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HomeMy WebLinkAboutUTILITY SERVICE CENTER MINOR SUBDIVISION - 16 90B - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGEOTECHN/CAL ENGINEERING REPORT CITY OF FORT COLLINS LIGHT AND POWER WOOD STREET CITY SERVICES CENTER EXPANSION FORT COLLINS, COLORADO ELI PROJECT NO. 20936144 Prepared for. RBD, INC. 209 SOUTH MELDRUM FORT COLLINS, COLORADO 80521 ATTN. MR. LLOYD MCLAUGHLIN Empire Laboratories, Inc. A Division of The Terracon Companies, Inc. RBD, /nc. Terracon EL/ Project No. 20935144 as a foundation soil in its in -situ condition. The majority of the fill material at the site is suitable for reuse as fill and/or backfill material providing all debris is removed and the design criteria and recommendations set forth in the "Earthwork" section of this report are met. 2. Silty Sand and/or Clayey Silty Sand. This light brown/tan, moist, loose to medium dense, fine granular stratum varies from a silty sand to a clayey silty sand, underlies the topsoil in all six (6) test: borings and extends to a depth of three and one-half (3'/:) to five and one- half (5'/x) feet below the surface. The silty sand and/or clayey silty sand exhibits generally low to moderate bearing characteristics in its moist, in -situ condition. 3. - Sand with Gravel: This granular stratum was encountered in all six test borings at depths of three and one-half (3 %) to five and one-half (5 A) feet below the surface and extends to the bedrock stratum below. The sand with gravel is medium dense to dense and exhibits generally moderate bearing characteristics in its saturated, in -situ condition. It is estimated that cobbles encountered throughout the granular stratum range in size from two (2) to six (6) inches in diameter. 4. Claystone/Sandstone/Siltstone Bedrock. The bedrock stratum was encountered in test borings 1, 2, 3 and 6 at depths of eight (8) to eleven (11) feet below the surface and extends beyond the depths explored. The upper one and one-half (1'/z) to three (3) feet of the bedrock is highly weathered; however, the underlying intermittent claystone/sandstone/siltstone is firm and exhibits high bearing characteristics. Laboratory_ Test Results- Laboratory test results indicate that the silty sand and/or clayey silty sand subsoils at shallow depth have non to low expansive potential. The. claystone/sandstone/siltstone bedrock exhibits low to moderately expansive potential. When water is added to compacted near -surface soils, the materials exhibit non to low expansion potential. Groundwater Conditions: Groundwater was encountered at depths of two and one-half (2%) to three and one-half (3'/2) feet below the surface at the time of the initial field exploration. When checked 24 hours after drilling, groundwater was measured at depths of two (2) to three (3) feet below the surface. These 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. 5 J Terracon RBA Inc. ELI Project No. 20935144 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. CONCLUSIONS AND RECOMMENDATIONS Site Development Considerations:The site appears suitable for the proposed construction. There are no known. geologic hazards which would preclude development as currently planned. Because of variations in the engineering properties of the on -site soils; foundation bearing levels, structural loads and possible final grades the following foundation system were evaluated for use on the site. Y conventional -type spread footings and/or continuous grade beams bearing on undisturbed soils; and, • conventional -type spread footings and/or continuous grade beams bearing on engineered fill. Slab -on -grade construction, for the proposed garage structure, is considered acceptable for use when subgrade soils consist of the on -site sand with gravel and/or imported granular fill material provided that design and construction recommendations discussed in the "Earthwork" section of this report are followed. Site grading for the proposed construction should be completed in accordance with the recommendations discussed in the "Earthwork" section of this report. j Foundation Systems: Due to the presence of low expansive swelling soils at the site, conventional 1 type spread footings and/or continuous grade beam foundation systems bearing on undisturbed 3 subsoils, recompacted native soils and/or engineered fill material is recommended for support of the proposed structure. The footings may be designed for a maximum bearing pressure of 1,500 f pounds per square foot (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. The bottom of the footings and/or grade beams should be located a minimum of two (2) feet above the groundwater level at an elevation of 52 or high (see Log of Borings in Appendix A). To satisfy the footing placement at a minimum of two (2) feet above the groundwater level, it is RBD, Inc. ELl Project No. 20935144 Terracon estimated a two (2) to three (3) feet layer of structural fill, material approved by the geotechnical engineer will be required for final overlot grading. The structural fill should extend a minimum of twice the footing width to the undisturbed soil below. Existing on -site fill material should not be used for support of foundations without removal and recompaction. Recommendations for the on -site fill material are discussed in the "Earthwork" section of this report. Footings should be proportioned to minimize differential foundation movement. Proportioning on the basis of equal total settlement is recommended; however, proportioning to relative constant dead -load pressure will also reduce differential settlement between adjacent footings. Total or differential settlements resulting from the assumed structural loads are estimated to be on the order of % inch or less, provided that: • foundations are constructed as we recommend, and • essentially no changes occur in water contents of foundation soils. 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. All footings, foundation walls, and m.ason.ry walls should be reinforced to reduce the potential for distress caused by differential foundation movements. 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 significantlyfrom 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 elements are: a Active: Cohesive soil backfill (on -site sand) ......................... 50 psf/ft Cohesionless soil backfill (on -site sand with gravel) .............. 40 psf/ft Cohesive structural fill (imported clay material) .............. 55 psf/ft Compacted imported granular backfill ........................ 40 psf/ft 17 RBD, Inc. Terracon ELI Project No. 20935144 e Passive: Cohesive soil backfill (on -site clayey sand) ................... 200 psf/ft j Shallow foundation walls ........................... 250 psf/ft Imported granular backfill ............................... 300 psf/ft Where the design includes restrained elements, the following equivalent fluid pressures are recommended: a At -rest: Cohesive soil backfill (on -site clayey sand) .... • • • • • • • • • • • • • • , 60 psf/ft Cohesive structural fill .............................. 55 psf/ft Imported granular backfill ... .. ........ 