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Home My WebLink AboutHARMONY MARKET PUD, 2ND FILING, BUILDERS SQUARE EXPANSION - PRELIMINARY & FINAL - 54-87S - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGEOTECHNICAL ENGINEERING REPORT ADDITION TO BUILDER'S SQUARE HARMONY ROAD FORT COLLINS, COLORADO ELI PROJECT NO. 20945042 l A Division of The Terracon Companies, Inc. GEOTECHNICAL ENGINEERING REPORT ADDITION TO BUILDER'S SQUARE HARMONY ROAD FORT COLLINS, COLORADO ELI PROJECT NO. 20945042 Prepared for: PROFESSIONAL ENGINEERING ASSOCIATES 2265 LIVERNOIS ROAD TROY, MICHIGAN 48083 ATTN: MR. MICHAEL SMALLEY, P.E. Empire Laboratories, Inc. A Division of the Terracon Companies, Inc. PgOR4 UN March 18, 1994 Professional Engineering Associates - 2265 Livernois Road Troy, Michigan 48083 _ Attn: Mr. Michael Smalley, P.E. Empire Laboratories, Inc. A Division of The Terracon Companies, Inc. P.O. Box 503 • 301 No. Howes Fort Collins, Colorado 80522 (303) 484-0359 FAX No. (303) 484-0454 Chester C. Smith, P.E. Neil R. Sherrod, C.P.G. NIND =? g A Re: Geotechnical Engineering Report, Addition to Builder's Square Harmony Road, Fort Collins, Colorado ELI Project No. 20945042 Empire Laboratories, Inc. (ELI) has completed a geotechnical engineering exploration for the proposed project to be located on the east side of the existing Builder's Square store on Harmony Road in southeast Fort Collins, Colorado. This study was performed in general accordance with our proposal number D2094064 dated February 23, 1994. The results of our engineering study, including the boring location diagram, laboratory test results, _ test boring records, and the geotechnical recommendations needed to aid in the design and construction of foundations and other earth connected phases of this project are attached. The subsurface exploration indicated conditions which are typical of soils commonly found in the ' southeast Fort Collins area. The subsurface soils at the site consisted of structural fill, lean clays — - with sand, sandy lean clay and clayey and/or silty sand with gravel. The information obtained by the results of field exploration and laboratory testing completed for this study indicates that the soils at the site have low to moderate expansive potential. The soils at anticipated foundation bearing depth have moderate load bearing capability. Based on the geotechnical engineering analyses, subsurface exploration and laboratory test results, we recommend that the proposed building be supported on a spread footing and/or grade beam foundation system. Slab -on -grade may be utilized for the interior floor system provided that care is taken in the placement and compaction of the subgrade soil. Other design and construction details, based upon geotechnical conditions, are presented in the report. r Offices of The Terracon Companies, Inc. Geotechnical, Environmental and Materials Engineers es Arizona: Tucson ■ Colorado: Colorado Springs, Denver, Ft. Collins, Greeley, Longmont ■ Idaho: Boise ■ Illinois: Bloomington, Chicago, Rock Island ■ Iowa: Cedar Falls, Cedar Rapids, Davenport, Des Moines, Storm Lake ■ Kansas: Lenexa, Topeka, Wichita ■ Minnesota: St. Paul ■ Missouri: Kansas City ■ Nebraska: Lincoln, Omaha ■ Nevada: Las Vegas ■ Oklahoma: Oklahoma City, Tulsa ■ Texas: Dallas ■ Utah: Salt Lake City ■ Wyoming: Cheyenne QUALITY ENGINEERING SINCE 1965 r Professional Engineering Associates Terracon ELI Project No. 20945042 We have appreciated being of service to you in the geotechnical engineering phase of this project, and are prepared to assist you during the construction phases as well. If you have any questions concerning this report or any of our testing, inspection, design and consulting services, please do not hesitate to contact us. Sincerely, EMPIRE LABORATORIES, INC. A Division of The Terracon Companies, Inc. A Neil R 5herr d Senior Engineering Geologist Reviewed by: Chester C. Smith, P.E. Division Manager NRS/CCS/cic Copies to: Addressee (3) '000G`� C Professional Engineering Associates ELI Project No. 20945042 TABLE OF CONTENTS Terracon Page No. Letter of Transmittal................................................... INTRODUCTION..................................................... 1 PROPOSED CONSTRUCTION ........................................... 1 SITE EXPLORATION .................................................. 2 Field Exploration ............................................... 2 Laboratory Testing .............................................. 2 SITE CONDITIONS ................................................... 3 SUBSURFACE CONDITIONS ............................................ 3 Geology..................................................... 3 Soil Conditions ................................................. 4 Laboratory Test Results .......................................... 4 Groundwater Conditions .......................................... 4 CONCLUSIONS AND RECOMMENDATIONS ................................. 5 General Considerations ........................................... 5 Foundation Systems ............................................. 5 Lateral Earth Pressures ........................................... 6 Seismic Considerations ........................................... 7 Floor Slab Design and Construction .................................. 7 Pavement Design and Construction .................................. 8 Earthwork................................................... 11 General Considerations ..................................... 11 Site Clearing ............................................ 12 Excavation ............................................. 12 Slab Subgrade Preparation ................................... 13 Pavement Subgrade Preparation ............................... 13 Fill Materials ............................................ 13 Placement and Compaction .................................. 14 Shrinkage.............................................. 15 Compliance............................................. 15 Excavation and Trench Construction ............................ 15 Drainage.................................................... 16 Surface Drainage ......................................... 16 Subsurface Drainage ....................................... 17 Additional Design and Construction Considerations ...................... 17 Exterior Slab Design and Construction .......................... 17 Corrosion Protection ....................................... 17 GENERAL COMMENTS ............................................... 