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Home My WebLink About20101351.tiff 1 I . 1 GEOTECHNICAL INVESTIGATION ' PART OF THE NW% OF SECTION 25, T.2N. , R. 68W. OF THE 6TH P.M. , t WELD COUNTY, COLORADO FOR DENNIS LOPEZ 1 1 . I • ' CDS ENGINEERING CORPORATION LOVELAND, COLORADO ' PROJECT NUMBER 99-0380 JANUARY 3 , 2000 • 2010-1351 CDSEngineering Corporation ' January 3 , 2000 Project No . 99-0380 Mr . Dennis Lopez 5096 WCR 18 Longmont, CO 80504 ' Dear Dennis, Enclosed is the report you requested of the geotechnical investigation for the proposed residence to be located on part of ' NWW' of Section 25, T.2N. , R. 68W. of the 6th P.M. , Weld County, Colorado . I • The site is suitable for the construction of the proposed residence, provided the design criteria and recommendations given in this report are met . If you have any further questions concerning the information in this report, please contact this office. ' Respectfully, ' CDS ENGINEERING CORPORATION Reviewed By : O2qo S Robert R. Greenwald II, E . I .T. ',cccl- -roe ?' J . Wernsinz,nY � .t, RG/add f� 55` ' Enclosures • 165 2nd Street S.W. • Loveland, CO 80537 • (970)667-8010 • Fax: (970) 667-8024 I ' • TABLE OF CONTENTS 1 Page ' Letter of Transmittal i Table of Contents ii IScope 1 Site Investigation 1 ISite Location and Description 1 ISubsurface Conditions 2 Foundation Recommendations 2 , 3 I - Continuous Spread Footing and/or Grade Beam 3 Slab Construction 3 , 4 I Concrete Reinforcement 4 I • Foundation Drain System 4 Conclusions 5 I ILocation of Test. Borings Drawing No . 1 Symbols and Soil Properties Diagram No . 1 ILog of Borings Drawing No . 2 ISwell-Consolidation Test Results Figure Nos . 1-1 to 1-3 Summary of Test Results Table No . 1 I Post-Construction Site Preparation and Maintenance Appendix 1 I I . ii 1 I • 1 ' SCOPE This report presents the results of a geotechnical investigation for the proposed residential building to be located on part of the NWW, Section 25, T.2N. , R. 68W. of the 6th P.M. , Weld County, Colorado. The investigation was prepared by means of test ' borings and laboratory testing of samples obtained from these borings . ' This investigation was made to determine the type and depth of foundation, allowable soil bearing pressures, groundwater conditions, and any problems that might be encountered during or after construction due to subsurface conditions . 1 SITE INVESTIGATION The field investigation performed on December 2 , 1999 consisted of drilling, logging, and sampling two (2 ) test holes . I • The Location of the Test Holes is shown on Drawing No. 1 . A Log of Borings is shown on Drawing No. 2 . A Summary of the Swell- Consolidation Test Results is shown on Figure Nos . 1-1 to 1-3 . A Summary of Test Results is shown on Table No. 1 . The test borings were advanced with a four-inch (4" ) diameter ' auger drill . Laboratory samples were obtained by driving a two and one-half inch (2%) California type sampler into undisturbed soils with a 140-pound hammer falling thirty inches (30 " ) and by taking bag samples of auger cuttings . ' Laboratory tests performed were - Swell-Consolidation, Natural Moisture, Natural Dry Densities, Grain-Size Analysis, Unconfined Compressive Strengths, and Atterberg Limits . ' SITE LOCATION AND DESCRIPTION The site is located west of the Town of Firestone, Weld ' County, Colorado, east of Interstate 25 . The site slopes slightly • to the south, and vegetation consists of various grasses and small ' brush. • 2 SUBSURFACE CONDITIONS Refer to Log of Borings, Drawing No . 