should Ídeally be hung from the underside of the structural floor and not laid on the bottom of the excavation. lt is prudent to maíntain the minimum clear space below all plumbing fines. lf trench- ing below the lines is necessaly, wê 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 con- trol humidity involve the use of a vapor retarder or vapor barrier (10 mil minimum) placed on the soils below accessible subfloor areas. The vapor retarderlbarrier should be sealed at joints and attached to concrete foundation elements. 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 basements and crawl spaces. Many factors affect the values of the design lateral earth pressure on below-grade walls. These factors GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJECT NO. GS06572.000,120 10 ffi 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 negligíble or very little deflection will occur, an "at-rest" lateral eadh pressure should be used in design. For walls that can deflect or rotate 0.5 to 1 percent of wall height (depending upon the backfill types), lower lateral earth pressures approaching the "active" condition may be appropriate. Our experience indicates typical below-grade walls in residences deflect or rotate slightly unde¡'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. For backfill soils conforming with recommendations in the Foundation Wall Backfill section that are not saturated, we recommend design of below-grade walls at this site using an equivalent fluid density of at least 45 pcf. This value assumes some deflection; some minor cracking of walls may occur. lf very little wall deflec- tion is desired, a higher design value closer to the "at-rest" condition may be ap- propriate. For the on-site soils, an at-rest lateral earth pressure of 60 pcf is rec- ommended. These equivalent densities do not include allowances for sloping backfill, surcharges or hydrostatic pressures. SUBSURFACE DRAINAGE Water from precipitation, snowmelt, and irrigation frequently flows through relatively permeable backfill placed adjacent to a residence and collects on the surface of less permeable soils at the bottom of foundation excavations. This can cause wetting of foundation soils, hydrostatíc pressures on below-grade walls and wet or moist conditíons in below-grade areas, such as basements and crawl spac- es after construction. To mitigate problems with subsurface water, we recommend construction of a foundation wall drain around the perimeter of below-grade areas of the proposed buildings. This includes the ADU/garage wall that will retain earth. GREEN LINE ARCHITECTS 5G5 FARANHYLL RANCH ROAD PROJECT NO. GS06572.000-1 20 11 ffi The foundation wall drains should consist of 4-inch diameter, slotted PVC pipe encased in free-draining gravel. A prefabricated drainage composite should be placed adjacent to foundation walls. Care should be taken during backfill opera- tions to prevent damage to drainage composites. The drains should discharge via positive gravíty outlets or lead to sumps where water can be removed by pumping. Gravity outlets should not be susceptible to clogging or freezing. lnstallation of clean-outs along the draínpipes is recommended. The foundation wall drain con- cepts are shown on Figures 7 and L SURFACE DRAINAGE Surface drainage is critical to the performance of foundations, floor