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Home My WebLink AboutROCKBRIDGE CONDO RESIDENCES PUD MINOR SUBDIVISION - 82 93B - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTu ' UNIFIED SOIL CLASSIFICATION SYSTEM Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Coarse -Grained Gravels more than Cleans Gravels Less Soils more than i0%of coarse than 5% fines` 504o retained on fraction retained No. 200 sieve on No. 4 sieve Fine -Grained Soils 50%or more passes the No. 200 sieve Sands 50% or more of coarse fraction passes No. 4 sieve Silts and Clays Liquid limit less than 50 Gravels with Fines more than 12% finest Clean Sands Less than 5% fines'` Sands with Fines more than 12% fines" inorganic organic Cu>4and1 <Cc<3' Cu < 4 and/or I > Cc > 3' Fines classify as NIL or MH Fines classify as CL or CH Cu > 6 and I < Cc < 3' Cu < 6 and/or I > Cc > 3' Fines classif\as ML or MH Fines classify as CL or CH PI > 7 and plots on or above "A" line' PI < 4 or plots below "A" line' Liquid limit - oven dried Liquid limit - not dried Silts and Clays inorganic PI plots on or above "A" line Liquid limit 50 or more PI lots below "A" line organic Liquid limit - oven dried Liquid limit - not dried High]\ organic soils Primarily organic matter. dart: in color- and organic odor "Based on the material passing the 3-in. (75- mm) sieve ECu•D °!D 10 C,. tD101 D XD alf field sample contained cobbles or boulders. 10 `° or both. add "with cobbles or boulders. or both" to group name. `Gravels with 5 to 12% fines require dual symbols: GW-GM "yell -graded gravel with silt GW-GC well -graded gravel with cla" GP -GM poorly graded gravel with silt GP -GC poorly graded gravel with clay "Sands with 5.to 12% fines require dual s}'mbols: SR'-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 it `If soil contains > IS%sand. add "with sand" to group name. °If fines classify as CL-ML. use dual symbol GC -CM. or SC-SM. "If fines are organic. add "with organic fines" to roup name. 'If soil contains > 15% gravel. add "with gravel" to group name. 'If Atterberg limits plot in shaded area. soil is a CL-ML. silty clay. Soil Classification Group Group Name" Symbol GW Well -Waded eravelr GP Poorly graded gravel! G\I Silt\ gravel. G. H GC Clayey gravel"'" SW Well -graded sand' SP Poorly graded sand' SM Silty sand""' SC Clayey sand`i"' CL Lean clay"'-"' ML Silt"''" Organic clay" MN < 0.75 OL Organic silt"-`") CH Fat clay"L" \1H Elastic Silt"" Organic clay".L".J` < 0.75 OH Organic silt"-" Q PT Peat "If soil contains 15 to 29% plus No. 200. add "with sand" or "with gravel". whichever is predominant. 'If soil contains > 30% plus No. 200 predominantly sand. add "sand\" to group name. "If soil contains > 30% plus No. 200. predominantly _gravel. add "gravelly" to group name. "PI > 4 and plots on or above "A" line. "PI < 4 or plots below "A" line. 'P1 plots on or above "A" line. "PI plots below "A" line. i:n4C LAi / / / / N- MLo+aL � to to zo 31 10 .. !° » 80 a° too u° DRILLING & SAMPLING SYMBOLS ■._ SS: Split Spoon - 1318" 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 Care in WD : \Vhile Drilling DCI: Dry Cave in BCR: Before Casing Removal AB : After Boring ACR: After Casting Removal Water levels indicated on the boring loos are the levels measured in the borines 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 weieht retained on a =200 sieve: thev 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 Densitv 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 fingemail. Shale. Siltstone and Claystone: Hard an 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. Poorlv Can be broken apart easily with fingers. Cemented EEG 14 ROCKBRIDGE CONDOMINIUMS FORT COLLINS, COLORADO PROJECT NO: 1952085 DATE: NOVEMBER 1995 LOG OF BORING B-7 RIG TYPE: CME45 SHEET 1 OF 1 WATER DEPTH FOREMAN: BDT START DATE 11/6195 WHILE DRILLING None AUGER TYPE: 4" CFA FINISH DATE 11I6195 AFTER DRILLING None SPT HAMMER: MANUAL SURFACE ELEV N/A 24 HOUR NIA SOIL DESCRIPTION D N OU MC I OD A•LIMITS Q00 SWELL LL I PI PRESSURE 500 PSF TYPE IFEE11 (BLOWSffTI IPSF) 1%) IPCF) (%I 5" TOPSOILNEGETATION SANDY LEAN CLAY WITH GRAVEL (CL) 1 brown stiff to very stiff 2 12 '9000. 