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Home My WebLink AboutSubsoils Report for Foundation DesignCT�13G�i��G��C'��G�� GEOTECHNICAL ENGINEERING INVESTIGATION SWEETWATER RANCH GUEST CABINS 4894 SWEETWATER ROAD GARFIELD COUNTY, COLORADO Prepared for: Beck Building Company P.O. Box 4030 Vail, CO 81658 CTLIT Project No. GS06935.000-125-R3 January 24, 2025 CTLIThompson, Inc. Denver, Fort Collins, Colorado 5 rin s, Glenwood Springs, Pueblo, Summit County — Colorado Cheyenne, Wyoming and Bozeman, Montana Table of Contents SCOPE............................................................................,............... 1 PROPERTY DESCRIPTION...................................................................................,........_............ 1 UPPER BUILDINGS SITE .............................. ................... 2 PROPOSED CONSTRUCTION...................................................................... ............................. 3 SITE GEOLOGY ................................................ ........... 4 SUBSURFACECONDITIONS..................................................................................: .................. 5 SITEEARTHWORK.................................................................................................................. 6 Excavations............ ..............................................................................................................6 Subexcavation and Structural Fill...............:......................................:............................ 7 Foundation Wall Backfill....................................................................................._......... 7 Utilities........................................................ ...... ........... ............................................... ._ 8 BUILDING FOUNDATION............................................................................................................... 9 Footings........................................................................................................................._._............ 9 SLAB -ON -GRADE CONSTRUCTION........................................................................................... 10 CRAWL SPACE CONSTRUCTION............................................................................................... 11 FOUNDATIONWALLS.................................................................................................-..-........-...- 11 SUBSURFACE DRAINAGE........................................................................................................... 12 SURFACEDRAINAGE.................................................................................................................. 13 CONCRETE................................................................................................................................... 14 CONSTRUCTION OBSERVATIONS............................................................................................ 15 GEOTECHNICAL RISK.............................................................-........................_..........-----. ... 15 LIMITATIONS......---................................................................................................................... 16 FIGURE 1 — PROPERTY BOUNDARY FIGURE 2 — DEVELOPMENT PLAN FIGURE 3 — PROPOSED UPPER BUILDINGS FIGURE 4 — PROPOSED GUEST CABIN 2 FIGURE 5 — PROPOSED GUEST CABIN 3 FIGURE 6 — PROPOSED GUEST CABIN 4 FIGURES 7 AND 8 — SUMMARY LOGS OF EXPLORATORY PITS FIGURE 9 AND 10 — GRADATION TEST RESULTS FIGURES 11 AND 12 — FOUNDATION WALL DRAIN CONCEPTS TABLE I — SUMMARY OF LABORATORY TESTING APPENDIX A — EXPLORATORY PIT PHOTOGRAPHS BECK BUILDING COMPANY SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 SCOPE CTLIThompson, Inc. (CTLIT) has completed a geotechnical engineering investigation regarding the guest cabins proposed at Sweetwater Ranch in Garfield County, Colorado. We conducted this investigation to evaluate subsurface conditions at the site and provide geotech- nical engineering recommendations for the planned construction. The scope of our investigation was set forth in our Proposal No. GS 24-0170-CM1. Our report was prepared from data developed from our field exploration, laboratory test- ing, engineering analysis, and our experience with similar conditions. This report includes a de- scription of the subsurface conditions found in our exploratory pits and provides geotechnical engineering recommendations for design and construction of the foundation, floor systems, be- low -grade walls, subsurface drainage, and details influenced by the subsoils. Recommendations in this report were developed based on our understanding of the currently planned construction. We should be provided with architectural plans, as they are further developed, so that we can provide geotechnical/geo-structural engineering input. PROPERTY DESCRIPTION The Sweetwater Ranch property is located west of the intersection of Sweetwater Road (County Road 40) and Sheep Creek Road (Forest Road 8450) in Eagle County, Colorado. The road intersection is about 1,000 feet northeast of the confluence of Sweetwater Creek and the East Fork of Sheep Creek. A property boundary map is included as Figure 1. The property is comprised of an east parcel of approximately 732 acres in Eagle County and a west parcel of about 1,953 acres in Garfield County. Sweetwater Creek flows to the south along the east property boundary. Mason Creek and Morris Creek, which are tributaries