55 psf/ft The lateral earth pressures herein are not applicable for submerged soils. Empire should be consulted for additional recommendations if such conditions are to be included in the design. Fill against grade beams should be compacted to densities specified in the "Earthwork" section of this report. Compaction of each lift adjacent to the walls should be accomplished with hand operated tampers or lightweight compactors. Overcompaction may cause excessive lateral earth pressures which could result in wall movements. Seismic Considerations: The project site is located in Seismic Risk Zone 1, 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, "Y' of 1.0 should be used for the design of structures for the proposed project (Uniform Building Code, Table No. 23-J). Floor Slab Desion and Construction: Non -expansive, or only low expansive soils will support the `. floor slab. Some differential movement of a slab -on -grade floor system is possible should the subgrade soils become elevated in moisture content. Such movements are considered within general tolerance for normal slab -on -grade movements. To reduce any potential slab movements, 1 the subgrade soils should be prepared as outlined in the earthwork section of this report. j For structural design of concrete slabs -on -grade, a modules of subgrade reaction of 150 pounds per cubic inch (pci) may be used for floors supported on existing or engineered fill consisting of on -site soils. A modules of 200 pci may be used for floors supported on non -expansive imported fill meeting the specifications outlined below. "j Terracon 1 RBD, Inc. EL/ Project No. 20935144 _i Additional floor slab design and construction recommendationsareas follows: O Positive separations and/or isolation joints should be provided between slabs and all foundations; columns or utility lines to allow independent movement. i 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. l -;1 a Interior trench backfill placed beneath slabs should be compacted in accordance with recommended specifications outlined below. o In areas subjected to normal loading, a minimum 4-inch layer of clean, graded gravel should be placed beneath interior slabs. For heavy loading, reevaluation of slab and/or clean gravel thickness may be required.. ® 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. s 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: Design of pavements for the project have been based on the procedures outlined in the 1986 Guideline for Design of Pavement Structures by the American Association of State Highway and Transportation Officials (AASHTO). Areas within proposed pavements on the site will be divided into two categories based upon anticipated traffic and usage. .J Traffic criteria provided for pavement thickness designs include Equivalent Single Axle Loads (ESAL's) of 36,500 for automobile parking, and 730,000 for drive bays/truck access. Based upon AASHTO criteria, Colorado is located within Climatic Region VI of the United States. 3 This region is characterized as being dry, with hard ground freeze and spring thaw. The spring thaw condition typically results in saturated or near -saturated subgrade soil moisture conditions. I The AASHTO criteria suggests that these moisture conditions are prevalent for approximately 12.5% of the annual moisture variation cycle. 9 J RBD, Inc. Terracon EL/ Project No. 20935144 I Local drainage characteristics of proposed pavements areas are considered to vary from fair to good depending upon location on the site. For purposes of this design analysis, fair drainage characteristics are considered to control the design. These characteristics, coupled with the approximate duration of saturated subgrade conditions, results in a design drainage coefficient of 1.0 when applying the AASHTO criteria for design. For flexible pavement design, a terminal serviceability index of 2.0 was utilized along with an inherit reliability of 70%. Using the correlated design R-value, appropriate ESAL/day, environmental criteria and other factors, the structural numbers (SN) of the pavement sections were determined on the basis of the 1986 AASHTO design equation. In addition to the flexible pavement design analyses, a rigid pavement design analysis was completed, based upon AASHTO design procedures. Rigid pavement design is based on an evaluation of the Modules of Subgrade Reaction of the soils (K-Value), the Modules of Rupture of the concrete, and other factors previously outlined. The design K-value of 100 for the subgrade soil was determined by correlation to the laboratory test. results. A Modules of Rupture of 700 psi (working stress 525 psi) was used for pavement concrete. The rigid pavement thicknesses for each traffic category were determined on the basis of the AASHTO design equation. Recommended alternatives for flexible and rigid pavements, summarized for each traffic area, are as follows: Recommended Pavement. Section Thickness (Inches) Asphalt Aggregate Plant Mix Pordond Traffic Area Ahemadve Concrete Surface Base Bituminous Base Select Subbase Cement TOTAL Course Course Concrete A 3.0 7.5 — 10.5 B 2.5 _ 3.5 - 6.0 Automobile Parking c — _ 5.0. ..- 5.0 A 4.0 6.0 6.0 — 20.0 6 3.0 6.5 — — _ 9.5 Main Traffic Corridors/Truck Access - _ — 7.0 7.0 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, drive 10 RED, Inc. Terracon EL/ Project No. 20935144 i bays or truck access. Rigid concrete pavement is recommended at the location of dumpsters 1 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 l 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 determine 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 3 to a minimum of 95% Standard Proctor density (ASTM D-698), 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 Marshall or Hve.em 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 specifications is recommended. The mix design should be submitted prior to construction to verify its adequacy. The asphalt material should be placed in maximum 3-inch lifts, and should be compacted to a jminimum of 95% Marshall or Hveem density (ASTM D-1559). Where rigid pavements are used the concrete should be obtained from an approved mix design with the following minimum properties: o Compressive Strength @ 28 days ................... 3750 psi minimum i e Modules of Rupture @ 28 days ..................... 700 psi minimum a Strength Requirements ............................... ASTM C-94 i o Minimum Cement Content .. ................... 5.5 sacks/cu.yd. e Cement Type Type I Portland j e Entrained Air Content ................................. 6% + 2% >� ® Concrete Aggregate ASTM C-33 and CDOT Section 103 • Aggregate Size ................................. 1 inch maximum e Maximum Water Content ....................... 0.49 IWO of cement o Maximum Allowable Slump ............................... 