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Home My WebLink About20150131.tiff PRELIMINARY GEOTECHNICAL INVESTIGATION FOR TRACT A,ARROWHEAD 4TH FILING, WELD COUNTY,COLORADO FOR ELMER LUNDVALL CDS ENGINEERING CORPORATION LOVELAND,COLORADO PROJECT NUMBER 14-6836 JUNE 3,2014 DSC =Engineering Corporation - - June 3, 2014 Project No. 14-6836 Mr. Elmer Lundvall PO Box 632 Greeley, CO 80632 Dear Elmer, Enclosed is the report you requested of the preliminary geotechnical exploration for the proposed subdivision of Tract A,Arrowhead 4th Filing, Weld County, Colorado. The site appears to be suitable for the construction of the proposed residences. If you have any further questions concerning the information in this report,please contact this office. Respectfully, FOR AND ON BEHALF OF CDS ENGINEERING CORPORATION ON O 38387 Kevin F. Becker,P. 14,O i�'/r?r� i E Enclosures 165 2nd Street S.W. • Loveland, CO 80537 • (970) 667-8010 • Fax (970) 66- .0 7 4 - miwor cds-eng.net TABLE OF CONTENTS Pau Letter of Transmittal i Table of Contents ii Scope 1 Site Investigation 1 Site Location and Description 2 Subsurface Conditions 2 Site Development 3 -Overlot Grading 3 -Basement Construction 3 Preliminary Foundation Recommendations 4 Slab Construction 4 Foundation Drain System 5 Conclusions 5 ATTACHMENTS Location of Test Borings Drawing No. 1 Symbols and Soil Properties Figure No. 1 Log of Borings Figure No. 2 Swell-Consolidation Test Results Figure No. 3 Summary of Test Results Table No. 1 ii 1 SCOPE This report presents the results of a preliminary geotechnical exploration for the proposed subdivision of Tract A,Arrowhead 4th Filing,Weld County,Colorado. The buildings are anticipated to be of typical wood frame construction. Full basement and/or crawlspace construction is anticipated for these structures. This exploration was conducted to provide preliminary recommendations pertaining to the type and depth of foundation system,soil bearing pressures,groundwater conditions,and to identify any complications that may be encountered during or after construction due to subsurface conditions. SITE INVESTIGATION The field investigation performed on March 19, 2014, consisted of drilling, logging, and sampling two(2)test borings across the 10-acre site. The borings ranged in depth from thirteen(13) to sixteen (16) feet. The location of the Test Holes is shown on Drawing No. 1. Boring locations were established by a representative of CDS Engineering Corporation based on a site plan provided by Wernsman Engineering. Distances from the referenced features were made by pacing and angles were estimated. Graphical logs of the borings are shown on Figure No. 2. The descriptions of the soils and/or bedrock strata are based, primarily, on visual and tactual methods which are subject to interpretation. The test borings were advanced using a truck mounted,four-inch(4")diameter,continuous flight auger drill rig. Laboratory samples were obtained by driving a two and one-half inch(2%2") diameter California Barrel Sampler twelve(12) inches(or as shown)into undisturbed soils with a 140-pound hammer falling thirty(30) inches. Bag samples of auger cuttings may have also been collected. Laboratory tests performed were - Swell-Consolidation, Natural Moisture, Natural Dry Densities, and Unconfined Compressive Strengths. All tests were conducted in accordance with ASTM standards. A Summary of the Swell-Consolidation Test Results is shown on Figure No.3. A Summary of Test Results is shown on Table No. 1. 