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Home My WebLink AboutEAST OAK TOWNHOMES - PDP230018 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGEOTECHNICAL SUBSURFACE EXPLORATION REPORT EAST OAK TOWNHOMES FORT COLLINS, COLORADO EEC PROJECT NO. 23-01-183 Prepared for: Davis Davis Architects 221 East Oak Street, Unit A Fort Collins, Colorado 80524 Attn: Mr. Robert Davis (rdavis@davisdavisarch.com) Prepared by: Earth Engineering Company, Inc. P.O. Box 271428 Fort Collins, Colorado 80527 GEOTECHNICAL SUBSURFACE EXPLORATION REPORT EAST OAK TOWNHOMES FORT COLLINS, COLORADO EEC PROJECT NO. 23-01-183 December 18, 2023 INTRODUCTION: Earth Engineering Company, Inc. (EEC) personnel have completed the geotechnical subsurface exploration you requested for the proposed multi-family townhome development to be constructed at 220 East Oak Street in Fort Collins, Colorado. Results of the subsurface exploration are provided in this report. We understand the proposed townhome buildings will be a three-story wood frame structures. We expect foundation loads for the structures will be light, with continuous wall loads less than 3 kips per lineal foot and individual column loads less than 50 kips. Small grade changes are expected to develop final site grades for the structures. The purpose of this report is to describe the subsurface conditions encountered in the test borings completed within and near the identified building envelopes on the site and provide geotechnical recommendations for design and construction of foundations and support of floor slabs and exterior flatwork. The proposed building locations are situated in an area to the northwest of the intersection of Matthews Street and East Oak Street in Fort Collins, Colorado. Site infrastructure, including pavements and utilities, has already been installed along with existing buildings located within the building envelopes. To develop information on existing subsurface conditions in the area of the proposed townhome structures, three (3) soil borings were extended to depths of approximately 20 to 35 feet below present site grades at the subject building envelopes. The locations of the test borings were established by pacing and estimating angles from site property corners and identifiable site features. The locations of the borings should be considered accurate only to the degree implied by the methods used to make the field measurements. The borings were performed using a truck-mounted, rotary-type drill rig equipped with a hydraulic head employed in drilling and sampling operations. The boreholes were advanced using 4-inch Earth Engineering Company, Inc. EEC Project No. 23-01-183 December 18, 2023 Page 2 nominal diameter continuous flight augers. Samples of the subsurface materials encountered were obtained using split-barrel and California barrel sampling procedures in general accordance with ASTM Specification D-1586. All samples obtained in the field were sealed and returned to the laboratory for further examination, classification and testing. An EEC field engineer was on site during drilling to evaluate the subsurface conditions encountered and to direct the drilling activities. Field boring logs were prepared based on observation of disturbed samples and auger cuttings. Based on results of the field borings and laboratory testing, subsurface conditions at the proposed residence locations can be generalized as follows: The near surface soils generally consisted of natural brown to reddish brown sandy lean clay soils. The natural sandy lean clay soils encountered in the borings were medium stiff to very stiff in consistency and contained gravel. The moderately plastic sandy lean clay soils exhibited a low potential for swelling and a low to moderate potential for consolidation at current moisture and density conditions. The sandy lean clay soils were underlain by brown sand and gravel materials at a depth of approximately 6 to 8 feet below present site grades at the completed site borings. The sand and gravel materials encountered in the borings were medium dense to very dense in consistency, contained cobbles and were underlain by