4 inches 11 RED, Inc. Terracon EL/ Project No. 20935144 Concrete should be deposited by truck mixers or agitators and placed a maximum of 90 minutes from the time the water is added to the mix. Other specifications outlined by the Colorado 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 spaced (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 depth 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: O Maintaining stable moisture content of the subgrade soils; and; A 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 j enhanced by minimizing excess moisture which can reach the subgrade soils. The following recommendations should be considered at minimum: o Site grading at a minimum 2% grade away from the pavements; e Compaction of any utility trenches for landscaped areas to the same criteria as the pavement subgrade; a Sealing all landscaped areas in, or adjacent to pavements to minimize or prevent moisture migration to subgrade soils; e Placing compacted backfill against the exterior side of curb and gutter; and, 12 II �j i RBD, Inc. Terracon ELi Project No. 20935144 Placing curb, gutter and/or sidewalk directly on su. bgrade soils without the use of base course materials. Preventative maintenance should be planned and provided for through an on -going pavement 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. Preventive 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: • Genera/ 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, utilities were not observed during site reconnaissance, such features might be encountered during construction. A clayey silty sand and brown sandy lean clay fill material was encountered at the surface of each test boring and extends to a depth of one (1) to four and one-half (4'/z) feet below the surface. It is recommended the upper one (1) foot of the fill material encountered at i the site beneath building, filled and "paved areas be removed and stockpiled for reuse in. planted areas or wasted from the site. HIC] J a 3 RBD, Inc. Terracon i ELl Project No. 20935144 ® Site_Clearina: 1. Strip and remove existing vegetation, debris; concrete and other deleterious materials from subgrade, existing on -site fill and proposed fill material under building, filled and paved 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, the excavation thoroughly cleaned and backfilled. All excavations should be observed by the geotechnical engineer prior to backfill placement. .3. Stripped materials consisting of 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 hill sections not exceeding 5 feet in height. 4. Sloping areas steeper than 2:1 to 3:1 (horizontalvertical) should be benched to reduce the potential for slippage between existing slopes and fills. Benches should be level and wide enough to accommodate compaction and earth moving equipment. 5. The site should be initially graded to create a relatively level surface to receive fill; and to provide for a relatively uniform thickness of fill beneath proposed building structures. 6. All exposed areas which will receive fill, once properly cleared and benched where necessary, should be scarified to a minimum depth of twelve inches, conditioned to near optimum moisture content, and compacted. 9 Excavation: 1. It is anticipated that excavations for the proposed construction can be accomplished with conventional earthmoving equipment. 2. Some additional effort may be necessary to extract boulder sized materials, particularly in deep narrow excavations such as utility trenches at a depth of approximately six (6) to seven (7) feet below the surface. `' 14 s Empire Laboratories, Inc. A Division of The Te.rracon Companies, Inc. P.O. Box 503 • 301 No. Howes Fort Collins, Colorado 80522 (303)484-M59 FAX No. (303) 484-0454 Chester C. Smith, P.E. Neil R. Sherrod, C.P.G. June 24, 1993 RBD, Inc. _ 209 South Meldrum Fort Collins, Colorado 80521 Attn: Mr. Lloyd McLaughlin Re: Geotechnica/ Engineering Report, City of Fort Collins Light and Power, Wood Street City Services Center Expansion, Fort Collins, Colorado ' ELi Project No. 26935144 Empire Laboratories, Inc. (ELI) has completed a geotechnical engineering exploration for the l proposed garage structure construction and the associated parking project to be located at the City ! of Fort Collins Light and Power Wood Street Center Services Center at the northeast corner of Elm Street and Wood Street in Fort Collins, Colorado. This study was performed in general accordance with our proposal number 2093031 dated April 7, 1993. 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 soils at the site consisted predominately of a silty sand and gravel material. The information obtained by the results of our field exploration and laboratory testing completed for this study indicate the soils and bedrock at the site have low to moderate expansive potential. Based on the geotechnical engineering analyses, subsurface exploration and laboratory test results, it is recommended the proposed garage structure be supported on a conventional -type spread footing, and/or continuous 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. Offices of The Terracon Companies, Inc. Geotechnical, Environmental and Materials Engineers Arizona: Tucson 0 Colorado: Colorado Springs, Denver, Ft. Collins, Greeley, Longmont 0 Idaho: Boise 0 gllnois: Bloomington, Chicago, Rock Island 0 Iowa: Cedar Falls. Cedar Rapids, Davenport, Des Moines, Storm Lake 0 Kansas: Lenexa, Topeka, Wichita 0 Minnesota: St. Paul 0 Missouri: Kansas City 0 Nebraska: Lincoln, Omaha 0 Nevada: Las Vegas 0 Oklahoma: Oklahoma City, Tulsa 0 Texas: Dallas 0 Utah: Salt Lake City 0 Wyoming: Cheyenne QUALITY ENGINEERING SINCE 1965 RSA Inc. Terracon EL/ Project No. 20936144 3. 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. 4. On -site clayey sand and/or silty sand 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. Use of lime, fly ash kiln dust, cement or geotextiles could also be considered as a stabilization technique. Adequate laboratory testing should be performed prior to use of chemical stabilization to evaluate this strength characteristics and the affect these materials have on the physical properties of the soils. Lightweight excavation equipment may be required to reduce subgrade pumping. ® Slab Subarade_Pieaaration: 1 Where existing on -site natural soils 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 the floor slab. b Pavement Subarade Preparation: The subgrade should be scarified, moistened as required, and recompacted for a minimum depth of 12 inches prior to placement of fill and pavement materials. • Fill Materials: 1. Clean on -site soils or imported materials may be used as fill material for the following: 15 RED, Inc. EL/ Project No. 20935144 Terracon ® general site grading • exterior slab areas • foundation areas ® pavement areas O interior floor slab areas O foundation backfill 2. Frozen soils should not be used as fill or backfill. 3. Imported soils (if required) should conform to the following: i Gradation (ASTM C136): percent finer by weight 6"............................................ 100 3" ........................................... 70-100 No. 4 Sieve ............................. ...... 50-100 No. 200 Sieve .................................. 15 (max) e Liquid Limit .................................... 30 (max) • Plasticity Index . ............................. 15 (max) 4. Aggregate base course for the proposed parking areas associated with the proposed construction should conform to Colorado Department of Transportation Class 5 or 6 specifications. e 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: 16 a j Terracon RBD, Inc. Al Project No. 20935144 Minimum Percent Material Compaction (ASTM D698) On -site soils: Beneath foundations ................................... 95 Beneath slabs .................................. ... 95 Beneath pavements ................. . . _ .. _ .... .. .. 95 Imported fill: Beneath foundations ........... 9b Beneath slabs ....................................... 95 Beneath pavements ......... .......................... 