to Sweetwater Creek, flow down to the east in the north and south parts of the property, respec- tively. The HMS Relocated Ditch trends south across the property on the west side of the county line. The property is generally comprised of a hummocky terrace that slopes down to the southeast. Steep slopes drop down from higher elevations adjacent to the property boundary at the west and south. The creek channels are incised in the terrace terrain. The east edge of the property is on the valley floor of the Sweetwater Creek drainage. Several reservoirs and ponds BECK BUILDING COMPANY Page 1 of 16 SWEETWATER RANCH — GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 are present on the upper parts property. Ranch roads provide access to various parts of the property and facilities, including residences and agricultural buildings. Numerous irrigated hay- fields and pastures are on the property. Natural vegetation adjacent to the irrigated areas con- sists of oak brush, pinion and juniper trees, aspen trees, and sage brush. UPPER BUILDINGS SITE The upper buildings are proposed within, and adjacent to, an irrigated hayfield that is about 1,200 feet west of the county line. The center of the development area is about 700 feet from the crest of the steep slope that drops down to the Morris Creek drainage. The alignment of the HMS Relocated Ditch is downhill of the general location, about 800 feet to the northeast. At this writing, the proposed buildings include a main residence, community barn, and three guest cabins. The development plan is shown on Figure 2. Guest Cabins 2, 3 and 4 are planned at the northwest, west, and southwest sides of the hayfield referenced above. The buildings are proposed on hillsides that generally slope down to the northeast at grades ranging from 5 to 20 percent. Vegetation at the sites consists of sage brush and grass with scattered pinion and juniper trees. We observed numerous sandstone cobbles and boulders at the ground surface. Photographs of the guest cabin sites below. The upper buildings site is shown on Figure 3. �i ... �.�� .�. _ .-�-w.-� -�•�..� n� ��f�'F .. s.�..w.iY •. �+�•� � t .:`�J.r.1k^.wi'-�.y � .�� Looking northwest toward Guest Cabin 2 site (beyond hayfield) BECK BUILDING COMPANY Page 2 of 16 SWEETWATER RANCH — GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 Looking southwest at Guest Cabin 3 site View northwest across Guest Cabin 4 site PROPOSED CONSTRUCTION CTLIT was provided with schematic design drawings for the Guest Cabins 2 and 4 by Centre Sky Architecture, LTD (dated December 13, 2024). The guest cabins are planned as BECK BUILDING COMPANY Page 3 of 16 SWEETWATER RANCH — GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 Li one -level buildings with attached or detached carports. Construction will include decks and entry patios. The schematic design drawings indicate that floors in living areas of the guest cabins will be structurally supported with crawl spaces below. The carports will have slab -on -grade floors. We expect similar construction for Guest Cabin 3. The proposed footprints of Guest Cabins 2, 3 and 4 are shown on Figures 4 through 6. The guest cabins will likely be steel and wood -framing with cast -in -place foundation walls. Maximum foundation excavation depths of about 8 to 10 feet are anticipated at the uphill sides of the buildings. We expect foundation loads between 2,000 and 3,000 pounds per linear foot of foundation wall and column loads of less than 50 kips. SITE GEOLOGY As part of our geotechnical engineering investigation, we reviewed geologic mapping by the U.S. Geological Survey (USGS) titled, "Geologic Map of the Leadville 1 Degree x 2 Degree Quadrangle, Northwestern Colorado", by Tweto, Moench, and Reed (dated 1978). We also re- viewed mapping by the Colorado geological surrey titled, "Geologic Map of the Dotsero Quad- rangle, Eagle and Garfield Counties. The maps indicate the soils at the planned site of the up- per buildings consist of landslide deposits of the Holocene and Pleistocene Epochs. These ma- terials are unconsolidated, unsorted, and unstratified. The materials are heterogeneous and range in size from cobbles and boulders to silt and clay. We judge the soils found in our explora- tory pits for the main residence are consistent with landslide deposits. Based on geologic mapping and our site observations, it appears the overburden soils are underlain at depth by bedrock of the Minturn Formation (Middle Pennsylvanian Period) and Belden Formation (Lower Pennsylvanian Period). The Minturn Formation is generally gray, tan, and red sandstone, conglomerate, and shale. The Belden Formation is dark gray to black shale and carbonate rocks and sandstone. The mapping indicates the bedrock formations are undi- vided in the vicinity of Sweetwater Creek. The weathered sandstone and sandstone bedrock encountered in our MR-C pit appeared consistent with The Minturn Formation. BECK BUILDING COMPANY Page 4 of 16 SWEETWATER RANCH — GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 SUBSURFACE CONDITIONS Subsurface conditions at the planned locations of Guest Cabins 2, 3, and 4 were investi- gated by directing excavation of six exploratory pits at the approximate locations shown on Fig- ures 3 through 6. GC2-A and GC2-B were excavated for Guest Cabin 2, GC3-A and GC-B, were excavated for Guest Cabin 3, and GC4-A and GC4-13 were excavated for Guest Cabin 4. The pits were excavated with a trackhoe on November 18, 2025. Exploratory