2 SITE LOCATION AND DESCRIPTION The site is located southwest of Greeley,west of 47th Avenue on the south side of 37`h Street, Weld County,Colorado. The site is generally in a plains region,and vegetation consists primarily of grasses,trees,and shrubs.The site has slopes in varying directions. No rock outcrops were observed at this site. An apparent wetlands area runs through the north side of the property. SUBSURFACE CONDITIONS Refer to the Log of Borings, Figure No. 2. The subsurface conditions appear uniform throughout the proposed building site. General descriptions of the soils and/or rock encountered are as follows: TOPSOIL—A thin layer of topsoil,approximately six(6)inches,overlies the site. The topsoil should not be used as foundation bearing material,structural fill,or backfill. It is suggested that the topsoil be stripped, stockpiled and used for landscaped areas. CLAY — Clays with slight to moderate amounts of silt, and slight amounts of sand were encountered in the upper two and one-half(2'/2)to three(3)feet of Test Hole Nos. 1 and 2. The clays appear to be moist, firm to stiff, and brown. The clays exhibit low swell potential. SILTSTONE — Siltstone bedrock strata with slight to high amounts of clay and sand were encountered from beneath the upper soils to the depths explored in Test Hole Nos. 1 and 2. The competent siltstone exhibits high bearing capacities with low swell potentials detected in our tests. Groundwater levels were recorded as the borings were advanced, after completion of the drilling operations,and twenty-four(24)hours after drilling operations were complete. During our field exploration groundwater was encountered in each test hole at a depth of ten (10) feet. The water levels listed above are the stabilized levels of the free groundwater surface at the time of this exploration and may not properly define yearly groundwater levels. 3 SITE DEVELOPMENT The preliminary geotechnical concerns which may influence development of this site are the shallow depth of bedrock. These issues can be mitigated with proper planning,engineering,design and construction. Other geotechnical issues for the site include site grading, utility construction, pavement subgrades, and construction of permanent slopes for long term stability and protection against erosion. These concerns are discussed in the flowing sections. Due to the preliminary nature of this project,site organization or grading plans have not been prepared,and therefore are not available for review in conjunction with this subsurface exploration program. Therefore, recommendations provided here are general and for planning purposes only. Overlot Grading Although evidence of fills or underground facilities such as silage pits, septic tanks, cesspools, basements and utilities were not observed during the field exploration and testing program,such features could be encountered during construction. If unexpected fill or underground facilities are encountered, such features should be removed and the excavation thoroughly cleaned prior to backfill placement and/or construction. In areas to be filled,the ground surface should be stripped of vegetation,scarified,moisture- conditioned and compacted to at least 95 percent of the standard Proctor maximum dry density (ASTM D-698). We anticipate stripping will require minimal cuts of six(6)to twelve(12)inches for the majority of the site. The on-site soils can be used as site grading fill provided it is free of vegetation and other organic materials, trash, rubbish and construction debris. Fill should not contain rocks or lumps greater than six (6) inches in diameter. Highly plastic and swelling clays and claystone bedrock strata should not be used or mixed with other soils for fill in areas with structures. Clay fill,if used, should be placed at a high moisture content to reduce swell potential. The placement and compaction of site grading fill should be observed and tested by a qualified Soils Engineer. Basement Construction Groundwater was encountered in the test holes at a depth of approximately ten (10) feet below existing ground surface and may rise with long term development