95 Aggregate base (beneath slabs) ........................... 95 Miscellaneous backfill....................................... 90 5. On -site clayey sand soils should be compacted within a moisture content range of 2 percent below, to 2 percent above optimum. Imported soils should be compacted within a moisture range of 2 percent below to 2 percent above optimum. a Slopes: 1. For permanent slopes in compacted fill areas, recommended maximum configurations for on -site materials areas follows: Maximum Slope Material Horizontal: Vertical Cohesive soils (clays and silts) ................................ 21 Cohesionless soils ........................................ 3:1 Bedrock _ 21 If steeper slopes are required for site development, stability analyses should be completed to design the grading plan. 17 3 RBD, Inc. Terracon EL/ Project No. 20935144 .l 2. The face of all slopes should be compacted to the minimum specification for fill embankments. Alternately, QI slopes can be over -built and trimmed to compacted material. o 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. o Utility Construction: Excavations into the on -site soils will encounter a variety of conditions. Excavations into the clays and bedrock can be expected to stand on relatively steep temporary slopes during construction. However, caving soils may also be encountered. 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. 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, we recommend that we be contacted immediately to evaluate the conditions encountered. 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. We recommend that the contractor retain a geotechnical engineer to monitor the soils exposed in all excavations and provide engineering services for such 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. 18 RBA inc. ELi Project No. 20935144 i Drainage: 6 Surface Draina4e: Terracon 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 eriminated. 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. 3. Downspouts, roof drains or scuppers should discharge into splash blocks or extensions when the ground surface beneath such features is not protected by exterior slabs or paving. 4. Sprinkler systems should not be installed within 5 feet of foundation walls. Landscape irrigation adjacent to the foundation system should be minimized or 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 nearthe 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. 19 RBD, Inc. Terracon Al Project No. 20935144 Additional Design and Construction Considerations: o 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 O 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 e allowing vertical movements in utility connections s Underground Utility Systems: All underground piping within or near the proposed structure should be designed with flexible couplings, so minor deviations in alignment do not result in breakage or distress. Utility knockouts in grade beams should be oversized to accommodate differential movements. e Corrosion Protection: Results of soluble sulfate testing indicate that ASTM Type I Portland cement is suitable for aft concrete on and below grade. However, if there is no, or minimal 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 318-121. GENERAL COMMENTS It is recommended that the Geotechnical Engineer be retained to provide a general review of final design plans and specifications in order that grading and foundation recommendations may be interpreted and implemented. In the event that any changes of the proposed project are planned, the conclusions and recommendations contained in this report should be reviewed and the report modified or supplemented as necessary. 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 confirm that satisfactory bearing materials are present and is considered a necessary part of continuing geotechnical engineering 20 i Terracon RBD, Inc. EL/ Project No. 20935144 i services for the project. Construction testing of fill placed on the site is considered part of continuing geotechnical engineering service for the project. Field and laboratory testing of concrete and steel should be performed to determine whether applicable requirements have been met. It would be logical for Empire Laboratories, Inc. to provide these services since we are most i 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 of the proposed project. This report is not a bidding document. Any contractor reviewing this i 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 for such contamination, other studies should be undertaken. We are available to discuss the scope of such studies with you. 21 I . RSD, Inc. Terracon EL/ Project No. 209351.44 Minimum Percent Material Comaction fASTMD6W On -site soils: Beneath foundations ................................... 95 Beneath slabs ..................... ...... 95 Beneath pavements ................................... 95 Imported fill: Beneath foundations ................................... 9b Beneath slabs ......................................... 95 Beneath pavements ................................... 95 Aggregate base (beneath slabs) ................................ 95 Miscellaneous backfill....................................... 90 5. On -site clayey sand soils should be compacted within a moisture content range of 2 percent below, to 2 percent above optimum. Imported soils should be compacted within a moisture range of 2 percent below to 2 percent above optimum. • Slopes: 1. For permanent slopes in compacted fill areas, recommended maximum configurations for on -site materials areas follows: Maximum Slope Material Hoiizontal.•Verdcal Cohesive soils (clays and silts) ................................ 2;1 Cohesion -less soils ........................................ 3:1 Bedrock................................... ....... 2:1 If steeper slopes are required for site development, stability analyses should be completed to design the grading plan. 17 i RBD, inc. Terracon ELi Project No. 20935144 4 2. The face of all slopes should be compacted to the minimum specification for fill embankments. Alternately, fill slopes can be over=built and trimmed to compacted material. 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. ® Utility Construction: Excavations into the on -site soils will encounter a variety of conditions. Excavations into the clays and bedrock can be expected to stand on relatively steep temporary slopes during construction. However, caving soils may also be encountered. 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. 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 j encountered at the time of construction, we recommend that we be contacted immediately to evaluate the conditions encountered. 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. J We recommend that the contractor retain a geotechnical engineer to monitor the soils j exposed in all excavations and, provide engineering services for such 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. is 1 RBD, inc. Teriracon ELi Project No. 20.035144 Drainave• ® 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. 3. Downspouts, roof drains or scuppers should discharge into splash blocks or extensions when the ground surface beneath such features is not protected by exterior slabs or paving. 