excavation opera- tions were directed by our engineer, who logged subsurface conditions encountered and ob- tained samples of the subsoils. Graphic logs of subsurface conditions found in our exploratory pits are shown on Figures 7 and 8. Photographs of the exploratory pits and excavated materials are attached as Appendix A. Subsurface conditions encountered in our exploratory pit, GC2-A, for Guest Cabin 2 consisted of about 6 inches of topsoil, 5.5 feet of sandy clay, and 2.5 feet of weathered sand- stone, underlain by competent sandstone. The hardness of the sandstone made exploratory excavation deeper than 9 feet not practical. GC2-B exposed 6 inches of topsoil and 2.5 feet of sandy clay, underlain by clayey gravel and sandy clay to the total excavated depth of 10 feet. Subsoils observed in our exploratory pit, GC3-A, for Guest Cabin 3 consisted of about 1 foot of topsoil over sandy clay and clayey gravel to the total excavated depth of 12 feet. GC3-13 exposed 1 foot of topsoil, 6 feet of clayey gravel and sandy clay, and 3 feet of weathered sand- stone, underlain by competent sandstone. The hardness of the sandstone made exploratory excavation deeper than 10.5 feet not practical. The subsoils found in our exploratory pit, GC4-A, for Guest Cabin 4 consisted of about 6 inches of topsoil and 1 foot of sandy clay, underlain by clayey gravel and sandy clay to the total excavated depth of 12 feet. Subsurface conditions in GC4-13 were 6 inches of topsoil and 7.5 feet of clayey gravel and sandy clay, underlain by competent sandstone. The hardness of the sandstone made exploratory excavation deeper than 8.5 feet not practical. Groundwater was not encountered in our exploratory pits at the time of our subsurface investigation. The pits were backfilled immediately after exploratory excavation operations were completed. BECK BUILDING COMPANY Page 5 of 16 SWEETWATER RANCH — GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 dui Samples of the subsoils obtained from our exploratory pits were returned to our laborato- ry for pertinent testing. Laboratory testing included Atterberg limits and gradation analyses. Gradation analysis results are shown on Figures 9 and 10. Laboratory testing is summarized on Table I. SITE EARTHWORK Excavations Based on our subsurface investigation, we expect excavations for construction of the main residence can be accomplished using conventional, heavy-duty excavating equipment, such as a medium-sized trackhoe. Excavations more than a few feet into the bedrock may re- quire a hydraulic hammer attachment on a trackhoe. From a "trench safety" standpoint, sides of excavations must be sloped or retained to meet local, state, and federal safety regulations. The soils in excavations at this site will likely classify as Type B and Type C soils, based on OSHA criteria. Excavations deeper than 5 feet and above groundwater should be sloped no steeper than 1 to 1 (horizontal to vertical) in Type B soils and 1.5 to 1 in Type C soils. Groundwater seepage into excavations can cause slumps and sloughing and the need for flatter slopes. 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. CTLIT did not encounter a groundwater table in our exploratory pits. Our experience in similar geologic conditions in the region indicates that the upper soils can become saturated during snowmelt in spring and early summer. Zones of groundwater seepage could occur in ex- cavations at the site. It appears feasible that construction dewatering can be accomplished by sloping excavations to gravity outlets or to sump pits where water can be removed by pumping. Trenches along the perimeter of the excavation, outside the structure footprint, can help convey water to outlets or sumps. We recommend that excavation and earthwork operations commence after peak snowmelt has occurred. BECK BUILDING COMPANY Page 6 of 16 SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 Subexcavation and Structural Fill The overburden soils at this site are relatively heterogeneous. Furthermore, the soils have not been subject to geologic loads and have potential for consolidation when wetted under building loads. We judge the use of footings and slabs -on -grade is reasonable, provided poten- tial for differential building movement is mitigated. To create more uniform support conditions and reduce the potential for differential movement of foundations for the building, we recommend subexcavation of the soils below the bottoms of footings and floor slabs to a depth at least 3 feet. The sub -excavated areas should extend laterally at least 1 foot beyond the edges of footings and slabs. The excavated soils should be replaced with densely -compacted, structural fill. The excavated soils can be reused as structural fill, provided they are screened to re- move rocks larger than 4 inches in diameter, organics, and debris. Import soil needed for struc- tural fill should consist of a clayey sand or gravel with a maximum rock size of 4 inches and 20 to 40 percent silt and clay sized material. A sample of potential import soil for structural fill should be submitted to CTLIT for approval prior to the hauling to the site. Structural fill should be placed in loose lifts of 8 inches thick or less, moisture - conditioned to within 2 percent of optimum moisture content and compacted to at least 98 per- cent of standard Proctor (ASTM D 698) maximum dry density. Moisture content and density of structural fill should be checked by a representative of CTLIT during