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Home My WebLink About20043348.tiff n April 22, 2004 lierracon 1289 First Avenue Post Office Box 1744 Greeley,Colorado 80632-1744 (970)351-0460 Fax:(970)353-8639 P &A Turkey Farms, Inc. P.O. Box 22253 Denver, Colorado 80222 Attn: Mr. Sam Pluss Re: Supplement to Geotechnical Engineering Report Proposed Residential Subdivision Southwest Corner of Weld County Roads 49 & 52 Terracon Project No. 21005009 Mr. Pluss, Please accept this letter and the attached site plan, boring logs, and laboratory test results, as a supplement to our original geotechnical engineering report prepared for the above-referenced project (see Geotechnical Engineering Report, Terracon Project No. 21005009, dated May 17, 2000). The purpose for this supplement is to provide updated groundwater conditions, as requested by Weld County, near the locations of test borings B-4, B-13, and B-18, and also to provide a pavement thickness design as requested. The supplemental study was performed in general accordance with our proposal number P2104037g dated March 8, 2004. Groundwater Conditions Groundwater was not observed in test borings B-4A, B-13A, B-18A, and P-1 at the time of field exploration, nor when checked one day after the drilling. These observations represent groundwater conditions at the time of the field exploration, and may not be indicative of other times, or at other locations. Groundwater conditions can change with varying seasonal and weather conditions, and other factors. Pavement Design and Construction The shallow sandstone bedrock may contain inter-bedded claystone lenses. Claystone bedrock, if encountered within 3 feet of proposed pavement subgrade, should be overexcavated to a minimum depth of 3 feet below pavement subgrade and replaced with non-expansive engineered fill placed in accordance with the recommendations outlined our original report. Design of pavements for the project have been based on the procedures outlined in the 1993 Guideline for Design of Pavement Structures by the American Association of State Highway and Transportation Officials (AASHTO) as well as Colorado Department of Transportation (CDOT) design procedures. Arizona■Arkansas■Calitornia■Colorado■Georgia■Idaho■Illinois■Iowa■Kansas■Kentucky■Minne' —" --"- Montana■Nebraska■Nevada■New Mexico■North Carolina■Oklahoma■Tennessee■Texas■Utah■Wisr Consulting Engineers&Scientists Since 1965 2004-3348 www.terracon.com Supplement to Geotechnical Engineering Report Proposed Residential Subdivision Southwest Corner of Weld County Roads 49 and 52 Terracon Traffic criteria assumed for pavement thickness designs include 18-kip equivalent single axle loads (ESAL's) of 36,500 for local streets. Local drainage characteristics of proposed pavement areas are considered to vary from fair to good depending upon location on the site. For purposes of this design analysis, fair drainage characteristics are considered to control the design. These characteristics, coupled with the approximate duration of saturated subgrade conditions, results in a design drainage coefficient of 1.0 when applying the AASHTO criteria for design. For flexible pavement design, a terminal serviceability index of 2.0 was utilized along with an inherent reliability of 85% and a design life of 20 years. Using the correlated design R-value of 20, appropriate ESAL, environmental criteria and other factors, the structural number (SN) of the pavement section was determined on the basis of the 1993 AASHTO design equation. The required total thickness for the pavement structure is dependent primarily upon the foundation soil or subgrade and upon traffic conditions. Based