17 Professional Engineering Associates Terracon ELI Project No. 20945042 TABLE OF CONTENTS (Cont'd) Page No. APPENDIX A Figure No. SITE PLAN ......................................................... 1 Logs of Borings .......................................... Al thru A6 APPENDIX B Consolidation Test .............................................. B1 Summary of Test Results ......................................... B2 APPENDIX C: GENERAL NOTES Drilling & Exploration ............................................ C1 Unified Soil Classification ......................................... C2 Laboratory Testing, Significance and Purpose ........................... C3 Report Terminology ............................................. C4 APPENDIX D Recommended Preventative Maintenance -Asphalt Concrete Pavements ......... D1 Recommended Preventative Maintenance -Jointed Concrete Pavements ......... D2 v Terracon GEOTECHNICAL ENGINEERING REPORT ADDITION TO BUILDER'S SQUARE HARMONY ROAD FORT COLLINS, COLORADO ELI PROJECT NO. 20945042 MARCH 18, 1994 INTRODUCTION This report contains the results of our geotechnical engineering exploration for the proposed project to be located on the east side of the existing Builder's Square store on Harmony Road west of Lemay Avenue in southeast Fort Collins, Colorado. The site is located in the Northeast 1 /4 of Section 1, Township 6 North, Range 69 West of the 6th Principal Meridian. The purpose of these services is to provide information and geotechnical engineering recommendations relative to: • subsurface soil conditions • groundwater conditions • foundation design and construction • lateral earth pressures • floor slab design and construction • pavement design and construction • earthwork • drainage The conclusions and recommendations contained in this report are based upon the results of field and laboratory testing, engineering analyses, and experience with similar soil and structural conditions. PROPOSED CONSTRUCTION The proposed construction will consist of a new 80-foot in width addition to the east side of the existing Builder's Square store. The finished first floor of the addition will match the finished first floor of the existing building and will have similar construction. A garden shop and lumber staging area is planned east of the existing building. Additional parking is planned to the north of the proposed addition east of the existing parking lot. Professional Engineering Associates ELI Project No. 20945042 SITE EXPLORATION Terracon The scope of the services performed for this project included site reconnaissance by an engineering geologist, a subsurface exploration program, laboratory testing and engineering analyses. Field Exploration: A total of six test borings were drilled on March 8, 1994 to depths of 10 to 15 s feet at the locations shown on the Site Plan, Figure 1. Four borings were drilled within the footprint of the proposed building and garden shop, and two borings were drilled in the area of proposed new pavement. Boring locations were determined by Professional Engineering Associates. All borings were advanced with a truck -mounted drilling rig, utilizing 4-inch diameter solid stem auger. y The location of borings were positioned in the field by measurements from existing building — corners and existing site features. Elevations were taken of the ground surface at each boring location by measurements with an engineer's level from a temporary bench mark (TBM) shown _ on the Site Plan. The accuracy of boring locations and elevations should only be assumed to the level implied by the methods used to determine each. i Continuous lithologic logs of each boring were recorded by the engineering geologist during the drilling operations. At selected intervals, samples of the subsurface materials were taken by means of pushing thin -walled Shelby tubes, or by driving split -spoon samplers. Representative bulk samples of subsurface materials were obtained from pavement borings. A. L_ Penetration resistance measurements were taken with each sampling with the split -spoon by driving the sampler with a 140-pound hammer falling 30 inches. When properly interpreted, the ro, penetration resistance is a useful index to the consistency, relative density or hardness of the materials encountered. �L Groundwater conditions were evaluated in each boring at the time of site exploration, and two days after drilling. ELaboratory Testing: All samples retrieved during the field exploration were returned to the laboratory for evaluation by the project geotechnical engineer, and were classified in accordance L AIL with the Unified Soil Classification System described in Appendix C. At that time, the fie ld descriptions were confirmed or modified as necessary, final boring logs prepared, and an applicable laboratory testing program was formulated to determine engineering properties of the subsurface materials. Boring Logs for the project are presented in Appendix A. L At 2 Professional Engineering Associates Terracon ELI Project No. 20945042 y Selected soil samples were tested for the following engineering properties: • Water content • Expansion • Dry density • Plasticity • Consolidation • Soluble sulfate content y • Compressive strength 1 The significance and purpose of each laboratory test is described in Appendix C. Laboratory test results are presented in Appendix B, and were used for the geotechnical engineering analyses, and the development of foundation and earthwork recommendations. All laboratory tests were y performed in general accordance with the applicable ASTM, local or other accepted standards. 'SITE CONDITIONS �. The proposed addition will be located on the east side of the existing Builder's Square building. The west portion of the area is currently a fenced -in garden shop. The east half of the site is an undeveloped area vegetated with native grass, weeds and pine trees. The property is relatively flat and has moderate drainage to the east. A drainage ditch runs north -south through the middle of this portion of the site. The existing building is a single -story, slab -on -grade structure. SUBSURFACE CONDITIONS Geology: The project area is located within the Colorado Piedmont section of the Great Plains physiographic province. The Colorado Piedmont, formed during Late Tertiary and Early quaternary time (approximately 2,000,000 years ago), is a broad, erosional trench which separates the �-- Southern Rocky Mountains from the High Plains. Structurally, the site lies along the western flank of the Denver Basin. During the Late Mesozoic and Early Cenozoic Periods (approximately 70,000,000 years ago), intense tectonic activity occurred, causing the uplifting of the Front Range and associated downwarping of the Denver Basin to the east. Relatively flat uplands and broad valleys characterize the present-day topography of the Colorado Piedmont in this region. The Cretaceous Pierre Formation underlies the site at approximate depths of 20 feet below the surface. The bedrock is overlain by residual and alluvial soils of Pleistocene and/or Recent Age. i - 1: 3 i r Professional Engineering Associates Terracon ELI Project No. 20945042 J_ Mapping completed by the Colorado Geological Survey ('Hart, 1972), indicates the site in an area of "Moderate Swell Potential". Potentially expansive materials mapped in this area include bedrock, weathered bedrock and colluvium (surficial units). Soil Conditions: As presented on the Logs of Boring, the subsurface soils were encountered in order of increasing depths as follow: • Silty Topsoil: A 6-inch layer of silty topsoil was encountered at the surface of Borings 2, 5 and 6. The topsoil has been penetrated by root growth and organic matter. • Fill Material: A 1 to 5 %2 foot layer of fill material was encountered at the surface of the Borings 1, 4 and 5 and consists of a mixture of lean clay with sand and sandy lean clay z with minor amounts of gravel. The fill is generally moist and very soft to very stiff in situ. • Lean Clay With Sand: This stratum underlies the topsoil and/or fill in Borings 1, 2 and 3 and extends to depths of 2 %2 to 7 feet below the surface. The brown lean clay is moist and medium to very stiff. Y • Sandy Lean Clay: This stratum was encountered in all borings at depths of 1 to 7 feet and extends to depths of 10 to 14 feet. A lower layer of sandy lean clay was encountered in Boring 4 at a depth of 8 feet and extends to a depth of greater than 15 feet. The sandy lean clay contains minor amounts of gravel, traces of cobbles, is moist and medium to very stiff in its natural condition. • Clayey and/or Silty Sand: This stratum was encountered below the upper clays in all but Boring 5 at depths of 3 to 14 feet below the surface and extends to depths of 8 feet to greater than 15 feet below the surface. The sand contains minor amounts of silt and clay, minor amounts of gravel, is loose to medium dense and moist to wet. Laboratory Test Results: Laboratory test results indicate that the clay subsoils at shallow depth have low to moderate expansive potential and moderate bearing characteristics. Groundwater Conditions: Groundwater was encountered at depths of 9'/2 to 14'/2 feet in Borings 1, 2, 3 and 6 at the time of field exploration. When checked two days after drilling, groundwater was measured Borings 1, 2, 3, 4 and 6 at depths of 9'/2 to 13'/2 feet. Borings 4 and 5 were dry at the time of drilling, and Boring 5 was dry when checked 2 days after drilling. These 'Hart, Stephen S., 1972, Potentially Swelrng Sof7 and Rock in the Front Range Urban Corridor, Colorado, Colorado Geological Survey, Environmental Geology No. 7. L- 4 Professional Engineering Associates Terracon ELI Project No. 20945042 observations represent only current groundwater conditions, and may not be indicative of other times, or at other locations. Groundwater levels can be expected to fluctuate with varying seasonal and weather conditions. Based upon review of U.S. Geological Survey maps ('Hillier, et al, 1983), regional groundwater is expected to be encountered in unconsolidated alluvial deposits on the site, at depths ranging — - from 10 to 20 feet below the existing ground surface at the project site. ft. Fluctuations in groundwater levels can best be determined by implementation of a groundwater monitoring plan. Such a plan would include installation of groundwater monitoring wells, and periodic measurement of groundwater levels over a sufficient period of time. The possibility of groundwater fluctuations should be considered when developing design and construction plans for the project. CONCLUSIONS AND RECOMMENDATIONS General Considerations: Because of variations in the engineering properties of the on -site soils, foundation bearing levels, structural loads, and possible final grades, the following foundation systems were evaluated for use on the site: r - • spread footings and/or grade beams bearing on undisturbed soils; • spread footings and/or grade beams bearing on engineered fill. Design and construction recommendations for foundation systems and other earth connected phases of the project are outlined below. Foundation Systems: Due to the presence of low- to moderate -swelling soils on the site, spread AW footing and/or grade beam foundations bearing upon undisturbed subsoils and/or engineered fill are recommended for support for the proposed structure. The footings may be designed for a �. maximum bearing pressure of 2,000 psf. In addition, the footings should be sized to maintain a minimum dead -load pressure of 500 psf. Exterior footings should be placed a minimum of 30 inches below finished grade for frost protection. Interior footings should bear a minimum of 12 inches below finished grade. 'Hillier, Donald E.; Schneider, Paul A., Jr.; and Hutchinson, E. Carter, 1983, Depth to waterTable (1979)in the Boulder -Fort Coi/Ins-Greeley Area, Front Range Urban Corridor Colorado, United States Geological Survey, Map 1-855-I. 5 J Terracon Professional Engineering Associates ELI Project No. 20945042 The existing fill on the site appears to be structural fill which was placed in conjunction with the construction of the existing Builder's Square building. Therefore, in our opinion, the existing fill on the site may be used for support of foundations. Finished grade is the lowest adjacent grade for perimeter footings and floor level for interior J footings. The design bearing capacities apply to dead loads plus design live load conditions. The L - design bearing capacity may be increased by one-third when considering total loads that include wind or seismic conditions. Footings should be proportioned to minimize differential foundation movement. Proportioning on the basis of equal total settlement is recommended; however, proportioning to relative constant i—_ dead -load pressure will also reduce differential settlement between adjacent footings. Total or _ differential settlement resulting from the assumed structural loads are estimated to be on the order of 3/4 inch or less, provided that foundations are constructed as recommended. �. Additional foundation movements could occur if water from any source infiltrates the