grey/tan and rust sandstone/claystone bedrock at a depth of approximately 16 feet below present site grades. The sandstone/claystone bedrock was hard in consistency and exhibited a low potential for swelling with variation in moisture content at current moisture/density conditions. The sandstone/claystone bedrock extended to the bottom of boring B-1 at a depth of approximately 20 feet below present site grades. The sandstone/claystone bedrock encountered at borings B-2 and B-3 were underlain by grey shale bedrock at a depth of approximately 27 and 23 feet below present site grades at borings B-2 and B-3, respectively. The shale bedrock encountered at borings B-2 and B-3 was hard in consistency and exhibited a low potential for swelling with variation in moisture content at current moisture/density conditions. The shale bedrock extended to the bottom of borings B-2 and B-3 at a depth of approximately 25 and 35 feet below present site grades. Observations were made at the time of drilling and approximately 24 hours after drilling of the borings to detect the presence and depth to the hydrostatic groundwater table. At the time of drilling, free water was not observed in the completed site borings on this property. Approximately 24 hours after drilling, borings B-1 and B-2 were backfilled and free water was observed at a depth Earth Engineering Company, Inc. EEC Project No. 23-01-183 December 18, 2023 Page 3 of approximately 24 feet below present site grades at boring B-3. Longer-term observations in holes which are cased and sealed from the influence of surface water would be required to more accurately determine fluctuations in groundwater levels over time. Fluctuations in groundwater levels can occur based on hydrologic conditions and other conditions not apparent at the time of this report. Zones of perched and/or trapped water may also be encountered in more permeable zones within the subgrade soils at times throughout the year. The stratification boundaries indicated on the boring logs represent the approximate locations of changes in soil types. In-situ, the transition of materials may be gradual and indistinct. Bedrock classification was based on visual and tactual observations of disturbed samples and auger cuttings; coring and/or petrographic analysis may reveal other rock types. In addition, the soil borings provide an indication of subsurface conditions at the test locations. However, subsurface conditions may vary in relatively short distances away from the borings. Potential variations in subsurface conditions can best be evaluated by close observation and testing of the subgrade materials during construction. If significant variations from the conditions anticipated from the test borings appear evident at that time, it may be necessary to re-evaluate the recommendations provided in this report. ANALYSIS AND RECOMMENDATIONS General It is our understanding the existing buildings located at the site will be removed prior to construction of the new townhome structures. We recommend the existing concrete foundation and any other concrete elements be entirely removed from the existing buildings prior to construction of the new structure. Some areas of backfill near the old buildings may be encountered during demolition and removal of the structures. To reduce the potential for differential movement in the foundation and floor slabs subsequent to construction, we recommend all foundation footings extend down to the natural essentially granular materials. The near surface site soils observed are comprised of sandy lean clay soils underlain by essentially granular materials at a depth of approximately 6 to 8 feet below present site grades. To reduce the potential for differential movement in the foundations subsequent to construction, we recommend all foundation footings extend through the sandy lean clay soils and be constructed to bear directly Earth Engineering Company, Inc. EEC Project No. 23-01-183 December 18, 2023 Page 4 on the deeper sand and gravel materials. Based on the observed depth to the essentially granular materials at the completed borings, we estimate the depth of the