placement. Observation of the compaction procedure is necessary. Foundation Wall Backfill Proper placement and compaction of foundation backfill is important to reduce infiltration of surface water and settlement from consolidation of backfill soils. This is especially important for backfill areas that will support exterior concrete flatwork, such as patios, walkways, and driveways. The excavated soils can be reused as backfill, provided they are screened to remove or- ganics, debris, and rocks larger than 6 inches in diameter. Backfill should be placed in loose lifts BECK BUILDING COMPANY Page 7 of 16 SWEETWATER RANCH — GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 of approximately 10 inches thick or less and moisture -conditioned to within 2 percent of opti- mum moisture content. Backfill soils that will not support exterior concrete slabs should be compacted to at least 95 percent of standard Proctor (ASTM D 698) maximum dry density. Backfill soils that will sup- port exterior concrete slabs should be compacted to at least 98 percent of ASTM D 698 maxi- mum dry density. Moisture content and density of the backfill should be checked during place- ment by CTLIT. Observation of the compaction procedure is necessary. Foundation backfill that will support exterior slabs requires strict adherence to specifica- tions. Even well -placed backfill will settle 0.5 to 1 percent of total backfill thickness. Structures placed over backfill zones will need to be designed to accommodate differential movement with respect to the building. If slabs and structures that are sensitive to settlement will be located above deeper zones of backfill, consideration should be given to designing'these elements as structurally supported. Utilities Sides of utility trenches should be sloped or braced to meet local, state and federal safe- ty requirements. Anticipated OSHA soil type classifications are provided in the Excavations sec- tion. We believe the natural soils at this site have low corrosion potential. We can perform re- sistivity testing to assist in judging corrosivity of the native soils, if desired. Water mains and other utilities may be constructed of common ductile iron pipe. Some municipalities recommend iron fittings, joints, couplings and appurtenances be wrapped with polyethylene for corrosion protection regardless of soil resistivity. Properly compacted backfill in utility trenches is important to reduce subsequent consoli- dation of backfill soils and infiltration of surface water. Backfill soils should consist of the on -site soils, free of rocks larger than 4 inches in diameter, organic matter and debris. Backfill should be placed in thin lifts, moisture conditioned to within 2 percent of optimum moisture content and compacted to at least 95 percent of standard Proctor (ASTM D 698) maximum dry density. Density and moisture content of backfill should be checked by CTLIT during placement. BECK BUILDING COMPANY Page 8 of 16 SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 BUILDING FOUNDATIONS The overburden soils at this site are relatively heterogeneous. Furthermore, the soils have not been subject to geologic loads and have potential for consolidation when wetted under building loads. We judge the use of footing foundations is reasonable for Guest Cabins 2, 3 and 4, provided potential for differential building movement is mitigated. To create more uniform support conditions and reduce the potential for differential movement of foundations for the buildings, we recommend subexcavation of the soils below the bottoms of footings to a depth at least 3 feet. The sub -excavated areas should extend laterally at least 1 foot beyond the edges of the building footprints. The excavated soils should be re- placed with densely -compacted, structural fill 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. Footings Footings should be supported by densely compacted, structural fill that is at least 3 feet thick. The structural fill should be in accordance with recommendations in the Subexcavation and Structural Fill section. 2. Footings on 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 1,000 psf increase in this bearing pressure is acceptable when using the alternative load combination of. IBC 2015, Section 1605.3.2 that include wind and earthquake load. 3. A friction factor of 0.35 can be used to calculate resistance to sliding between concrete footings and the structural fill. 4. Continuous wall footings should have a minimum width of at least 18 inches. Foundations for isolated columns should have minimum dimensions of 30 inches by 30 inches. Larger sizes may be required, depending upon foundation loads. 5. Grade beams and foundation walls should be well -reinforced. We recommend re- inforcement sufficient to span an unsupported distance of at least 12 feet. BECK BUILDING COMPANY Page 9 of 16 SWEETWATER RANCH — GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 6. The soils under exterior footings should be protected from freezing. We recom- mend the bottom of footings be constructed at least 42 inches below finished ex- terior grades for frost protection. The Garfield County building department should be consulted regarding frost protection requirements. SLAB -ON -GRADE CONSTRUCTION The overburden soils at this site are relatively heterogeneous. Furthermore, the soils have potential for consolidation when wetted under building loads. We judge the use of slab -on - grade floors and exterior flatwork is reasonable