and subsequent landscape 4 irrigation. Generally,full basement level construction would be considered feasible at this site. The relatively shallow groundwater level in these areas may limit foundation depths and the variety of structure styles which could be offered. PRELIMINARY FOUNDATION RECOMMENDATIONS The type of foundation system applicable to each specific building location will depend on the swell potentials of the upper soils and bedrock strata,the location and type of bedrock strata,the type and depths of construction, and other factors that may come up at the time of construction. Drilled pier foundations would be suited where moderately to highly expansive soils and/or bedrock are encountered within the influence zones of the foundation. The drilled pier foundations could range in depth from twenty (20)to thirty(30) feet. Spread footings may be an option where some type of ground modification is utilized. The spread footing foundations may have maximum allowable bearing pressures ranging from 1500 to 2500 pounds per square foot(dead load plus live load)and a minimum bearing pressures ranging from 0 to 750 pounds per square foot.Individual, site specific investigations are recommended to develop criteria for designing the foundations and floor systems. Based on the information gathered in our limited subsurface exploration and laboratory testing,it appears that the lots in the planned subdivision will require drilled straight shaft pier foundations. SLAB CONSTRUCTION The type of floor system will depend on the swell potential of the soils,the type of usage and the owner's tolerance to slab movement. At this site,slabs placed a minimum of three(3)feet above the bedrock,in our opinion,could be constructed on grade. Slabs placed within three(3)feet of the bedrock may require alternate methods such as soil replacement or structural floors. 5 FOUNDATION DRAIN SYSTEM A perimeter drain system shall be installed where below grade floors are constructed. The type of drain,interior,exterior or both should be determined by a more specific site exploration and at the time of the excavation observation. CONCLUSIONS The data presented in this report were collected to help determine the feasibility of this project. Recommendations provided are for planning purposes subject to change based on future testing for site development. The findings and recommendations of this report have been obtained in accordance with accepted professional engineering practices in the field of Geotechnical Engineering. However, standard Geotechnical Engineering practices and related government regulations are subject to change. The recommendations provided in this report are only valid as of the date of this report. If the construction is at a later date,we would be glad to review the information presented in this report with regard to updated governmental requirements or industry standards. There is no other warranty, either expressed or implied. We do not guarantee the performance of the project in any respect,but only that our engineering work and judgments rendered meet the standard of care of our profession. This report applies only to the type of construction anticipated in the area tested. The current technology is not at a stage where a guarantee of"absolutely no damage"can be assured by design and construction practices. I . I ,ia f ,: iiiktti r;' ;- .. -'r :..0 r. • rA , ; • ` tr i Y$, .TAY : o 'r •-• 1' y7 it r ffi� • 4 ~ �.: ,. 4*i el ,t8t \ . 1 ..t .. ... .., ..,.. ... .,, l 1 i_L 7 ..• 3-3 _^3'•••::::••,. r:i • f ` . it•�'r Ift c .L.' • ' ,�1 1 1 1 .. , i , F '� a • � ,-i `-A'• :- 1 i . ---y;.44. :••:-..-I,t:i..• - ••••••!,--'' ' •• . _ . • : ,. •i; T+'�t ~•.•.1t f ry, v� j .fi r� i. •4. 1 �.t !E. h r 't•'..1 i!• • . @*1 i:. ••�- . , t. ` At 1 '. .ii�-,•,Y Aa Ii. �� ka wt iy� I ..