12.8 SSS 3 4 SS 10 -4500 10.1 CLAYEY SILT WITH GRAVEL (ML-CL) 5 tan stiff 6 7 8 SANDY LEAN CLAY (CL) brownlred _ _ stiff 9 10 18 I '9000. 12.3 i 11 softer with depth ( 12 13 14 6 I '3D00 20.6 SS IS BOTTOM OF BORING 15' 16 17 1B 19 20 21 22 23 24 25 Earth Engineering Consultants 1 ROCKBRIDGE CONDOMINIUMS FORT COLLINS, COLORADO PROJECT NO: 1952085 DATE: NOVEMBER1995 LOG OF BORING 9-6 RIG TYPE: CME45 SHEET 1 OF 1 WATER DEPTH FOREMAN: BDT START DATE 11/6195 WHILE DRILLING None AUGER TYPE: 4" CFA FINISH DATE 1116/95 AFTER DRILLING None SPT HAMMER: MANUAL SURFACE ELEV NIA 5 DAYS AFTER DRILLING I N/A SOIL DESCRIPTION J D N oU MC 00 A -LIMITS -200 SWELL LL PI PRESSURE I%G 500PSF IfTYPE IFEETI IBLOWS/FTI IPSFI I%) IPCFI I%1 5" TOPSOILrVEGETATION SANDY LEAN CLAY (CL) 1 brown stiff to very stiff 2 12 '9000• 11.3 SS _3_ 4 14 •5000 10.1 I I I SS SANDY LEAN CLAY WITH GRAVEL (CL) 5 light brown/red - stiff to very stiff 6 7 8 less gravel with depth 9 I 11 •9000+ 9.2 I I I I SS 10 11 soft below 12 feet 12 13 3 29.8 014 SS 15 BOTTOM OF BORING 15' 16 17 18 19 20 21 22 23 24 25 Earth Engineering Consultants ROCKBRIDGE CONDOMINIUMS FORT COLLINS, COLORADO PROJECT NO: 1952085 DATE: NOVEMBER 1995 LOG OF BORING 8.5 RIG TYPE: CME45 SHEET 1 OF 1 WATER DEPTH FOREMAN: SOT START DATE 1116195 WHILE DRILLING None AUGER TYPE: 4" CFA FINISH DATE 11/6/95 AFTER DRILLING None SPT HAMMER: MANUAL SURFACE ELEV N/A 24 HOUR N/A SOIL DESCRIPTION 0 R I DU Me 0o A -LIMITS -200 SWELL LL PI PRESSURE 500P5F TYPE (FEET) IBLOWSIFTI IPSFI (%) (RCFI 1%) 5" TOPSOILfVEGETATION SANDY LEAN CLAY (CL) t brown stiff 2 10 '9000. 10.0 SS 3 4 SANDY CLAYEY SILT (ML•CL) SS 23 I '8000 12.1 tan 5 stiff to very stiff - 6 7 8 SANDY LEAN CLAY (CL) brown stiff SS 9 10 11 I -8500 19.0 11 12 more sand with depth 13 14 11 I 15500 18.3 _ _ ISS 15 BOTTOM OF BORING 15' 16 17 18 19 20 21 22 23 24 25 Earth Engineering Consultants ROCKBRIDGE CONDOMINIUMS FORT COLLINS, COLORADO PROJECT NO: 1952085 DATE: NOVEMBER 1995 LOG OF BORING B-4 RIG TYPE: CME45 SHEET 1 OF 1 WATER DEPTH FOREMAN: EDT START DATE 1116195 WHILE DRILLING None AUGER TYPE: 4" CFA FINISH DATE 11/6195 AFTER DRILLING I None SPT HAMMER: MANUAL SURFACE ELEV N/A 24 HOUR NIA SOIL DESCRIPTION D N OU MC DD A -LIMITS -200 SWELL LL FI PRESSURE 500 PSF TYPE (FEET) (BLOWSIFT) IPSFI fXl IPCF) (A) 5" TOPSOILIVEGETATION 1 SANDY LEAN CLAY (CL) tan 2 10 •9000+ 10.2 stiff to very stiff SS 3 4 11 •8500 1 1s.o 7-7 ss s 6 7 SANDY LEAN CLAY WITH GRAVEL (CL) red/brown stiff 8 9 15 •9000. I 12.3 i 10 11 12 13 SANDY LEAN CLAY (CL) brown 14 12 -9000* 15.6 stiff to very still SS 15 BOTTOM OF BORING 15' - 16 17 18 19 20 21 22 23 24 25 Earth Engineering Consultants ROCKBRIDGE CONDOMINIUMS FORT COLLINS, COLORADO PROJECT NO: 1952085 DATE: NOVEMBER 1995 LOG OF BORING B•3 RIG TYPE: CME45 SHEET 1 OF 1 WATER DEPTH FOREMAN: BDT START DATE 1 1116195 WHILE DRILLING None AUGER TYPE: 4-CFA FINISH DATE 11/6195 AFTER DRILLING None SPT HAMMER: MANUAL SURFACE ELEV I NIA 24 HOUR N/A SOIL DESCRIPTION D I N Ou MC DO A -LIMITS -200 SWELL LL PI PRESSURE %R 500 CSF TYPE IFEETI ISLOWSIFT) (PSF) (•n) (PCF) I%) 5" TOPSOIL/VEGETATION 1 SANDY LEAN CLAY JCL) tan/light brown 2 IO •8500 14.0 sitff to very stiff SS 3 4 11 I -9000+ I 11.3 SS 5 6 7 8 9 SS 22 •9000+ 17.6 SANDY LEAN CLAY (CL) 10 brown/tan stiff 11 12 13 14 COARSE SAND (SP) SS 17 •1500 20.0 brown, medium dense 15 BOTTOM OF BORING 15' 16 17 18 19 20 21 22 23 24 25 tarEn t_ngineenng consunants ROCKBRIDGE CONDOMINIUMS FORT COLLINS, COLORADO PROJECT NO: 1952085 DATE: NOVEMBER 1995 LOG OF BORING B-2 RIG TYPE: CME45 SHEET 1 OF 1 WATER DEPTH FOREMAN: SOT STARTDATE 11/6195 WHILE DRILLING I 19.0 AUGER TYPE: 4" CFA FINISH DATE 1116195 AFTER DRILLING NIA SPT HAMMER: MANUAL SURFACE ELEV NIA 24 HOUR NIA SOIL DESCRIPTION D N I OU MC I DD ALIMITS -200 SWELL LL PI PRESSURE R Q SW PSF TYPE (FEETI ISLOWLFT) IPSF) IXI IPCF) (%1 5" TOPSOIL(VEGETATION SANDY