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HomeMy WebLinkAbout20000277.tiff .............................. ....... ........ ... .. . .... HORIZON CONSTRUCTION SERVICES, L.L.C. If 1 �_� 0 :is 1 ENVIRONMENTAL - GEOTECHNICAL - MATERIALS TESTING .... June 30, 1999 John Carmichael 5052 WCR 52 Weld County, CO Re: GEOTECHNICAL INVESTIGATION FOR THE PROPOSED CONSTRUCTION SITE LOCATED AT 5052 WCR 52, WELD COUNTY, CO FOR JOHN CARMICHAEL Dear Mr. Carmichael: We are pleased to submit this Geotechnical Investigation Report for the proposed construction at the above referenced site, as you requested. Fm Based upon our investigation of this site and the subsurface conditions encountered, it is our opinion the site is suitable for the proposed construction, providing the design criteria and recommendations set forth in this report are met. The enclosed report presents our findings of the subsurface conditions and our recommendations based upon these findings. Sincerely, HORIZON CONSTRUCTION SERVICES, LLC Reviewed by: \\`\ mmum, PI : OR RED",,�o Shawn Stifle, EIT Thomas Co .E2499 "1: :• rl :`::ss: :::::::: iii:::iii:iii:ii:i:ii: :ta 3310 STATE STREET, EVANS, COLORADO ,• ; 2000-0277 (970) 330-3778 (970) 339-5216 - FAX . HORIZON CONTRUCTION SERVICES, LLC PROJECT NO, 99070 John Carmichael Geotech June 30, 1999 TABLE OF CONTENTS Scope 1 Site Location and Description 1 Site Investigation 1 Laboratory Tests and Examinations 2 Subsoil and Groundwater Conditions 2 Recommendations and Discussion 3 Foundation 3 Lateral Earth Pressure 4 Floor Slabs 5 Subsurface Drainage 6 General Recommendations 6 General Comments 7 Appendix A - Site Plan - Boring Logs Appendix B - Summary of Test Results Appendix C - Suggested Specifications for Placement of Structural Fill Appendix D - Percolation Data f�� ' HORIZON CONSTRUCTI? SERVICES. LLC (MPROJECT NO. 99065 John Carmichael Geotech June 30, 1999 GEOTECHNICAL INVESTIGATION REPORT SCOPE This report presents the results of a geotechnical investigation for the proposed residential site located in Section 6, Ti N, R68W of the 6th PM, Weld County, Colorado, more particularly known as 5052 WCR 1 , Weld County, Colorado. The investigation included two test borings to obtain soils and groundwater data. The objectives of this study were to: 1 . Evaluate the subsurface conditions at the site relative to the proposed construction, 2. Make recommendations regarding the design of the substructures, and 3. Recommend certain precautions that should be taken because of adverse soil and/or groundwater conditions. 4. Determine soil types and percolation rate for the proposed leach field. The conclusions and recommendations presented in this report are based upon analysis of field and laboratory data and experience with similar subsurface conditions in the general vicinity. SITE LOCATION AND DESCRIPTION The proposed building site is located in Section 6, T1 N, R68W of the 6th PM, Weld County, Colorado. Based on the information provided, the proposed building site will be a two story house without a garage. The property is bordered by a property fence on all four sides, with the western side of the property located about 300 feet east of Weld County Road 1 . The direction of the drainage flow pattern is southerly. SITE INVESTIGATION The field investigation was conducted on June 4, 1999, and consisted of two borings located approximately as shown on the Site Plan (Appendix A). The two borings were drilled to obtain soil samples for laboratory examination, determine field parameters and determine groundwater levels. Boring field logs include field visual classifications and Standard Penetration Tests (SPT) Page 1 of 8 HORIZON CONSTRUCTICP •RVICES. LLC ' `PROJECT NO. 99065 Jonn Carmichael Geotech June 30, 1999 of the materials encountered during sampling. Final boring logs in this report represent the field findings and additional information determined by laboratory observations and tests. One soil profile boring was also drilled to a depth of 8 feet to determine soil types and ground water level in the proposed leach field area. Six percolation test holes were also drilled to a depth of 3 feet. Geotechnical investigation borings were advanced using 4.0-inch diameter continuous flight augers powered by a CME-75 truck mounted drilling rig. Soils were obtained to determine an index of the soils relative density and consistency with the Standard