-1,,,-•.l ' •� „. .a• �.M.a ,.,.. 'sue' P.4, i w -a f I. yf L i r4. sa Client: Elmer Lundvall LOCATION OF TEST BORINGS Tract A, Arrowhead 4th Filing, Project: Weld Colorado CDS Engineering Corporation Approximate Scale: 1" = 200' 165 2nd St. S.W. Loveland, CO 80537 Project No. 14-6836 Tele: (970) 667-8010 Dwg. No.: 1 Sy-- bol s & Soil DroDerties FIGURE NO. 1 - Fill Gravel N/12 CALIFORNIA Sand / / Silt N/12 SPLIT SPOON Silty Clay Clay THIN WALLED (SHELBY) %, Weathered Bedrock Siltstone BAG SAMPLE Claystone Sandstone I Limestone PITCHER SAMPLE r r Igneous & Metamorphic rr r r r Penetration Resistance and Strength Classifications are Based on The Standard Penetration Test Number of Blows Relative Density Consistency Approximate Per foot (N)* Cohesionless Soils Cohesive Soils Cohesion ksf** 0-4 Very Loose Soft Less than 0.5 4-10 Loose Firm 0.5-1.0 10-30 Medium Stiff 1.0-2.0 30-50 Dense Very Stiff 2.0-4.0 50+ Very Dense Hard Greater than 4.0 * BLOWS PER FOOT - BLOWS OF 140 LB. HAMMER DROPPED 30 IN. TO DRIVE SPL (IN.)IT (ASTM DL586I SPOON R6N7)I SAMPLER ** EQUIVALENT TO PP/2 AND Qu/2 CEngineering 165 2nd St. S.W. D s Lovel d, CO 80537 Corporation Tele: 970) 667-8010 0 0 0 z TH-1 TH-2 m m 0 FT. - — 0 FT. m 0 m rn 1- r 10/12 �� 15/12 5FT. 5FT. 50/11 — 48/12 10 FT. .. T- _L 10 FT. 50/0 — 15 FT. Refusal on _ 15 FT. _— hard strata 20 FL • .. .... 20 FT. 25 FT. 25 FT. 30 FT. -- 30 FT. 35 FT. 35 FT. CLAY: silty, sl. sandy, moist, firm to Borings drilled 03/19/14 using �� stiff, brown a 4" diameter, continuous flight truck mounted drilling rig. SILTSTONE: wx. to competent, clayey, sl. sandy, moist, hard, tan/brown to dark brown = Groundwater CP drilling = Groundwater on 03/20/14 All soA and/or rock contacts shown on boring logs ore approximate and represent subsurface conditions at time of drilling. Boring logs and information presented on 1093 are subject to discussion and limitations of this report. LOG OF BORINGS CLIENT: Elmer Lundvall CDS Engineering PROJECT NO. 14-6836 Corporation PROJECT LOCATION Tract A, Arrowhead 4th Filing, 165 ad o 8x637 Weld County, Colorado Tele: (970)c 667-6010 Fig. No.: 2 SWELL/CONSOLIDATION TEST CURVES Client: Elmer Lundvall Project: Tract A,Arrowhead 4th Filing Project No.: 14-6836 Boring: TH-1 Description: Silty Clay Depth,ft: 2 Water Content: 22.0% Swell(%):* 0.4 Dry Density,pcf: 94.7 Approximate Swell Pressure,psf: 2400 Pressure,psf 100 1000 10000 6 - 5 4 3 2 d 1 as O -2 -3 -5 -6 Boring: TH-2 Description: Clayey Siltstone Depth,ft: 7 Water Content: 21.1% Swell(%):* 1.9 Dry Density,pcf: 103.1 Approximate Swell Pressure,psf: 2600 Pressure,psf 100 1000 10000 6 5 4 — - — 3 0 0 1 7 -1 -3 -5 - -6 *negative values indicate consolidation GDS Gorporatton Figure 3 r> co v a) O o .Q To o y � . r U a a> i — ' C , a a) Cn ax cv . w. CI CO U U a_ : .V::. -V ..,... m a o to d - • ≥ C to I N G pp�• • V ... • ys H C U 0 is • r W Et a to r W 8• O .-1 h d OO1 co Q. O ` J O = O O Z fl Ca0. 9, u N tp co us 0 v m • U • lID •;• },.as r. O ;.a6 O : r m w .3- ul o N tQ Z ,c,:j. r ':i is d N 3 o N `c•` O .:CV N E 0 CI +�� 1 . eL 3 C N i4 C1t. . . PRELIMINARY PERCOLATION TEST RESULTS AND SEPTIC SYSTEM RECOMMENDATIONS FOR TRACT A,ARROWHEAD 4TH FILING, WELD COUNTY,COLORADO FOR ELMER LUNDVALL CDS ENGINEERING CORPORATION LOVELAND,COLORADO PROJECT NUMBER 14-6836 JUNE 3,2014 C - Engineering Corporation : ; June 3,2014 Project No. 14-6836 Mr. Elmer Lundvall PO Box 632 Greeley, CO 80632 Dear Elmer, Enclosed is the report you requested of the preliminary percolation test results and septic system recommendations for the proposed subdivision to be located on Tract A, Arrowhead 4th Filing, Weld County, Colorado. The preliminary recommendations provided in this report are in compliance with Weld County regulations for Individual Sewage Disposal Systems. If you should have any questions concerning the information in the report,please feel free to contact this office. Respectfully, FOR AND ON BEHALF OF CDS ENGINEERING CORPORATION D.9..9. I.G,S(04/ f /7. ___/ f•• F. BFC•..9 f Y ' • ▪ 38387 . � � Kevin F. Becker, P .c . ' ff.