The URL can be used to link to this page

Home My WebLink AboutSoils Report 09.25.200604/25/2007 09:33 9708765221 CARIBOU CONSTRUCTION SEP -29--2005 10;59 H—P GEOTECH HEPWORTH • PAWLAK GEO TCCHN1CA1. 1 lepaarth,Pawlnk hu. 5020 C61111(1, Rausd 154 (-Atwood ('oI r,d,) 8] 601 Phone; 970-+')45.7'168 Fax: 970445.8454 lirgerittbrcenLecii.croa al,.cr SUBSOIL STUDY FOR FOUNDATION DESIGN PROPOSED RESIDENCE LOT 17, SUN MEADOW ESTATES NORTH MEADOW DRIVE GARFIELD COUNTY, COLOR4] O JOB Kt 105 363 SEPTEMBER 29, 2006 PREPARED FOR CARIBOU CONSTRUCTION ATTN: PRD COOKS 734 MAIN STREET SILT, COLORADO 81652 Parker 303-841-7139 • Colorado Springs 719-633-5562 • SilvertFrnrne 970-468-1989 PAGE 02/15 P.02/15 04/25/2007 09:33 9708765221 CARIBOU CONSTRUCTION SEP -29-2M 10159 H -P GEOTECH PAGE 03/15 P.03/15 TABLE OF CONTENTS PURPOSE AND SCOPE OF STUDY - I - PROPOSED CONSTRUCTION - 1 - SITE CONDITIONS - 2 - FIELD EXPLORATION - 2 - SUBSURFACE CONDITIONS - DESIGN RECOMMENDATIONS - 3 - FOUNDATIONS. - 3 FLOOR SLABS - 4 - UNDERDRATN SYSTEM ...... ......- 5 - SURFACE DRAINAGE - 5 - FR.OFILE BORING - 6 - LIMITATIONS - 6 - FIGURE 1 - LOCATION OF EXPLORATORY BORINGS ficrtin 2- LOGS OF EXPLORATORY BORINGS FIGURE 3 - LEGEND AND NOTES FIGURE 4- SWELL -CONSOLIDATION TEST RESULTS TABLE 1 - SUMMARY OF LABORATORY TEST RESULTS B4/28/2007 09:33 9708765221 CARIBOU CONSTRUCTION SEP -29-2006 10:59 H -P GCDTECH FURPOSE AND SCOPE OF STUDY PAGE 04/15 P.04/15 This report presents the results ofa subsoil study for a proposed residence to be located at Lot 17, Sun Meadow Estates, Garfield County, Colorado. The project site is :shown on Figure 1, The purpose of the study was to develop recommendations for the foundation design. The study was conducted in accordance with our agreement for geotechnical engineering services to Caribou ibou Construction dated May 3, 2005, liepworth-Pawl,tk Geotochnical inc., previously ,performed a preliminary geotechnical study for Sun Meadow Estates (formerly Marnms View) and presented our findings in a report dated March 28, 2000, Job No. 100159. A field exploration program consisting done exploratory boring in the building area and one profile boring in the septic disposal area was conducted to obtain information on the subsurface conditions. Samples ofthe subsoils obtained during the Field exploration were tested in the laboratory to determine their classification, compressibility or kwoll and other engineering characteristics. The results of the field exploration and laboratory testing were analyzed to develop recommendations for foundation types, deplhss and allowable pressures for the proposed building foundation. This report summarizes the data obtained during this study and presents our conclusions, design recommendations and other geotechnical engineering considerations based on the proposed construction and the subsurface conditions encountered. TROPOSED CONSTRUCTION the proposed residence will be one story wood frame construction above a erawlspctce with an attached garage. Garage floor will be slab. on -grade. Grading for the Structure is assumed to be relatively minor with cut depths between about 2 to 4 :feet. We asstune relatively light foundation loadittgy, typical ofthe proposed type o1 aor:struution. • If building loadings, location or grading plans change sigtaificantly from those described above, we should be notified to re~cvaltrste the recommendations contained in this report. Job No. il15163'" -^T x 04/25/2007 09:33 9708765221 SEP -29-2005 1059 H -P GEOTECH CARIBOU CONSTRUCTION PAGE 05/15 P. 03/15 -2- SITE CONDITIONS Lot 17 is located on the north side of North Meadow Drive and was vacant at the time of our field visit. The lot is bordered to the east by an access and water utillty.easement. The building area is located in the central part of the lot. Vegetation eonshii.s of scattered brash, sparse grass and weeds. The ground surface in the building area is relatively flat with a gentle slope down to the south at a grade of about 3 to 4 percent. FIELD EXPLORATION The field exploration for the project was conducted on August 30, 2006, One exploratory boring was drilled in the building area and a profile boring was drilled in the septic disposal arca at the locations shown on Figure 1 w evaluate the subsurface conditions. The borings were advanced with 4 inch diameter continuous fight augers powered by a truck -mounted CME -458 drill rig. The borings were logged by a representative of Hcpworth-Pawlak Geotechnical, Juc. A