Penetration Test (SPT) split spoon sampler. The "N" values listed on the Summary of Test Results is the number of blows required to drive the 2-inch diameter split-spoon sampler 12-inches into undisturbed soil by a 140-pound hammer dropped 30 inches. The "N" values are also listed on the boring logs. Undisturbed samples for laboratory analytical use were obtained with 3-inch outer diameter thin wall samplers (Shelby Tubes). All materials were preserved at natural moisture content until testing. f "\ Boring logs are provided in Appendix A and include visual classifications of each soil, location of subsurface changes, and SPT results. A qualified soils technician from Horizon Construction Services, LLC, was present during all drilling activities and continuously observed the fieldwork. Final boring logs in this report represent the field findings and additional information determined by laboratory observations and tests. LABORATORY TESTS AND EXAMINATIONS Samples obtained from test borings were subjected to testing and inspection in the laboratory to provide a sound basis for determining the physical properties of site subsurface soils. Moisture contents and dry unit weights were determined. A summary of the test results and laboratory analyses can be found in Appendix B. SUBSOIL AND GROUNDWATER CONDITIONS The soil profile at the site consists of strata of materials arranged in different combinations. In order of increasing depths, they are as follows: tm� Page 2 of 8 HORIZON CONSTRUCTIC.. SERVICES, LLC PROJECT NO 99065 John Carmichael Geotech June 30, 1999 -:\ 1 . Grass and Silty Sandy Topsoil: This stratum was encountered from grade to approximately 1 foot below grade in both borings. This material should be removed, segregated, and remain unused for onsite backfill material. 2. Brown Silty Sand: This stratum was encountered in Boring 1 from 1 feet to 9 feet, including some root structure, and in Boring 2 from 2 to 6 feet and also contained little clay. This material will have a low swelling potential with low bearing capacity. 3. Brown Silty Clay: This stratum was encountered in Boring 1 from 9 to 14 feet, including trace sand, and in Boring 2 from 1 to 2 feet and from 17 to 18 feet, also containing sand with trace gravels from 17 to 18 feet. 4. Brown Silty Clayey Sand: This stratum was encountered in Boring 1 from 14 to 15 feet and in Boring 2 from 6 to 17 feet will have a low swelling potential with low bearing capacity. 5. Brown Siltstone and Washed 3/4" minus Gravelly Sand: This stratum was encountered in Boring 2 from 18 to 20 feet and will have a low swelling potential with a moderate bearing capacity. 6. Groundwater: At the time of the investigation groundwater was located at a depth of 4 and 5.5 feet in Borings 1 and 2, respectively. Water levels in this area are subject to change due to irrigating and seasonal variations. RECOMMENDATIONS AND DISCUSSION Our recommendations are based on the assumption that the subsurface conditions are similar to those disclosed by the borings. If variations are noted during construction or if changes are made in the site plan, foundation type or floor levels, we should be notified so we can supplement our recommendations, as applicable. It is our understanding the proposed building will consist of a stick frame structure placed over a crawl space. We do not anticipate foundation loading to be unusual for this type of construction. FOUNDATION In view of the loads transmitted by the proposed structure and the soil conditions encountered at the site, a conventional spread footing foundation is recommended. The following design criteria should also be observed: a) All grass and other organics should be removed from the structural fill area. Page 3 of 8 HORIZCN CONSTRUCT: nERVICES. LLC r PROJECT NO. 99065 John Carmichael Geotech June 30, 1999 b) All exterior footings should be placed a minimum of thirty inches below finished grade for frost protection. c) Footings may be designed for a maximum allowable bearing capacity (dead load plus maximum live load) of one thousand pounds per square foot (1000 psf). The predicted settlement or heave under the above loading-siT Ul be less than one inch (1"), generally considered to be within acceptable tolerances. These loads were based on the in-situ material remaining partially saturated and the engineer's recommendations provided as discussed in this report. d) Minimal swell potential is anticipated for these soils.