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Home My WebLink About20050089 High Plains Engineering Nq rwc 735 Denver Avenue • Fort Lupton CO 8062 I Phone 303-857-9280 • Fax 303-857-9238 e August 12, 2004 Land Professionals, LLC Attn: Lauren Light 4311 Highway 66, Suite 4 Longmont, CO 80504 Subject: Consultation - Aggregate Pit Development "Finley" 12557 WCR 8 Weld County, Colorado Job No. 04-4122 Lauren: On July 19, 2004, we visited the subject site to observe the drilling of four(4) exploratory holes to evaluate the thickness of the aggregates, which underlay the site, and to obtain samples for testing. This letter summarizes the results of conditions found in exploratory test holes and our opinion regarding the viability of the property for recovery of aggregates. SITE CONDITIONS The 9 +/-acre property is formerly known as 12557 WCR 8, Parcel #1471 18 000036, which is located north of WCR 8 and east of Highway 85 in Weld County, CO. For the most part the topography is gently rolling with slopes of 0.5% to the North to Northwest. SUBSURFACE CONDITIONS During our investigation, a total of four(4) exploratory borings (numbered 1, 3, 4, 6) were excavated using a small commercial size drilling rig using 6" diameter bits. We logged conditions found in each test hole. The site map shows the general location of these holes with the profile logs graphically representing the conditions found. 2005-0089 At most locations we encountered 0 to 4 feet of silty or clayey sand and silty gravel underlain by sand and gravel of various sizes. The sands and gravels are underlain by clay or shale at varying depths. The clay or shale appears to occur at a depth of approximately 51 to 52 feet in the entire site. Please see the attached soil profile logs. Samples of the on site materials were obtained at most boring locations at varying depths. The gradation logs provided summarize the gradation of the"in place" materials obtained. The gradation logs provided show gradations for fine to course aggregate with the samples tested on Number 4, 8, 10, 20, 40, 100 and 200 sieves. There was material larger than 1-'/ inches in diameter and up to 3 inches in diameter to be removed prior to the sieve operation. Our scope did not include running physical property testing for quality on the aggregate. Our investigation indicates the thickness of the fine aggregate and gravel to vary between 3 and 51 feet. The drilling equipment used was capable of achieving depths in excess of 55 feet. CONCLUSION The small size of the lot and location of this site would dramatically limit the marketability of the gravel resources for mining. The quantity of gravel available from this 9 +/- acres, assuming reasonable side slopes, and maintaining legal setbacks from the property lines and utilities, would likely make this site cost prohibitive to mine. We believe that it is not economically feasible to mine this site for gravel. LIMITATIONS The conclusions presented in this letter were developed based upon conditions disclosed in exploratory borings and our experience. Should you have any questions regarding this subsurface exploration, please call 303-857-9280. DO RE Sincerely, QP C/p 548 Todd M. Schroeder, PE 3 •.eV/Voil_�a O 30 31 j 2 SILTY CLAY WITH LOW PLASTICITY(CL-ML) 32 3 33 4 34 SILLY GRAVEL(GM) 5 35 WELL GRADED GRAVEL(GW) G 36 7 POORLY GRADED GRAVEL(GP) 37 8 35 9 39 j% 10 40 j/ II 41 /// 12 42 1 / ./7 13 43 7// /// 14 44 /// //i 15 45 %/, 16 4G //1 17 WELL GRADED SAND(55) 47 POORLY GRADED GRAVEL(GE) j% 15 45 //, 19 49 i// 20 50 /7 //74 / 21 51 /././ / 22 52 /// 23 53 //. 24 54 /// 25 55 26 56 27 SHALE 57 WELL GRADED GRAVEL(GW) 25 55 29 59 30 6O SOIL PROFILE #1 0 ^ / GAY WITH LOW PLASTICITY(CL) *4*, SILTY GRAVEL(GM) ..a��. 3 / Dlowcounts 19/12 // 4 / /j/ 5 / //j G /j/ / 7 //j/ 8 / / Dlowcounts 27/12 j / 9 / ./ 10 / 1 1 /j 12 / / WELL GRADED SAND (51/10 jj 13 // 14 /j / 15 /// / " IG /// // 17 / /// lb j % 19 j 20 j / 21 j / 22 /j //j 23 / /j 24 • //: 25 SOIL PROFILE #2 O 30 31 CLAY WITH LOW PLASTICITY(CL) 2 32 3 33 4 SILTY GRAVEL(GM) 34 WELL GRADED GRAVEL(GW) 5 35 6 36 POORLY GRADED GRAVEL(GO 7 37 8 35 9 39 10 f 40 /. II // 41 12 /%; 42 13 //./243 14 j%j 44 WELL GRADED SAND(SW) 5 // 45 16 ///. 46 17 i/j/ 47 W)WELL GRADED GRAVEL(G I8 45 19 49 20 50 POORLY GRADED GRAVEL(GP) 21 51 22 52 23 53 SHALE 24 54 25 55 26 27 28 29 30 SOIL PROFILE #3 30 // 1 SILTY GRAVEL(GM) �/ 31 Y 2 %% 32 POORLY GRADED GRAVEL(GP) . // 3 /./ 33 /77 / �/ // 4 // 34 // 5 /7 // 35 /// G/// ///%/ 36 / /// 7 // 37 /// // /// 8 /A 38 WELL GRADED SAND(5W) /// i// 9 // 39 7// 10 /// 40 /// I // // / 12 / / // 42 // WELL GRADED SAND(SW) // /// ,//, 13 /% 43 /// 14 // 44 /% 15 /% 45 /// 16 7� 46 '// // ! 17 • // 47 /// /// 18 48 ,/7 /// 19 49 /// POORLY GRADED GRAVEL(GE) /7/ 20 50 /// /// 21 51/ / 22 52 !!/i /7/ 23 53 SHALE ,//. 24 54 /// 25 55 /// 2G /// /%i 27 '//' 28 /7/ 29 /// 30 ..-• SOIL PROFILE #4 0 7/ I SANDY CLAY(SC) p0 2 SILTY GRAVEL (GM) 3 Blowcounts 19/12 4 5 C 7 • Blowcounts 27/12 9 10 II 12 WELL GRADED GRAVEL (GW) 13 14 I5 17 18 I9 20 21 22 23 24 25 SOIL PROFILE #5 r 0 ^ p% 30 // 31 POORLY GRADED SILTY GRAVEL(GE-GM) // 2 �// 32 // 3 /%i 33 POORLY GRADED GRAVEL.