for Guest Cabins 2, 3 and 4, provided potential for differential movement is mitigated. To create more uniform support conditions and reduce the potential for differential movement of foundations for the building, we recommend subexcavation of the soils below the bottoms of interior slabs to a depth at least 3 feet. The sub -excavated areas should extend lat- erally at least 1 foot beyond the edges of the slabs. A minimum structural fill thickness of 12 inches is recommended below exterior flatwork. The excavated soils should be replaced with densely -compacted, structural fill in accordance with recommendations in the Subexcavation and Structural Fill section Based on our analysis of field and laboratory data, as well as our engineering experi- ence, we recommend the following precautions for slab -on -grade construction at this site. Slabs should be separated from footings and columns pads with slip joints which allow free vertical movement of the slabs. 2. The use of underslab plumbing should be minimized. Underslab plumbing should be pressure tested for leaks before the slabs are constructed. Plumbing and utili- ties which pass through slabs should be isolated from the slabs with sleeves and provided with flexible couplings to slab supported appliances. 3. Exterior patio slabs and concrete flatwork should be isolated from the building. These slabs should be well -reinforced to function as independent units. 4. Frequent control joints should be provided, in accordance with American Con- crete Institute (ACI) recommendations, to reduce problems associated with shrinkage and curling. 5. The International Building Code (IBC) may require a vapor retarder be placed be- tween the base course or subgrade soils and concrete slab -on -grade floors. The merits of installation of a vapor retarder below floor slab depend on the sensitivity BECK BUILDING COMPANY Page 10 of 16 SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 of floor coverings and building to moisture. A properly installed vaper retarder (10 mil minimum) is more beneficial below concrete slab -on -grade floors where floor coverings will be sensitive to moisture. The vapor barrier/retarder is most effec- tive when concrete is placed directly on top of it. A sand or gravel leveling course should not be placed between the vapor barrier/retarder and the floor slab. CRAWL SPACE CONSTRUCTION The schematic design drawings indicate that crawl space areas may be constructed be- low parts of the main -level floors in the guest cabins. The required crawl space height depends on the materials used to construct the floor system above the crawl space. Building codes nor- mally require a clear space of at least 18 inches between exposed earth and untreated wood components of the structural floor. Utility connections, including water, gas, air duct, and exhaust stack connections to ap- pliances on structural floors should be capable of absorbing some deflection of the floor. Plumb- ing 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. Control of humidity in crawl spaces is important for indoor air quality and performance of wood floor systems. We believe the best current practice to control humidity involves the use of a vapor retarder or vapor barrier (10 mil minimum) placed on the soils below accessible subfloor areas. The vapor retarder/barrier should be sealed at joints and attached to concrete foundation elements. It may be appropriate to install a ventilation system that is controlled by a humidistat. FOUNDATION WALLS Foundation walls that 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 pres- sure. 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 deflect or rotate 0.5 to 1 percent of wall height (depending upon the backfill types), design for a lower "active" lateral earth pressure BECK BUILDING COMPANY Page 11 of 16 SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 may be appropriate. Our experience indicates typical below -grade walls in residences deflect or rotate slightly under normal design loads, and that this deflection results in satisfactory wall per- formance. 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 sec- tion 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 deflection; some minor cracking of walls may occur. If very little wall deflection is desired, a higher design value for the "at -rest" condition is appropriate using an equivalent fluid pressure of 60 pcf. SUBSURFACE DRAINAGE Our experience in similar geology and topography in the region indicates the upper soils can become saturated during snowmelt in spring and early summer months. Frozen ground dur- ing spring runoff can also create a perched condition. Additionally, 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 ex- cavations. These sources of water can cause wet or moist conditions in below -grade areas after construction. To reduce the likelihood water pressure will develop outside foundation walls, we recommend provision of foundation wall drains around the perimeters of the guest cabin founda- tion. 