-with a minimum required dead load of twenty five pounds per square foot.{a psf). e) Footings should be proportioned as much as practicable to minimize differential movement. Spread footings should be a minimum of 16 inches in width. Pad footings should be a minimum width of 24 inches. Continuous concrete foundation walls should be well-reinforced top and bottom. f) The base for structural fill should include all areas within a 1 :1 horizontal to vertical slope from the edge of the footings. g) A geotechnical engineer should inspect all subbase and imported material prior to placement of any foundation concrete. LATERAL EARTH PRESSURES Lateral pressures on walls depend on such factors as the type of wall, hydrostatic pressure behind the wall, type and slope of backfill material, degree of backfill compaction, allowable wall movements, and surcharge loading conditions. Where anticipated wall movements are greater than approximately 0.5 percent of the wall height or wall movement is constrained lateral earth pressures should be estimated for an "at rest" condition. Where anticipated wall movements are greater than 0.5 percent of the wall height, lateral earth pressures should be estimated for "active" condition. Walls backfilled with on-site silty sand should be designed for an equivalent fluid lateral earth pressure of 55 pounds per cubic foot for the "active" condition and 45 pounds per cubic foot for the "at rest" condition. We recommend a coefficient of sliding resistance between the concrete and bearing soils of 0.4 be assumed in the analysis. These values do not consider Page 4 of 8 HORIZON CONSTRUCTIO. JERVICES, LLC PROJECT NO. 99065 John Carmichael Geotech June 30, 1999 sloping backfill, surcharge loading, hydrostatic pressures, or horizontal swelling pressures. If any of these conditions are anticipated, lateral earth pressures will need to be adjusted. Disturbed subbase material and fill against footings, stem walls and retaining walls should be compacted to a density of 95% of maximum density and within 3% of optimum moisture, in accordance with ASTM D698. Medium to high plasticity clay soils should not be used as subbase or structural backfill material. FLOOR SLABS The following recommendations are to be provided during construction: 1 . Slabs should be designed for the imposed loading and be structurally independent of bearing members and utilities. 2. To minimize and control shrinkage cracks that may develop in slabs, control joints are recommended every 15 feet and at areas of potential cracking. The total area contained within these joints should be no greater than 225 square feet. 3. Slabs should be continuously reinforced with wire mesh or equivalent. 4. The structural fill base should include all areas within a 1 :1 horizontal to vertical slope from the footing edge. 5. Structural fill beneath footings or slabs should be placed in maximum 8- inch lifts compacted to ninety-five percent (95%) and three percent (3%) of optimum moisture in accordance with ASTM D698. 6. Proposed material to be used for structural fill should be evaluated by a geotechnical engineer prior to installation. A geotechnical engineer should closely observe structural fill installation. 7. Exterior slabs exposed to de-icing chemicals or extreme weathering should be constructed using Type II cement with higher air contents and higher compressive strengths. Page 5 of 8 HORIZON CONSTRUCTIC, . SERVICES, LLC PROJECT NO. 99065 John Carmichael Geotech June 30, 1999 SUBSURFACE DRAINAGE Groundwater was encountered at a depth of four feet at the time of the subsurface investigation. Surface water from irrigation systems may influence the level of the ground water therefore the following is recommended: 1) During construction, a drainage system with a perimeter drain should be installed around the top of the footer sloping to a sump area at a slope of one-eighth inch per foot (1/8"/1'). The drain should be constructed with four inch (4"), or greater, perforated pipe and should be surrounded in a gravel bed with a minimum of eight inches (8") of one and one-half inch (1-1/2") or three quarter inch (3/4") clean washed gravel. Building paper should be placed above the gravel prior to backfilling. 