foundation soils; therefore, proper drainage should be provided in the final design and during construction. It is recommended the proposed addition be constructed structurally independent of the existing L—_ building. The influence and interaction of the existing and proposed footings on the foundation soils should be evaluated by the structural engineer. This should be taken into account in the design of the proposed structure. Care should be taken during construction to avoid effecting the foundation of the existing structure. i— Foundations and masonry walls should be reinforced as necessary to reduce the potential for distress caused by differential foundation movement. The use of joints at openings or other discontinuities in masonry walls is recommended. Foundation excavations should be observed by the geotechnical engineer. If the soil conditions encountered differ significantly from those presented in this report, supplemental recommendations will be required. _ Lateral Earth Pressures: For soils above any free water surface, recommended equivalent fluid pressures for unrestrained foundation elements are: A • Active: w Cohesive soil backfill (on -site clay) .......................... 40 psf/ft Cohesionless soil backfill (on -site sand) ....................... 35 psf/ft 0 Terracon Professional Engineering Associates ELI Project No. 20945042 • Passive: Cohesive soil backfill (on -site clay) ......................... 350 psf/ft Cohesionless soil backfill (on -site sand) ...................... 450 psf/ft Where the design includes restrained elements, the following equivalent fluid pressures are recommended: _ • At rest: Cohesive soil backfill (on -site clay) .......................... 60 psf/ft Cohesionless soil backfill (on -site sand) ....................... 55 psf/ft The lateral earth pressures herein are not applicable for submerged soils. Additional recommendations may be necessary if such conditions are to be included in the design. Fill against grade beams and retaining walls should be compacted to densities specified in "Earthwork". Compaction of each lift adjacent to walls should be accomplished with hand - operated tampers or other lightweight compactors. Overcompaction may cause excessive lateral earth pressures which could result in wall movement. L_ Seismic Considerations: The project site is located in Seismic Risk Zone I, of the Seismic Zone Map of the United States as indicated by the Uniform Building Code. Based upon the nature of �~ the subsurface materials, a seismic site coefficient, "s" of 1.0 should be used for the design of structures for the proposed project (Uniform Building Code, Table No. 23-J). Floor Slab Design and Construction: Low to moderately expansive soils or engineered fill will support the floor slab. Some differential movement of a slab -on -grade floor system is possible L" should the subgrade soils become elevated in moisture content. Such movements are considered within general tolerance for normal slab -on -grade construction. To reduce any potential slab movements, the subgrade soils should be prepared as outlined in the earthwork section of this report. Additional floor slab design and construction recommendations are as follows: • Positive separations and/or isolation joints should be provided between slabs and L� all foundations, columns or utility lines to allow independent movement. • Contraction joints should be provided in slabs to control the location and extent of cracking. Maximum joint spacing of 15 to 20 feet in each direction is recommended. 7 Terracon Professional Engineering Associates ELI Project No. 20945042 • Interior trench backf ill paced beneath slabs should be compacted in accordance with recommended specifications outlined below. • In areas subjected to normal loading, a minimum 4-inch layer of clean -graded gravel should be placed beneath interior slabs. For heavy loading, a 6-inch layer of aggregate base course should be placed beneath the slabs. • If moisture sensitive floor coverings are used on interior slabs, consideration should be given to the use of barriers to minimize potential vapor rise through the slab. • Floor slabs should not be constructed on frozen subgrade. • Other design and construction considerations, as outlined in the ACI Design Manual, Section 302.1 R are recommended. Pavement Design and Construction: 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, the type and volume of traffic and using a group index of 5 as the criterion for pavement design, the following minimum new pavement thicknesses are recommended: Recommended Pavement Section Thickness (Inches) Asphalt Aggregate Plant Mix Bituminous Portland Traffic Area Alterna- tive Concrete Base Base Cement TOTAL Surface Course Course Concrete A 3„ 5„ 8, B 2 3" 5" Passenger Car Parking C 5,. 5„ A 3„ 8,. 4" 6" Driveway and Truck Loading B 2" Areas C 6" 6" Each alternative should be investigated with respect to current material availability and economic conditions. In view of the subgrade soil conditions and projected traffic, either full -depth asphalt or rigid concrete pavement sections should be considered in areas of main traffic corridors, 8 Terracon Professional Engineering Associates ELI Project No. 20945042 driveways or truck access. Rigid concrete pavement is recommended at the location of dumpsters where trash trucks will park and load. Aggregate base course (if used on the site) should consist of a blend of sand and gravel which meets strict specifications for quality and gradation. Use of materials meeting Colorado Department of Transportation Class 5 or 6 specifications is recommended. In addition, the base course material should be moisture stable. Moisture stability is determined by R-value testing which shows a maximum 12 point difference in R-values between exudation pressures of 300 psi and 100 psi. Aggregate base course material should be tested to determined compliance with these specifications prior to importation to the site. 