at-grade (i.e. garage) footing foundation bearing levels would be approximately 6 to 8 feet below present site grades resulting in ‘tall’ at-grade (i.e. garage) foundation walls. Foundations Based on the materials observed at the test boring locations, it is our opinion the proposed lightly loaded multi-family residences could be supported on conventional footing foundations bearing in the near surface low swell potential essentially granular materials. We recommend all foundation footings extend through the sandy lean clay soils and be constructed to bear directly on the low swell potential essentially granular materials. For design of footing foundations bearing in the medium dense to very dense essentially granular materials, we recommend using a net allowable total load soil bearing pressure not to exceed 1,500 psf. The net bearing pressure refers to the pressure at foundation bearing level in excess of the minimum surrounding overburden pressure. Total load should include full dead and live loads. Exterior foundations and foundations in unheated areas should be located at least 30 inches below adjacent exterior grade to provide frost cover protection. We recommend formed continuous footings have a minimum width of 12 inches and isolated column foundations have a minimum width of 24 inches. We recommend the foundation footing design loads be balanced to promote relatively uniform settlement, thereby reducing the potential for differential settlement. As an alternative to balancing the design loads solely on settlement, designing the foundation such that the dead-load pressure is balanced throughout the foundations could be considered. Balancing the dead-load pressure would also reduce the potential for differential settlement between adjacent footings. We estimate the long-term movement of footing foundations designed and constructed as recommended above would be less than 1 inch. No unusual problems are anticipated in the construction of the footing foundations. Care should be taken to avoid disturbing the bearing soils. The natural site soils may be easily disturbed by construction activities. Soils which are disturbed by the construction activities or materials which have become dry and desiccated or wet and softened should be reworked or removed from the Earth Engineering Company, Inc. EEC Project No. 23-01-183 December 18, 2023 Page 5 foundation excavation prior to the placement of foundation concrete. We estimate the long-term movement of footing foundations designed and constructed as outlined above would be less than 1 inch. Floor Slab and Exterior Slab-on-Grade Subgrades Any existing vegetation and/or topsoil should be removed from floor slab areas. After stripping and completing all cuts and prior to placement of any floor slabs or fill, we recommend the exposed subgrades be scarified to a minimum depth of 9 inches, adjusted in moisture content and compacted to at least 95% of the material's maximum dry density as determined in accordance with ASTM Specification D-698, the standard Proctor procedure. The moisture content of the scarified soils should be adjusted to be within the range of ±2% of standard Proctor optimum moisture at the time of compaction. Scarification and compaction of subgrades in the basement areas of the structures would not be required. Fill soils required to develop the floor slab subgrades should consist of approved, low-volume change materials which are free from organic matter and debris. It is our opinion the on-site soils could be used as low-volume change fill in the floor areas. Those fill materials should be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content as recommended for the scarified soils and compacted to at least 95% of standard Proctor maximum dry density. After preparation of the subgrades, care should be taken to avoid disturbing the in-place materials. Subgrade materials loosened or disturbed by the construction activities or materials which become dry and desiccated or wet and softened should be removed and replaced or reworked in place prior to placement of the floor slab concrete. As a precaution, the floor slabs should be