LEAN CLAY(CL) 1 brownfli0ht brown stiff to very stiff 2 SILTY SANDY LEAN CLAY WITH ss 45 I -8000 3.3 GRAVEL(CL) tan/white _3_ stiff to very stiff 4 I 28 L .5500 4.2 I ss SAND AND GRAVEL, TRACE 5 FINES (SP/SC) - red/brown 6 medium dense to loose more clay with depth i 8 9 Ss 14 I •9000+ 10.3 I COARSE SAND AND GRAVEL (SP/GP) 10 redttan/brown loose to medium dense 11 12 13 14 14 I 5.1 SS 15 16 17 18 19 20 21 22 WEATHERED SHALE olivelrust/gn soft to moderately hard 23 24 22.7 AS BOTTOM OF BORING 25' 25 Earth Engineering Consultants ROCKBRIDGE CONDOMINIUMS FORT COLLINS, COLORADO PROJECT NO: 1952085 DATE: NOVEMBER 1995 LOG OF BORING B•1 RIG TYPE: CME45 SHEET 1 OF 1 WATER DEPTH FOREMAN: BDT START DATE 1116195 WHILE DRILLING I None AUGER TYPE: 4" CFA FINISH DATE 1116/96 AFTER DRILLING 1 None SPT HAMMER: MANUAL SURFACE ELEV N/A 24 HOUR I NIA SOIL DESCRIPTION D N DU MC OD A -LIMITS .200 SWELL LL PI PRESSURE % $00 PSF TYPE IFEETI (BLOWSIFT) IPSFI 1•AI (PCF) 1%) 5" TOPSOILNEGETATION 1 SANDY LEAN CLAY (CL) brown/light brown 2 35 '9000• 9.6 stiff to very Stitt .SS 3 SANDY LEAN CLAY (CL) tanked 4 1 43 '9000. 4.6 very stiff SS 6 less clay with depth gravel with depth 6 7 8 SANDY SILTY LEAN CLAY (CL) redttan 9 20 -3000 7.7 stiff Ss 10 11 12 LEAN CLAY W/ VERY LITTLE SAND (CL) tan/red soft 13 14 8 I '3500 7.7 SS 15 BOTTOM OF BORING 15' 16 17 18 19 20 21 22 23 24 25 Earth Engineering Consultants B-3 N B-4 B-2 B-7 u C B-5 B-1 0 B-6 _ 0 w x HARMONY DRIVE BORING LOCATION DIAGRAM ROCKBRIDGE CONDOMINIUMS FORT COLLINS, COLORADO EARTH ENGINEERING CONSULTANTS I, 1 Earth Eneineerine Consultants. Inc. Rockbridee Condominiums November 10, 1995 - Paoe 7 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 that 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. This report has been prepared for the exclusive use of The Nichols Partnership, Inc. for specific application to the project 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 modified or verified in writing by the geotechnical engineer. Earth Engineering Consultants, Inc. Rockbridge Condominiums November 10, 1995 Pate 6 . After preparation of the subgrades, care should be taken to avoid disturbing the in -place materials. Subgrade materials which are loosened or disturbed by the construction activities or materials which become dry and desiccated or wet and softened should be removed and replaced or densified in place prior to construction of the overlying floor slabs or pavements. Positive drainage should be developed away from the new buildings to avoid wetting the bearing or subgrade materials. Positive drainage should also be developed across and away from the pavement edges to avoid wetting the pavement base and/or subgrade. Pavements We anticipate the traffic on the on -site pavements will involve low to moderate volumes of light vehicles including automobiles and light trucks. Based on previous experience with similar subgrade and traffic conditions, we recommend the pavement section for this project consist of 3 inches of hot bituminous pavement overlying 6 inches of aggregate base. Asphalt for the pavement should consist of SCI or SCII surface asphalt in accordance with City of Fort Collins standard criteria. Aggregate base should be compatible with. Class 5 or Class 6 base as defined by Colorado Department of Transportation Standard Specifications for Road and Bridge Construction. Thinner pavement sections could be used in areas where the pavement will be used solely for parking of automobiles. The recommended pavement section is a minimum and, as such, periodic maintenance should be expected. 