previous exploratory boring (Boring $) from the preliminary geotechnical study is Located in the middle east side of the property. Samples of the subsoils were taken with a 2 inch T.D. spoon salvia. The sampler was driven into the subsoils at various depths with blows from a i 40 pound harmtner failing 30 inches. This test is similar to the standard penetration test described by ASTM Method D4586. The penetration resistance values are an indication or the relative density or cnnvistency of'the subsoils. Depths at which the samples were taken and the penetration resistance values are shown on the Logs of Exploratory Borings, Figure 2, The samples were returned to our laboratory for review by the project engineer and testing. SUBSURFACE COND11TIONS Graphic logs of the subsurface conditions encountered at the site are shown on Figure 2. The subsoils at Boring 1, below about %, foot of topsoil. consist of sandy silty:lay down to the depth explored of 26 feet. job Nn, 03 363 04/25/2007 09:33 9708765221 8EP-29-2006 11:10 H -P C rTECH CARIBOU CONSTRUCTION PAGE 07/15 P.0?/15 -4. 3) Exterior footings and footings beneath unheated areas should be provided with adequate soil cover above their bearing elevation for frtis; Protection. Placement of foundations at least 36 inches below exterior grtude is typically used in this area. 4) Continuous foundation walls should be reinforced top and bottom to span local anomalies such as by rtsstiming an unsupported length of at least 12 feet. Foundation walls acting as retaining structures should also be designed to resist a lateral earth pressure corresponding to an equivalent fluid unit weight of at least 55 pet 5) The topsoil and any loose or disturbed soils sluoukl be removed and the footing bearing level extended down to the undisturbed natural soils. The exposed soils throughout the building area should then be evatuated for expansion potential. Subexoavation of the expansive soils up to about 3 feet below bearing level and replacement with non -expansive 'granular soil such as road base compacted to at least 95% of standard Procter density could be needed to limit the heave potential. 6) A representative of the geotechnical engineer should o'bservi all footing excavations prior to concrete placement to evaluate bearing conditions. FLOOR SLABS me! natural clay soils could be expansive and there is risk of heave to lightly loaded slab - on -grade construction. The expansion potential should be further evaluated' &t the time of construction for possible mitigation methods if needed. To reduce the effects'ofsorne differential movement, floor slabs should be separated from all bearing wal is and columns with expansion joints which allow unrestrained vertical movement. Floor slab control joints should be used to reduce gage due to shrinkage cracking. The requirements ,For. joint spacing and slab reinforcement should be established by the; designer based on experience and the intended slab use. t1. nxitxiur►um 4 inch layer of free - draining gravel should be placed beneath pascrnent level slabs to facilitate drainage. this rixateriud should consist of minus 2 inch aggregate with at last W/;0 retained an the No. 4 sieve and less thorn 2% passing:the No. 2003 sieve. Joh O. 10$363 04/25/2007 09:33 9708765221 'SEP -29-2006 11:00 H -P GEDTECH CARIBOU CONSTRUCTION PAGE 06/15 Laboratory testing performed on samples obtained from Boring 1 included natural moisten content, density, percent finer than sand size and Atterberg limits. Results of swell -consolidation testing performed on relatively undisturbed drive samples of the clay soils, presented on Figure 4, indicate low to moderate compressibility under light'loading and existing moisture conditions with a manor to low swell potential when wetted. The laboratory testing its summarized in Table 1. No free water was encountered in the boring at the time of drilling and the subsoils were slightly moist to moist with depth. DESIGN RECOMMENDA'T'IONS FOUNDATIONS The clay soils encountered at shallow depth have an expansion potential aid there coria be heave of shallow spread footing foundations. Considering the subsurface conditions encountered in the exploratory boring and the nature of the proposed construction, the hualding can be founded with spread footings bearing an the natural soils with some risk of movement. The expansion potential of the bearing soils should be further evaluated at the time of constructian. P.06/15 The design and