`s .YTC Enclosures 165 7 S.W. (970) 2Fax (9 ( ) 667-80 .:1 v'a,r,� r r_ '( net �.;�d Sheet ,1, • Loveland. CO 3G5:s7 • 667-8010 ;.. . ) :�; �.; v�-U�+ n TABLE OF CONTENTS Em. Letter of Transmittal i Table of Contents ii Scope 1 Site Investigation 1 Site Location and Description 1 Subsoils and Groundwater Conditions 1 Percolation Test Results 2 Septic System Recommendations 2 Conclusions 3 ATTACHMENTS Location of Test Borings Drawing No. 1 Symbols and Soil Properties Figure No. 1 Log of Borings Figure No. 2 ii 1 SCOPE This report provides preliminary percolation test results and septic system recommendations for the proposed subdivision of Tract A,Arrowhead 4th Filing, Weld County, Colorado. SITE INVESTIGATION A field investigation, performed on March 19, 2014, consisted of drilling profile holes to depths of thirteen(13)to sixteen(16)feet and two(2)percolation holes to an average depth of thirty (30)inches,at each site. Percolation tests were performed on March 20,2014. The Location of the Test Holes is shown on Drawing No. 1. A Log of Borings is shown on Figure No. 2. SITE LOCATION AND DESCRIPTION The site is located southwest of Greeley, west of 47th Avenue, on the south side of 37th Street, Weld County, Colorado. The site is generally in a plains region, and vegetation consists primarily of grasses,trees, and shrubs. The site has slopes in varying directions. No rock outcrops were observed at this site. An apparent wetlands area runs through the north side of the property. SUBSOILS AND GROUNDWATER CONDITIONS Topsoil-A thin layer of topsoil,approximately six(6)inches,overlies the site. The topsoil should be stockpiled and used as backfill over the absorption field. CLAY —Clays with slight to moderate amounts of silt,and slight amounts of sand were encountered in the upper two and one-half(2%)to three(3)feet of Test Hole Nos. 1 and 2. The clays appear to be moist,firm to stiff, and brown. The clays exhibit low swell potential. 2 SILTSTONE - Siltstone bedrock strata with slight to high amounts of clay and sand were encountered from beneath the upper soils to the depths explored in Test Hole Nos. 1 and 2. The competent siltstone exhibits high bearing capacities with low swell potentials detected in our tests. Groundwater levels were recorded as the borings were advanced, after completion of the drilling operations, and twenty-four (24) hours after the drilling operations. During our field explorations groundwater was encountered in the profile holes at a depth of ten (10) feet. The groundwater table could be expected to fluctuate throughout the year depending on seasonal moisture variations. PERCOLATION TEST RESULTS A total of two (2) percolation tests were conducted at each site, using the Standard Test Method,as described by the Weld County Health Department. Percolation test holes were presoaked on March 19, 2014,and the test was performed on March 20, 2014. The percolation exploration indicates average percolation rates of 100 minutes per inch at site 1; and 132 minutes per inch at Site 2. Due to the slow percolation rates, and shallow bedrock,we anticipate that engineered septic systems will be required for these conditions. Based on these conditions,Evapotranspiration absorption or low pressure drip systems would be applicable at these sites. SEPTIC SYSTEM RECOMMENDATIONS The beds should be constructed by a licensed septic system installer,in accordance with the I.S.D.S.R.for Weld County. An effluent filter could be installed in or after the septic tank and may provide a longer life for the system. The beds should lie a minimum of ten(10)feet