(GE) /// 4 / 34 // / /// 5 /�/ 35 /' 6 /// // / / // '// / 7 / 37 /' / i7/ 8 // 38 j%i 9 /% 39 WELL GRADED SAND(SW) /// 10 // /// // 40 j/ // I I /// 41 /// 12 // '// // 42 /// i 3 // 43 r %/ 14 // 44 /// 15 //// 45 // 10 WELL GRADED SAND(5W) // 40 /./d,// % 17 // // 47 /// 18 ' %i 48 %% 19 // 49 /// 20 //' 50 /// POORLY GRADED GRAVEL(GP) /// 21 51 /� 22 52 ///, 23 53 SHALE /// 24 54 %% 25 55 26 //// 27 //' i%i 25 '// 29 /▪ / 30 r. SOIL PROFILE #G Project Name Date Moisture Content Land Pro/WCR 8#1 7/23/2004 Wet Weight 250.6 Depth of Sample Dry Weight 235.9 0-4' Weight of Moisture 14.7 %Moisture 5.87 Grain Size Analysis Dry Weight Washed @#200 Dry Weight #VALUE! Percent of soil washed #VALUE! Sieve Analysis Sieve S No.4 No. 10 No.20 No.40 No. 100 No. 200 Pan Atterberg Limit Determination Liquid Limit Determination Can No. 8 Wt Of wet soil+can 27 Wt Of dry soil+can 24.3 Wt. Of can 15 Wt. Of dry soil 9.3 Wt. Of moisture 2.7 Water content,w% 29.03 No. of blows 19 Plastic Limit Determination Liquid Limit 28.08 Can No. 9 Plastic Limit 22.22 Wt. Of wet soil +can 23.7 Plasticity Index IP 5.86 Wt. Of dry soil+can 22.1 Wt. Of can 14.9 Soil Classification Wt. Of dry soil 7.2 Clay w/ Low Plasticity (CL) Wt. Of moisture 1.6, Water content, w%=wp 22.22 ) ) ) Location of P,, : Land Pro/WCR 8 # 1 I Boring No.l J Sample No:J Well Graded Gravel • of 25'-30' 1 Tested By:( J Date:J Moisture Content Soil Sample Size (ASSM•D114044) Wet Weight: 503.5 g. Approximate Minimum Dry Weight: 492.5 g. Nominal Diameter of Largest Particle Weight of Sample (g.) % Moisture: 2.2 g. No. 10 Sieve 200 No. 4 Sieve 500 Grain Size Analysis -Mechanical Dry Weight: 492.5 Washed a#200 Dry Weight: 482.4 Sieve No. Wt.Retained % Retained 100 % Passing J No. 4 131.6 28,72 73.28 No. 10 131.3, 28,66 48.62 No. 20 85.2 17.30 29.32 No. 40 75.3 15.29 14.03 No. 100 52.3 10.62 3.41 No. 200 6.5 1.32 2.09 Pan 10.3 2.09 0.00 492.5 ) ) ) ) Locatiopot Project: Land Pro/WCR 8 # 1 1 Boring No.j I Sample No:! Daec ` 1 Well Graded Gravel Depth ci : 25'-30' I Tested By:I I Date:1 Moisture Content Soil Sample Size(ASTM D1140.54). ' - Wet Weight: 514.7 g. " Approximate Minimum Dry Weight: 504.4 g. Nominal Diameter of Largest Particle Weight of Sample (g.) % Moisture: 2.0 g. No. 10 Sieve 200 No. 4 Sieve 500 Grain Size Analysis-Mechanical } Dry Weight: 504,4 Washed a#200 Dry Weight: 496.2 Sieve No. Wt. Retained %Retained 100 % Passing I No. 4 170.4 33.78 66.22 No. 10 122.3 24.25 41.97 No. 20 80.8 16.02 25.95 No. 40 68.4_ 13.56 12.39 No. 100 48.9 9.69 2.70 No. 200 5.7 1.13 1.57 Pan 7.9 1.57 0.00 504.4 ) ) ) Location of Project: Land Pro/WCR 8# 1 I Boring No.j I Sample No:I W Poorly Graded Gravel c.pth O tm ae: 42'-52' ( Tested°By:I I Dote: Moisture Content SOW Sample Site C1w1,011.40.1;i4)= Wet Weight: 863.9 g. Approximate Minimum Dry Weight: 831.2 g. Nominal Diameter of Largest Particle Weight of Sample (g.) % Moisture: 3.8 & - No. 10 Sieve 200 No. 4 Sieve 500 Grain Size Analysis-Mechanical ) Dry Weight: 831.2 Washed ©#200 Dry Weight: 816.9 Sieve No. Wt.Retained frafrieW014 100tH Passing No. 4 568.6 88.41 31.59 No. 10 78.8 9.48 22.13 No. 20 88.2 7.96 14.17 No. 40 57.8 6.95 7.22 No. 100 40.9 4.92 2.30 No. 200 4.7 0.57 1.73 Pan 14.4 1.73 0.00 831.2 ``�� v'EL ice,° "rte 3u ,N i.7/r4✓4E ue- ) ) ) ) i , Location of Pripet: Land Pro/WCR 8 #2 1 Boring No.1 1 Sample No:1 Desc tl 44O Well Graded Sand (SW) Depth of Simp e:_4'-5' 1 Tested By:I I Date:] Moisture Content Soil Sample Size(ASTM D1140-54) Wet Weight: 513.5'g. Approximate Minimum Dry Weight: 508.6 g. Nominal Diameter of Largest Particle - Weight of Sample (g.) % Moisture:_ 1.3 g. No. 10 Sieve 200 No. 4 Sieve 500 Grain Size Analysis -Mechanical Dry Weight: 506.6 Washed a#200 Dry Weight: 485.9 Sieve No. Wt. Retained %A vows 100 %Passing No. 4 124.4 24.58 75.44 No. 10 131.2 25.90 49.54 No. 20 100.7 19.88 29.88 No. 40 66.4_ 13.11- 16.55 No. 100 52.5 10.36 6.19 No. 200 9.9 1.95 4.24 Pan 21.5 4.24 0.00 506.6 ) ) ) Location of . , ct: Land Pro/WCR 8 #3 1 Boring No.1 I Sample No:1 . - ''. ' apt. Well Graded Sand (SW) Ds of 40'-45' I Tested BSI:J 1 Date:J Moisture Content, Soli Sample Size(ASTM Di 1440 Wet Weight: 500.7 g. Approximate Minimum Dry Weight:, 483.9 . Nominal Diameter of Largest Particle Weight of Sample (g.) % Moisture: 3.4 9. No. 10 Sieve 200 No. 4 Sieve 500 ) Grain Size Analysis -Mechanical Dry Weight: 483.9 Washed e#200 Dry Weight: 481.0 Sieve No. Wt.Retained %Rained 100.