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), within a moisture content range of 2 percent below to 2 percent above optimum. Where base course thickness exceeds 6 inches, the material should be placed and compacted in two or more lifts of equal thickness. Asphalt concrete should be obtained from an approved mix design stating the Hveem properties, optimum asphalt content, job mix formula, and recommended mixing and placing temperatures. — Aggregate used in asphalt concrete should meet a particular gradation. Use of materials meeting , Colorado Department of Transportation Grading C or CX specification is recommended. The mix design should be submitted prior to construction to verify its adequacy. The asphalt materials should be placed in maximum 3-inch lifts and should be compacted to a minimum of 95 % Hveem density (ASTM D1561). j Plant -mixed bituminous base course should be composed of a mixture of aggregate, filler and additives if required and approved bituminous material. The bituminous base should conform to an approved mix design stating the Hveem properties, optimum asphalt content, job mix formula, and recommended mixing and placing temperatures. Aggregate used in plant -mixed bituminous base course should meet a particular gradation. Use of aggregates meeting Colorado Department of Transforation Grading G or C specifications is recommended. The mix design should be submitted prior to construction to verify it adequacy. The asphalt material should be placed in maximum 3-inch lifts, and should be compacted to a minimum of 95% Hveem density (ASTM D1561). Where rigid pavements are used, the concrete should be obtained from an approved mix design with the following minimum properties: E Terracon Professional Engineering Associates L_ ELI Project No. 20945042 L_ • Compressive Strength @ 28 days ................... 3750 psi minimum • Modulus of Rupture (a) 28 days ........................ 650 minimum • Strength Requirements ................................ ASTM C94 L_ • Minimum Cement Content ......................... 5.5 sacks/cu. yd. • Cement Type .................................... Type I Portland • Entrained Air Content ................................... 6 to 8% • Concrete Aggregate ................. ASTM C33 and CDOT Section 703 • Aggregate Size ................................. 1 inch maximum • Maximum Water Content ....................... 0.49 lb/lb of cement • Maximum Allowable Slump ............................... 4 inches Concrete should be deposited by truck mixers or agitators and placed a maximum of 90 minutes from time the water is added to the mix. Other specifications outlined by the Colorado I- 1: Department of Transportation should be followed. Longitudinal and transverse joints should be provided as needed in concrete pavements for expansion/contraction and isolation. The location and extent of joints should be based upon the final pavement geometry and should be placed (in feet), at roughly twice the slab thickness (in inches), on center in either direction. Sawed joints should be cut within 24-hours of concrete placement, and should be a minimum of 25% of slab thickness plus 1/4 inch. All joints should be sealed to prevent entry of foreign material and dowelled where necessary for load transfer. Where dowels cannot be used at joints accessible to wheel loads, pavement thickness should be increased by 25 percent at the joints and tapered to regular thickness in 5 feet. Future performance of pavements constructed on the clay soils at this site will be dependent upon several factors, including: • maintaining stable moisture content of the subgrade soils; and, • providing for a planned program of preventative maintenance. Since the clay soils on the site have shrink/swell characteristics, pavements could crack in the future primarily because of expansion of the soils when subjected to an increase in moisture content to the subgrade. The cracking, while not desirable, does not necessarily constitute structural failure of the pavement. The performance of all pavements, but in particular the recommended asphalt sections, can be enhanced by minimizing excess moisture which can reach the subgrade soils. The following recommendations should be considered at minimum: 10 Terracon Professional Engineering Associates �— ELI Project No. 20945042 �� • Site grading at a minimum 2% grade away from the pavements; • Compaction of any utility trenches for landscaped areas to the same criteria as the pavement subgrade; • Sealing all landscaped areas in or adjacent to pavements to minimize or prevent �— moisture migration to subgrade soils; • Placing compacted backfill against the exterior side of curb and gutter; and, • Placing curb, gutter and/or sidewalk directly on subgrade soils without the use of base course materials. Preventative maintenance should be planned and provided for through an on -going pavement l_ management program in order to enhance future pavement performance. Preventative maintenance activities are intended to slow the rate of pavement deterioration, and to preserve the pavement investment. L L- L_ L- L" Preventative maintenance consists of both localized maintenance (e.g. crack sealing and patching) and global maintenance (e.g. surface sealing). Preventative maintenance is usually the first priority when implementing a planned pavement maintenance program and provides the highest return on investment for pavements. Recommended preventative maintenance policies for asphalt and jointed concrete pavements, based upon type and severity of distress, are provided in Appendix D. Prior to implementing any maintenance, additional engineering observation is recommended to determine the type and extent of preventative maintenance. Earthwork: • General Considerations: The conclusions contained in this report for the proposed construction are contingent upon compliance with recommendations presented in this section. Although fills or underground facilities, such as septic tanks, cesspools, basements, and/or utilities, were not observed during site reconnaissance, such features might be encountered during construction. 11 Terracon Professional Engineering Associates ELI Project No. 20945042 • Site Clearing: 1. Strip and remove existing vegetation, debris, and other deleterious materials from proposed building and pavement areas. All exposed surfaces should be free of mounds and depressions which could prevent uniform compaction. -- 2. If unexpected fills or underground facilities are encountered during site clearing, such features should be removed and the excavation thoroughly cleaned prior to backfill placement and/or construction. All excavations should be observed by the geotechnical engineer prior to backfill placement. 3. Stripped materials consisting of vegetation and organic materials should be wasted from the site or used to revegetate exposed slopes after completion of grading operations. If it is necessary to dispose of organic materials on -site, they should be -- placed in non-structural areas and in fill sections not exceeding 5 feet in height. 