isolated from structural portions of the building to prevent distress to the structure due to differential movement of the structural elements. We also recommend isolating the basement floor slab from non-load bearing partitions to help reduce the potential for distress in upper sections of the building due to slab movement. That isolation is typically developed through the use of a voided wall which is suspended from the overhead first floor joist. Care should be exercised when framing doors, drywalling and finishing to maintain a voided space which will allow for movement of the floor slab without transmission of stresses to the overlying structure. Earth Engineering Company, Inc. EEC Project No. 23-01-183 December 18, 2023 Page 6 While laboratory testing completed for this report indicated the site soils sampled exhibited relatively low swell potential, floor slab and exterior flatwork movement could occur and should be expected. Slab movement is common in Colorado even in areas with relatively low-swelling soils. Mitigation techniques to reduce the potential for post-construction movement, such as overexcavation, moisture conditioning and replacement could be considered; however, the risk for slab movement cannot be eliminated. Below Grade Areas We recommend a perimeter drain system be placed around all below grade areas to help reduce the potential for hydrostatic loads developing on below grade walls and/or seepage of infiltration water into below grade areas of the structure. In general, a perimeter drain system would consist of perforated metal or plastic pipe placed around the exterior perimeter of the structure and sloped to gravity drain to a sump area or free outfall where reverse flow cannot occur in the system. The drain line should be surrounded by a minimum of 6 inches of appropriately sized granular filter soil and either the drain line or filter soil should be surrounded by an appropriate filter fabric to reduce the potential for an influx of fines into the system. Backfill placed above the perimeter drain system should consist of approved, low-volume change fill materials which are free from organic matter and debris. The on-site soils could be used for backfill in these areas. If free draining soils are used as backfill, the top 2 feet should be an essentially cohesive material to help reduce the potential for immediate surface water infiltration into the backfill. We recommend those fill materials be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content and compacted to be within the range 94 to 98% of the material's maximum dry density as determined in accordance with ASTM Specification D-698, the standard Proctor procedure. The moisture content of the backfill soils should be adjusted to be within the range of -1% to +3% of standard Proctor optimum moisture at the time of compaction. Care should be taken during backfill placement to avoid placing excessive lateral stresses on the below grade walls. Basement walls for residential structures are commonly designed using an active lateral stress distribution analysis. In that analysis, slight rotation/deflection of the basement wall is assumed. A deflection equal to approximately 0.5% times the height of the wall may be assumed for Earth Engineering Company, Inc. EEC Project No. 23-01-183 December 18, 2023 Page 7 development of the active stresses. That deflection can result in cracking of the basement wall concrete, particularly towards the center of spans. Based on an active stress distribution analysis, we recommend an equivalent fluid pressure of 45 pounds per cubic foot be used for design of the below grade walls. That equivalent fluid pressure does not include a factor of safety nor an allowance for hydrostatic loads. Surcharge loads placed adjacent to the tops of the walls or point loads placed within the wall backfill can also add to the lateral stresses on the below grade walls. Other Considerations Positive drainage should be developed away from the structure with a minimum slope of 1 inch per foot for the first 10 feet away from the building. Care should be taken in planning of landscaping adjacent to the