on the soil conditions encountered at the site and the anticipated type and volume of traffic as the criterion for pavement design, the following minimum pavement thickness is recommended: Recommended Pavement Thicknesses(Inches) Traffic Area Alternative Asphalt Concrete Aggregate Base Portland Cement Total Surface Course ' Concrete Local Street A 3 6 — 9 Aggregate base course should consist of a blend of sand and gravel that meets specifications for quality and gradation. Use of materials meeting Colorado Department of Transportation (CDOT) Class 5 or 6 specifications is recommended for base course. Aggregate base course should be placed in lifts not exceeding six inches and should be compacted to a minimum of 95% Standard Proctor Density (ASTM D698). Asphalt concrete should be composed of a mixture of aggregate, filler and additives, if required, and approved bituminous material. The asphalt concrete should conform to approved mix designs stating the Marshall or Superpave properties, optimum asphalt content, job mix formula and recommended mixing and placing temperatures. Aggregate used in asphalt concrete should meet particular gradations. Material meeting Colorado Department of Transportation Grading S or SX specification is recommended for asphalt concrete. Mix designs should be submitted prior to construction to verify their adequacy. Asphalt material should be placed in maximum 3-inch lifts and should be compacted to within a range of 92% to 96% of maximum theoretical specific gravity. ,.1 Supplement to Geotechnical Engineering Report Proposed Residential Subdivision Southwest Corner of Weld County Roads 49 and 52 Terracon GENERAL COMMENTS Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide testing and observation during excavation, grading, foundation and construction phases of the project. The analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur between borings, across the site, or due to the modifying effects of weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided. The scope of services for this project does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken. This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that 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 Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing If you have any questions regarding this letter, or if you require further information, please do not hesitate to contact us at (970) 351-0460. onto llllll REG/sl Sincerely, J7.••...•...... le TERRACON CONSULTANTS, Inc. = tt •v••�4. Qy0F•0 1: • Andrei Bedoya, E.I. Ty G. Alexander, P.E. ''',4;SSIONALE �.�`��` Staff Engineer Office Manager • s e OT I LIT] B-I 5-18 5-2 �� i 8-1�48S18A ® ® LOT2 C I B-4 t B4A A �i� g_3 `4% B-I9 B-'L y5 LOTS LOTS iv pB-G® me B-5 t r-I f1 LOTS O.% B -1-8® ii 5-7 55 B-IG OV LOT4 B-10® B-9eie ®B-14 ii LOTS B-12�� B-136B-13A \ B-1I LOTe S OIRLOTLi AyiwltunVCoasenation Easement 79627 xres OIRLOTC AyrieullunUConsenaaou Easement I 933,s14,0 n t w -u Mil J ,maam MIMI RUB NON S B LEGEND 11%11 FIGURE I: REVISED SITE PLAN PROPOSED RESIDENTIAL SUBDIVISION (9 TEST BORINGS DRILLED ON 4/01/04 SW CORNER OF WCR 49 & 52 WELD COUNTY, COLORADO ® TEST BORINGS DRILLED ON 2/25/00 Project Mngr. Project No. 21005009 r Designed By. 1r"erracon Scale: 1- - 500' Checked L., 1289 FIRST AVENUE Date. 10-06-03 Approved By: GREELEY, COLORADO 80631 Drown By: AB DIAGRAM IS IFORNi GENERAL LOCATION ONLY, INT AND IS NOT ENDED FOR CONSTRUCTION PURPOSES. Name: 21005009.dwg Figure No. 1 LOG OF BORING NO. B-4A Page 1 of 1 CLIENT P&A Turkey Farms SITE SW Corner of Weld County Roads 49&52 PROJECT Weld County, Colorado Proposed Residential Development SAMPLES TESTS 