4. The site should be initially graded to create a relatively level surface to receive fill V and to provide for a relatively uniform thickness of fill beneath proposed building structures. 5. All materials derived from the demolition of existing structures and pavements j should be removed from the site and not be allowed for use in any on -site fills. 6. All exposed areas which will receive fill, once properly cleared and benched where necessary, should be scarified to a minimum depth of <>ten <>twelve inches, conditioned to near optimum moisture content, and compacted. • Excavation: It is anticipated that excavations for the proposed construction can be accomplished with conventional earthmoving equipment. 2. Depending upon depth of excavation and seasonal conditions, groundwater may be encountered in excavations on the site. Pumping from sumps may be utilized to control water within excavations. Well points may be required for significant groundwater flow, or where excavations penetrate groundwater to a significant depth. 12 Terracon Professional Engineering Associates ELI Project No. 20945042 • • Slab Subgrade Preparation: 1. Where existing clay soils or structural fill will support floor slab, the soils should be scarified, moisture -conditioned and compacted to a minimum depth of 12 inches. 2. A minimum 4-inch layer of clean -graded gravel should be placed beneath slabs. Slabs supported by heavy floor loads should be underlain by a minimum of 6 inches of crushed aggregate base course. Pavement Subgrade Preparation: 1. The subgrade should be scarified, moistened as required, and recompacted for a minimum depth of 8 inches prior to placement of fill and pavement materials. 2. On -site clay soils may pump or become unstable or unworkable at high water contents. Workability may be improved by scarifying and drying. Overexcavation of wet zones and replacement with granular materials may be necessary. Lightweight excavation equipment may be required to reduce subgrade pumping. Use of lime, fly ash, kiln dust, cement or geotextiles could also be considered as a stabilization technique. Laboratory evaluation is recommended to determine the effect of chemical stabilization on subgrade soils prior to construction. Fill Materials: 1. Clean on -site soils or approved imported materials may be used as fill material for the following: • general site grading • exterior slab areas • foundation areas • pavement areas • interior floor slab areas • foundation backfill 2. Imported soils (if required) should conform to the following: • Gradation (ASTM C136): percent finer by weight 13 Terracon Professional Engineering Associates ELI Project No. 20945042 6.. ................................................... 100 3.. ................................................ 70-100 No.4 Sieve .......................................... 50-100 No.200 Sieve ....................................... 35(max) • Liquid Limit ......................................... 35 (max) • Plasticity Index ...................................... 15 (max) 3. Aggregate base should conform to Colorado Department of Transportation Class 5 or 6 specifications. • Placement and Compaction: 1. Place and compact fill in horizontal lifts, using equipment and procedures that will produce recommended moisture contents and densities throughout the lift. 2. Uncompacted fill lifts should not exceed 10 inches loose thickness. 3. No fill should be placed over frozen ground. 4. Materials should be compacted to the following: Minimum Percent Material Compaction (ASTM D698) On -site soils: Beneath foundations ............................ 95 Beneath slabs ................................ 95 Beneath pavements ............................ 95 Utility trenches below building & paved areas .......... 95 Utility trenches below grassed areas ................. 90 Imported fill: Beneath foundations ............................ 95 Beneath slabs ................................ 95 Beneath pavements ............................ 95 Utility trenches below building & paved areas .......... 95 Utility trenches below grassed areas ................. 90 14 Terracon Professional Engineering Associates ELI Project No. 20945042 Aggregate base (beneath slabs) ........................ W Miscellaneous backfill................................ 90 5. If a well defined maximum density curve cannot be generated by impact compaction in the laboratory for any fill type, engineered fill should be compacted to a minimum -- of 80 percent relative density by determined by ASTM D4253, D4254. 6. On -site clay soils should be compacted within a moisture content range of optimum moisture to 2 percent above optimum. On -site clays below paved areas, on -site sand and imported soils should be compacted within a moisture range of 2 percent below to 2 percent above optimum. • Shrinkage: For balancing grading plans, estimated shrink or swell of soils and bedrock �— when used as compacted fill following recommendations in this report are as follows: L— Estimated Shrink(-) Swell (+ ) Material Based on ASTM D698 On -site soils: Clays...........................................-15to-20% Silty and/or clayey sands ............................. .10 to -15 % • Compliance: Recommendations for slabs -on -grade, foundations and pavement elements supported on compacted fills or prepared subgrade depend upon compliance with "Earthwork" recommendations. To assess compliance, observation and testing should be performed under the direction of the geotechnical engineer. • Excavation and Trench Construction: Excavations into the on -site soils will encounter a variety of conditions. Excavations into the clays can be expected to stand on relatively steep temporary slopes during construction. Excavation into the granular soils will encounter caving soils and possibly groundwater. The individual contractor(s) should be made responsible for designing and constructing stable, temporary excavations as required to maintain stability of both the excavation sides and bottom. All excavations should be sloped or shored in the interest of safety following local, and federal regulations, including current OSHA excavation and trench safety standards. 