from property lines, twenty (20) feet from the proposed structure, and one-hundred (100) feet from most water features,such as ditches and wells. The contractor and/or owner must carefully plan the elevations of the structures if gravity flow of the wastewater to the septic system is desired. We recommend 3 that the top of the bed or trench be a minimum of one foot below any floor level with gravity sewer otherwise a pump system may be required. CONCLUSIONS These tests are only preliminary for the area tested. The findings and recommendations of this report have been obtained in accordance with accepted engineering practices in the field of Geotechnical Engineering. The county health department has final acceptance over these test results and referenced system. All construction shall be in compliance with the septic system permit. ,e- '-,:.7-'2..y. ' ••',;' . !4•,.•-„ 1,•- , .- •••..„ _....::::;• ..... ...,. r . • ,,::: ...4, . •,.,• ,• , ... . ,•,: . . ...,„ : 1.::- ';';=-..,'... .. .0 4 - . At, .. . . • • N Eit S the 1 'ti Y >,1-.„ A • y ��"' � till t•I----. ,•( �•��= .r; 1} . , _.-/' @ Irk mo ; 1 r''''' �. --•c••z.? ' ,...-.- • ':' • - - _ --: -Pl.'s- :•-• 44 li • , fie, 44At ... .- -' t • ...d f1:•. Client: Elmer Lundvall LOCATION OF TEST BORINGS Project: Tract A, Arrowhead 4th Filing, Weld Colorado CDS Engineering Corporation Approximate Scale: 1" = 200 165 2nd St. S.W. Loveland, CO 80537 Project No. 14-6836 Tele: (970) 667-8010 Dwg. No.: 1 Symbols 8c Soil � ro3erties FIGURE NO. 1 Fill Gravel I N/12 CALIFORNIA 7. Sand / / / Silt i N/12 SPLIT SPOON i Silty Clay Clay THIN WALLED (SHELBY) Weathered Bedrock — — Siltstone —._ BAG SAMPLE __ Claystone - Sandstone { PITCHER SAMPLE I Limestone LJ J Igneous & Metamorphic Penetration Resistance and Strength Classifications are Based on The Standard Penetration Test Number of Blows Relative Density Consistency Approximate Per foot (N)* Cohesionless Soils Cohesive Soils Cohesion ksf** 0-4 Very Loose Soft Less than 0.5 4.10 Loose Firm 0.5-1.0 10-30 Medium Stiff 1.0-2.0 30-50 Dense Very Stiff 2.0-4.0 50+ Very Dense Hard Greater than 4.0 * BLOWS PER FOOT - BLOWS OF 140 LB. HAMMER DROPPED 30 IN. TO DRIVE SPLIT SPOON OR CALIFORNIA SAMPLER 12" (IN.) (ASTM DL586-67) ** EQUIVALENT TO PP/2 AND Qu/2 Engineering 165 2nd St. S.W. CDS Loveland. CO 80537 C o rp o r ati o n Tele: {970) 667-6010 m un o TH-1 TH-2 a r'1 m a' OFT. � OFT. as O 0 A 10/12 15/12 5 FT. — _, • 5 FT. -- .II 50/11 i 48/12 10 FT. - - - 10 FT. • 50/0 15 FT. Refusal on 15 FT. hard strata - - 20 FT. 20 FT. 25 FT. -25 FT. 30 FT. -- 30 FT. 35 FT. ---35 FT. '/, CLAY: silty, sl. sandy, moist, firm to Borings drilled 03/19/14 using / ` stiff, brown a 4" diameter, continuous flight truck mounted drilling rig. SILTSTONE: wx. to competent, clayey, sl. r_-_ sandy, moist, hard, tan/brown to dark brown = Groundwater 0 drilling = Groundwater on 03/20/14 All soli and/or rock contacts shown on boring logs ore approximate and represent subsurface conditions of time of drilling. Boring loos and Information presented on logs are subject to discussion and limitations of this report. LOG OF BORINGS CLIENT: Elmer Lundvall CDS Engineering PROJECT NO. 14-6836 Corporation PROJECT LOCATION Tract A, Arrowhead 4th Filing, Lovei 2nd S.W. Weld County, Colorado Tele: (970) 667—8010 Fig. No.: 2 Iimit WERNSMAN ENGINEERING, INC. 1011 42nd STREET • EVANS, CO 80620 Phone (970) 353-4463 Fax (970) 353-9257 Chris Gathman Weld County Planning Services 1555 N 17th Avenue Greeley, CO 80631 RE: Change of Zone and Re-subdivide for Parcel 0959-27-1-07-005 Dear Chris Elmer Lundvall wishes to request a waiver of the mineral resource statement due to the fact the parcel contains only 10.2 acres and the lot is adjacent to an existing lake and residences. Thank you for your consideration. Sincerely <-5-: Eric Wernsman Hello