% Passing I No. 4 125.0 25.83 74.17 No. 10 180.4 37.28 38.89 No. 20 88.7 17.92 18.97 No. 40 52.4 10.83 8.14 No. 100 33.8 8.94 1.20 No. 200 2.9, 0.80 0.80 Pan 2.9 0.80 0.00 483.9 ) ) ) . Location of Project Land Pro /WCR 8#4 I Boring No.] ] Sample Nod De iiptie n it Well Graded Sand (SW) Depth of : 7'-12' 1 Tested By:I I Date:I Moisture Content Soil Sample Size (ASTM D1140-54) Wet Weight: 522.0 g. Approximate Minimum Dry Weight: 512.4 g. Nominal Diameter of Largest Particle Weight of Sample (Q) % Moisture: 1.8 g. No. 10 Steve 200 No. 4 Sieve 500 Grain Size Analysis-Mechanical Dry Weight: 512.4 Washed (rp#200 Dry Weight: 503.6 Sieve No. i Wt. Retained %:Rind: ,_ 100 %Passing I No. 4 132.2 25.80 74.20 No. 10 149.8 29.23 44.97 No. 20 93.5 18.25 26.72 No. 40 67.5 13.17 13.55 No. 100 53.2 10.38 3.17 No. 200 7.2 1.41 1.76 Pan 9.0 1.76 0.00, 512.4 I I ) ) ) Location of P ect:'Land Pro/WCR 8 #5 J Boring No.1 L Sample No:[ _t Silty Gravel (GM) Depth ,` pie:'4'-5' I Tested Sy:J I Date 1 Moisture Content Soil Sample Size( N D1140.54) Wet Weight: 518.0 g, Approximate Minimum Dry Weight: 509.5 g. Nominal Diameter of Largest Particle Weight of Sample (g.) _ % Moisture: 1.6 g. No. 10 Sieve 200 No. 4 Sieve 500 Grain Size Analysis -Mechanical Dry Weight: 509.5 Washed (I#200 Dry Weight: 441.7 Sieve No. Wt. Retained ' Fed 100`;%Passing I No. 4 189.4 37.17 62.83 No. 10 73.6 14.45 48.38 No. 20 63.2 12.40 35.98 No. 40 45.2 8.87 27.11 No. 100 47.7 9.38 17.75 No. 200 21.6 4.241 13.51 Pan 68.8 13.50 0.01 509.5 �,I,i-TA-,ivt�0 CN'`.)eL (A t2 / /e�cH IN � ( Wi�t'"r 2 ) ) ) Location of Project: Land Pro/WCR 8#6 I Boring No.I I Sample No:J Dcsctlptlpr►≥ ~ GP-GM Depth o(I ampler 1'-3' I Tested By:I I Date:I Moisture Content Sol Sample Size4AStllf D1140.54) Wet Weight: 701.2 g. Approximate Minimum Dry Weight: 887.8 g. Nominal Diameter of Largest Particle Weight of Sample (g.) % Moisture: 1.9 g. No. 10 Sieve 200 No. 4 Sieve 500 Grain Size Analysis-Mechanical ) Dry Weight: 687.6 Washed ®#200 Dry Weight: 812.9 Sieve No. Wt.Retained % 100%Passing No. 4 375.8 54.85 45.35 No. 10 80.0 11.63 33.72 No. 20 40.1 5.83 27.89 No. 40 37.4 5.44 22.45 No. 100 52.2 7.59 14.88 No. 200 25.0 3.84 11.22 Pan 77.1 11.21 0.01 887.6 C N '& Ca./ft/EL L �,P / 5/.2 /N /Jr14Vh� ) I Project Name Date Moisture Content Land Pro/WCR 8#6 7/23(2004 Wet Weight 253.1 Depth of Sample Dry Weight 2122 51'-55' Weight of Moisture 40.9 % Moisture 16.16 Grain Size Analysis Dry Weight Washed 01200 Dry Weight #VALUE! Percent of soil washed #VALUE! Sieve Analysis Sieve 1 No.4 No. 10 No.20 No.40 No. 100 No.200 Pan Atterberg Limit Determination Liquid Limit Determination Can No. 8 Wt. Of wet soil+can 27.8 Wt Of dry soil+can 24.9 Wt Of can 15 Wt.Of dry soil 9.9 Wt. Of moisture 2.9 Water content,w% 29.29 No. of blows 15 Plastic Limit Determination Liquid Limit 27.54 Can No. 9 Plastic Limit 20.48 Wt Of wet soil+can 24.9 Plasticity Index IP 7.06 Wt Of dry soil+can 23.2 Wt. Of can 14.9 Soil Classification Wt. Of dry soil 8.3 Clay w/Low Plasticity (CL) Wt. Of moisture 1.7 Water content,w%=wp 20.48 s I W O Co O oo Li) I I O I I A#6 II , „-- _--- ,-- _--- ,-- ,--- / w (// /� I #5 m o II I N 0 0 II Z k\ l I APPROX. LOCATION / n OF FORMER LUPTON / I / \#4 SHORT LINE DITG I II In \\ co II I I\ = SITE MAP CD NOT TO SCALE = II A#3 (.Sj I II D I CONTAINS: I, 9.020 ACRES =1- \\ #2 I I I I I Z SEPTIC LEGEND: SYSTE A CS' 501E PROFILE TO 55 FEET Q / ` #1 SOIL PROFILE TO 25 FEET I WATER ct WELL o s I I ., , 1I 0= _ WCR 8 ii 0 I II ° � I A#6 I I i i 11-- .......-- / i � W ///� I #5 m in o II I N 0 O 0 Z II II I I kI . APPROX. LOCATION /\\ OF FORMER LUPTON / 1� 1 A#4 SHORT LINE DITC I II in II II I \\ = SITE MAP I NOT TO SCALE I A#3 = II I (S) I I D I CONTAINS: II 9.020 ACRES =/- \\ #2 I \ iBSAND LEGEND: O1�° TIC SYSTE\ A\ SOIL PROFILE TO 55 FEET 1 /\#1 I I i. Li SOIL PROFILE TO 25 FEET Ict WATER WELL Io 'er I Soso` I t I 1 WCR 8 s : High Plains Engineering 4 /35 Denver Avenue • fort Lupton CO 8002 I Phone 303-857-9780 • Lax 303 857-923[3 PRELIMINARY SUBSURFACE INVESTIGATION AND FOUNDATION RECOMMENDATIONS Prepared For Land Professionals, LLC 4311 Highway 66, Suite 4 Longmont, CO 80504 Job Site Located At: 12557WCR 8 Weld County, CO August 11, 2004 JOB # 044122 ,T% scim `9 •o Todd M. Schroeder, PE 8g/au 4 � j AGREEMENT OF PURPOSE AND DISCLAIMER: The parties specifically agree and contract that the purpose of the provided "blanket type" subsurface investigation is to test, analyze, and provide preliminary geotechnical recommendations for the re-zoning of this tract of land. This report presents a description of subsurface conditions encountered at the site, recommended foundation system, and design and construction criteria influenced by the subsurface conditions. The opinions and recommendations presented in this report are based on the data generated during this field exploration, laboratory testing, and our experience. A foundation design sealed by a Professional Engineer is required to obtain a building permit but is not included in this report. The parties specifically agree that High Plains Engineering has not been retained nor will they render an opinion concerning environmental issues, hazardous waste or any other known and or unknown conditions that may be present on the job site, since this is not our area of expertise. LOCATION AND SITE CONDITIONS: This report represents the results of the data obtained during the subsoil investigation at 12557 WCR 8, Weld County, CO. The site is a small parcel consisting of 9+/- acres of land. The site is reasonably level with approximate slopes of 0.5% to the North. The lot appears to be well drained with no erosion evident. SUBSOIL CONDITIONS: Two, four inch diameter holes were drilled to a depth of twenty five feet, as shown on the attached site map, for the purpose of soil analysis on July 15, 2004. Four, six inch diameter holes were