15 Terracon Professional Engineering Associates ELI Project No. 20945042 The soils to be penetrated by the proposed excavations may vary significantly across the site. The preliminary soil classifications are based solely on the materials encountered in widely spaced exploratory test borings. The contractor should verify that similar conditions exist throughout the proposed area of excavation. If different subsurface conditions are encountered at the time of construction, the actual conditions should be evaluated to determine any excavation modifications necessary to maintain safe conditions. As a safety measure, it is recommended that all vehicles and soil piles be kept to a _ minimum lateral distance from the crest of the slope equal to no less than the slope height. The exposed slope face should be protected against the elements. The contractor should retain a geotechnical engineer to monitor the soils exposed in all excavations and provide engineering services for slopes. This will provide an opportunity to monitor the soil types encountered and to modify the excavation slopes as necessary. It also offers an opportunity to verify the stability of the excavation slopes during construction. Drainage: • Surface Drainage: 1. Positive drainage should be provided during construction and maintained throughout the life of the proposed facility. Infiltration of water into utility or foundation excavations must be prevented during construction. Planters and other surface features which could retain water in areas adjacent to the building or pavements should be sealed or eliminated. 2. In areas where sidewalks or paving do not immediately adjoin the structure, we recommend that protective slopes be provided with a minimum grade of approximately 10 percent for at least 10 feet from perimeter walls. Backfill against footings, exterior walls, and in utility and sprinkler line trenches should be well compacted and free of all construction debris to reduce the possibility of moisture infiltration. i 3. Downspouts, roof drains or scuppers should discharge into splash blocs or -- extensions when the ground surface beneath such features is not protected by exterior slabs or paving. 16 L_ L__ Professional Engineering Associates ELI Project No. 20945042 Terracon 4. Sprinkler systems should not be installed within 5 feet of foundation walls. Landscaped irrigation adjacent to the foundation system should be minimized or e - eliminated. • Subsurface Drainage: Free -draining, granular soils containing less than five percent fines �- (by weight) passing a No. 200 sieve should be placed adjacent to walls which retain earth. A drainage system consisting of either weep holes or perforated drain lines (placed near the L_ base of the wall) should be used to intercept and discharge water which would tend to saturate the backfill. Where used, drain lines should be embedded in a uniformly graded filter material and provided with adequate clean -outs for periodic maintenance. An impervious soil should be used in the upper layer of backfill to reduce the potential for water infiltration. L- Additional Design and Construction Considerations: • Exterior Slab Design and Construction: Exterior slabs -on -grade, exterior architectural features, and utilities founded on, or in backfill may experience some movement due to the volume change of the backfill. Potential movement could be reduced by: • minimizing moisture increases in the backfill • controlling moisture -density during placement of backfill - • using designs which allow vertical movement between the exterior features and adjoining structural elements �+ • placing effective control joints on relatively close centers • allowing vertical movements in utility connections • Corrosion Protection: Results of soluble sulfate testing indicate that ASTM Type I Portland cement is suitable for all concrete on and below grade. However, if there is no, or minimal L+ cost differential, use of ASTM Type II Portland cement is recommended for additional sulfate resistance of construction concrete. Foundation concrete should be designed in accordance with the provisions of the ACI Design Manual, Section 318, Chapter 4. L_ J GENERAL COMMENTS L_ It is recommended that the Geotechnical Engineer be retained to provide a general review of final • design plans and specifications in order to confirm that grading and foundation recommendations L_ have been interpreted and implemented. In the event that any changes of the proposed project LJ 17 J L _. I — Professional Engineering Associates Terracon ELI Project No. 20945042 Lare planned, the conclusions and recommendations contained in this report should be reviewed and the report modified or supplemented as necessary. I The Geotechnical Engineer should also be retained to provide services during excavation, grading, foundation and construction phases of the work. Observation of footing excavations should be performed prior to placement of reinforcing and concrete to conform that satisfactory bearing materials are present and is considered a necessary part of continuing geotechnical engineering services for the project. Construction testing, including field and laboratory evaluation of fill, backfill, pavement materials, concrete and steel, should be performed to determine whether applicable project requirements have been met. It would be logical for Empire Laboratories, Inc. to provide these additional services since we are most qualified to determine consistency of field conditions with those data used in our analyses. The analyses and recommendations in this report are based in part upon data obtained from the field exploration. The nature and extent of variations beyond the location of test borings may not become evident until construction. If variations then appear evident, it may be necessary to reevaluate the recommendations of this report. Our professional services were performed using that degree of care and skill ordinarily exercised, under similar circumstances, by reputable geotechnical engineers practicing in this or similar localities. No warranty, express or implied, is made. We prepared the report as an aid in design J of the proposed project. This report is not a bidding document. Any contractor reviewing this report must draw his own conclusions regarding site conditions and specific construction techniques to be used on this project. This report is for the exclusive purpose of providing geotechnical engineering and/or testing information and recommendations. The scope of services for this project does not include, either specifically or by implication, any environmental assessment of the site or identification of contaminated or hazardous materials or conditions. If the owner is concerned about the potential J for such contamination, other studies should be undertaken. 