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 foun- dation wall exteriors. Care should be taken during backfill operations to prevent damage to drainage composites. The drains should discharge via positive gravity outlets. The gravity out- lets should not be susceptible to clogging or freezing. We recommend installation of clean -outs along the drainpipes. A representative of our firm should be called to observe the drain con- struction, prior to backfilling. To further mitigate subsurface water, we recommend a drainage layer (below slabs and on crawl space floors) consisting of 4-inch diameter, slotted PVC pipe installed on 8 to 10-foot centers and embedded in at least 6 inches of screened rock. If a vapor barrier/retarder is placed BECK BUILDING COMPANY Page 12 of 16 SWEETWATER RANCH — GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 ■WI■ below the slabs, the gravel layer should be below the barrier. The pipes should convey water to perimeter drain collector pipes. Water collected should be discharged via positive gravity out- lets. The foundation wall drain concepts are shown on Figures 11 and 12. 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 irrigation practices can help control the amount of surface water that penetrates to foundation levels and contributes to settlement of soils that support the building foundation and slabs -on -grade. Positive drainage away from the buildings foundation and avoidance of irrigation near the foundations also help to avoid excessive 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 guest cabins should be sloped to rapidly convey surface water away from the building in all directions. We recommend a constructed slope of at least 12 inches in the first 10 feet (10 percent) in landscaped areas around the buildings, where practical. 2. Backfill around the foundation walls should be moisture -treated and compacted pursuant to recommendations in the Foundation Wall Backfill section. 3. We recommend that the guest cabins be provided with roof drains or gutters and downspouts. The drains or downspouts should discharge well beyond the limits of all backfill. Splash blocks and/or extensions should be provided so water dis- charges onto the ground beyond the backfill. We generally recommend against burial of downspout discharge pipes. 4. Landscaping should be designed and maintained to minimize irrigation. Plants placed close to foundation walls should be limited to those with low moisture re- quirements. Irrigated grass should not be located within 5 feet of the foundations. Sprinklers should not discharge within 5 feet of foundations. Plastic sheeting should not be placed beneath landscaped areas adjacent to foundation walls. Geotextile fabric will inhibit weed growth and allow some evaporation to occur. BECK BUILDING COMPANY Page 13 of 16 SWEETWATER RANCH — GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 CONCRETE Concrete in contact with soil can be subject to sulfate attack. Our experience with pro- jects in similar geology indicates the soils have water soluble sulfate concentrations of less than 0.10 percent. Pursuant to our test and ACI 332-20, this concentration corresponds to a sulfate exposure class of "Not Applicable" or RSO as indicated on the table below. SULFATE EXPOSURE CLASSES PER ACI 332-20 Water -Soluble Sulfate (SO) Exposure Classes in Soil A Not-A-ppricable RSO < 0.10 Moderate RS1 0.10 to 0.20 Severe RS2 0.20 to 2.00 Very Severe RS3 > 2.00 V A) Percent sulfate by mass in soil determined by ASTM C1580 For this level of sulfate concentration, ACI 332-20, "Code Requirements for Residential Concrete", indicates no special cement type requirements for sulfate resistance as indicated on the table below. CONCRETE DESIGN REQUIREMENTS FOR SULFATE EXPOSURE PER ACI 332-20 Cementitious_ Material T es B Maximum Minimum Calcium Chlo- Exposure Water/ Compressive ASTM ASTM ASTM ride Admix - Class Cement Strength A C150/ C595/ C1157/ tures Ratio (psi) C150M C595M C1157M No Type No Type No Type No RSO N/A 2500 Restrictions Restrictions Restrictions Restrictions RS1 0.50 2500 11 Type with (MS) MS No Designation Restrictions RS2 0.45 3000 FV c Type with (HS) HS Not Permitted Designation !!! Type with (HS) RS3 0.45 3000 V + Pozzolan or Designation plus HS + Pozzolan or Not Permitted Slag Cement ° Pozzolan or Slag Slag Cement E Cement E A) Concrete compressive strength specified shall be based on 28-day tests per ASTM C391C39M B) Alternate combinations of cementitious materials of those listed in ACI 332-20 Table 5.4.2 shall be permitted when tested for sulfate resistance meeting the criteria in section 5.5. C) Other available types of cement such as Type III or Type I are permitted in Exposure Classes RS1 or RS2 if the C3A contents are less than 8 or 5 percent, respectively. D) The amount of the specific source of pozzolan or slag to be used shall not be less than the amount that has been determined by service record to improve sulfate resistance when used in concrete containing Type V cement. Alternatively, the amount of the specific source of the pozzolan or slab to be used shall not be less BECK BUILDING COMPANY Page 14 of 16 SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 than the amount tested in accordance with ASTM C1012/C1012M and meeting the criteria in section 5.5.1 of ACI 332-20. E) Water-soluble chloride ion content that is contributed from the ingredients including water aggregates, ce- mentitious materials, and admixtures shall be determined on the concrete mixture ASTM C1218/C1218M between 29 and 42 days. Superficial damage may occur to the exposed surfaces of highly permeable concrete. 