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 between borings or across the site. The nature and extent of such variations may not become evident until c 9 Earth Engineering Consultants, Inc. Rockbridee Condominiums November 10, 1995 Page 5 minimum width of 30 inches. Trenched foundations could be used in the near surface cohesive soils. If used, we recommend those foundations have a minimum width of 12 inches. Care should be taken during construction to avoid disturbing the bearing materials. Materials which are loosened or disturbed by the construction activities. or materials which become dry and desiccated or wet and softened should be removed and replaced prior to placement of foundation concrete. We estimate the lone -term settlement of footing foundations designed and constructed as outlined above would be less than 3/4 inch. Floor Slab and Pavement Subgrades All existing vegetation and/or topsoil should be removed from the floor slab areas. After stripping and completing all cuts and prior to placement of any floor slabs, fill or pavements, 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 prior to compaction. Fill materials required to develop the floor slab or pavement subgrade should consist of approved. low -volume change soils which are free from organic matter -and debris. Normally, low volume change soils will have a liquid limit of 40 or less and plasticity index of 18 or less. Based on results of the field borings and laboratory testing, we believe the near surface soils could be used as low -volume change fill beneath the floor slabs and pavements. Soils in these areas should be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content as recommended for the scarified materials and compacted to at least 95 % of the material's maximum dry density as determined in accordance with the standard Proctor procedure. J Earth EnEineering Consultants, Inc. Rockbridge Condominiums November 10, 1995 Page 4 WATER LEVEL OBSERVATION Observations were made while drilling and after completion of the borings to detect the presence and depth to hydrostatic groundwater. Free water was observed only in boring B-2 at the time of drilling. The depth to groundwater at that location was approximately 19 feet. The site cohesive soils would have low permeability so that longer term observations would be required to more accurately evaluate groundwater conditions. Zones of perched and/or trapped water may also be encountered at times throughout the year in the more permeable zones in the interbedded soils. The location and amount of perched/trapped water and the depth to the h} drostatic groundwater table can vary over time depending on hydrologic conditions and other conditions not apparent at the time of this report. ANALYSIS AND RECONUMENDATIONS Foundations Based on results of the field borings and laboratory testing as outlined in this report, it is our opinion the proposed condominium buildings could be supported on conventional footing foundations bearing in the natural site soils. We recommend footing foundations extend through all existing vegetation and/or topsoil and bear in the natural, stiff to very stiff sandy lean clay or medium dense silty/clayey fine to medium sand. For design of footing foundations bearing on the natural, stiff to very stiff cohesive soils or medium dense essentially granular materials, we recommend using a net allowable total load soil bearing pressure not to exceed 2,500 psf. The net bearing pressure refers the pressure at foundation bearing level in excess of the minimum surrounding overburden pressure. Total load should include both dead and live loads. A minimum dead load pressure of 500 psf should be used on the footings to reduce the potential for movement of the footings with moisture fluctuations in the bearing soils. Exterior foundations and foundations in unheated areas should be located a minimum of 30 inches i below final adjacent exterior grades to provide frost protection. We recommend formed continuous footings have a minimum width of 16 inches and isolated column foundations have a Earth Eneineerin_ Consultants, Inc. Rockbridse Condominiums November 10, 1995 — Pa2e 3 grass Around covering. Site drainage appears to be the south and east with maximum difference in ground surface elevations across the site on the order of 2 to 3 feet. Evidence of prior building construction was not observed at the site by EEC field personnel. An EEC geologist