4. Sprinkler systems should not be installed within 5 feet of foundation walls. Landscape irrigation adjacent to the foundation system should be minimized or 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 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. 19 Terracon RED, Inc. EL/ Project No. 20935144 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 feel free to contact us. Sincerely, EMPIRE LABORATORIES, INC. A Division of The Terracon Co panes, Inc. z,q ---1 / David A. Richer, P.E. Geotechnical Engineer Reviewe/d' bbV. / Chester C. Smith, P.E. Division Manager DAR/CCS/drrif Copies to: RBD, Inc. (3) Z a ✓ oeeepen�cc S/) f''i� ` Gq;oP��ISTFR�o�%icy 0 T wr u or, Goa�.77 � nN LLiV ae ti o `` �'• `o RBD, Inc: Terracon ELI Project No. 20935144 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 O 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 s Underaround Ua ty Systems: All underground piping within or near the proposed structure should be designed with flexible couplings, so minor deviations in alignment do not result in breakage or distress. Utility knockouts in grade beams should be oversized to accommodate differential movements. s 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 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 318-121. GENERAL COMMENTS It is recommended that the Geotechnical Engineer be retained to provide a general review of final design plans and specifications in order that grading and foundation recommendations may be interpreted and implemented. In the event that any changes of the proposed project are planned, the conclusions and recommendations contained in this report should be reviewed and the report modified or supplemented as necessary. 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 -1 performed prior to placement of reinforcing and concrete to confirm that satisfactory bearing materials are present and is considered a necessary part of continuing geotechnical engineering 20 J r Terracon RBD, Inc. EL/ Project No. 20935144 services for the project. Construction testing of fill placed on the site is considered part of continuing geotechnical engineering service for the project. Field and laboratory testing of concrete and steel should be performed to determine whether applicable requirements have been met. It would be logical for Empire Laboratories, Inc. to provide these 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 - 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 for such contamination, other studies should be undertaken. We are available to discuss the scope of such studies with you. 21 I to n u H g M � •1 SL V ti ry C N n"i y O m N it o _ � U +� c " 0 it CS g O � m .. o � a Q 111 LOG OF BORING NO. 1 Page 1 of 1 CLIENT - ARCIi]'I'ECT/ENGINEER City of Fort Collins - RBD Inc. SITE Wood Street PROIECr Fort Collins Colorado Pro osed Pavement Design SAMPLES TESTS 0 o J LL a H� H DESCRIPTION r N x Z\ z = IL 2 a W E a > i (N Fes- Cn 0 Z z w U N z > c� w f-0 o-.a H o >-W zo wu_ u z(nm A Approx. Surface Elev:: 52.5 fL PP o z o= cnm r- on_ =Du1n. FILL_Silty clay with sand 1 SS 12" 11 14.4 Black, moist 2 SS 12" 11 2.0 � 50:5 _ PA SILTY SAND Q Tan, moist to wet, medium dense SIV1 3 ST 12" 18.2 113 4.5 48.0 5 SM --4 -- -SS 12" 10 20.9 a PA �. SAND. -WITH GRAVEL e" Tan, wet, medium dense e. 4 a - SP 5 SS 12" 16 21.7 PA a _q 10 11.0 _41.5 WRATH FRFD 3ILTSTONE/ 12.0 SA�Ni STONE 40.5 Tan/gray, wet, hard — —_ SILTSTONE/SANDSTONE_ Tan/gray, wet, very hard u. 14.5 6 SS 7" 50/7" 17.5 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 BORING STARTED 6-14-93 WL 4 2.81 w'•D S 1.71 A.B. BORING COMPLETED 6-14-93 - RIG CME-55 FOREMAN DL wL Division of Tecracon W'1- Checked 24-hrs. A.B. APPROVED DAR IJOB# 20935144 LOG OF BORING NO. 2 Page I of 1 CLIENT ARCHITECT/ENGINEER City of Fort Collins RBD Inc. stTfi Wood Street PROJECT Fort Collins Colorado Pro osed Pavement.Desi n. SAMPLES: TESTS-- J N Z H DESCRIPTION u_ r_ Y w Z\ W � 2 H� 2 =. N W > i cn t°- w O ZZ. 0- 6E to to W O 3 Uf O W- 0. U Cn E EL U I—O H }LL WwU. � Approx. Surface Elev.: 51.9 ft. c z ►}- z U?03 E of MUM 1 SS 12" 17 10.3 FILL -Clayey silty Sand with gravel 2 SS 12" 17 Black, moist PA 3:5 48.4 SC 3 SS 12` 10 21.4 SILTY CLAYEY SAND PA Tan, moist to wet, medium dense 5 5.5 46.4 a — - - w SAND WITH GRAVEL Tan, moist to wet iw Medium dense to dense .a SP 4 SS 12" 37 143 9.0 42:9 10 WEATHERED SILTS'i_'ONE/ SANDSTONE 10.5 Tan/gray, Wet, hard 41.4 PA — STT TSTONE/SANDSTONE Tan/gray, wet, very hard .T 5 SS 8" 5619" 20.7 14.7 37.2 --- BOTTOM OF BORING THE STRATIFICATION LINES REPRESENT THE APPROXIMATEBOUNDARY LINES BETWEEN SOIL AND ROCK TYPES:__IN-SITU, THE TRANSITION NAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 6-14-93 Empire Laboratories Incorporated Division ofTenacon WL g 2.8' W:D -T 2.69 A.B. BORING COMPLETED 6-14-_93 ,,,,I RIG CME_ -55 FOREMAN DL wI Checked 24 tiis._A.B._ APPROVED DAR JOB # 20935144 LOG OF BORING NO. 3 page-1 of 1 CLIENT ARc1lnT=/ElacIN=ER City of Fort Collins RBD Inc. SITE Wood Street PROJECT` Fort Collins Colorado Pro osed Pavement Design SAMPLES_ _ _ _ TESTS. H I-- O p C J IL >- U.W N ZS DESCRIPTION Ir Z\ ce H N o: w w I~ic~a = 2 W 9 I Uf F O Z Z Q. 0 U E d V FO H Y4. U�IL CD Approx. Surface Elev.: 51.2 ft. o 0 z ►- W Uwo z oa wia, 1 SS 12" 9 12.7 FILL_ -Silty lean clay Black, moist 2 SS 12" 6 PA 2.5 48.7 9 .TY SAND 3.5 Tan, moist to wet, medium 47.7 SM 3 ST 12" 11.9 132 SP 4 SS 12" 14 5.9 SAND WITH GRAVEL. - dipTan, wet, medium dense to dense 5 PA SP 5 5S 12" 26 ..g m. 118.81 0 9:5 41.7 10 PA WEATH ED_ SANDSTONE/ SILTSTONE 11.0 Tan, wet, medium dense to dense 40'2 SANDSTONE/SIT.TSTONE . Tan, wet, hard 14.S 36.] 14.5 36.7 — 6 -SS 5" 50/5" 20.2 BOTTOM OF BORING THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: 1N-SITU, THE TRANSIT16N MAY BE GRADUAL. WATM LEVEL OBSERVATIONS L Empire Laboratories Incorporated Division ofTerracon BORING STARTED 6-14-93 _ WC $ 2.0' W.D $ 1,3� A.B. BORING COMPLETED 6-14-93 WL RICE CME-55 FOREMAN DL �'I- Checked 24 hrs. A.B. APPROVED _ DAR JOB! 20935144 I LOG OF BORING NO. 4 Page 1 of I CUNT ARcHrrECTtENGINEER City of Fort Collins RBD Inc. SITE Wood Street PROJECT Fort Collins, Colorado Pco sed Pavernent.Design SAMPLES TESTS X 0 -j 0 j U. to xo 0 DESCRIPTION Z\ aLa zHCWn HWz Ur- W W > I U) 1.- 0 zz a. C to r- W ft- 8 0 U) H >-LL oui UQ:U_ IX Approx. Surface Elev.: 56.2 ft. W 0 Cn :3 :3 z >- W W (L-j Won 0 r- WU On. Z�-(n Mai Q. FILL -Silty sand with clay 1 SS: 12" 5 10.6 Tan/brown, moist, 1 1 2 SS 12" 3 2.0 54.2 SILTY SAND PA Tan, moist to wet, medium dense 'ST SM 3 12" 19.6 110 Sz .550 SM 4 SS 12" 5 27.1 5.0 $1.2 PA SANT) WITH GRAVEL Tan, wet, medium dense to dense SP 5 SS 12" 33 12.3 10.0 -46.2 - BOTTOM OF BORING THE STRATIFICATION LINES REPRESENT THE AP-PROX11.9A.T.E BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 6-14-93 Empire Laboratories Incorporated DiVision of Teffacon LZ j.-W- 5' D 3.2' A.B. - BOMG COMPLETED 6-14-93 rWL RIG CMIE.55 D L Y' Checked 24 hrs. A.B. APPROVED DAR I JOB # 20935144,j LOG OF BORING NO. 5 e 1 of 1 CLIENT ARCFITiECTIENGINEER City of Fort Collins RBD Inc. srrE Wood Street PROS Fort Collins Colorado Pro osed Pavement Design SAMPLES.