residence to avoid features which would pond water adjacent to the foundations or stemwalls. Plants which require an irrigation system and/or cause substantial fluctuations in the moisture content of the subgrade soils should not be placed adjacent to the structure. Lawn watering systems should not be placed within 5 feet of the perimeter of the building. Spray heads should be designed to spray water away from the structure. Roof drains should be designed to discharge at least 5 feet away from the structure and away from paved areas. GENERAL COMMENTS The analysis and recommendations presented in this report are based upon the data obtained from the soil borings performed at the indicated locations and from any other information discussed in this report. This report does not reflect any variations which may occur across the site. The nature and extent of such variations may not become evident until construction. If variations appear evident, it will be necessary to re-evaluate the recommendations of this report. It is recommended that the geotechnical engineer be retained to review the plans and specifications so comments can be made regarding the interpretation and implementation of our geotechnical recommendations in the design and specifications. It is further recommended that the geotechnical engineer be retained for testing and observations during earthwork and foundation construction phases to help determine that the design requirements are fulfilled. Earth Engineering Company, Inc. EEC Project No. 23-01-183 December 18, 2023 Page 8 This report has been prepared for the exclusive use of Davis Davis Architects for specific application to the subject lots discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranty, express or implied, is made. In the event that any changes in the nature, design or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the conclusions of this report are modified or verified in writing by the geotechnical engineer. We appreciate the opportunity to be of service to you on this project. If you have any questions concerning this report, or if we can be of further service to you in any other way please do not hesitate to contact us. Very truly yours, Earth Engineering Company, Inc. Michael J. Coley, P.E. Principal Engineer MJC/sll DRILLING AND EXPLORATION DRILLING & SAMPLING SYMBOLS: SS: Split Spoon - 13/8" I.D., 2" O.D., unless otherwise noted PS: Piston Sample ST: Thin-Walled Tube - 2" O.D., unless otherwise noted WS: Wash Sample R: Ring Barrel Sampler - 2.42" I.D., 3" O.D. unless otherwise noted PA: Power Auger FT: Fish Tail Bit HA: Hand Auger RB: Rock Bit DB: Diamond Bit = 4", N, B BS: Bulk Sample AS: Auger Sample PM: Pressure Meter HS: Hollow Stem Auger WB: Wash Bore Standard "N" Penetration: Blows per foot of a 140 pound hammer falling 30 inches on a 2-inch O.D. split spoon, except where noted. WATER LEVEL MEASUREMENT SYMBOLS: WL : Water Level WS : While Sampling WCI: Wet Cave in WD : While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB : After Boring ACR: After Casting Removal Water levels indicated on the boring logs are the levels measured in the borings at the time indicated. In pervious soils, the indicated levels may reflect the location of ground water. In low permeability soils, the accurate determination of ground water levels is not possible with only short term observations. DESCRIPTIVE SOIL CLASSIFICATION Soil Classification is based on the Unified Soil Classification system and the ASTM Designations D-2488. Coarse Grained Soils have move than 50% of their dry weight retained on a #200 sieve; they are described as: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are described as : clays, if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse grained soils are defined on the basis of their relative in- place density and fine grained soils on the basis of their consistency. Example: Lean clay with sand, trace gravel, stiff (CL); silty sand, trace gravel, medium dense (SM). CONSISTENCY OF FINE-GRAINED SOILS Unconfined Compressive Strength, Qu, psf Consistency < 500 Very Soft 500 - 1,000 Soft 1,001 - 2,000 Medium 2,001 - 4,000 Stiff 4,001 - 8,000 Very Stiff 8,001 - 16,000 Very Hard RELATIVE DENSITY OF COARSE-GRAINED SOILS: N-Blows/ft Relative Density 0-3 Very Loose 4-9 Loose 10-29 Medium Dense 30-49 Dense 50-80 Very Dense 80 + Extremely Dense PHYSICAL PROPERTIES OF BEDROCK DEGREE OF WEATHERING: Slight Slight decomposition of parent material on joints. May be color change. Moderate Some decomposition and color change throughout. High Rock highly decomposed, may be extremely broken. HARDNESS AND DEGREE OF CEMENTATION: Limestone and Dolomite: Hard Difficult to scratch with knife. Moderately Can be scratched easily with knife. Hard Cannot be scratched with fingernail. Soft Can be scratched with fingernail. Shale, Siltstone and Claystone: Hard Can be scratched easily with knife, cannot be scratched with fingernail. Moderately Can be scratched with fingernail. Hard Soft Can be easily dented but not molded with fingers. Sandstone and Conglomerate: Well Capable of scratching a knife blade. Cemented Cemented Can be scratched with knife. Poorly Can be broken apart easily with fingers. Cemented Earth Engineering Company Group Symbol Group Name Cu≥4 and 1<Cc≤3E GW Well-graded gravel F Cu<4 and/or 1>Cc>3E GP Poorly-graded gravel F Fines classify as ML or MH GM Silty gravel G,H Fines Classify as CL or CH GC Clayey Gravel F,G,H Cu≥6 and 1<Cc≤3E SW Well-graded sand I Cu<6 and/or 1>Cc>3E SP Poorly-graded sand I Fines classify as ML or MH SM Silty sand G,H,I Fines classify as CL or CH SC Clayey sand G,H,I inorganic PI>7 and plots on or above "A" Line CL Lean clay K,L,M PI<4 or plots below "A" Line ML Silt K,L,M organic Liquid Limit - oven dried Organic clay K,L,M,N Liquid Limit - not dried Organic silt K,L,M,O inorganic PI plots on or above "A" Line CH Fat clay K,L,M PI plots below "A" Line MH Elastic Silt K,L,M organic Liquid Limit - oven dried Organic clay K,L,M,P Liquid Limit - not dried Organic silt K,L,M,O Highly organic soils PT Peat (D30)2 D10 x D60 GW-GM well graded gravel with silt NPI≥4 and plots on or above "A" line. GW-GC well-graded gravel with clay OPI≤4 or plots below "A" line. GP-GM poorly-graded gravel with silt PPI plots on or above "A" line. GP-GC poorly-graded gravel with clay QPI plots below "A" line. SW-SM well-graded sand with silt SW-SC well-graded sand with clay SP-SM poorly graded sand with silt SP-SC poorly graded sand with clay Silts and Clays Liquid Limit 50 or more CGravels with 5 to 12% fines required dual symbols: Kif soil contains 15 to 29% plus No. 200, add "with sand" or "with gravel", whichever is predominant. <0.75 OH Primarily organic matter, dark in color, and organic odor ABased on the material passing the 3-in. (75-mm) sieve ECu=D60/D10 Cc= HIf fines are organic, add "with organic fines" to group name LIf soil contains ≥ 30% plus No. 200 predominantly sand, add "sandy" to group name. MIf soil contains ≥30% plus No. 200 predominantly gravel, add "gravelly" to group name. DSands with 5 to 12% fines require dual symbols: BIf field sample contained cobbles or boulders, or both, add "with cobbles or boulders, or both" to group name.FIf soil contains ≥15% sand, add "with sand" to Unified Soil ClaSSifiCation SyStem Soil Classification Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests Sands 50% or more coarse fraction passes No. 4 sieve Fine-Grained Soils 50% or more passes the No. 200 sieve <0.75 OL Gravels with Fines more than 12% fines Clean Sands Less than 5% fines Sands with Fines more than 12% fines Clean Gravels Less than 5% fines Gravels more than 50% of coarse fraction retained on No. 4 sieve Coarse - Grained Soils more than 50% retained on No. 200 sieve Silts and Clays Liquid Limit less than 50 IIf soil contains >15% gravel, add "with gravel" to group name JIf Atterberg limits plots shaded area, soil is a CL- ML, Silty clay GIf fines classify as CL-ML, use dual symbol GC- CM, or SC-SM. 0 10 20 30 40 50 60 0 10 20 30 40 50 60 70 80 90 100 110 PL A S T I C I T Y I N D E X ( P I ) LIQUID LIMIT (LL) ML OR OL MH OR OH For Classification of fine-grained soils and fine-grained fraction of coarse-grained soils. Equation of "A"-line Horizontal at PI=4 to LL=25.5 then PI-0.73 (LL-20) Equation of "U"-line