construction criteria presented below should be observed fora tspread footing foundation system. I) Footings placcd on the undisturbed natural soils should be de signed for are allowable bearing pressure of 1„504 psf. Based on experience, we expert settlement of footings designed and constructed as discussed 'irr this section will be about 1 inch or less. Time could be some additional differential m vemeirt if the beating soils become wetted, 2) The footings should have a minimum width of 16 inches for continuous walls and 2 feet for isolated pads. Join No. 105 363 04/25/2007 09:33 9708765221 S£P-29-2006 11:00 H—P 13EOTECN CARIBOU CONSTRUCTION PAGE 08/15 -5. P. id8r 15 ,til f11 materials for support of floor slabs should be compacted to at least 95% of maximum standard Proctor density at a moisture content near optimum, Required fill can consist of the on-site granular soils devoid of vegetation and topsoil, UNDFRDRAIN SYSTEM ,Although free water was not encountered during oia. exploration, it has been our experience in the area that local perched groundwater can develop during times of heavy precipitation or seasonal runoff. Fromm ground during spring runoff can create a perched condition. We recommend below -grade construction, such as retaining wails and crawlspace areas, be protected from wetting and hydrostatic pressure buildup by girt underdraln system. A shallow crawlapace (up to about 3 feet deep) should not require an undcrdrain system provided the exterior backfill is properly compacted and graded, if. drains are installed, they should consist of drainpipe placed in to bottom of the w411 backfill surrounded above the invert level with free -draining granular material. The drain should bo placed at each level of excavation and at least 1 foot below lowest adjacent finish grade and sloped at a minimum 1% to a suitable gravity outlet, dry well or sump and pump. Free• -draining granular material used in the underdrain system should contain less than 2% passing the No. 200 sieve, less than 50% passing the No. 4 sieve and have a maximum size oft inches. The drain gravel backfill should be at least 1'/,. Beet deep, SURFACE DRAINAGE The following drainage precautions should be observed during construction and Maintained at all times after the residence has been completed: 1) inundation of the foundation excavations and underslab areas. hould be avoided during oonstructian, 2) Fxterior backfill should be adjusted to near optimum moisture *trio cpinpiict di to at least 95% of the maximum standard 1 roctor bolt? In Job No. 105163 04/25/2007 09:33 9708765221 .SEP -9-6 11:00 H—P GEOTECH CARIBOU CONSTRUCTION PAGE 09/15 -6- P.09/15 pavement and slab areas and to at least 90% of the maximurn standard Proctor density .In landscape areas. 3) The ground surface surrounding the exterior of the building should be sloped to drain away from the foundation in all directions, We recommend a minimum slope of 6 inches in the first 10 feet in unpaved areas and a minimum slope of 3 inches in the first 10 feet in paved areas. Free-dralning wall backfill should be capped with about 2 feet of the on- site soils to reduce surface water infiltration, 4) Roof downspouts and drains should discharge well beyond the limits of all backfill. 5) Landscaping which requires regular heavy irrigation should be located at least 5 feet from foundation walls. Consideration should be 'given to use of xeriscape to reduce the potential for wetting of soils below the building caused by irrigation. PROFILE BORING A profile boring was drilled in the proposed septic disposal arta at the location shown on 1~ iptre 1. The subsoils encountered, below about 1/2 foot of topsoil, consisted of sandy silty clay to the bottom hole depth of 11 feet. The log of the profile boring is Shown on Figatre 2. No free water was observed at the time of drilling and the subsoils were slightly moist, LE IITAf ONS This study has been conducted in accordance with generally accepted ,geotechnical engineering principles and practises in this area at this time. We: Make no wrnTanty either ixpress or implied. The conclusions and recommendations submitted in thiireporx are based upon the data obtained from the exploratory borings drilled at the 1poations indicated an figure 1, the proposed type ofconstruction and ow experieni'e to tate area. Qtir. services do not include determhtingth e pretence, prevention or'posaihility of niold or Other biological'oontamin€nts (MOBC) developing in the