drilled to a depth of fifty five feet at the building site on July 19, 2004, as shown on the attached site map, for the purpose of mineral investigation. Samples of the soil were taken at two-foot intervals. These samples were analyzed in the field and laboratory to determine the characteristics of the soil (per Unified Soil Classification System) for identification. Please refer to the Soil Profile logs near the end of this report for soil types at specific depths. The Standard Penetration Test similar to ASTM D1586 showed 19 to 20 blows for 12-inch penetration at a depth of 4 feet, and 25 to 30 blows for a 12-inch penetration at a depth of 9 feet. Please note that actual subsurface soil conditions may vary between samples and locations tested. HPE 3 Job#04-4122 1 of 8 r One-dimensional swell/consolidation tests were performed on selected samples to evaluate the expansive, compressive and collapsing nature of the soils and/or bedrock strata. These tests indicated a consolidation potential of 0.8% to an expansion potential of 0.3 at a depth of 4 feet, and an expansion potential of 0.3% at a depth of 52 feet. The soils in this report were classified using the American Society of Testing Materials (ASTM) procedures. The geotechnical practice in State of Colorado utilizes a relative scale to evaluate swelling (expansion) potentials. When a sample is wetted under a surcharge pressure of 500 pounds per square foot (psf), the measured swell is classified as low, moderate, high, or very high. The following table represents the relative classification criteria. Please note that the measured swell is not the only criteria for slab-on-grade recommendations and additional factors are considered by the engineer when evaluating the risk for slab-on-grade construction. TABLE I SLAB PERFORMANCE REPRESENTATIVE RISK CATEGORY PERCENT SWELL (500 PSF SURCHARGE) LOW 0 TO <3 MODERATE 3 TO <5 HIGH 5 TO <8 VERY HIGH ≥8 Source: Colorado Association of Geotechnical Engineers, Guideline for Slab Performance Risk Evaluation and Residential Basement Floor System Recommendations (Denver Metropolitan Area), 1996 SUBSURFACE ANALYSIS AND RECOMMENDATIONS: The preliminary recommendations presented in this report are based on the assumption that the site has variable soil conditions within the proposed site. As a result, we recommend that supplementary geotechnical engineering exploration should be performed for each of the proposed structures on this site. Supplemental geotechnical explorations will be used to confirm or modify the recommendations made in this report. Based on the geotechnical engineering analysis, subsurface exploration and laboratory test results, all of the test holes represented a low expansion-consolidation potential. HPE 3 Job#04-4122 2 of 8 Those sites with low expanding soil types would be founded on spread footings with allowable soil bearing capacities of approximately 1500-2000 psf at 4 to 8 foot depths. Foundation designs shall be based on a final Subsurface Investigation to be performed when the specific building envelopes are determined. GROUNDWATER: Groundwater levels were recorded at the time of our field investigation; free water was encountered in all test holes at approximately 25 feet. The groundwater can be expected to fluctuate throughout the year depending on variations in precipitation, surface drainage and irrigation on the site. The possible presence of shallow bedrock/dense clays beneath the surface is favorable for the formation of "perched" groundwater. We recommend that the bottom of the basement or crawlspace excavations be maintained at least 4 feet above the free groundwater level. The ground water levels recorded represent the free, static water levels after equalization of hydrostatic pressures in the test hole borings. It is possible that the groundwater levels recorded in the test hole borings may not be present at those levels in the foundation excavatiions. Flow rates, seepage paths, hydrostatic pressures, seasonal groundwater fluctuations, water quality and other factors were not determined in this investigation. A program, which may include special well construction, test procedures, long-term monitoring program and analysis would be necessary to determine these factors. FOUNDATION DRAIN: The external drainage system should be lined with a 10 mil plastic liner, which will contain a 4-inch diameter perforated drainpipe (rigid perforated PVC pipe is recommended) encased in a minimum of 8-inches deep by 12-inches of clean, 3/4-inch to 11/2-inch river rock. The drain should extend around the lower level of the footing perimeter with the invert at the high end of the drain being placed a minimum of four- inches below the bottom of the footing, The drain should be run to a non-perforated sump pit with a lift pump and high water alarm, or provide a free flow gravity outlet to the surface at a minimum slope of 1/8 inch per foot to facilitate efficient removal of water, (1/4 inch per foot is desired). The river rock should be placed a minimum of 8 inches over the pipe for the full width of the trench. The top of the gravel should be covered with Geotextile filter fabric