2 . The subsurface ' conditions appear uniform throughout the site . A general description of the soils and/or rock encountered are as follows : Topsoil - A layer of approximately six inches ( 6" ) of topsoil overlies the site. The topsoil should not be used as foundation bearing material, structural fill, or backfill . It is suggested that the topsoil which has been stripped be stockpiled and used for landscaped areas . ' Sandy Clay- Brown, medium stiff, slightly moist sandy clay was encountered beneath the topsoil to a depth of two to three feet (2-3 ' ) . Clayey Sand-Brown, moist to wet, clayey sand was encountered I • beneath the top soil to a depth of five to eight feet (5 ' -8 ' ) . ' Sandy Clay- Brown, wet, soft, sandy clay was encountered beneath the clayey sand to a depth of twelve feet (12 ' ) . ' Bedrock- Olive-brown, moist, weathered to unweathered claystone beneath the sandy clay to a depth of sixteen feet (16 ' ) , where ' drilling operations ceased. ' Groundwater was encountered in the test holes twenty-four (24) hours after drilling at a depth of six feet ( 6 ' ) . FOUNDATION RECOMMENDATIONS ' The type of foundation best suited for a particular building site is dependant not only on the characteristics of the soil and rock but also depends on the type of structure, depth to ' groundwater, the proposed depth of excavation, and owner • preference. The recommendations that follow are primarily based on ' the type of soil encountered. • 3 ' The upper soils at the site exhibit no swell pressures and a volume change as high as -0 . 1% when wetted. The lower soils ' exhibit no swell pressures with no volume change . Due to the conditions mentioned above, we recommend the foundation be a continuous spread footing and/or grade beam foundation. Continuous Spread Footing and/or Grade Beam Foundations The foundation should be a continuous spread footing and/or ' grade beam foundation designed for a maximum allowable bearing capacity of 1000 pounds per square foot (dead load plus full live load) . The foundation is to bear on sandy clay/clayey sand, and not on uncompacted fill, topsoil, or frozen ground. The bottom of all foundation components should be kept at least ' twenty-four inches (24" ) above the highest groundwater depth and at least thirty inches (30 " ) below finished grade for frost I , protection. The open excavation should not be left open for an extended period of time or exposed to adverse weather conditions . The completed open excavation should be inspected by a representative of CDS Engineering Corporation in order to verify the subsurface conditions from test hole data . ' SLAB CONSTRUCTION Changes in the moisture contents may result in consolidation or swelling of the subsoils, resulting in vertical slab movement . Therefore, slabs constructed should be " free-floating" so that the ' slabs can move unimpaired. Slabs placed on potentially expansive soils are expected to heave . ' Slabs should be isolated from all structural members of the foundation, utility lines, and partition walls . There should be a minimum two-inch (2 " ) void placed above or below partition walls ' located over slabs for slabs placed on the upper soils . The void • should be increased to four inches (4" ) for slabs placed on bedrock ' stratum. Failure to allow the slab to float independently will I I . 4 Imost likely result in structural , architectural, and utility line damage . All slabs should be scored into maximum 225 square foot I areas or maximum dimensions of fifteen feet (15 ' ) with a minimum depth of one inch (1" ) to localize and control any cracking due to heaving. Slabs less than thirty foot (30 ' ) square should be scored I at least once in each direction. The minimum slab thickness should be four inches (4" ) , with four inches (4" ) of clean, washed gravel Iunder the slab. A polyethylene moisture barrier is recommended under slabs in habitable areas to prevent moisture migration Ithrough slabs . CONCRETE REINFORCEMENT The reinforcement listed below are recommended minimums . I Caissons