Vertical at LL=16 to PI-7, then PI=0.9 (LL-8) CL-ML 220 EAST OAK STREET EAST OAK TOWNHOMES FORT COLLINS, CO EEC PROJECT No. 23-01-183 DECEMBER 2023 EAST OAK TOWNHOMES FORT COLLINS, COLORADO PROJECT NO: 23-01-183 DATE:DECEMBER 2023 LOG OF BORING B-1 RIG TYPE: CME75 SHEET 1 OF 1 WATER DEPTH FOREMAN: SM START DATE 12/12/2023 WHILE DRILLING NONE AUGER TYPE: 4" CFA FINISH DATE 12/12/2023 AFTER DRILLING NONE SPT HAMMER: AUTO SURFACE ELEV N/A 24 HOUR BACKFILLED SOIL DESCRIPTION D N QU MC DD A-LIMITS -200 SWELL TYPE (FEET)(BLOWS/FT)(PSF)(%)(PCF)LL PI (%)PRESSURE % @ 500 PSF _ _ SANDY LEAN CLAY (CL)2 brown/light brown CS _ _7 9000+13.1 112.4 25 12 51.8 < 500 psf None stiff 4 silty with gravel CS _ _6 9000+17.5 106.0 < 500 psf None 6 _ _ SAND AND GRAVEL (SP-GP)8 brown _ _ medium dense CS 10 20 --8.5 cobbles _ _ 12 _ _ 14 very dense SS _ _50/10"--2.6 16 SANDSTONE/CLAYSTONE _ _ grey/tan/rust 18 hard _ _ CS 20 50/6"9000+14.3 104.4 < 1000 psf None@1000 20' BOTTOM OF BORING _ _ 22 _ _ 24 _ _ 26 _ _ 28 _ _ 30 _ _ 32 _ _ 34 _ _ 36 _ _ 38 _ _ 40 _ _ 42 _ _ 44 _ _ 46 _ _ 48 _ _ 50 Earth Engineering Company EAST OAK TOWNHOMES FORT COLLINS, COLORADO PROJECT NO: 23-01-183 DATE:DECEMBER 2023 LOG OF BORING B-2 RIG TYPE: CME75 SHEET 1 OF 1 WATER DEPTH FOREMAN: SM START DATE 12/12/2023 WHILE DRILLING NONE AUGER TYPE: 4" CFA FINISH DATE 12/12/2023 AFTER DRILLING NONE SPT HAMMER: AUTO SURFACE ELEV N/A 24 HOUR BACKFILLED SOIL DESCRIPTION D N QU MC DD A-LIMITS -200 SWELL TYPE (FEET)(BLOWS/FT)(PSF)(%)(PCF)LL PI (%)PRESSURE % @ 500 PSF _ _ SANDY LEAN CLAY (CL)2 brown to reddish brown _ _ very stiff 4 silty with gravel CS _ _11 9000+8.8 125.1 33 21 13.5 < 500 psf None 6 _ _ 8 _ _ SAND AND GRAVEL (SP-GP)CS 10 50/9"--12.0 brown _ _ very dense 12 cobbles _ _ 14 SS _ _50/8"--2.0 16 _ _ SANDSTONE/CLAYSTONE 18 grey/tan/rust _ _ hard CS 20 50/6"9000+13.9 97.9 < 1000 psf None@1000 _ _ 22 _ _ 24 CS _ _50/4"9000+13.1 93.2 < 1000psf None@1000 26 _ _ 28 SHALE _ _ grey 30 hard to very hard _ _ 32 _ _ 34 _ _ 35' BOTTOM OF BORING 36 _ _ 38 _ _ 40 _ _ 42 _ _ 44 _ _ 46 _ _ 48 _ _ 50 Earth Engineering Company EAST OAK TOWNHOMES FORT COLLINS, COLORADO PROJECT NO: 23-01-183 DATE:DECEMBER 2023 LOG OF BORING B-3 RIG TYPE: CME75 SHEET 1 OF 1 WATER DEPTH FOREMAN: SM START DATE 12/12/2023 WHILE DRILLING NONE AUGER TYPE: 4" CFA FINISH DATE 12/12/2023 AFTER DRILLING NONE SPT HAMMER: AUTO SURFACE ELEV N/A 24 HOUR 24' SOIL DESCRIPTION D N QU MC DD A-LIMITS -200 SWELL TYPE (FEET)(BLOWS/FT)(PSF)(%)(PCF)LL PI (%)PRESSURE % @ 500 PSF _ _ SANDY LEAN CLAY (CL)2 brown CS _ _4 9000+13.6 109.9 < 500 psf None medium stiff to very stiff 4 silty with gravel CS _ _11 9000+14.8 114.0 < 500 psf None 6 _ _ 8 _ _ SAND AND GRAVEL (SP-GP)SS 10 50/9"--2.3 brown _ _ very dense 12 cobbles _ _ 14 SS _ _50/9"--5.0 16 _ _ SANDSTONE/CLAYSTONE 18 grey/tan/rust _ _ hard CS 20 50/6"9000+14.2 102.3 34 16 54.9 < 1000 psf None@1000 _ _ 22 _ _ SHALE 24 grey, hard CS _ _50/4"9000+13.1 97.9 < 1000 psf None@1000 25' BOTTOM OF BORING 26 _ _ 28 _ _ 30 _ _ 32 _ _ 34 _ _ 36 _ _ 38 _ _ 40 _ _ 42 _ _ 44 _ _ 46 _ _ 48 _ _ 50 Earth Engineering Company SWELL / CONSOLIDATION TEST RESULTS Material Description:Brown/Light Brown Sandy Lean Clay with Gravel Sample Location:B-1, S-1 @ 2' Liquid Limit: 25 Plasticity Index: 12 % Passing #200: 51.8 Beginning Moisture: 13.1%Dry Density: 112.4 pcf Ending Moisture: 21.5% Swell Pressure: < 500 psf % Swell @ 500 psf:None Project: East Oak Townhomes Fort Collins, Colorado Project No.: 23-01-183 Date: December 2023 -10 -8 -6 -4 -2 0 2 4 6 8 10 0.01 0.1 1 10 Pe r c e n t M o v e m e n t Load (TSF) Water Added Sw e l l Co n s o l i d a t i o n SWELL / CONSOLIDATION TEST RESULTS Material Description:Brown/Light Brown Sandy Lean Clay with Gravel Sample Location:B-1, S-2 @ 4' Liquid Limit: --Plasticity Index: -- % Passing #200: -- Beginning Moisture: 12.4%Dry Density: 106.0 pcf Ending Moisture: 17.7% Swell Pressure: < 500 psf % Swell @ 500 psf:None Project: East Oak Townhomes Fort Collins, Colorado Project No.: 23-01-183 Date: December 2023 -10 -8 -6 -4 -2 0 2 4 6 8 10 0.01 0.1 1 10 Pe r c e n t M o v e m e n t Load (TSF) Water Added Sw e l l Co n s o l i d a t i