Allure. If 11< oiont is • Jo6No 105363 04/25/2007 09:33 9708765221 SEP -29-2006 11:01 H -P GEOTECH CARIBOU CONSTRUCTION PAGE 10/15 -7- concerned about MOBC, then a professional in this special field of practice should be consulted. Our finding; include interpolation and extrapolation of the subsurface conditions identified at the exploratory borings and variations in the subsurface conditions may not become evident until excavation is, performed, ifconditions encountered during construction appear different from those described in this•report, we should be notified so that re-evaluation of the recommendations may be made. This report has been prepared for the exclusive use by our client for design purposes. We arc; not responsible for technical interpretations by others of our information, As the project evolves, we should provide continued consultation and field services during construction to review and monitor the implementation of our recommendations, and to verify that the recommendations have been appropriately interpreted. Signiflcruxt design changes may require additional analysis or modifications to the recommendations presented herein. We recommend on-site observation of excavations and fdu dation hearing strata and testing of structural fill by a representative of the geotechnical engineer. Respectfully Submitted, 1'11 PWORTh-1- PAWLAK GEOTECHNICAL, INC. Louis E. Eller JobNo, 103 363 P.10/15 04/25/2007 09:33 9708765221 CARIBOU CONSTRUCTION SEP -29-2066 11:0i H -P GEOTECH APPROXIMATE SCALE r y 00' 5542 5540 LOT 18 105 0363 5544 Y �~ ~ Y r- PAGE 11/15 P.11/15 UTILITY, ACCESS AND WATER TANK EASEMENT r-„..,.. 553$ f 6636 • PROPOSED PROFILE RESIDENCE BORING •rnl EN LOT 17 NORTH MEADOW DRIVE 1 — 3544 -- 5542 5540 p �p+�i/� C O 80:FO G. b (PREVIOUS STUDY} — 5535 - 8638' LOT 18 LOCATION OF EXPLORATORY E ORINGE Fi-gure 1 04/25/2007 09:33 9708765221 CARIBOU CONSTRUCTION 'SEP -29-2006 11 H -P GEOTECH ti 5 X10 15 20 25 BORING 1 LOT 17 ELEV.— 5540' 1 1 37/12 42/12 WC»7,0 DD= -115 30/12 WC -6.1 DD=121 -200 C5.3 10/12 37/12 25/12 WC -11.7 DD --123 ..200 7Y} LL•=22 PI*0 PROFILE BORING LOT 17 ELEV.= 5539' 58/12 802 Note; Explendon of symbols Is shown pn Fgure 3, PAGE 12/15 P,12/15 5 10 �.,.. {5 20 _ .. 04/25/2007 09:33 9708765221 SEP -29-2006 11:01 H -P GEOTECH M t CARIBOU CONSTRUCTION PAGE 13/15 F. i3/1.5 LEGEND: 2 , TOPSOIL; sandy sift and clay, organic, firm, slightly moist, brown, CLAY (Ct.); sandy, silty, very stiff, slightly mist to moist with depth, brown, low piasticity. Relatively undisturbed drive sample; 2•inch I.D. California liner sample. Drive sample blow count; indicates that 37 blows of a 140 pound harnMer falling 30 Menet were required to drive the California sampler 12 Inches. —7 r, 37/12 NOTES: ' 1, Exploratory boriings were drilled on August 30, 2006 with 4 -Inch diameter continuous flight power ai.r, jflr. 2, Locations of exploratory borings were measured approximately by pacing from features shown Mesita plan provided. 3. Elevations of exploratory borings were obtained by interpolation between contours shown on the site On provided. 4. The exploratoryboring locations and elevations should be considered accurate only to the degree *Plied by the method used, 5. The lines between sneterels shown on the exploratory boring logs represent the approximate boundaries. between material types and transitions may be gradual. 6. No free water was'enoountered in She borings at the time at drilling. Fluctuation in water level may occur with time. 7. Laboratory Testing Results: Wt Water OQrrterit (%) DD = Dry Densitjy (,p f) -200 a Percent passing No. 200 sieve LL – Liquid limit (%} PI = Plasticity index (%) . 105 036,1 6244. LEGEND AND NOTES Figure }M W.. f I..' AmAK teAi. 04/25/2007 09:33 9708765221 SEP -29-2006 11;02 H -P GEOTECH 1 0 1 2 CARIBOU CONSTRUCTION PAGE 14/15 P.14/1S Moisture Content = 7.0 Dry Density = 115 Sample 01; Sandy Clay From: Boring 1st 6 Feet 0.1 .0 10 APPLIED PRESSURE - ksl 105 0363 A14 . APPLIED PAE$$I 3E - ksf 04 • 100 SWELL -CONSOLIDATION FEST RESULTS Flgure 4 -- — `Sample Moisture Dry From: Density of: Suring Content Sandy 1 a 6.1 121 Clay et 10 Feet per6en1 ' ucf Expansi0'1 upon wetting , 105 0363 A14 . APPLIED PAE$$I 3E - ksf 04 • 100 SWELL -CONSOLIDATION FEST RESULTS Flgure 4 04/25/2007 09:33 9708765221 -SEP-2S-2006 11 02 H -P GEOTECH Job No. 105 0363 CARIBOU CONSTRUCTION 0. Y WW u v 1 Sandy Silty Clay 11 Z 4: a 16 u _. gk C.1 H H M I, 7 T P. S .----e. _ PAGE 15115 P.15/ 15 TOTAL P.15