2) Damp-proofing measures should be included during construction, and may include damp proofing sprayed onto the foundation walls and/or an impervious membrane installed adjacent to the exterior of the foundation wall. A clean granular backfill placed adjacent to the barrier should be installed to allow surface water to enter the perimeter drain described above. Installation of a water stop should be placed between any footings and foundation walls. GENERAL RECOMMENDATIONS The following recommendations should be followed during construction and maintained at all times after the structure has been completed: 1) Finished grade should be sloped away from the structures on all sides to give positive drainage. A minimum slope of 6 inches for the first 10 feet is suggested. 2) Gutters and down spouts should be designed to carry roof runoff water well beyond the limits of the backfill area. 3) Underground sprinkling systems should be designed such that piping is placed a minimum of 5 feet outside the backfill of the structures. Heads should be designed so that irrigation water is not sprayed onto foundation walls. These recommendations should be taken into account for planned landscaping. Page 6 of 8 HORIZON CONSTRUCTION SERVICES, LLC PROJECT NO, 99065 John Carmichael Geotech June 30. 1999 4) Backfill around the exterior foundation walls in non-structural areas should be moistened and compacted to at least ninety percent (90%) of Standard Proctor in accordance with ASTM 0698. 5) Lawn edging used around the exterior of the structure should be perforated to prevent surface water ponding in the vicinity of backfill soils. 6) The exterior backfill should not be covered with polyethylene moisture barrier. A weed suppressant geotextile fabric, to allow for natural evaporation of the backfill soils, should be used instead. 7) Footings should be proportioned as much as practicable to minimize differential movement. 8) Compaction requirements should be completed as described in Appendix C, " Suggested Specifications for Placement of Structural Fill". 9) A Registered Professional Structural Engineer should design the sub- structures, and they should take into account the findings and recommendations of this report. 10) Backfill material should be free of frozen soil.. dried clods and organic matter. Backfilling should only be accomplished when concrete strength and adequate support to foundation walls are applied and acceptable to the Structural Engineer. GENERAL COMMENTS This report has been prepared to aid in the evaluation of the property and to assist the architect and engineer in project design. In the event any changes in the design of the structures or their locations are contemplated, the conclusions and recommendations contained in this report will not be valid unless said changes are reviewed and conclusions of this report modified or approved in writing by Horizon Construction Services, LLC. The professional judgments expressed in this report meet the standard of care of our profession. Every effort was made to provide comprehensive site coverage through careful locations of the test borings, while keeping the site investigation economically viable. Variations in soil and groundwater conditions between test borings may be encountered during construction. In order to permit correlation between the reported subsurface conditions and the actual conditions encountered during construction and to aid in carrying out Page 7 of 6 HORIZON CONSTRUCTIOI,, SERVICES, LLC PROJECT NO. 99065 John Carmichael Geotech June 30, 1999 the plans and specifications as originally contemplated, we recommend that a geotechnical engineer be retained to perform continuous excavation and foundation construction review. Horizon Construction Services, LLC, assumes no responsibility for compliance with the recommendations included in this report unless we are retained to perform adequate on-site review during construction. Analyses were performed and this report was prepared for the exclusive purpose of providing geotechnical engineering and/or testing information and recommendations. Environmental and flood plain assessments were not conducted and are not within the scope of this study. ASTM methods, if any, used in this report apply only to the specified test and any cross references listed in that specific ASTM are not implied or to be inferred. We were not provided with information or have knowledge of any hidden structures or other historical events which may effect this property. TM:. Page 8 of 8 HORIZON CONSTRUCTION SERVICES, LLC PROJECT NO. 99064 John Carmichael APPENDIX A Site Plan Boring Logs • John Carmichael Residence NORTH t Approximatelc 1/2 mi to WCR 52 from North property fence John Carmichael I Proposed Residence 1, Property Fence 5052 WCR 52 Weld County. CO ---------- BH I 1 40' 4 ti Approximatelc 300'to WCR I BH 2 him' West propel)y fend 40' Proposed leach Field } 71' Mag 18.00 Thu Jul 01 09:08 1999 Scale 1:1,758(at center) 50 Meters Local Road US Highway Railroad O C Horizon Constmcuou Services. tIC 1998 DeLonnc.'Street Alias USA LOG OF BORINGS Boring #1 John Carmichael Geotechnical Investigation ! 