o n SWELL / CONSOLIDATION TEST RESULTS Material Description:Grey/Tan/Rust Sandstone/Claystone Sample Location:B-1, S-5 @ 19' Liquid Limit: --Plasticity Index: -- % Passing #200: -- Beginning Moisture: 14.7%Dry Density: 104.4 pcf Ending Moisture: 22.1% Swell Pressure: < 1000 psf % Swell @ 1000 psf:None Project: East Oak Townhomes Fort Collins, Colorado Project No.: 23-01-183 Date: December 2023 -10 -8 -6 -4 -2 0 2 4 6 8 10 0.01 0.1 1 10 Pe r c e n t M o v e m e n t Load (TSF) Water Added Sw e l l Co n s o l i d a t i o n SWELL / CONSOLIDATION TEST RESULTS Material Description:Reddish Brown Sandy Lean Clay with Gravel Sample Location:B-2, S-1 @ 4' Liquid Limit: 33 Plasticity Index: 21 % Passing #200: 13.5 Beginning Moisture: 8.8%Dry Density: 125.1 pcf Ending Moisture: 14.0% Swell Pressure: < 500 psf % Swell @ 500 psf:None Project: East Oak Townhomes Fort Collins, Colorado Project No.: 23-01-183 Date: December 2023 -10 -8 -6 -4 -2 0 2 4 6 8 10 0.01 0.1 1 10 Pe r c e n t M o v e m e n t Load (TSF) Water Added Sw e l l Co n s o l i d a t i o n SWELL / CONSOLIDATION TEST RESULTS Material Description:Grey/Tan/Rust Sandstone/Claystone Sample Location:B-2, S-4 @ 19' Liquid Limit: --Plasticity Index: -- % Passing #200: -- Beginning Moisture: 13.8%Dry Density: 97.9 pcf Ending Moisture: 24.6% Swell Pressure: < 1000 psf % Swell @ 1000 psf:None Project: East Oak Townhomes Fort Collins, Colorado Project No.: 23-01-183 Date: December 2023 -8 -6 -4 -2 0 2 4 6 8 10 12 0.01 0.1 1 10 Pe r c e n t M o v e m e n t Load (TSF) Water Added Sw e l l Co n s o l i d a t i o n SWELL / CONSOLIDATION TEST RESULTS Material Description:Grey/Tan/Rust Sandstone/Claystone Sample Location:B-2, S-5 @ 24' Liquid Limit: --Plasticity Index: -- % Passing #200: -- Beginning Moisture: 13.2%Dry Density: 93.2 pcf Ending Moisture: 25.6% Swell Pressure: < 1000 psf % Swell @ 1000 psf:None Project: East Oak Townhomes Fort Collins, Colorado Project No.: 23-01-183 Date: December 2023 -8 -6 -4 -2 0 2 4 6 8 10 12 0.01 0.1 1 10 Pe r c e n t M o v e m e n t Load (TSF) Water Added Sw e l l Co n s o l i d a t i o n SWELL / CONSOLIDATION TEST RESULTS Material Description:Light Brown Sandy Lean Clay with Gravel Sample Location:B-3, S-2 @ 4' Liquid Limit: --Plasticity Index: -- % Passing #200: -- Beginning Moisture: 13.0%Dry Density: 109.9 pcf Ending Moisture: 19.8% Swell Pressure: < 500 psf % Swell @ 500 psf:None Project: East Oak Townhomes Fort Collins, Colorado Project No.: 23-01-183 Date: December 2023 -10 -8 -6 -4 -2 0 2 4 6 8 10 0.01 0.1 1 10 Pe r c e n t M o v e m e n t Load (TSF) Water Added Sw e l l Co n s o l i d a t i o n SWELL / CONSOLIDATION TEST RESULTS Material Description:Light Brown Sandy Lean Clay with Gravel Sample Location:B-3, S-2 @ 4' Liquid Limit: --Plasticity Index: -- % Passing #200: -- Beginning Moisture: 16.0%Dry Density: 114.0 pcf Ending Moisture: 20.0% Swell Pressure: < 500 psf % Swell @ 500 psf:None Project: East Oak Townhomes Fort Collins, Colorado Project No.: 23-01-183 Date: December 2023 -10 -8 -6 -4 -2 0 2 4 6 8 10 0.01 0.1 1 10 Pe r c e n t M o v e m e n t Load (TSF) Water Added Sw e l l Co n s o l i d a t i o n SWELL / CONSOLIDATION TEST RESULTS Material Description:Grey/Tan/Rust Sandstone/Claystone Sample Location:B-3, S-5 @ 19' Liquid Limit: 34 Plasticity Index: 16 % Passing #200: 54.9 Beginning Moisture: 14.2%Dry Density: 102.3 pcf Ending Moisture: 23.1% Swell Pressure: < 1000 psf % Swell @ 1000 psf:None Project: East Oak Townhomes Fort Collins, Colorado Project No.: 23-01-183 Date: December 2023 -10 -8 -6 -4 -2 0 2 4 6 8 10 0.01 0.1 1 10 Pe r c e n t M o v e m e n t Load (TSF) Water Added Sw e l l Co n s o l i d a t i o n SWELL / CONSOLIDATION TEST RESULTS Material Description:Grey Shale Sample Location:B-3, S-6 @ 24' Liquid Limit: --Plasticity Index: -- % Passing #200: -- Beginning Moisture: 13.0%Dry Density: 97.9 pcf Ending Moisture: 22.6% Swell Pressure: < 1000 psf % Swell @ 1000 psf:None Project: East Oak Townhomes Fort Collins, Colorado Project No.: 23-01-183 Date: December 2023 -10 -8 -6 -4 -2 0 2 4 6 8 10 0.01 0.1 1 10 Pe r c e n t M o v e m e n t Load (TSF) Water Added Sw e l l Co n s o l i d a t i o n