__ _._ TESTS F a F o -- o ., Jo J E U.H Z CD U_ >- W (A = Ix H U DESCRIPTION >- M z\ M z HF- W. a H (A c: W W U.0 m w\ = 2 W. D. I to 1---0 zz n:►-J CL F- d fA U toW S- n. o U 3 FO in H YP_w ow UMLL W H n_ HE \ CD Approx. Surface Elev.: 48.7 ft. c Cn z X vain E oa wia ¢-i-i Flj j�-Sandy lean clay with gravel 1 SS 12" 5 12.0 18/NV/NP 1.0 Tan, moist 47.7 SC 2 SS 12" 9 CLAYEY SILTY SAND Tan, moist to wet, medium - Y PA Q SC 3 ST 12' 24.5 99 410 - 4.5 44,2 5 4 SS 12" 17 21.2 e SP PA SAND WITH GRAVEL Tan, wet, medium dense to dense c9: ..a SP 5 SS 12" .32 22.0 10.0 -- 38.7 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 Temcon BORING STARTED 6=14-93 wL s 3& w.D s 2.41 A.B. BORING COMPLECED 6-14-93 W.I. I RIG CME-55 IFOROAAN DL W Checked_Z4_lus. A.B. APPROVED DAR _ _ - JOB!! 20935144 I LOG OF BORING NO. 6 Page 1 of 1 CUENT ARC M =/1ENGINEER _City of Fort Collins RBD Inc. Wood Street PROJ Fort Collins., Pro osed, Pavement Design -,Colorado --SAMPLES;—TESTS- X >. 0 0 D co DESCRIPTION U. >. >. ce zU. w Cn z z = H = w a.H 0: w w > I U) 9w Fw C3 LL (9 zz co (n \ w1___j a. F= w 0 w 0 3 w ow wHa. Cn. U E a- L) F_o H >_ U_ UMLL, f=X\ m Approx. surface Elev.: 48.7 ft. w 0 w :3 0 4 >_ 1— U) (z a. _j W to 0 CCU 0 n. (n 0. F�H_j (C_j_j EILL-Sandy lean clay with gravel IISSI 12w 7 15.61 22/1418 1.0 Tan, moist 47.7 1 CLAYEY SILTY SAND SC 2 SS 12" 11 Tan, moist to wet, medium PA 3.5 45.2. 3 ST 12" 19.0 109 400 74r SAND WITH GRAVEL SP 4 SS 124 23 24.1 Tan, wet, medium dense to dense PA ar 8.0 40.7 1 1 WEATHERED CLAYSTONE/ SILTSTONR Tan/gray, hard 10.0 3.8..7 SP 5- SS 12" N 26.2 BOTTOM OF BORING L THE STRATIFICATION LINES REPRESENT THE APPROXIMATE. BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE ik4NSft10N NAYREGRADUAL. WATER LEVEL OBSERVATIONS S BORING STARTED 6-14-93 Empire Laboratories Incorporated Division ofterracon 3 *3 1 W.D 2.31 A.B. BORING COMPLETED 6-14-93 Tj3 RIB CME_55 FOREMAN DL Checked 24 hrS. AeB. APPROVED DAR JOB # 20935144 .442 .441 .44k 43E a H .43i cy A .43E a .43` .434 .432 .431 CONSOLIDATION TEST PRO. 20935144 BORING NO.: 1 DEPTH: 3.0 DRY DENSI7Y:114.4 PCF t4OISTUFE: L$.4 % N11-s 0.1 0.25 0.3 X 0.s —L .8 0.5 1.0 5 110 APPLIED PRESSURE — TSF 0.1 0.25 0.5 1.0 5 APPLIED PRESSURE — TSF EMPIRE LABORATORIES INC. 10 RBD, Inc. EL/ Project No. 20935144 TABLE OF CONTENTS Page No. Letter of Transmittal ................................................... i INTRODUCTION..................................................... 1 PROPOSED CONSTRUCTION 1 T SITE EXPLORATION .................................................. 2 _ Field Exploration ..... 2 Laboratory Testing ........................................... 3 SITE CONDITIONS ... ............. 3 CONDITIONS 4 SUBSURFACE .... ........ Geology 4 ........................... .... 4 Soil and Bedrock Conditions ....................................... ^� Laboratory Test Results ...... .... 5 • .... • ........ • .. Groundwater Conditions 5 • .. • . • • . • ......... CONCLUSIONS AND RECOMMENDATIONS 6 Site Development Considerations .................................... 6 Foundation Systems ............................................. 6 Lateral Earth Pressures . ................................._... 7 Seismic Considerations ....................... ........... ..... 8 Floor Slab Design and Construction .................................. 8 Pavement Design and Construction ..................... .... .... 9 Earthwork...................................... ... 13 General Considerations ..... ......... ................... 13 Site Clearing ................................... ....... 14 Excavation ............. 14 Slab Subgrade Preparation . ..... .... ..... 15 Pavement Subgrade Preparation ............................... 15 Fill Materials ............ 15 Placement and Compaction .................................. 16 Slopes 17 Compliance .................. 18 Utility Construction .... 18 Drainage.................................................... 19 Surface Drainage ..... 19 Subsurface Drainage..... .... pm ••••••.••••........••••• 19 Additional Design and Construction Considerations ...................... 20 Exterior Slab Design and Construction ........................ 20 Underground Utility Systems ................................. 20 Corrosion Protection ................... 20 IGENERAL COMMENTS ................... .................... 20 i to� k � 2n E-4 g F\ �z O� >\ j C4 — N - w - - � = 2 2 n ■ 04 \% \ 2 » k02 ■-3 I \§§ 2= \ $ g < /\ /d k)© k � . .. /ka06 � §)■ $ 2k \/k � \E fie u ° ƒ\f § ) ) 7 2 $ ] ■ J ) m _ ] - # _ \ n \ eq f_ CDR § 7 3 d _ § _ 4 o - _ ¥ o . - 06 d - m - a ■ � « \� &M �e��■ie ili��nim� ��111111'�����1 ■11 1 Illllli� 11111' J t11 IN� AN ■ N 11 1 IIN l�i � a RESISTANCE R-VALUE AND EXPANSION PRESSURE OF COMPACTED SOIL AETM — D 2844 CLIENT: RED PROJECT: CITY SERVICE CENTER LOCATION OF SAMPLE: BORING 6 COMPOSITE @ 1.0-3.5' SAMPLE DATA TEST SPECIMEN 1 2 3 COMPACTION PRESSURE - PSI 10 150 180 DENSITY - PCF 120.1 121.7 123.6 MOISTURE - % 14.9 12.1 10.8 EXPANSION PRESSURE - PSI 0.00 0.00 0.00 HORIZONTAL PRESSURE @ 160 psi 159 147 139 SAMPLE HEIGHT - in. 2.61 2.44 2.50 EXUDATION PRESSURE - PSI _ 111 295 406 UNCORRECTED R-VALUE .4 6.0 10.1 CORRECTED R=VALUE .5 5.8 10.1 R-VALUE AT 300 PSI EXUDATION PRESSURE = 6.0 100 80 w 60 J 40 20 0 L*1 100 200 300 400 600 600 EXUDATION PRESSURE — psi EMPIRE LABOFRTORIES INC. 700 800 .I DRILLING AND EXPLORATION DRILLING & SAMPLING SYMBOLS: R : Ring Barrell - 2.42" I.D.; 3" O.D., unless otherwise noted SS : Split Spoon - 1%" I.D., 2" O.D., unless otherwise noted PS : Piston Sample PIS ST :. Thin -Walled Tube - 2" O.D., unless otherwise noted : Wash Sample PA : Power Auger FT : Fish Tail Bit HA : Hand Auger RB : Rock Bit DB : Diamond Bit = 4", N, B BS : Bulk Sample AS : Auger Sample PM : Pressure Meter HS : Hollow Stem Auger DC : Dutch Cone WB : Wash Bore Penetration Test: Blows per foot of a 140 pound hammer falling 30 inches on a 2-inch O.D. split spoon, except where noted.. WATER LEVEL MEASUREMENT SYMBOLS: WL : Water Level WS : While Sampling_ WCI : Wet Cave in WD :While Drilling DCI : Dry Cave in BCR : Before Casing Removal AB ; After Boring ACR : After Casting Removal Water levels indicated on the boring logs are the levels measured in the borings at the time indicated. In pervious soils, the indicated levels may reflect the location of groundwater. In low permeability soils, the accurate determination of groundwater levels is not possible with only short term observations. DESCRIPTIVE SOIL CLASSIFICATION: Soil Classification is based on the Unified Soil Classification system and the ASTM Designations D-2487 and D-2488. Coarse Grained Soils have more than 50% oftheir dry weight retained on a #200 sieve; they are described as: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are described as: clays; if they are plastic, and silts if they are slightly plastic or non -plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse grained soils are defined on the basis of their relative in -place density and fine grained soils on the basis of their consistency. Example: Lean clay with sand, trace gravel, stiff (CL); silty sand, trace gravel, medium dense (SM). CONSISTENCY OF RN_E-GRAINED SOILS. - Unconfined Compressive Strength, Mr. psf Consistency < 500 Very Soft 500 - 1,000 Soft 1,001-2,0.00 Medium 2,001 - 4,060 Stiff 4,001 - 8,000 Very Stiff 8,001-16,000 Very Hard RELATIVE PROPORTIONS OF SAND AND GRAVEL Descriptive Term(s) (of Components Also Percent of Present in Sample) Dry Weight Trace < 15 With 15 - 29 Modifier > 30 RELATIVE PROPORTIONS OF FINES