was on site during drilling to evaluate the subsurface materials encountered and direct the drilling activities. Field loos prepared by the EEC geologist were based on visual and tactual observation of disturbed samples and auger cuttings. Final boring logs included with this report may include modifications to those field logs based on the results of laboratory testing and engineering evaluation. Based on the results of the field borings and laboratory testing. subsurface conditions can be generalized as follows. Approximately 4 to 5 inches of vegetation and/or topsoil was encountered at the ground surface at the boring locations. The topsoil/vegetation was underlain by brown and light brown lean clay with varying amounts of silt and sand. The cohesive soils were stiff to very stiff and exhibited low to moderate plasticity. At some boring locations. interbedded zones of silry/clayey sand were encountered in the predominately cohesive soil subgrade. The thickness of the granular or essentially granular soils ranged from 2 to 6 feet. The granular site soils were medium dense. The interbedded cohesive and granular soils extended to depth of approximately 21 feet in boring B-2 and to the bottom of the other borings at depths of approximately 15 feet. In boring B-2, the overburden soils were underlain by highly weathered shale bedrock. The shale bedrock was colored light brown and was soft to moderately hard. Those materials were moderately to highly plastic. The highly weathered bedrock extended to the bottom of boring B-2 at a depth of approximately 25 feet below existing ground surface. The stratification boundaries indicated on the boring logs represent the approximate locations of changes in soil and rock types; in -situ, the transition of materials may be gradual and indistinct. Classification of the bedrock was based on visual and tactual observation of disturbed samples Iand auger cuttings. Coring and/or petrographic analysis may reveal other rock types. J Earth Ensineering Consultants, Inc. Rockbridee Condominiums November 10. 1995 Paee 2 The borings were performed using a truck mounted. CME 45 drill rig, equipped with a hydraulic head employed in drilling and sampling operations. The boreholes were advanced using 4-inch nominal diameter continuous flight augers and samples of the subsurface materials encountered were obtained using split -barrel sampling techniques in general accordance with ASTM Specifications D-1546. In the split -barrel sampling procedure, a standard 2-inch O.D. split -barrel sampling spoon is driven into the ground by means of a 140 pound hammer falling a distance of 30 inches. The number of blows required to advance the split barrel sampler is recorded and is used to estimate the in -situ relative density of cohesionless materials and, to a lesser degree of accuracy, the consistency of cohesive soils and hardness of weathered bedrock. All samples obtained in the field were sealed and returned to the laboratory for further examination, classification and testing. Moisture content tests were performed on each of the recovered samples. The unconfined compressive strength of appropriate samples was estimated using a calibrated hand penetrometer. Atterberg limits and washed sieve analysis tests were performed on selected samples to establish the quantity and plasticity of fines in the subgrade materials. Swell/consolidation tests were also performed on selected samples to evaluate the soils tendency to change volume with variation in moisture content. Results of the outlined tests are indicated on the attached borine log and summary sheets. As a part of the testing program, all samples were examined in the laboratory by an engineer and classified in accordance with the attached General Notes and the Unified Soil Classification System, based on the soil's texture and plasticity. The estimated group symbol for the Unified Soil Classification System is shown on the boring logs and a brief description of that classification system is included with