50' South,87' West of oeoth Property Fence Line n. H Grass and Silty Sand's Topsoil N=5 - I Moisture: 14.23% Brown Moist Loose Silty Sand Recovery: 12.12" — _ with Some Roots Depth: 1-2' 5' L_ \'=3 _ r Moisture: 15.2_4°0 L_ Brown Wet Ven'Loose Silty I Recovery: 12'12" Sand with Trace Roots Depth:3-4' 10' Moisture:29.93% : Brownish Gray Moist Finn I Recovery: 12/12" Depth:5-6' Mottled Silty Clay with Trace Sand %% i .. Moisture:27.65°0 � t5' a:; Brown Wet Loose Siln Clayey. Recovery: 12'IT' — J Sand Depth'9-10' N=.1 Moisture:23.07°° — Recovery: I2:'IT' Deolh: 1a-15' 20' 251 Water was detected in the bore hole at a depth of 4 feet. HORIZON CONSTRUCTION SERVICES, LLC. rN / e,-;•....,, P/7.7%% (_„.._, r -... LOG OF BORINGS Borinq#2 John Carmichael Geotechnical Investigation ' -70'South,40'West of Depth Property Fence Line Grass and Silty Sandy Topsoil N=5 — �/r I Moisture: 15.85% I Recovery: Brown Silty Clay 12:12" — Depth:2-3' 5 `- r .. Brown Loose Silty Sand with . N=6 ••• Little Clay Recovery: 12/12" — J`;,.?r::.;.:; — Depth:3-4' Brown Wet Loose Silty Clayey Recovery: 12/12" — to' Sand Depth: N=3 — il`p Brown.Wet Very Loose Silty Moisture:29.57% — t5' Claye Sand Recovery: 12/12" i Depth: 14-15' T— //.: Brown Silty Sandy Clay with Trace �7�^ Gravels N=32 — _ Brown Very StiffSiltstone and Ioisture:20.09% - 20' Washed'/."Gravelly Sand I____, Recovery: 12.'I2" — Depth: 19-20' 25' Water was detected in the bore l hole at a death of 5.5 feet. HORIZON CONSTRUCTION SERVICES, LLC. HORIZON CONSTRUCTION SERVICES, LLC PROJECT NO. 99064 John Carmichael APPENDIX B Summary of Test Results r—" '' John Carrnich.. .. eotech SUMMARY OF TEST RESULTS Dry Unconfined Swell % % AAS1-17O Boring Depth Moisture Liquid Plasticity USCS Density Conpressive Pressure Passing Passing CLASS/ "N" Value No. (H.) (%) Limit(%) Index(%) Classification (PCF) Strength(PSF) (PSF) No.40 No.200 GROUP 1 1-2' 14.23 5 1 3.4' 15.24 111.39 3 1 4-5' 20.99 106.64 1 5-6' 29.93 85.89 2 1 9-10' 27.65 93.14 5 1 14-15' 23.07 114.32 4 A-7-6 2 1-2' 19.65 98.60 11.7 99.02 60.69 43 27 15 CL 2 2-3' 15.85 107.81 5 2 3-4' 6 2 5-6' 24.01 105.92 2 6-7' 28.48 4 2 14-15' 29.57 3 2 19-20' 20.09 32 1 Project No 99064 tfaizon Construction Senates,I I C r'v rm., CONSOLIDATION TEST • PROJECT NAME: John Carmichael JOB NO 99064 DATE 6/8/1999 0 00 % 'O 0 50 100 I 1 150 3.50 1 I , I 3G0 \ C 350 T to 4.00 _ _ _ O 450 5.00 5.50_ I 6.00 6.50 I 700 I 7.50 I I I I I 8 C I I I \ III . 650 I 900 I I I 9.5G I I I I I I � STRESS.TSF i 0595 0.56 I ] L I 0 565 ICN I I 0550 I I I I 0 535 CC CZ 0 505 YJ o sos �� > 0 490 I I I I I I 0475 I I I 0.460 I I I I 0 445 I I I I I I 0 430 I I I I I 1 I I 0.415 I I I III I I I I I I 0.400 I I -I 1 C1 t 10 STRESS,TSF coring N.,./. Depth Classification t i ° CD MC i° 2 I 1-2' Brown Silty Clay 1102.5 19.7 Liquid Limit = 43 Plasticity Index = 27 I Pass #40 = 99.02 ,: 810 Pass #200 = 60.69 I (Degree of Saturation 87.45% HORIZON CONSTRUCTION SERVICES, LLC 3310 STATE ST EVANS. CC 80620 HORIZON CONSTRUCTION SERVICES, LLC PROJECT NO. 99064 John Carmichael r—"\ APPENDIX C Suggested Specifications for Placement of Structural Fill f�� HORIZON CONSTRUCTION SERVICES, LLC PROJECT NO. 99064 John Carmichael Suggested Specifications for Placement of Structural Fill General A geotechnical engineer shall be on-site to provide continuous observation during filling and grading operations and shall be the owner's representative to inspect placement of all compacted fill and/or backfill on the project. The geotechnical engineer shall approve all earth materials prior to their use, the methods of placing, and the degree of compaction obtained. Materials Soils used for all compacted fill and backfill shall be approved by the geotechnical engineer prior to their use. No material, including rock, having a