18 Pp f�kI� el o� �Ix SST i �Lc V. � 1—�' — �a-� ��•2 _ __ 05� h o+a(zv�� X i h-FG, STFra I N� � J I 5��•1�� , bb � f c� I low �Tfial.L��ls� aaLa�Ai� �'U'AL� P'= Ioo.i �I• p�� '�'S°Q'� Empire Laboratories, Inc. A Division of The Terracon Companies. Inc_ LOG BORING No. 1 Page 1 of 1 CLIENT ARCHITECT/ENGINEER Professional Engineering Associates Professional Engineering Associates SITE 813 East Harmonv Road PROJECT Fort Collins, Colorado Builders Square Addition SAMPLES TESTS x r o CD 0 .J 0 J LL co E >- W W (n W Z S W 0 DESCRIPTION >- W X z\ z H M = 2 F- M o0 W 7 0 I to 3 F- (n O ZZ O W J(n J (n Q (L U M a- U HO H >_LL UQ�It WWLL m Z H WC 00 �U)a_ U 0 Approx. Surface Elev.: 100.0 ft. z (La_ 1 SS 12" 2 26.2 FILL -Sandy lean clay CL 2 SS 12" 3 with gravel, and lean clay with sand Brown/gray, moist Very soft to very stiff 3 ST 12" 19.4 106 4180 140 4 SS 12" 11 19.4 5.5 94.5 5 5 SS 12" 14 LEAN CLAY WITH SAND CL Brown, moist, very stiff 7.0 93.0 CL 6 ST 12" 14.8 103 2310 7 SS 12" 9 13.7 SANDY LEAN CLAY Red/tan, moist Stiff to very stiff 10 14.0 1 86.0 CLAYEY SAND WITH GRAVEL SC 8 SS 12" 15 19.3 15.0 Red, wet, medium dense e 85.0 15 BOTTOM OF BORING THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 3-8-94 Empire Laboratories Division of Termcon WL !Z 14.5 W.D. LE 13.8 A.B. BORING COMPLETED 3-8-94 wL IIncorporated RIG CNIE-55 FOREMAN DML WL Checked 24 hrs. A.B. APPROVED NRS JOB # 20945042 LOG BORING No. 2 Page 1 of 1 CLIENT ARCHITECT/ENGINEER Professional Engineering Associates Professional Engineering Associates SITE 813 East Harmony Road PROJECT Fort Collins, Colorado Builders S uare Addition SAMPLES TESTS w 1: z O_ >_ o: � U � F- LL z\ I cn H O cn in N W Q� H z >- H H LO z o } Ly o Q_ O W z 2 H H zz ow Li - � u) a- Lo O J U CD DESCRIPTION Approx. Surface Elev.: 95.3 ft. F LL v CL o J O m E >- U I""^" 0.5 6" TOPSOIL 94.8 LEAN CLAY WITH SAND 1 SS 12" 8 23.6 Brown, moist, stiff CL 2.5 92.8 2 ST 12" 23.5 101 1590 3 SS 12" 7 21.1 SANDY LEAN CLAY Red/tan, moist to wet, medium 5 CL 4 ST 12" 21.9 99 5 SS 12" 6 20.8 1 10 14.0 81.3 CLAYEY SAND WITH GRAVEL Sc 6 SS 12" 15 18.5 15.0 Red, wet, medium dense 80.3 15 BOTTOM OF BORING THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 3-8-94 Empire Laboratories Incorporated WL g 9.7 W.D. __ 9.7 A.B. BORING COMPLETED 3-8-94 WL RIG CME-55 FOREMAN DMI, Division of Terracon `h I Checked 24 hrs. A.B. APPROVED NRS JOB tt 20945042 LOG BORING No. 3 Page 1 of 1 CLIENT ARCHITECT/ENGINEER Professional Engineering Associates Professional Engineering Associates SITE 813 East Harmony Road PROJECT Fort Collins, Colorado Builders Square Addition SAMPLES TESTS F— \ F}- O CD O O J H m LL H W H DESCRIPTION > Z\ W 2 2 W w _> i (n H w 0 LHL � Z Z J (n CL Q I- (L (n U co Z W 0- O U 3 H O (n H ?- LL O W U� LL J to W W LL Approx. Surface Elev.: 100.1 ft. o M z W U) m � o 0- � (i (L can cL a- XXX 1 SS 12" 3 23.5 FILL -Sandy lean clay with gravel, and lean CL 2 SS 12" 6 clay with sand Red brown, moist Soft to medium 3.5 96.6 115 3 ST 12" 18.1 107 2680 LEAN CLAY WITH SAND 4.5 Brown, moist, stiff 95.6 5 CL 4 SS 12" 8 19.7 SANDY LEAN CLAY CL Red/tan, moist, stiff 6.5 93.6 SILTY SAND WITH GRAVEL SM 5 ST 12" 5.3 112 Red, moist to wet Loose to dense 6 SS 12" 9 5.9 10 11.5 With cobbles below 11.5 ft. 88.6 (4 to 6" diameter) _ 7 SS 12" 43 12.1 z_ 15.0 85.1 15 BOTTOM OF BORING THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS Empire Laboratories Incorporated Division of Terracon BORING STARTED 3-8-94 WL SL 14.3 W.D. T 13.7 A.B. BORING COMPLETED 3-8-94 WL RIG CME-J5 FOREMAN DML WL ' Checked .,4 hrs. A.B. APPROVED NRS JOB N 20945042 LOG BORING No. 4 Page 1 of 1 CLIENT ARCHITECT/ENGINEER Professional Engineering Associates Professional Engineering Associates SITE 813 East Harmony Road PROJECT Fort Collins, Colorado Builders Square Addition SAMPLES TESTS J LL 00 m > W W (n z 2 U DESCRIPTION .. >- Q� z\ M z H F- _ _ w cn ►_— o zz D_ F- (n In W O 3 fn ow <C a U z d U F- O H >- LL UQ� U_ Approx. Surface Elev.: 97.4 ft. W o to =) > z >- F- W a: CL J cn m O z M U Ma- z F- U)LO cn a - FILL -Sandy lean clay CL I. SS 12" 7 20.7 1.0 With gravel, and lean 96.4 clay with sand Brown/red, moist, stiff CL SANDY LEAN CLAY WITH GRAVEL 3.0 Red/tan, moist, medium 94.4 2 ST 12" 4.9 CLAYEY SAND WITH GRAVEL SC 3 SS 12" 10 4.2 Red, moist, medium dense 5 4 ST 12" 2.9 8.0 89.4 5 SS 12" 8 18.4 SANDY LEAN CLAY CL Red/tan, moist to wet, medium 10 1 14.0 83.4 CLAYEY SAND SC 6 SS 12" 6 21.4 15.0 Red, wet, loose 82.4 15 BOTTOM OF BORING STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 3-8-94 Empire Laboratories Incorporated Division of Terracon 7 None W.D. = 13.0 A.B. BORING COMPLETED 3-8-94 rWL RIG CME-55 FOREMAN DML Checked '4 hrs. A.B. .. APPROVED NRS JOB /i 20945042 LOG BORING No. 5 Page 1 of 1 CLIENT ARCHITECT/ENGINEER Professional Engineering Associates Professional Engineering Associates SITE 813 East Harmonv Road PROJECT Fort Collins, Colorado Builders Square Addition SAMPLES TESTS x >- (D .. J OJ F- m Lt_ H W (D LL E >- W (n z 2 = H DESCRIPTION >- Q� z \ � z H F- W a. H (n W W W Lr_ cD (n (n \ r S W D. I O F- O ZZ Q�F-J a_ F- (n m W O 3 (n ow W H d Q a. U z d U F- O H >-Li- U CyLi- F- E\ W (n > >- W O_ J O W U Z F- (n F- H _I LD Approx. Surface Elev.: 98.2 ft. o :3 z F- W (n m E O CL D (n a. " " n" " 0.5 6" TOPSOIL 97.7 1 SS 12" 5 19.4 28/16/12 2 SS 12" 5 i SANDY LEAN CLAY WITH GRAVEL Red/brown, moist, medium CL 3 SS 12" 4 10.4 5 4 SS 12" 5 20.5 10.0 88.2 10 BOTTOM OF BORING THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 3-8-94 Empire Laboratories Incorporated Division of Termcon 9 None W.D. i None A.B. BORING COMPLETED 3-8-94 LWL WL, RIG CME-55 FOREMAN DML `� Checked 24 hrs. A.B. APPROVED NRS JOB # 20945042 LOG BORING No. 6 Page 1 of 1 CLIENT ARCHITECT/ENGINEER Professional Engineering Associates Professional Engineering Associates SITE 813 East Harmony Road PROJECT Fort Collins, Colorado Builders S uare Addition SAMPLES TESTS X >- CD - J O O F- H O J F- m LL H W CD LL E >- W (n z 2 Q� H L) DESCRIPTION r Q� Z\ Q� z H w O_ H (n W W O W LL co m (n \ = 2 W :> 1 (n H O Zz WHJ IL H (n cc W O 3 U O W WHCL Q CL U = (L U H O H >- LL U W LL 1— E\ W CD Approx. Surface Elev.: 96.9 ft. Ld O U O z >- F- W 0r (LJ (n rn O E 0ZU o a- ZHO (n CL f_HJ ¢ —1 " " 0.5 6" TOPSOIL 96.4 1 SS 12" 5 24.7 2 SS 12" 5 31/18/13 SANDY LEAN CLAY WITH GRAVEL Red/brown, moist, medium CL 3 SS 12" 5 17.3 5 8.0 88.9 SILTY SAND WITH GRAVEL Red, moist to wet, medium dense SM 4 SS 12" 15 12.4 = W. 10.0 86.9 10 BOTTOM OF BORING THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS Empire Laboratories Incorporated Division of Terracon BORING STARTED 3-8-94 7 9.5 W.D. 1 9.5 A.B. BORING COMPLETED 3-8-94 LWL `VL, RIG CME-55 FOREMAN DML WL Checked 24 hrs. A.B. APPROVED NRS JOB # 20945042