or equivalent, to minimize clogging of the river rock and perforated pipe by backfill material. To help prevent secondary damage that could be caused by slab movement, the following construction techniques are additional recommendations for the foundation construction. HPE 3 Job#04-4 122 3 of 8 SLAB ON GRADE CONSTRUCTION: 1 . When and where slabs-on-grade are chosen and the owners are willing to accept the risks associated with slab movement, the following recommendations are to be followed: a.)Slabs should be constructed as "free floating". Positive separations and/or isolation joints should be provided between slabs and all foundation walls, bearing members (columns), plumbing and utility lines. Isolation may be achieved with 1/2 inch expansion material or by sleeving. Vertical movement of the slabs should not be restricted. b.) Eliminate plumbing under slabs where feasible. Where such plumbing is unavoidable, it should be thoroughly pressure tested during construction. c.) Place the slab directly on the undisturbed natural soils, or properly compacted fill soil. Floor slabs and footings should not be constructed on frozen sub grade. Slabs should be reinforced with rebar, wire mesh or fiber mesh to help control crack separation. 2. Provide frequent scoring of the slabs to provide joints for controlled cracking of the slab. Control joints should be placed to provide approximate slab areas of 150 square feet, with a maximum dimension of thirteen feet between joints. The depth of sawed control joints should be '/a of the slab thickness. Install a good quality sealant in these joints to prevent surface discharges of liquid from penetrating slab sub grades. 3. The soils that will support the concrete slabs should be kept moist during construction by occasional sprinkling of water. The soils should be moistened to +/- 2 % optimum moisture within 48 hours of pouring the slabs. This procedure will help maintain the moisture content of the underlying soil. **Heavy watering or pooling of any kind next to the foundation or within the backfilled area is not recommended.** 4. A minimum void or clear space of 3 inches should be provided at or near the bottom of all non-bearing partitions. In finished room areas, all drywall and paneling should be stopped approximately 3 inches above the top of the slab. This will allow some space for upward movement of the slab before pressures are applied to the wall and upper levels of the structure. The builder should provide a 'h inch space at the bottom of all doorjambs to allow for limited movement of the floor slab. The owner is hereby notified that it is their responsibility to maintain these void spaces. HPE 3 Job#04-4122 4 of 8 5. If a forced air heating system is used and the furnace is located on the slab, we recommend provision of a collapsible connection between the furnace and the ductwork. In the event a hot water heating system is used, the piping should not be placed beneath the concrete slab, BACKFILL AND SURFACE DRAINAGE: The foundation and retaining walls must be well cured and well braced prior to backfilling. Any soil disturbed adjacent to bearing foundation components are to be re- compacted to a minimum of 85% Standard Proctor Density (ASTM D698). Backfill that bears concrete slabs shall be compacted to 95% Standard Proctor Density (ASTM D698). Mechanical compaction methods shall be utilized, (water-flooding techniques are strictly prohibited). See Compaction Section for more information regarding compaction requirements and techniques. Proper drainage away from the foundation walls shall be provided. The owners are advised to immediately fill any settled areas to eliminate water accumulation near the foundation. A minimum slope of 12 inches in the first 10 feet from the perimeter of the building is recommended. Roof downspouts and sill cocks should discharge into long concrete splash blocks (5 feet long min.) or into gutter extensions to deposit runoff water beyond the limits of the backfill soil near the foundation walls. Plastic membranes should not be used to cover the ground surface immediately surrounding the structure; geotextile fabric should be utilized for weed control. Any drainage water from uphill shall be diverted around the structure. Sprinkling systems should not be installed or direct water to be within 10 feet of the foundation. The owner/builder is also advised that irrigation lines can leak and/or break, resulting in release of excessive amounts of water near the foundation. This can cause damage to slabs and foundation walls. WATER ACCUMULATION AROUND FOUNDATION ELEMENTS IS THE MAIN CAUSE OF DISTRESSED FOUNDATIONS. COMPACTION: Placing Fill: No brush, sod, frozen material, perishable material, unsuitable material, or stones of four inches or greater in maximum dimension shall be placed in the fill. The distribution of the material on the fill shall be such as to avoid the formation of layers of materials differing substantially in characteristics from the surrounding materials. The materials are to be delivered to the backfill surface at a uniform rate, and in such quantity as to permit a satisfactory construction