maximum dimension greater than six (6) inches shall be placed in any fill. Any fill containing rock should be carefully mixed to avoid nesting and creation of voids. In no case shall frozen material be used as a fill and/or backfill material. Preparation of Subgrade All topsoil, vegetation (including trees and brush), timber, debris, rubbish, and other unsuitable material shall be removed to a depth satisfactory to the geotechnical engineer and disposed of by suitable means before beginning subgrade preparation. The subgrade surface of the area to be filled shall be scarified a minimum depth of six (6) inches, moistened as necessary, and compacted in a manner specified below for the subsequent layers of fill. Fill shall not be placed on frozen or muddy ground. Placing Fill No sod, brush, frozen or thawing material, or other unsuitable material shall be placed in the fill, and no fill shall be placed during unfavorable weather conditions. All clods shall be broken into small pieces, and distribution of material in the fill shall be such as to preclude the formation of lenses of material differing from the surrounding material. The materials shall be delivered to and spread on the fill surface in a manner that results in a uniformly compacted fill. Each layer shall be thoroughly blade mixed during spreading to ensure uniformity of material and moisture in each layer. Prior to compacting, each layer shall have a maximum thickness of Ty eight (8) inches, and its upper surface shall be approximately horizontal. Each successive 6" to 8" lift of fill being placed on slopes or hillsides Page 1 of 3 • HORIZON CONSTRUC ION SERVICES, LLC PROJECT NO. 99064 John Carmichael should be benched into the existing slopes, providing good bond between the fill and existing ground. Moisture Control While being compacted, the fill material in each layer shall as nearly as practical contain the amount of moisture required for optimum compaction or as specified, and the moisture shall be uniform throughout the fill. The contractor may be required to add necessary moisture to the fill material and to uniformly mix the water with the fill material if, in the opinion of the geotechnical engineer, it is not possible to obtain uniform moisture content by adding water on the fill surface. If, in the opinion of the geotechnical engineer, the material proposed for use in the compacted fill is too wet to permit adequate compaction, it shall be dried in an acceptable manner prior to placement and compaction. Compaction When an acceptable, uniform moisture content is obtained, each layer shall be compacted by a method acceptable to the geotechnical engineer and as specified in the foregoing report as determined by applicable standards. r j Compaction shall be performed by rolling with approved tamping rollers, pneumatic-tired rollers, three-wheel power rollers, vibrator compactors, or other approved equipment well suited to the soil being compacted. If a sheepfoot roller is used, it shall be provided with cleaner bars attached in a manner that will prevent the accumulation of material between the tamper feet. The rollers should be designed so that effective weight can be increased. Moisture-Density Determination Samples of representative fill materials to be placed shall be furnished by the contractor to the geotechnical engineer for determination of maximum density and optimum moisture or percent of Relative Density for these materials. Tests for this determination will be made using methods conforming to requirements of ASTM D 698, ASTM D 1557, or ASTM D 2049. Copies of the results of these tests will be furnished to the owner, the project engineer, and the contractor. These test results shall be the basis of control for all compaction effort. Page 2 of 3 rTh i-h HORIZON CONSTRUC,i ION SERVICES, LLC PROJECT NO. 99064 John Carmichael A...y Density Tests The density and moisture content of each layer of compacted fill will be determined by the geotechnical engineer in accordance with ASTM D 1556, ASTM D 2167, or ASTM D 2922. Any material found not to comply with the minimum specified density shall be re-compacted until the required density is obtained. Sufficient density tests shall be made and submitted to support the geotechnical engineer's recommendations. The results of density tests will also be furnished to the owner, the project engineer, and the contractor. Page 3 of 3 Hello