this report. SITE AND SUBSURFACE CONDITIONS The Rockbridge Condominiums will be constructed north of Harmony Road and west of Wheaton Drive in Fort Collins, Colorado. The development site is an existing open field with weed and 9 SL"BSLRFACE EXPLORATION REPORT PROPOSED ROCKBRIDGE CONDOMINIUMS HARMONY ROAD AT WHEATON DRIVE FORT COLLINS, COLOR -ADO EEC PROJECT NO. 1952085 INTRODUCTION The subsurface exploration for the proposed Rockbridge Condominiums at Harmony Road and Wheaton Drive in Fort Collins. Colorado, has been completed. Seven soil borings extending to depths ranging from approximately 15 to 25 feet below present site grades were advanced in the proposed development area to obtain information on existing subsurface conditions. Individual boring Ions and a diagram indicating the approximate boring locations are included with this report. We understand this project involves the development of approximatel} 10 acres of open field located north of Harmony Road and west of Wheaton Drive in Fort Collins. Colorado. The development will include 24, 17 and 26 plex condominium units as two and three-story wood frame structures. Foundation loads for the proposed buildings will be light with continuous wall loads less than 4 kips per lineal foot and column loads less than 100 kips. Paved drive and parking areas will be constructed as a part of the condominium development. Cuts and fills less than 2 feet will be required to develop the final site grades. The purpose of this report is to describe the subsurface conditions encountered in the borinss. analyze and evaluate the test data and provide geotechnical recommendations concerning design and construction of foundations and support of floor slabs and pavements. EXPLORATION AND TESTING PROCEDURE The boring locations were established in the field by Earth Engineering Consultants, Inc. (EEC) personnel. The field locations were determined by pacing and estimating angles from the references indicated on the attached boring location diagram. The locations of the borings should be considered accurate only to the degree implied by the methods used to make the field measurements. I 0-1 November 10. 1995 The Nichols Partnership. Inc. >j Madison Street. Suite 280 Denver, Colorado 80206 Attn: Ms. Joii Robertson Re: Subsurface Exploration Report RockbridQe Condominiums Harmony Road and Wheaton Drive Fort Collins. Colorado EEC Project No. 1952085 Ads. Robertson: EARTH ENGINEERING CONSULTANTS, INC. Enclosed, herewith, are the results of the subsurface exploration you requested for the RockbridQe Condominiums to be constructed northwest of the intersection of Harmony Road and Nk7heaton Drive in Fort Collins. Colorado. In summary, the subsurface soils at this site consisted of low plasticity cohesive materials with varying amounts of sand interbedded with essentially granular materials containing van-ing amounts of low plasticity fines. Weathered shale bedrock was encountered at a depth of approximately 21 feet in one of the test borings. Based on the results of the field borings and laboratory testing, it is our opinion the near surface soils could be used for direct support of the proposed site structures using conventional footing foundations. The near surface low plasticity soils could also be used for direct support of floor slabs and pavements for this project. Geotechnical recommendations concerning design and construction of foundations and support of floor slabs and pavements are presented in the text of the attached report. If you have any questions concerning the enclosed report, or if we can be of further service to you in any other wvay, please do not hesitate to contact us. Very truly yours. Earth Engineering Consultants, Inc. Lester L. Litton. P.E. ' Principal Engineer LLL/dmf Centre For Advanced Technology 2301 Research Boulevard, Suite 104 Fort Collins, CO 60526 (970) 224-1522 FAX 224-4564 SUBSURFACE EXPLORATION REPORT ROCKBRIDGE CONDOMINIUMS HARMONY ROAD AND WHEATON DRIVE FORT COLLINS, COLORADO EEC PROJECT NO. 1952085