procedure. Unnecessary concentration of backfill machinery travel tending to cause ruts and other hollows more than six inches in depth, are to be re-graded and compacted. After dumping of HPE 3 Job#04-4122 5 of 8 fill material on the backfill surface, the material is to be spread by approved methods in approximately 6 inches compacted thickness. Moisture Control: The material in each layer shall be compacted by rolling and shall contain the optimum moisture required for maximum compaction, as nearly practicable and as determined by the soils engineer. The moisture content shall be uniform throughout all layers. If in the opinion of the soils engineer it is not possible to obtain moisture content by adding water on the fill surface, the contractor may be required to add the necessary moisture to backfill material in the borrow area. Compaction: When the moisture condition and content of each spread layer is satisfactory, it shall be compacted by a method approved by the soils engineer to 95% ASTM D698 (Standard Proctor Density) for slab areas, and 98% ASTM D698 for footing and/or pad areas. A Standard Proctor test is to be performed for each typical fill material and frequent tests of the density of the fill must be taken. In general, to compact cohesion-less free-draining materials, the above guidelines also apply. When compacting cohesion-less free-draining materials such as gravel and sand, the materials shall be deposited in layers and compacted by treads of a crawler type tractor, surface of internal vibrators, pneumatic or smooth rollers, power or hand tampers, or by any other means approved by the soils engineer. The thickness of the horizontal layers after compaction is not to exceed 6 inches compacted thickness if compaction is performed by tractor treads, surface vibrators or similar equipment, or not more than penetrating length of the vibrator head if compaction is performed by internal vibrators. When the moisture content and condition of each spread layer is satisfactory, it shall be compacted by a method approved by the soils engineer to 95% ASTM D1557 (Modified Proctor Density) for slab areas, and 98% ASTM D1557 for footing and/or pad areas. RADON: Most counties in Colorado have average radon levels (measured in home) above the U.S. EPA recommended "action level" of 4 picocuries per liter of air (pCi/1). Results of a 1987-1988 EPA-supported radon study for Colorado indicated that granite rocks, in particular, generally have elevated levels of uranium. These rocks have the potential of producing higher than average levels of radon gas in the home. Increasing ventilation of basements and crawl spaces and sealing of joints can mitigate build-ups of radon gas. This mitigation is best implemented during the design and construction phases of residences. HPE 3 Job#04-4122 6 of 8 The Colorado Geologic Survey {www.dnr.state.co.us/geosurvey} and the U.S. EPA {www.epa.gov/iaq/radon} are both good sources for additional radon information. PRELIMINARY ENGINEERING ANALYSIS AND RECOMMENDAIONS: The preliminary recommendations presented in this report are based on the assumption that the site has variable soil conditions within the proposed site. As a result, we recommend that supplementary geotechnical engineering exploration should be performed for each of the proposed structures on this site. Supplemental geotechnical explorations will be used to confirm or modify the recommendations made in this report. CONSTRUCTION DETAILS - GENERAL COMMENTS: In any soil investigation, it is necessary to assume that the subsurface soil conditions do not vary greatly from the conditions encountered in the field and laboratory testing. The accompanying design is presented using best professional judgment based on the limits of the extent of testing commissioned by the client. Our experience has been that at times, soil conditions do change and variations do occur. These may become first apparent at the time of excavation for the foundation system. **If soils conditions are encountered which appear different from the test borings as presented in this report, it is required that this office be called to make an observation of the open excavation prior to placing the footings, The cost of this observation is not part of this report.** This project should be constructed by a qualified contractor with experience in similar projects. The owner/builder is advised to observe and document the construction process to ensure the construction is performed in accordance with the design drawings and technical specifications. This report does not address general hillside stability, landslide potential, and/or other natural hazards. Several areas in the Colorado Front Range have known geologic hazards associated with them. We recommend that readers of this report educate themselves further as to the existence of geologic hazards on or around their specific property of interest. The Colorado Geologic Survey {www.dnr.state.co.us/geosurvey or 303-866-2611} is a good source for publications (maps, reports, etc.) dealing with specific geologic issues and/or issues related to specific geographic areas. The foundation