slabs and concrete flatwork. Site grading should be designed and constructed to rapidly convey surface water away from the buildings. Proper surface drainage and irriga- tion 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 support foundations and slabs-on-grade. PositÍve drainage away from the founda- tions and avoidance of irrigation near the foundations will also help to avoid ex- cessive 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 soils. we recommend the following precautions. The ground surface surrounding the exterior of the buildngs should be sloped to drain away from the buildings in all directions. We rec- ommend a minimum constructed slope of at least 12 inches in the first 10 feet (10 percent) in landscaped areas around the buildings. 2. Backfill around the foundation walls should be moistened and com- pacted p section. ursuant to recommendations in the Foundation Wall Backfill 3.We recommend the buildings be provided with roof gutters and downspouts. Roof downspouts should discharge well beyond the lim- its of all backfill. splash blocks and/or extensions should be provided GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJECT NO. GS06572.000-120 1 12 ffi at all downspouts so water discharges onto the ground beyond the backfill. we generally recommend against burial of downspout dis- charge. Where it is necessary to bury downspout discharge, solid, rigid pipe should be used, and the pipe should slope to an open gravity outlet. Landscaping should be carefully designed and maintained to mini- mize irrigation. Plants placed close to foundation walls should be lim- ited to those with low moisture requirements. lrrigated grass should not be located within 5 feet of the foundation. sprinklers should not discharge within 5 feet of foundatíons. Plastic sheeting should not be placed beneath landscaped areas adjacent to foundation walls or grade beams. Geotextile fabric will inhíbit weed growth yet still allow natural evaporation to occur. CONCRETE Concrete in contact with soil can be subject to sulfate attack. We,measured a soluble sulfate concentration of 0.00 percent in a sample of soil from the site (see Table l). For this level of sulfate concentration, ACI 332-08 "Cade Require- ments for Residentìal Concrete" indicates there are no special cement require- ments for sulfate resistance in concrete in contact with the subsoils. ln our experience, superficial damage may occur to the exposed surfaces of highly permeable concrete, even when sulfate levels are relatively low. To control this risk and to resist freeze-thaw deterioration, the water-to-cementitious materials ratio should not exceed 0.50 for concrete in contact with soils that are likely to stay moist due to surface drainage or high-water tables. Concrete should have a totaf air content of 6 percent +l- 1.5 percent. We recommend all foundation walls and grade beams ín contact with the subsoils be damp-proofed. CONSTRUCTION OBSERVATIONS We recommend that CTL I Thompson, lnc. be retained to provide construc- tion observation and materials testing services for the project. This would allow us the opportunity to verify whether soil condítions are consistent with those found 4. GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJECT NO. GS06572.00Q-120 t3 ffi during this investigation. lf others perform these