Descriptive Termfs) (of Components Also Percent of Present in Sample) Dry Weight Trace < 5 With 5-12 Modifier > 12 RELATIVE DENSITY OF COARSE -GRAINED SOILS. N-Blows/ft. Relative Density 0-3 Very Loose 4-9 Loose 10-29 Medium Dense 30-49 Dense 50-80 Very Dense 80+ Extremely Dense GRAIN SIZE TERMINOLOGY Major Component of Sample Size Range Boulders Over 12 in. (300mm) Cobbles 12 in. to 3 in. (300mm to 75mm) Gravel 3 in. to #4 sieve (75mm to 4.75mm) Sand #4 to #200 sieve. (4.75mm to 0.075mm) Silt or Clay Passing #200 Sieve (0.075nim) Empire Laboratories, Inc. A Division of The Terrecon Companies, Inc:. i UNIFIED SOIL CLASSIF/CAT/ON SYSTEM 1i} 1 Criteria for Assigning Group Symbob and Group Names Using Laboratory Tests" � Goarse-Grained i Soils more than ' S0% retained on No. 200 sieve Fine -Grained Soils 50% or more passes the No. 200 sieve Gravels more than Clean Gravels Less Cu > 4 and 1 < Cc <3' 50% of coarse than 5% fines"' — — — fraction retained on No. 4 sieve Cu < 4 and/or 1 > Cc > Gravels with Fines more than 12% finest Fines classify as ML or MH Sands 50% or more Clean Sands Less of coarse fraction than 5% fines' passes No. 4 sieve Sands wfth Fines more than 12% fines° Sifts and Clays inorganic Liquid limitless than 50 organic Silts and Clays inorganic Liquid limit 50 or more organic Cu < 6 and/or 1 > Cc > Fines classify as ML or MI PI > 7 and plots on or above "A line' PI <. 4 or plots below "A" line' Liquid limit - oven dried < 0.75 Liquid limit - not dried PI plots on or above "A" line PI lots below "A" line Liquid limit - oven dried- - < 0.75 Liquid limit - not dried Soo Group Group Name' Well -graded gravel' GVy GP GM SM SC CL ML 1 CH MH Silty gravel,G,H Clayey gravelr•e•" Well -graded sand' Poorly graded sand' Silty sand s"' Clayey sands•"I Lean clay"'LM Silt'"" Organic clayl(LI" Organic siltrL'"•o Fat clay'--" Elastic Silt"`"' Organic clay"i'"' Organic silt"•" Hi hl or anic soils Primarily organic matter dark in color, and organic odor PT Peat ABased on the material passing the 3-in. "If soil contains 15 to 29% plus No. 200, add (75-mm) sieve sCu=Dr,/D1e Cc = I$e1° "with sand" or "with gravel, whichever is 'lf field sample contained cobbles or DiO x Dro predominant. boulders, or both, add "with cobbles or 4 soil contains > 30% plus No. 200 boulders, or both" to group name. predominantly sand, add "sandy" to group "Gravels with 5 to 12% fines require dual 'if soil contains > 15% sand, add "with name. symbols: sand" to group, name. "'lf soil contains > 30% plus No. 200, GW-GM well -graded gravel with.silt elf fines classify is CL-ML, use dual symbol predominantly gravel, add "gravelly" to group GW-GC well -graded gravel with clay GC -GM, or SC-SM. name. GP -GM poorly graded gravel with silt "if fines are organic, add "with organic fines" "PI > 4 and plots on or above "A"line. GP -GC poorly graded gravel with clay to group name. oPl < 4 or plots below A" line. 'Sandi; with 5 to 12% fines require dual 'If soil contains > 15% gravel, add "with "Pl plots on or above A" line. symbols: gravel" to group name. ePl plots below "A" line. SW-SM well -graded sand with silt 'If Atterberg limits plot in shaded area, soil is SW-SC'well-graded sand with clay a CL-ML, silty clay. SP-SM poorly graded sand with silt SP-SC poorly graded sand with clay e0 - r«. m.�lieenen .1. ene-y.eMw :al. i aria OmN.aIMA l,villenel <eane- % grimed �.�1 Eeuotien M "- — FN �r IV NaAxe A el . . ♦ to LL 2s.s J/ V� EowUen el V— G"e 0� - VMicd of LL . 18 to R . 7,0.0 0 MH 01R OH 0 0 10 16 20 30 ♦0 >0 W 70 e0 W 100 Ito LIQUID UNIT (LL) - Empire Laboratories, Inc. A Division of The Tenacon Companies, Inc. ROCK CLASSIFICATION (Based on ASTM C-294) Sedimentary Rocks Sedimentary rocks are stratified materials laid down by water or wind. The sediments may be composed of particles of pre-existing rocks derived by mechanical weathering, evaporation or by chemical or organic origin. The sediments are usually indurated by cementation or compaction. Chert Very fine-grained siliceous rock composed of micro -crystalline or crypto- crystalline quartz, chalcedony or opal. Chert is various colored, porous to dense, hard and has a conchoidal to splintery fracture. Claystone Fine-grained rock composed of or derived by erosion of silts and clays or any rock containing clay. Soft: massive; gray, black, brown, reddish or green and may contain carbonate minerals. Conglomerate Rock consisting of a considerable amount of rounded gravel, sand and cobbles with or without interstitial or cementing material. The cementing or interstitial material may be quartz, opal, calcite, dolomite, clay, iron oxides or other materials. Dolomite A fine-grained carbonate rock consisting of the mineral dolomite (CaMg (CO3)21. May contain noncarbonate impurities such as quartz; chert, clay minerals, organic matter, gypsum and sulfides. Reacts with hydrochloric acid (HCL). Limestone A fine-grained carbonate rock consisting of the mineral calcite (CaCO3)' May contain noncarbonate impurities such as quartz, chert, clay minerals, organic matter, gypsum and sulfides. Reacts with hydrochloric acid (HCL). Sandstone Rock consisting of particles of sand with or without interstitial and cementing materials. The cementing or interstitial material may be quartz, opal, calcite, dolomite, clay, iron oxides or other material. Shale Fine-grained rock composed of, or derived by erosion of silts and clays or any rock containing clay. Shale is hard, platy, or fissile may be gray, black, reddish or green and may contain some carbonate minerals (calcareous shale). Siltstone Fine grained rock composed of, or derived by erosion of silts or rock containing silt. Siltstones consist predominantly of silt sized particles (0.0625 to 0.002 mm in diameter) and are intermediate rocks between claystones and sandstones, may be gray, black, brown, reddish or green and may contain carbonate minerals. Empire Laboratories, Inc. A Division of The Terracon Companies, Inc. LABORATORY TESTS SIGNIFICANCE AND PURPOSE TEST SIGNIFICANCE PURPOSE California Used to evaluate the potential strength of subgrade soil, subbase; Pavement Bearing and base course material, including recycled materials for use in Thickness Ratio road and airfield pavements. Design Used to develop an estimate of both the rate and amount of both Foundation Consolidation differential and total settlement of a.structure. Design Used to determine the consolidated drained shear strength of soil Bearing Capacity, Direct or rock. Foundation Design & Shear Slope Stability Dry Used to determine the in -place density of natural, inorganic, fine- Index Property Density grained soils. Soil Behavior. Used to measure the expansive potential of fine-grained soil and to Foundation & Slab Expansion provide a basis for swell potential classification. Design Used for the quantitative determination of the distribution of Soil Gradation particle sizes in soil. Classification Liquid & Used as an integral part of engineering classification systems to soil Plastic Limit, characterize the fine-grained fraction of soils, and to specify the Classification Plasticity Index fine-grained fraction of construction materials; Oxidation- Used to determine the tendency of the soil to donate or accept Corrosion Reduction electrons through a change of the oxidation state within the soil. Potential Potential Used to determine