should be reinforced with a minimum of two (2) No. 5 Grade 60 rebar for the full length and extending into the grade beams I . with a minimum of twelve inches (12 " ) . Grade beams should be reinforced with two (2 ) No. 5 Grade 60 rebar top and bottom with a I middle row of two (2) rebar for basement heights . Spread Footings should be reinforced with a minimum of two (2) No.4 Grade 60 rebar . I Foundation walls on footings should be reinforced the same as the grade beams for caissons with the exception that No. 4 rebar may be used. Floating slabs should be reinforced with a minimum WWF 6 x I6 10/10 . I FOUNDATION DRAIN SYSTEM I A peripheral or perimeter drain system is recommended where slabs are to be placed below finished grade . The drain should flow I by daylighting. If this is not possible, the drain should be connected to the storm sewer, or provisions for a sump pump for ' future installation. 1 i • 5 CONCLUSIONS The soils and rock at the site shows a low consolidation 1 potential; therefore, future owners should be cautioned that there is a low risk of future damage caused by introduction of excess 1 water to the soils and/or rock. All future owners should be directed to those items under " Post-Construction Site Preparation and Maintenance" in Appendix I, included in this report . Our experience has shown that damage to foundations usually results from saturation of the foundation soils caused by improper 1 drainage, excessive irrigation, poorly compacted backfills, and leaky water and sewer lines . The elimination of the potential sources of excessive water will greatly minimize the risks of construction at this site . 1 The findings and recommendations of this report have been obtained in accordance with accepted professional engineering practices in the field of Geotechnical Engineering. There is no I • other warranty, either expressed or implied. This report applies only to the type of construction anticipated in the area tested. 1 The current technology is not at a stage where a guarantee of "absolutely no damage" can be assured by design and construction practices . 1 1 1 1 • 1 1 • BORING LOCATION PLAN ' NW 1/4, SECT. 25, T 2N, R 68W WELD COUNTY, ' COLORADO ' WCR 18 , 4 0 I I 1 • I I PH6 A PH{ PROPOSED SEPTIC'nap PFi1 PPH2 PHJ I PROPOSED HOUSE SCALE: NTS PROJECT NO.: 99-0380 DATE: 12/28/99 CDS Engineering Corporation DRAWING NO.: 1 OFLD BOOK: REVISION NO.: ' DRAWN: RRG 165 2nd St. S.W. CLIENT: DENNIS LOPEZ Loveland, CO 80537 CHECKED: AJW Tele: (970) 667-8010 SHEET 1 OF1 I SYMBOLS AND SOIL PROPERTIES II • SOIL AND POCK - DIAGRAM NO. 1 SAMPLERS I CLAY (CL,OL,M . CH,OH) ' CALIFORNIA iii% SILT (ML,OL ) THIN-WALLED iii. N. ' SAND (SN,SP,SM,SC) SPLIT BARREL ' s � GRAVEL (GW,GP,GM,GC) i BAG SAMPLE 17 .7 K.)' WEATHERED ROCK ��.• II PITCHER I thgq SHALE & CLAYSTONE JAR SAMPLE ' • SANDSTONE ' II PENETRATION RESISTANCE FOR COHES I ONLESS SOILS ON STRENGTH CLASSIFICATIONS FOR COHESIVE SO ' • BASIS OF THE STANDARD PENETRATION TEST NUMBER OF BLOWS II PER FT. , N * RELATIVE DENSITY CONSISTENCY COHESION. KSF""y 0 - 4 VERY LOOSE SOFT LESS THAN 0.5 I 4 - 10 LOOSE FIRM 0 . 5 - 1 .0 I0 - 30 MEDIUM STIFF 1 . 0 - 2.0 30 - 50 DENSE VERY STIFF 2 .0 - 4 . 0 OVER 50 VERY DENSE HARD GREATER THAN 4 .0 I ^ BLOWS PER FOOT - BLOW OF 140 LB, ** EQUIVALENT TO PP/2 AND OU/2 HAMMER DROPPED 30 IN. TO DRIVE 2- INC. SPLIT-BARREL SAMPLER ONE I FOOT (ASTM DL586-67 ) . I . ' • ' gg- LOG OF BORINGS oi I cNI 1112 I SANDY LEA&) /LAY -- fin, a►tLU., 5+'ff I _ : . f , • (LSY 3,ao - ,, sz.w'�,/ SAint LEAD WY - botoi) sof+, so'st-ix+ I c-`° r 1-ill • i '7 ' SalniEarAts Stack - 5rtnic- tuagaiefell K =� ` I I bciaeD a vi- Ii I ' DRAWING NO. . et (50uMK La (AMU Della. 