observations, they must accept responsibility to judge whether the recommendations in this report remain appro- priate. lt is also beneficial to projects, from economíc and practical standpoints, when there is continuity between engineering consultation and the construction observation and materials testing phases. STRUCTURAL ENGINEERING SERVICES CTL I Thompson, lnc. is a full-service geotechnical, structural, materials, and environmental engineering firm. Our services include preparation of structural framing and foundatíon plans. We can also design temporary and permanent earth retention systems. Based on our experíence, CTL I Thompson, lnc. typically pro- vides value to projects from schedule and economic standpoints, due to our com- bined expertise and experience with geotechnical, structural, and materials engi- neering. We can provide a proposal for structural engineering design services, if requested. GEOTECHNICAL RISK The concept of risk is an important aspect with any geotechnical evaluation primarify because the methods used to develop geotechnical recommendations do not comprise an exact science. The analyticaltools which geotechnical engineers use are generally empirical and must be tempered by engineering judgment and experience. Therefore, the solutions or recommendations presented in any ge- otechnical evaluation should not be considered risk-free and, more importantly, are not a guarantee that the interaction between the soils and the proposed struc- tures will result in performance as desired or intended. The engineering recom- mendations in the preceding sectíons constitute our estimate of those measures necessary to help the buildings perform satisfactorily. GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJECT NO. G506572.000"120 14 ffi This report has been prepared for the exclusive use of the client. The infor- mation, conclusions, and recommendations presented herein are based upon consideration of many factors including, but not límited to, the type of structures proposed, the geologic setting, and the subsurface conditions encountered. Standards of practice continuously change in the area of geotechnical engineer- ing. The recommendations provided are appropriate for about three years, lf the proposed project is not constructed within three years, we should be contacted to determine if we should update this report. LIMITATIONS Our exploratory boring and pits provide a reasonable characterization of subsurface conditions at the site. Variations in the subsurface conditions not índi- cated by the boring and pits will occur. We should be provided with architectural plans, as they are further developed, so we can provide geotechnical/geo- structural engineering input. This investigation was conducted in a manner consistent with that levelof care and skill ordinarily exercised by geotechnical engineers currently practicing under similar conditions in the locality of this project. No warranty, express or im- plied, is made. lf we can be of fufther service in discussing the contents of this re- port, please call. es D. Kellogg, sion Manager cTL I THOMPSON, B *(*e &es JDK:abr GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJECT NO. cS06s72.000-f 20 ¡T,\ ,z\ l5 ffi 0 1500 3000 NOTE: SCALET 'l'= 3000' GBEEN LINE ARCHITECTS 565 Fa¡anMl Rånah Road PROJËCT NO. GSO6572.OOO-1 20 