and retaining walls must be well cured and well braced prior to backfilling. HPE 3 Job#04-4122 7 of 8 DISCLAIMER: We do not guarantee the performance of the project in any respect, but only that our engineering work and judgments rendered meet the standard care of our profession. The presence of underground workings (e.g. coal mines) and subsidence potential from any workings was not part of this investigation. The owner should contact the State and County agencies to determine if mining has been conducted in the area and if any precautions are recommended. THE PARTIES SPECIFICALLY AGREE THAT HIGH PLAINS ENGINEERING, INC, HAS NOT BEEN RETAINED NOR WILL THEY RENDER AN OPINION CONCERNING ANY ENVIRONMENTAL ISSUES, HAZARDOUS WASTE OR ANY OTHER KNOWN OR UNKNOWN CONDITIONS THAT MAY BE PRESENT ON SITE. DUE TO CHANGING TECHNOLOGY, BUILDING CODES AND CITY/COUNTY REQUIREMENTS, THIS SOIL REPORT MUST BE USED WITHIN ONE YEAR OF THE DATE ON THE FRONT OF THE REPORT OR MUST BE REVISED. HPE 3 Job#04-4122 8 of 8 .17 O 30 31 2 SILTY CLAY WITH LOW PLASTICITY(CL-ML) 32 3 33 4 34 SILTY GRAVEL(GM) 5 35 WELL GRADED GRAVEL(GW) G 3G 7 POORLY GRADED GRAVEL(GP) 37 8 35 9 39 /� 0 40 /// r/7/ I I 41 /// 12 42 ^` j/. 13 • 43 /// /// 14 44 // /j 15 45 �// I6 46 V/ /// 17 WELL GRADED SAND(SW) 47 POORLY GRADED GRAVEL(GP) 7// %% Ib 44 /� 19 49 / i// 20 50 /7' //// 21 5I /// r// 22 52 /// 23 53/ // 7.6 24 54 25 55 2C 50 SHALE 27 57 WELL GRADED GRAVEL(GM 24 54 29 59 30 CO SOIL PROFILE#I o I CLAY WITH LOW PLASTICITY (CL) 2 SILTY GRAVEL (GM) / 3 Blowcounts 19/12 /// 4 �j/i 5 /jj G // / / 7 5 Blowcounts 25/12 / 9 // 10 7/2/ I I j 12 / WELL GRADED SAND (SW) �/ 13 // / / // 14 /j / /j/j 1 5 / • ///:::. 1G //j 17 ////// �* IS >/// 19 /// 20 ///i 21 // / 22 ///# j 23 //// 24 •//;i 25 SOIL PROFILE #2 • 0 � 30 31 CLAY WITH LOW PLASTICITY(CL) 2 32 3 33 4 SILLY GRAVEL(GM) 34 WELL GRADED GRAVEL(GW) 5 35 36 POORLY GRADED GRAVEL(GP) 7 37 2 8 38 9 39 10 . � 40 I I %/, 41 2 /// 42 �^ 3 1// 43 /// 4 // 44 WELL GRADED SAND(SW) 15 /// 45 //./ z 6 4G //i 17 �// 47 WELL GRADED GRAVEL(GW) //./ 8 •' 48 19 49 20 50 POORLY GRADED GRAVEL(GP) 21 51 22 52 23 53 SHALE 24 54 25 55 2G 27 28 29 30 SOIL PROFILE #3 O 0/ 3 // SILTY GRAVEL(GM) /%/ 31 2 // 32 POORLY GRADED GRAVEL(GP) . // / 3 // 33 /' /// 4 //i 34 / 5 // 35 //% G /./ 3G ./// // / /// 7 • �/ 37 /// // // 8 // 38 WELL GRADED SAND(5W) /// /// 9 %/ 39 /%' I O /// 40 /// // 41 '// // /// 2 • // 42 /� WELL GRADED SAND(5W) // �// 13 /// 43 r, . /// 14 /7 44 /// // /// I5 /// 45 /// 0 // // 40 '// // /// 17 • // 47 /// // /// I8 48 //' 7/ 19 49 /// POORLY GRADED GRAVEL(GP) // 20 50 /// 21 51 /7/, . 22 52 /// 23 53 5EIALE //, 24 54 /// 25 55 //// 26 // /// 27 /// '// 25 ///// 29 •/,/• 30 SOIL PROFILE #4 0 /� SANDY CLAY (SC) SILTY GRAVEL(GM) 3 Blowcounts 20/12 4 5 G 7 8 Blowcounts 30/12 9 0 II 12 WELL GRADED GRAVEL (GW) 13 14 I5 IG 17 I8 I9 20 21 22 23 24 25 SOIL PROFILE #5 0 2% 30 // // 31 POORLY GRADED SILTY GRAVEL(GP-GM) %% 2 // 32 3 // 33 POORLY GRADED GRAVEL.(GP) // 4 // 34 /// 5 /// 35 //// // // i 6 //. 36 // %/ 7 %/ 37 //i • // /%� B %% 38 WELL GRADED SAND(SW) j// 9 /// 39 (O 10 /% 40 /// I 1 /// 41 j/ 12 // 42 ///• 13 // / 43 ,i., //I/ 14 // 44 // / // • Is / 45 %. 16 WELL GRADED SAND(SW) ./ .• 46 / / /// 17 // 47 .// //. //i 18 ' // 48 /// / (// 19 // 49 //7 //' / 20 50 /// POORLY GRADED GRAVEL(GP) V/ 2I 51 /// 22 52 7// ,// 23 53 SHALE //4• 24 54 %� 25 55 /// 26 /// 27 //' i/j 28 Y./ 29 /// 30 r SOIL PROFILE #6 • 12% 10% ) 8% - --T _ .. �. 69'0 496 2% 0% •- • __- -29'0 H2O -- -4% ADDED _G% - - -8% - -1O% - - - • -. - 100 500 I000 2000 3000 10000 GRAPH OF FOUR FOOT DEPTH X X SOIL TYPE NOLfI DEPTH L.L. P.L. P.I. EXPANSION CONSOLIDATION 4 28.08 22.22 5.86 0.3 SILTY CLAY WITH LOW PLASTICITY(CL-ML) �-- 12% . 1 10% — - 8% — .— -- --' — 2% polo -2% —H2G- ADDED -4% - - -6% -8% -10% - — I T - • ' - I00 500 1000 2000 3000 10000 GRAPH OF FOUR FOOT DEPTH X X SOIL TYPE HOLE# DEFTI1 L.L. P.L. -. P.I. EXPANSION CONSOUDATION 6 4 NON MASTIC 0.8 POORLY GRADED SILTY GRAVEL(GP-GM) JO5 NO:1 041122 JOB LOCATION- DATE: 8/10,04 1 2557 WCR DRAWN' JON WELD COUNTY.CO CHECKED: HIGH PLAINS ENGINEERING �,M1 735 DENVER AVENUE, FORT LtJPT❑N, CO 80621 1'4N PHONE - (303) 857-9280 FAX - (303) 857-9238 '1,• 12% 10% 8% a all 6% - A a 4% 2% J0% . `~�► ,� W ADDED Z -4%LA w -6% 0 -8% -107. 100 500 1000 2000 3000 10000 LOADING (PSF) GRAPH OF FIFTY TWO FOOT DEPTH X X SOIL TYPE HOLE N DEPTH LL. 4 PL. P.I. EXPN4 Th CONSOLIDATION 6 52 27.54 20.48 7.06 03 CLAY WITH LOW PLASTICITY (CL) JOB NO?04-4122 JOB LOCATION, DATE'8/10/04 12557 WCR 8 DRAWNI%Jon WELD COUNTY, CO CHECKED High Plains Engineering 735 Denver Avenue • Fort Lupton CO 8062 1 Phone 303-857-9280 • fax 303-857-9238 -4 e WELL SLOPED- 17'PER BRACE WALLS,TOP& 10Fl.MIN. BOTTOM PRIOR TO BACKFILLING I I DAMP PROOFING FOUNDATION WALL i-BACKFILL AREA? SLAB LEVEL GEOTEXTILE FILTER FABRIC 10 MIL PLASTIC LINER GLUED TO WALL GRADE • • OR EQUIVALENT WITH FIBERED ROOFING ADHESIVE OR EQUIV. AND EXTEND ALONG BOTTOM OF EXCAVATION TO A MINIMUM z OF 6 INCHES ABOVE BOTTOM • • .s3<''-'tAf7 r r OF PIPE ALONG EXTERIOR OF EXCAVATION N 12'MINIMUM DEPTH OF CONCRETE FOOTER 3/4 TO 1-1/2'CLEAN RIVER