2 I CDS ENGINEERING CORPORATION NPOOJECT (n-0380 SWELL CONSOLIDATION RESULTS TH2@ 5' 0 100 10 1000 1D000 5 (0b00 -0.1 - Ii II -0.2 - I -J J W -0.3 - y H a W -0.4 - re -0.5 - NS.01 s0 -0.6 - 1000 O -0.7 - —1 l ___ J i SURCHARGE (psf) a - a a I a a a am a i e o o nu s o n e • • • SWELL CONSOLIDATION RESULTS TH1@ 8' 0100� X 000 1 D000 j .--_I _ _1 I ' 00 -01 -0.2 --J -J W 500.01 to Z -0.3 - w a -0.4 - � Ili -0.5 1 -7 1000 ; %n -0.6 1 I I - I _ l _1.____1_ 1 II I c SURCHARGE (psf) t MS MIS a a M I a - - - a SWELL CONSOLIDATION RESULTS TH1@ 3' o 1-00- - T , 1 0O0 10000 i 144300 -0.05 -0.1 -0.15 J w -0.2 - 3 -0.25 w re -0.3 - a- -0.35 -0.4 - 8.01 -7/ 0.45 1000 I -0.5 SURCHARGE (psf) 0 ' TABLE I SHEET 1 OF 1 SUMMARY OF TEST RESULTS DATE: January 4, 2000 WIHOLE NO. TH 1 TH 1 I TH 1 TH 2 ' DEPTH (FT.) 3 8 16'Grab 5 Clayey Sandy Bedrock Sandy iSOIL OR ROCK Sand Clay Clay I NATURAL MOISTURE (%) 12.1 19.6 16.9 21.8 13.9 23.2 22.5 DRY DENSITY (PCF) 112.6 107.2 104.6 111.2 107.8 PENETRATION 4/12 12/12 4/12 (BLOWS/ IN.) % SWELL @ 500 PSF -0.1 0.0 -0.1 SWELL PRESSURE (PSF) UNCONFINED 572 2404 COMPRESSIVE STRENGTH (PSF) % STRAIN ill (PPM) LIQUID LIMIT 55.9 28.1 PLASTICITY INDEX 39.9 10.1 % PASSING #200 75.8 44.8 USC CL SC AASHTO GROUP INDEX MAXIMUM DRY DENSITY (PCF) OPTIMUM MOISTURE CONTENT (%) CBR R-VALUE ICDS ENGINEERING CORPORATION, Loveland, CO Project No: 99 -0380 ' • I ' • APPENDIX I POST-CONSTRUCTION SITE PREPARATION AND MAINTENANCE Backfill ' When encountering potentially expansive or consolidating soils, measures should be taken to prevent the soil from being wetted during and after construction. Generally, this can be accomplished ' by ensuring that the backfill placed around the foundation walls will not settle after completion of construction, and that this backfill material is relatively impervious . Water may need to be ' added to backfill material to allow proper compaction -- do not puddle or saturate. Backfill should be mechanically compacted to at least 95% of Standard Proctor around all structures, and 90% of Standard Proctor elsewhere. Compaction requirements should be ' verified with field tests by the Engineer. Surface Drainage ' The final grade should have a positive slope away from the foundation walls on all sides . A minimum of twelve inches (12 " ) in the first ten feet (10 ' ) is recommended. Downspouts and sill cocks ' should discharge into splash blocks that extend beyond the limits of the backfill . Splash blocks should slope away from the foundation walls . The use of long downspout extensions in lieu of splash blocks is advisable . Surface drainage away from the foundation should be maintained throughout the lifetime of the structure . t Lawn Irriaation Do not install sprinkler systems next to foundation walls, porches, or patio slabs . If sprinkler systems are installed, the sprinkler heads should be placed so that the spray from the heads under full pressure does not fall within five feet (5 ' ) of foundation walls, porches, or patio slabs . Lawn irrigation must be carefully controlled. ' If the future owners desire to plant next to foundation walls, porches, or patio slabs, and are willing to assume the risk of ' structural damage, etc . , then it is advisable to plant only flowers and shrubbery (no lawn) of varieties that require very little moisture . These flowers and shrubs should be hand watered only. Landscaping with a plastic covering around the foundation area is not recommended. I. I • Check with your local landscaper for fabrics which allow evaporation when inhibiting plant growth when a plastic landscape ' covering is desired. Experience shows that the majority of problems with foundations due ' to water conditions are generally due to the owner ' s negligence of maintaining proper drainage of water from the foundation area. The future owners should be directed to pertinent information in this report . 1 1 1 • ' REV 06/17/85 1 • 1 Hello