SATELLITE IMAGE FROM GOOGLE EARTH (DATED JUNE 2017) Vicinity Map 565 Foronhyll Ronch Rood Flg. 1 LEGEND: TP_ 1il r. ¡ ) ffiAPPROXIMATE LOCATION OF EXPLORATORY PIT APPROXIMATE LOCATION OF EXPLORATORY BORING APPROXIMATE LOCATION OF PROPERTY BOUNDARY SATELLITE IMAGE FROM GOOGLE EARTH (DATED JUNE 2017) 0 100 200 NOTE: SCALE: 1' = 200' GREEN LINE ARCHÍrECTS 565 FaranMl Ranch Road PROJECT NO. cSO6 57 2.OOO-1 20 Aerial Photograph rP-2TP_,I ¡: ¡ 1 Flg. 2 LEGTND: TP_1 APPROXIMATEI EXPLoRATORY I }.i. I APPROXIMATE*$ EXPLORATORY ffi LOCATION PIT LOCATION BORING OF OF 0 NOTE: GREEN LINEARCH]TECTS 5€:t Fåtanfry{l Råñch Road PROJECT NO. GSO6 57 2.OOO-1 20 BASE DRAWING BY GREEN LINE ARCHTTECTS (DATED APRTL 14, 2021) tl !l I îlJ ÊÈå' /lII ì I \ 11r {,I rì,¡1 :JI I '{\t. I 1 I I TP_2 I I I I I I ! t I I I I I I I ti ¡ I I 1 I t '¡ rl tì ¡Ì l\ 1l ll .t'I t\ ¡ I 1¡ ! 1 I' Proposed Construct¡on Hs.3 l\\ \. ¡.\'ì\ I I I ì I I I I t I I lllt itt¡ ,r I I , I ¡ TP_1 TH-1 TP-1 1An2 36/5.5 10 15 GREEN LINEARCHITECTS 565 FAMNHYLL RANCH ROAÞ CTLIT PROJECT NO. c506572.000-120 Logs of lt'*t TP-2 5 0 LEGEND: TOPSOIL, CLAY, SANDY, SILT, DARK BROWN, ORGANICS, CLAY, SANÞY, MEDIUM STIFF, MOIST, BROWN, DARK BROWN. (CL) GRAVEL, CLAYEY, SAND, COBBLES, BOULDERS, MEDIUM DENSE, MOIST, BROWN, GRAY, (GC, SC) DRIVE SAMPLE. THE SYMBOL 1O/l2INDICATES 1O BLOWS OF AN AUTOMATIC 14o-POUND HAMMER FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5-INCH O.D. CALIFORNIA-BARREL SAMPLER 12 INCHES. INDICATES BULK SAMPLE FROM EXCAVATED SOILS PRACTICAL SOLID-STEM AUGER REFUSAL ON COBBLES AND BOULDERS. NOTES: EXPLORATORY BORING WAS DRILLED ON MAY 6, 2021 WITH 4jNCH DIAMETER, SOLID-STEM AUGER AND A TRACK,Ii¡OUNTED DRILL RIG. THE BORING WAS BACKFILLED IMMEDIATELY AFTER EXPLORATORY DRILLING OPREATIONS WERE COMPLETED. 2. EXPLORATORY PITS WERE EXCAVATED ON MAY 2I, 2021 WITH A TRACKHOE. THE PITS WERE BACKFILLED IMMEDIATELY AFTER EXPLORATORY EXCAVATION OPERATIONS WERE COMPLETED. 3. GROUNDWATER WAS NOT FOUND IN EXPLORATORY BORING OR PITS AT THE TIME OF DRILLING AND EXCAVATION. PVC PIPE WAS INSTALLED IN OUR BORING AND PITS, PRIOR TO BACKFILLING, TO FACILITATE SUBSEQUENT CHECKS OF GROUNDWATER. 4. LOCATIONS OF OUR EXPLORATORY BORING AND PITS ARE APPROXIMATE. 5. THËSE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS, AND CONCLUSIONS CONTAINED IN THIS REPORT. Þtrll¡lu- IFo- UJo t-r!tuIL Tt:IL lrJo 10 15 þ F T Summarv Explorató Boiing an FIG.4 ffi 1 6 4 3 2 0 -2 -3 fi-+ anz O- -çX"tu sz^O-o6 U'luÉ.- ù-t Eoo -8 0.1 APPLIED PRESSURE . KSF Somple of CLAY, SANDY (CL) 10 DRY UNIT WEIGHT= MOISTURE CONTENT= 109 19.4 Swell-Consolidation Test Results 100 PCF %From TH-,I AÏ 4 FEET GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJECT NO. GS06572.000-120 k | || EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTINGllll l t|lltt\ \ ) 1.0 FIG.5 ffi SANDS GRAVELCLAY (PtASTtC) TO SttT (NoN-pt_AsTtÇ) FINE MED'UM COARS FINE COARSE COBBLÉS ANALYSIS SIEVE _*_t__t_ -l_.__¡; __t -t-+_._ __t__.--'- t-È-_- -_t*- - _t *,_-___|-: -:= _-t___t_=---_-_444 .1-_1____t--_t_ -|-i- ------]_-----------f------ -t_-___,.- -,_-1.