5L9 0 DESCRIPTION m a _ w >- K W 1- F- Z F Z u_ 7 a. = 0) W > Z to CL W Z Z Z a. D I- O 2 d 03 w 0 U }-O I-Z } OK ce C7 O D Z H CL CO CO 5O 0 a D V~] '� ' `n5 TOPSOIL _ SILTY SAND, moist, tan (SM) 5— WEATHERED BEDROCK, claystone, moist, gray to tan 4^ 10 15 END OF BORING 15 (N 0 0 0 0 aU 25 The stratification lines represent the approximate boundary lines `m between soil and rock types: in-situ,the transition may be gradual. WATER LEVEL OBSERVATIONS,ft BORING STARTED 4-1-04 WL V None WD None AB lerraconBO RING COMPLETED 4-1-04 WL 7 CME-55 FOREMAN AB WL AB checked after 24 hours. JOB# 21005009 • LOG OF BORING NO. B-13A Pagel of 1 CLIENT P&A Turkey Farms SITE SW Corner of Weld County Roads 49&52 PROJECT Weld County,Colorado Proposed Residential Development SAMPLES TESTS DESCRIPTION m > = O W > z&) a'W Z Z� F- ti m w O 3 uF Ow O w 0 2 as} 0 a~o QO K"- (pccc o D Z F 2 ym o a 7<q Lt n F TOPSOIL SILTY SAND, moist, tan (SM) — • 5 . 6 WEATHERED BEDROCK, _ sandstone/claystone, moist, gray to tan _ • I 10 12 BEDROCK, claystone, gray to tan, moist 15 20 END OF BORING 20 cu cu z 0 U QU W The stratification lines represent the approximate boundary lines between soil and rock types: in-situ,the transition may be gradual. WATER LEVEL OBSERVATIONS,ft BORING STARTED 4-1-04 oWL None WD None AB 1lBOerracon RGRINGCOME55EFOREMAN D 4-1-04 AB m WL AB checked after 24 hours. JOB# 21005009 LOG OF BORING NO. B-18A page 1 of 11 CLIENT P&A Turkey Farms SITE SW Corner of Weld County Roads 49&52 PROJECT Weld County, Colorado Proposed Residential Development SAMPLES TESTS DESCRIPTION m >-7o a U_ W h Fit = N W > Zm CLw Z ZU W Mw 0 o Ct z }a LU O a� ¢O Wi Orr 0 5 TOPSOIL _ SILTY SAND, moist, tan (SM) — 5 8 WEATHERED BEDROCK, _ sandstone/claystone, moist, gray to tan 10 — BEDROCK, claystone, moist, gray to tan 10 15 END OF BORING 15 0 CD 0 O QU W The stratification lines represent the approximate boundary lines a� between soil and rock types: in-situ,the transition may be gradual. WATER LEVEL OBSERVATIONS,ft BORING STARTED 4-1-04 o WL None WD None AB lierracon R G CME55 FOREMAN BORING COMPLETED 4-1-04 AB W L AB checked after 24 hours. JOB# 21005009, LOG OF BORING NO. P-1 Page 1 of 1 CLIENT P&A Turkey Farms SITE SW Corner of Weld County Roads 49&52 PROJECT Weld County,Colorado Proposed Residential Development SAMPLES TESTS C:7 in DESCRIPTION m > a _ >- W o_ = w > zm �w Z zz C a CO o 0 I-O tw-z >- OUrr CO Z H K ranm 3OO Co. 7f) ,' . 05 TOPSOIL SILTY SAND, medium dense, moist,tan _SM 1 SS 18 4.3 2 ($M) WEATHERED BEDROCK, sandstone, moist, gray to tan _ 5 _ 2 SS 19 8.3 END OF BORING 5 0 a U 0 O QU W r% The stratification lines represent the approximate boundary lines between soil and rock types: in-situ,the transition may be gradual. WATER LEVEL OBSERVATIONS, ft BORING STARTED 4-1-04 o WL None WD None AB lierracon R G OME-55 FOREMAN RING COMPLETED 4 1AB • WL AB checked after 24 hours. JOB# 21005009 • U.S.SIEVE OPENING IN INCHES I U.S.SIEVE NUMBERS HYDROMETER 6 4 3 2 1.5 13/4 1/2 3 4 6 610 1416 20 30 40 60 100 140 200 100 I I line. III 95 90 85 80 75 70 _ 65 i W60 >- 55 m cc z 50 LL z 45 w (±) 40 w 0 35 30 1\-- 25 20 15 10 5 0 100 10 1 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS COBBLES GRAVEL SAND SILT OR CLAY coarse J fine coarse I medium fine Specimen Identification Classification LL PL PI Cc Cu • P-1 0.5ft SILTY SAND(SM) NP NP NP 0 a Specimen Identification D100 D60 D30 D10 %Gravel %Sand %Silt I %Clay 8 • P-1 0.5ft 9.5 0.209 0.096 0.2 81.2 18.5 z 0 QU o .. GRAIN SIZE DISTRIBUTION i Project: Proposed Residential Development lierracon Site: SW Corner of Weld County Roads 49 & 52 Weld County, Colorado Job#: 21005009 Date: 4-22-04 Hello