ROCK 4"DIA. PERFORATED PLASTIC PIPE *RIGID PERFORATED PVC PIPE IS PREFERRED* DETAILS OF PERIPHERAL DRAIN SYSTEM (OUTSIDE) THE DRAIN SHOULD BE RUN TO A NON-PERFORATED SUMP PIT WITH A LIFT PUMP AND A HIGH WATER ALARM OR PROVIDE A FREE GRAVITY OUTLET TO THE SURFACE, AT A MINIMUM SLOPE OF 1/8" PER FOOT. . �- Hi . h Plains Engineering I, 735 Denver Avenue ° Fort Lupton CO 8062 Phone 303-6.57-9280 • Fax 303-657-92.38 FOUNDATION GRADING DETAIL 5' MIN 1 i 1 ' L- -"C)ECORAIlVE GRAVEL OR STONE AREA F ray GRADE Z. o �IEVy- METAL OR WOOD EDGE FOUNDATION WALL W/ i/2` SPACE AT BOTTOM TO ALLOW FOR 1HE RELEASE OF WATER 'CEOTErTILE FABRIC 1. PROVIDE A MINIMUM OF 12" IN THE FIRST 1O'-O` FROM HOUSE (lox) 2. DOWNSPOUTS AND EXTENSIONS SHOULD EXTEND BEYOND THE GRAVEL OR STONE AREA High Plains Engineering 11x,,,1 735 Denver Avenue • Fort Lupton CO 80021 Phone 303-857-9280 • Fax 303-857-9238 Report Terminology (Based on ASTM D653) Note: This is a list of general Geotechnical terminology. These terms may or may not appear within any given High Plains Engineering,Inc.docnmeatation. Allowable Soil Bearing Capacity The recommended maximum contact stress developed at the interface of the foundation element and the supporting material. Alluvium Soil,the constituents of which have been transported in suspension by flowing water and subsequently deposited by sedimentation. Aggregate Base Course A layer of specified material placed on a subgrade or subbase usually beneath slabs or pavements. Bedrock A natural aggregate of mineral grains connected by strong and permanent cohesive forces. Usually requires drilling, wedging,blasting or other methods of extraordinary force for excavation. Bench A horizontal surface in a sloped deposit. Caisson A concrete foundation element cast in a circular excavation that may have an enlarged base. Sometimes referred to as a cast-in-place pier or drilled shaft. Coefficient of Friction A constant proportionality factor relating normal stress and the corresponding shear stress at which sliding starts between the two surfaces. Colluvium Soil,the constituents of which have been dyntsited chiefly by gravity such as the foot of a slope or cliff. Compaction The densification of a soil by means of mechanical manipulation. Concrete Slab-on-Grade A concrete surface layer cast directly upon a base,subbase or subgrade,and typically used as a floor system. Differential Movement Unequal settlement or heave between,or within,foundation elements of structure. Earth Pressure The pressure exerted by soil on any boundary such as a foundation wall. ESAL Equivalent Single Axle Load,a criteria used to convert traffic to a uniform standard. Equivalent Fluid A hypothetical fluid having a unit weight such that it will produce a pressure against a lateral support presumed to be equivalent to that produced by the actual soil. This simplified approach is valid only when deformation conditions are such that the pressure increases linearly with depth and the wall friction is neglected. Existing or Man-made Fill Materials deposited throughout the action of man prior to exploration of the site. Existing Grade The ground surface at the time of field exploration. Expansive Potential The potential of a soil to expand due to absorption of moisture. Finished Grade The final grade created as part of a project. Footing A portion of the foundation of a structure that transmits loads directly to the soil. Foundation The lower part a structure that transmits the loads to the soil or bedrock. Frost Depth The depth at which the ground becomes frozen. Grade Beam A foundation element or wall,typically constructed of reinforced concrete,used to span between other foundation elements such as drilled piers. Groundwater Subsurface water found in the zone of saturation of soils or within fractures in bedrock. Heave Upward movement. Lithologic The characteristics which describe the composition and texture of soil and rock by observation. Native Grade The naturally occurring ground surface. Native Soil Naturally occurring on-site soil. Optimum Moisture Content The water content at which a soil can be compacted to a maximum dry unit weight by a given compactive effort. Perched Water Groundwater. Scarify To mechanically loosed soil or break down existing soil structure. Settlement Downward movement of soil. Skin Friction or Side Shear '!'he frictional resistance developed between soil and an element of the structure such as a drilled pier. Soil Sediments or other unconsolidated accumulations of solid particles produced by the physical and chemical disintegration of rocks,and which mayor may not contain organic matter. Strain The change in length per unit of length in a given direction. Stress The force per unit area acting within a soil mass. Structural Fill Specified material placed and compacted to a specified density and/or moisture conditions under observations of a representative of a geotechnical engineer. Strip To remove from present location. Subbase A layer of specified material in a pavement system between the subgrade and base course. Subgrade The soil prepared and compacted to support a structure,slab or pavement system. Hello