- -*--l--l-- 0 10 ?0 30 40 50 60 70 60 90 '100 oUz þ rlJdt-z LIJ d.u ,4 90 80 100 .001 0_002 .005 .009 .019 .037 ,074 .149 DIAMETER OF PARTICLE IN MILLIMETERS u.s. 5'6" ß" SERIES .16 '10 .8 CLÊAR SOUARE OPENINGS 3t8" 3t4" 'tyi' 3' 30 20 10 0 .297 ,590 0.42 25 HRi 7 HR. 45 MtN. 15 MtN. 1.19 ?.o 2.38 4.76 e.s2 19..t 36..1 76.2 121si!oo 60 MtN. 19 MtN. 4 MtN. I MtN. .200 .100 .50 .40 .30 Somple of snxo, cLAyEy (Sc)From TP - 1 AT 8-9 FEET GRAVEL SILT E CLAY PLASTICITY INDEX GRAVEL SILT & CLAY PLASTICITY INDEX SAND l-¡ouro t-t¡¡tt 29 be % % 32% a/o o/o Somple of From GREEN LINE ARCHITECTS 565 FARANHYLL RANCH ROAD PROJECT NO. GS06572.000-1 20 % SANDo/o LIQUID LIMIT o/o otfo Yo Gradation Test Results SANDS GRAVELCLAY (PI-AST|C) TO StLT (NON-PLAST|C) FINE MEDIUM COARS FINE COARSE COBBLES SIEVE --.__-..t-___.t_t__ -------+---------"-t-__t__ _-_,_t--=- .-t__. ---_-.-f- -l- __t_ _t--_ .. __t_ otozıØ ff60Fz ö50É. uJ9o 30 20 1o 0 DIAMETER OF PARTICLE IN MILLIMETERS Fzl! t¡I 27 2A0 152 90 80 100 10 20 30 40 50 60 7A 80 90 100.00t 0.002 ,005 .009 .019 .037 .074 .l4S 1.19 2.0 2.38 4.76 9.32 19.1 36,1 76.2 1 RÊAÞINGS U.S, STANDARD SERIES '100 '50'40 '30 .16 .10 '8 CLEAR SQUARE OPENINGS 318" 314" 1yi' 3' 5'6" .297 .590 0.4? 60 MtN. t9 MtN. 4 MtN. 1 MtN, .200 25 HR. 7 HR, 45 MtN. 15 MtN. FIG.6 ffi 2-3' **¡OSIJA COIER E}-ITIRE HDTT{ OF BELOW-GMDE ITAIL SUP JOINT DRAI].¡{GE coMPosm (M|RADRA¡N 6000 oR Eau¡vAt_EM) ATTACH PLASNC SHEENNG TO FOUNDATION E'MINIMUM OR BEYOND GRAVEL WITH NON-WOIEN GEOtÐfir-E FABRTC (Umnn 140N OR EOUVAUUI). I:1 SLOPE FROM BOTTOM OF FOOTNG (rvHtcHEvER ts GREATER) 1:lNgH DTAMEIER PERFORATED RtctD DRATN ptpE THE ptpE sHour.D BE p¡âcED lN ¡ rns{CH *mi A,SLOPE OF AT IEAST I¿I8-INCH DROP PER FOOT OF DRAIN. ENCÁSE ptpE tN 1/2. TO 1-1/2. SCREENED cRAvEL ÐcEND cRAvEL urEillrv ro FooTtNc AND AT tEASr 1/2 HAø{r OF FOOT|NG. Rtt EÌ\MRE TRENCH W¡N{ GRA\ÆL NOTE: IHE_BOTTOM OF Tt{E DRATN SHOULD BE ÂT tsAsf 2 tNcHES BELOTV BOTTOM OF EggIlNG AT THE HtGHEsr potul Ar.¡D slopE_Dotvir¡¡vARit-ïo n Fosirn-€-ô¡väiffOUI1EÍ OR TO A SUMP TYHERE IYAIER CNN gr NN¡OIAO'FÍ 'PUUCÑd GREEN LINEARCHITECTS A85 FARANFÍYI-LRANCH ROAD PROJECT NO. GSO6572.OOO-1 20 Foundation Wall Drain Goncept Êla a ffi SLOPE OSHA COIÆR ENNRE WDTT{ OF DRAltl¡AcE COMPOSIIE (MIRADRA|N 60(x) oR EQuMA|"E}{T) ATTACH PI..ASflC SHEENNC TO FOUNDAIION IYAI.I SLOPE FROM CRAWL s}¡çE -/PER GRAIEL IYÍTH NON-ITOIEN GEOTÐfltE FABRIC (MIRAFI l,+ON OR EAUVATENÐ.RECOMME}IDED vnpoR BARRIER MINIMUM BETOND gt OR 1:f ENC,ASE PIPE IN GRA\EL ÐfiEND AT.ID AT TEAST E}{TIRE TRENCH GREEN L¡NEARCH]rECTS 665 FARANI-ÍYLL RANCH ROAD BOTTOM OF FOONNG (TYH|CHEVER tS GREATER) _4:lNcH DtA¡rnER PERFORATED DRATN PtpE THEPIPE SI{OUI,.D BE PI.ACED IN A TRENCH W[M-A- çLOtsE OF AT |-EAST t/8-tNCH DROP pER FOOTOF DRA¡N. 1/2'TO 1-1/2'.SCREENED GRAVET I.ATERAI..LY TO FOOTNG1/2 HAGfiÍ OF FOOrNc. RtL IVIÍH GRAIÆL NOTE: P¡ryry qïgvlD BE AMAsr 2 NcHEs BELoTT BoTToM oF FoonNc ÆTHE HIOHEST PONr AND SLOPE DOIVNWARD-iOï POöirrI'L 'GAÃ'üffi "' oullEr oR T0 A suMp tïFtERE WATER CÂr.t BE Rn¡ó'Éb-Br'pùuÞwa. Foundation Wall Drain Concept STRUCruRAL FLOOR PROJECT NO. GSO6572.OOO-1 20 Flo.8 TABLE ISUMMARY OF LABORATORY TESTINGPROJECT NO. cS06572.000-120ffiDÊSCRIPTIONSANDYCLAY. SANDY (CL)SAND, CLAYEY (SC)CLAY, SANDY (CL)CLAY, SANDY (CL)PASSINGNO.200SIEVEloÄ\772086PERCENTSAND(o/o\32PERCENTGRAVEL(o/o)29SOLUBLESULFATES(o/o\0.00-SWELL(o/ol0.3APLASTICITYINDEX(%\LIOUIDLIMIT(o/o\DRYDENSITY(PCF)109MOISTURECONTENT(%\19.4DEPTHIFËËT)45-68-94-57-8EXPLORATORYBORING AND PITTH-1TP.1TP-,ITP.2TP-?. SWELL MEASURED WITH lOOO PSF APPLIED PRESSURE.NEGATIVE VALUE INDICATES COMPRESSION.Page I of I