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 sur- face drainage or high-water tables. Concrete should have a total air content of 6% +1-1.5%. We recommend foundation walls and grade beams in contact with the subsoils be damp -proofed. CONSTRUCTION OBSERVATIONS We recommend that CTLIT be retained to provide construction observation and materi- als 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 ob- servations, they must accept responsibility to judge whether the recommendations in this report remain appropriate. It is also beneficial to projects, from economic and practical standpoints, when there is continuity between engineering consultation and the construction observation and materials testing phases. 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 geotechnical recommendations do not comprise an exact science. We never have complete knowledge of subsurface conditions. Our analysis must be tempered with engineering judgment and experience. Therefore, the rec- ommendations presented in any geotechnical evaluation should not be considered risk -free. We cannot provide a guarantee that the interaction between the soils and the proposed guest cab- ins will lead to performance as desired or intended. Our recommendations represent our judg- ment of those measures that are necessary to increase the chances that the buildings will per- form satisfactorily. It is critical that all recommendations in this report are followed. BECK BUILDING COMPANY Page 15 of 16 SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 LIMITATIONS This report was prepared for the exclusive use of Beck Building Company with respect to Guest Cabins 2, 3 and 4 proposed at Sweetwater Ranch. The information, conclusions, and recommendations provided 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 report are not valid for use by others. Standards of practice continuously change in geotechnical engineering. The recommendations provided in this report are appropriate for about three years. If the proposed . building is not constructed within three years, we should be contacted to determine if we should update this report. Our exploratory pits provide a reasonable characterization of subsurface conditions at the planned guest cabin locations. Variations in subsurface conditions not indicated by the 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 level of care and skill ordinarily exercised by geotechnical engineers currently practicing under similar conditions in the locality of this project. No warranty, express or implied, is made. Please contact us if we can be of further service in discussing the contents of this report. CTLITHOMPSON, IN r 1 a. V;v mes D. Kellogg, P. enior Principal Engine rq_ LIC�� K 38298 � 0 1 Z aC �°IMF• Reviewed by: i6000LP ', sn 61683 f R n R. Barbone, P. E, % Division Manager '�iy��eZgti rbarbonepctifhomps BECK BUILDING COMPANY Page 16 of 16 SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 LEGEND: APPROXIMATE LOCATION OF PROPERTY BOUNDARY APPROXIMATE LOCATION OF COUNTY LINE a +mo woo ® NOTE: SATELLITE IMAGE FROM MAXAR (COPYRIGHT 2022) BECK BLU DMO COMPANY Property Prolea No. GODS=.000-, 25M Boundary o soo tcoo sane® — APPROXIMATE LOCATION OF PROPf]ill' BOUNDARIES NOTE: SATELLITE IMAGE FROM GOGGLE EARTH (DATED AUGUST 3, 2023) - t C eecR 6UYACIG COMPANY s�mwa�rwnt_aaraw Pr 1ct No. OSOOM.000•1 25-M Development Plan Rg. 2 LEGEND: 7FF -� APPROXIMATE LOCATION OF EXPLORATORY Prr p �® NOTE: BASE DRAWING BY BWEGRE N ASPEN swe P . mC , � Gvn�! Catln 7 ,.1, � uoin Hea�dor7cer- MA -B �.5 uesL Ca➢in } .ca-B ^GCS r f• ;� f `\ ; y -A J.. � f Proposed Upper BECKINLILD COMPANY Project No. 6soOM.000-125-W Buildings PI,. s 0 30 60 SCALE. V a 60' LEGEND: GC2-A APPROXIMATE LOCATION OF F] EXPLORATORY PIT NOTE: BASE DRAWING BY BLUEGREEN ASPEN (DATED DECEMBER 3. 2024) J BECK BUILDING COMPANY SWEETWATER RANCH - GUEST CABINS CTLJT PROJECT NO. GS06935.000-125-R3 Proposed Guest Cabin 2 Flg. 4 00 0 30 60 SCALE: 1' - 60' LEGEND: GC3-A APPROXIMATE LOCATION OF p EXPLORATORY PIT NOTE: BASE DRAWING BY BLUEGREEN ASPEN (DATED DECEMBER 3, 2024) 1 00 Z— GC3-A r r r Proposed Guest BECK BUILDING COMPANY SWEETWATER RANCH - GUEST CABINS CTLJT PROJECT NO. GS06935.000-125-R3 Cabin ` FAA• 5 0 30 60 SCALE. 1' - 60' LEGEND: GC4—A APPROXIMATE LOCATION OF 11 EXPLORATORY PIT NOTE: BASE DRAWING BY BLUEGREEN ASPEN (DATED DECEMBER 3, 2024) ° \ GC4—B \ Proposed \ i Guest Cabin 4 \ ---------------\--------- \ � r 7770 / GC4—A El BECK BUILDING COMPANY SWEETWATER RANCH - GUEST CABINS CTLfr PROJECT NO. GS06935.000-125-R3 Proposed Guest Cabin 4 Li Fig. 6 GC2-A GC2-9 GC3A GC3-B GC4-A GC4-B El- T728 EL 7718 EL 7782 EL. 7772 EL 7775 EL 7768 7730 7785 7785 7780 7780 GUEST CABIN 2 FLOOR EL 7726 7725 T780 7780 7775 7775 GUEST CABIN 3 FLOOR EL 7777 7720 7775 7775 7770 GUEST CABIN 7T70 FLOOR EL 7768 7 7715 7770 7770 iT85 _ 7785 P 7710 7765 7765 7780 7760 J 770s 7780 7700 7755 7755 SUMMARY LOGS OF EXPLORATORY PITS FIG 7 LEGEND: ® TOPSOIL, CLAY, SANDY, MOIST, DARK BROWN. CLAYEY GRAVEL AND SANDY CLAY, SCATTERED ANGULAR SANDSTONE COBBLES, MEDIUM DENSE OR STIFF, MOIST, BROWN, TAN. (GC, SC, CL) CLAY, SANDY, MEDIUM STIFF TO STIFF, MOIST, BROWN. (CL) ®WEATHERED SANDSTONE, SILTY, ANGULAR, SLIGHTLY MOIST, TAN. BEDROCK SANDSTONE, HARD TO VERY HARD, TAN, GRAY. SYMBOL INDICATES A BULK SAMPLE OBTAINED FROM EXCAVATED SOILS. SYMBOL INDICATES A HAND DRIVE SAMPLE OBTAINED DURING EXCAVATION. NOTES: 1. THE EXPLORATORY PITS WERE EXCAVATED WITH A TRACKHOE ON NOVEMBER 18, 2024. 2. GROUNDWATER WAS NOT FOUND IN OUR EXPLORATORY PITS AT THE TIME OF EXCAVATION. THE PITS WERE BACKFILLED IMMEDIATELY AFTER EXPLORATORY EXCAVATION OPERATIONS WERE COMPLETED. 3. EXPLORATORY PIT ELEVATIONS WERE ESTIMATED FROM GROUND SURFACE CONTOURS SHOWN ON FIGURE 3. 4. THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN THIS REPORT. Summary Logs of Exploratory BECK BUILDING COMPANY Pits RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 FIG. 8 HYDROMETER ANALYSIS SIEVE ANALYSIS 25 HR. 7 HR. TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 45 MIN. 15 MIN. 80 MIN. 19 MIN. 4 MIN. 1 MIN. '200 '100 '50 '40 '30 '16 '10 '8 '4 3W W4' 1%" 3" 5"6' 8" 0 100 - — -- — --- - 10 so - 80 20 30 Z70 _ -- - - Z a60 — - _ 40 It _ 50 cr - LLI a40 — 60 IL - 30 70 20 10 F 90 --- 100 0 .001 0.002 .005 .009 .019 .037 .074 .149 .297 .590 1.19 2.0 2.38 4.76 9.52 19.1 35.1 76.2 127152 0.42 - DIAMETER OF PARTICLE IN MILLIMETERS 00 CLAY(PLASTIC)TOSILT (NON -PLASTIC) SANDS I GRAVEL FINE I MEDIUM I COARS I FINE COARSE I COBBLES Sample of CLAY, SANDY (CL) From GC2-A AT 5 FEET GRAVEL % SAND 13 % SILT & CLAY 87 % LIQUID LIMIT % PLASTICITY INDEX % HYDROMETER ANALYSIS I 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 '4 318" 314" 1W' 3" 5"6" 80" 100- - 10 90 20 60 - ---- - C070 -- �= 30 W z z � ---40 u (60— -- I� - _ - 50 '60 — u w - w 0-40 — - 70 30 20 80 - 90 10 — — - 100 0 .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 I COARS FINE COARSE I COBBLES Sample of CLAY, SANDY (CL) From 5C3-A AT 6 FEET BECK BUILDING COMPANY SWEETWATER RANCH - GUEST CABINS PROJECT NO. GS06935.000-125-R3 GRAVEL 10 % SAND 31 % SILT & CLAY 59 % LIQUID LIMIT % PLASTICITY INDEX % Gradation Test Results FIG.9 HYDROMETER ANALYSIS I 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 31T 3/4" 1W' 3" IrG W 0 100 — 90 — 10 80 — - - — - — 20 30 CD70 _ Z f 160 40 U50 50 LZU _ — V W --- cc a40 --- - 60 a - --- 7D 30 20 80 10 90 — 100 0 .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 COARSE I COBBLES FINE I MEDIUM I COARS I Sample of CLAY, SANDY (CL) From GC4-13 AT 6 FEET GRAVEL 20 % SAND 13 /0 SILT & CLAY 67 % LIQUID LIMIT % PLASTICITY INDEX % HYDROMETERANALYS(S 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 '4 318" 3/4" 11/2" 3" 5"6" v 100 10 90 20 80 30 w 070 z _ — x -- - - ---40 a co — - - - --- - — — 50 0 — — U a- - - a40 60 -" 70 30 --`80 20 u 90 10 - - 100 .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 0.42 152 DIAMETER OF PARTICLE IN MILLIMETERS 200 C (PLASTIC) TO SILT (NON -PLASTIC) SANDS GRAVEL FINE MEDIUM I COARS FINE COARSE I COBBLES Sample of From BECK BUILDING COMPANY SWEETWATER RANCH - GUEST CABINS PROJECT NO. G506935.000-125-R3 GRAVEL % SAND SILT & CLAY % LIQUID LIMIT % PLASTICITY INDEX % Gradation Test Results FIG.10 SLOPE PER OSHA COVER ENTIRE WIDTH OF - GRAVEL WITH NON -WOVEN GEOTEXTILE FABRIC MIRAFI 14ON OR EQUIVALENT). �f ;lA 2-3' BACKFILL PREFABRICATED DRAINAGE COMPOSITE (MIRADRAIN 60DO OR EQUIVALENT) ATTACH PLASTIC SHEETING TO FOUNDATION WALL--% 18` MINIMUM 1� 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- SCREENED GRAVEL EXTEND GRAVEL LATERALLY TO FOOTING AND AT LEAST 1/2 HEIGHT OF FOOTING. FILL ENTIRE TRENCH WITH GRAVEL SLIP JOINT a• a• ri S �•�: r' 4 +6w PVC DRAIN NETWORK EMBEDDED IN WASHED CONCRETE AGGREGATE 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. Foundation Wall Drain BECK BUILDING COMPANY Concept SWEE- WATER FVWCH - GUEST CABINS Project No. GS06935.000-125-R3 Fig. 11 SLOPE PER OSHA COVER ENTIRE WIDTH OF - GRAVEL WITH NON -WOVEN GEOTE)MLE FABRIC MIRAFl 14ON OR EQUIVAL£ SLOPE 2-3' BACKFILL PREFABRICATED DRAINAGE COMPOSITE (MIRADRAIN 6000 OR EQUIVALENT) ATTACH PLASTIC SHEETING TO FOUNDATION WALL---,, MINIMUM W MINIMUM OR mo- 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" SCREENED GRAVEL EKTEND GRAVEL LATERALLY TO FOOTING AND AT LEAST 1/2 HEIGHT OF FOOTING. FILL ENTIRE TRENCH WITH GRAVEL STRUCTURAL FLOOR CRAWL SPACE -f "MUD SLAB" OR VAPOR. BARRIER PVC DRAIN NETWORK EMBEDDED IN WASHED CONCRETE AGGREGATE 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. BECK BUILDING COMPANY SWEEMATER RANCH -OUEW CABINS Project No. GS06935.000-125-R3 Foundation Wall Drain Concept Fig. 12 lk Z O a_ U U U U U U U w o 0 0 0 0 ❑ z Z Z W Z Z V) CO U) U) U U U U U 0 Z LLJ N i W \ ,Q •M Ll] 00 c0 t0 O Z U la- H Z ❑ U z o M M w v C W a ~ J zLU W W � •J a0 WU) W _ m .- D LQLe J J O� U) ul J J w : 0 v � x z� IL im {1'❑H IL❑�-i < J �U)U ❑wa 0 W �Z O w Z o rn CV o ti CV c dj ro •O 2O 2 F- w W W :r- LO c0 c0 to OHO Q Q m Q m Of N M c7 It sm U O U C9 U C9 U C7 'U 0 x 11 wl 1 1 1 1 1 1 1 1 Lj-J.- I I I I [---J—Iit—I m rn m a Z O J O U) z O U W J W c� W Z W Ix D U U W Ix (L W J a a a W C0 a 0 O O W Z D ❑ W U Q W J J w U) APPENDIX A EXPLORATORY PIT PHOTOGRAPHS BECK BUILDING COMPANY SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 Soils exposed in Guest Cabin 2 — Pit A Soils excavated from Guest Cabin 2 — Pit A BECK BUILDING COMPANY A-1 SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 Soils exposed in Guest Cabin 2 — Pit B Soils excavated from Guest Cabin 2 — Pit B BECK BUILDING COMPANY A-2 SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 Soils exposed in Guest Cabin 3 — Pit A Soils excavated from Guest Cabin 3 — Pit A BECK BUILDING COMPANY A-3 SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 Soils exposed in Guest Cabin 3 — Pit B Soils excavated from Guest Cabin 3 — Pit B BECK BUILDING COMPANY A_4 SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 Soils exposed in Guest Cabin 4 — Pit A Soils excavated from Guest Cabin 4 — Pit A BECK BUILDING COMPANY A-5 SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3 Soils exposed in Guest Cabin 4 — Pit B Soils excavated from Guest Cabin 4 — Pit B BECK BUILDING COMPANY • A_6 SWEETWATER RANCH - GUEST CABINS CTLIT PROJECT NO. GS06935.000-125-R3