the capacity of soil or rock to conduct a liquid Groundwater Permeability or gas. Flow Analysis Used to determine the degree of acidity or alkalinity of a soil. Corrosion P H Potential Used to indicate the relative ability of a soil medium to carry Corrosion Resistivity electrical currents. Potential Used to evaluate the potential strength of subgrade soil, subbase, Pavement R-Value and base course material, including recycled materials for use in Thickness road and airfield pavements. Design Soluble Used to determine the quantitative amount of soluble sulfates Corrosion Sulphate within a soil mass. Potential Used to determine the quantitative amounts of sulfides within a Contusion Sulfide Content soil mass. Potential To obtain the approximate compressive strength of soils that Bearing Capacity Unconfined possess sufficient cohesion to permit testing in the unconfined Analysis for Compression state. Foundations Water Used to determine the quantitative amount of water in a soil mass. Index Property Content Soil Behavior Empire Laboratories, Inc. n n6.:'..:>. -4: 'M. rnbfnnniAC inC_ � - - n vwwrvn v� •nc REPORT TERMINOLOGY (Based on ASTM D653) Allowable Soil The recommended maximum contact stress developed at the interface of the Bearing Capacity foundation element and the supporting material. Alluvium Soil, the constituents of which have been transported in suspension by flowing water and subsequently deposited by sedimentation. Aggregate Base A layer of specified material placed on a subgrade or subbase usually beneath Course slabs or pavements:.: Backfill A specified material placed and compacted in a confined area.. Bedrock A natural aggregate of mineral grains connected by strong and permanent. cohesive forces. Usually requires drilling, wedging_ , blasting or other methods of extraordinary force for excavation. Bench A horizontal surface in a sloped deposit. Caisson (Drilled pier A concrete foundation element cast in a circular excavation which may have an or Shaft) enlarged base. Sometimes referred to as a cast -in -place pier or drilled shaft.: Coefficient of A constant proportionality factor relating normal stress and the corresponding Friction shear stress at which sliding starts between the two surfaces. Colluvium Soil, the constituents of which have been deposited chiefly by gravity such as at the foot of a slope or cliff.. Compaction The densification of a soil by means of mechanical manipulation. Concrete Slab -on- A concrete surface layer cast directly upon a base, subbase or subgrade, and Grade typically used as a floor system. Differential Unequal settlement or heave between, or within foundation elements of a Movement structure. Earth Pressure The pressure or force exerted by soil on any boundary such as a foundation wall. ESAL Equivalent Single Axle. Load, a criteria used to convert traffic to a uniform standard, (18,000 pound axle loads). Engineered Fill Specified material placed and compacted to specified density andlor moisture conditions under observations of a representative of a geotechnical engineer. Equivalent Fluid A hypothetical fluid having a unit weight such that it will produce a pressure against a lateral support presumed to be equivalent to that produced by the actual soil. This simplified approach is valid only when deformation conditions are such that the pressure increases linearly with depth and the wall friction is neglected. Existing Fill (or Materials deposited through the action of man prior to exploration of the site. man-made Ell) Existing Grade The ground surface at the time of field exploration. Empire Laboratories, Inc. A Division of The Terracon Companies, Inc. is REPORT TERMINOLOGY (Based on ASTM D653) Expansive Potential The potential of a soil to, expand (increase in volume) due to absorption of moisture. Finished Grade The final grade created as a part of the project. Footing A portion of the foundation of a structure that transmits loads directly to the soil. Foundation The lower part of a structure that transmits the loads to the soil or bedrock. Frost Depth The depth of which the ground becomes frozen during the winter season. Grade Beam_ A foundation element or wall, typically constructed ofreinforced concrete; used to span between other foundation elements such as drilled piers. Groundwater Subsurface water found in the zone of saturation of soils, or within fractures in bedrock. Heave Upward movement. Lith'ologic The characteristics which describe the composition and texture of soil and rock by observation. Native Grade The naturally occuring ground surface. Native Soil Naturally occurring on -site soil, sometimes referred to as natural soil. Optimum Moisture The water content at which a soil can be compacted to a maximum dry unit Content weight by a given compactive effort. Perched Water Groundwater, usually of limited area maintained above a normal water elevation by the presence of an intervening relatively impervious continuing stratum. Scarify To mechanically loosen soil or break down existing soil structure. Settlement Downward movement. Skin Friction (Side The frictional resistance developed between soil and an element of structure Shear) such as a drilled pier or shaft. Soil (earth) Sediments or other unconsolidated accumulations of solid particles produced by the physical and chemical disintegration of rocks; and which may or may not contain organic matter. Strain The change in length per unit of length in a given direction. Stress The force per unit area acting within a soil mass. Strip To remove from present location. Subbase A layer of specified material in a pavement system between the subgrade and base course. Subgrade The soil prepared and compacted to support a structure, slab or pavement system. Empire Laboratories, Inc. A Division of The Terracon Companies, Inc. TABLE D1 RECOMMENDED PREVENTATIVE MAINTENANCE POLICY FOR ASPHALT CONCRETE PAVEMENTS Distress Distress Recommended Distress Distress Recommended Type Severity Maintenance Type Severity Maintenance Low None Low None Alligator Cracking Patching & arty Cut Patching Medium Full -Depth Asphalt Concrete Patch Medium - Full -Depth Asphalt Concrete Patch High - - - - - High Low - None _ Low Bleeding A .Polished ate ggre9 None - Medium - Surface Sanding Medium High Shallow AC Patch High Fog Seal. Low None Low Shallow AC Patch Medium Clean & Seal Medium Full -Depth Asphalt Concrete Mock Cracking Potholes High All Cracks High Patch Sumps & Sags a9 Low None Railroad Crossing Low No Policy for This Project Medium Shallow AC Patch Medium High Full -Depth Patch High Low None Low None Medium Full -Depth Asphalt Concrete Patch Medium Shallow AC Patch Corrugation Rutting High High Full -Depth Patch Low None Low None Medium Shallow AC Patch Medium - Mill & Shallow AC Depn3ssion Shoving High Full -Depth Patch High Patch Low None Low None Medium Seal Cracks Medium Shallow Asphalt Concrete Edge Cracking Slippage Cracking High Full -Depth Patch High Patch Low Clean & Low None Joint Reflection Seal All Cracks Swell Medium Medium Shallow AC Patch - High Shallow AC Patch High Full Depth Patch Low None Low Lane/Shoulder Drop -Off gr Weathering Fog Seal Medium - Regrade Shoulder Medium High - High Low None Longitudinal & Transverse CrackingF Medium Clean & sea' All Cracks Empire Laboratories, Inc. A Division of The Terracon Companies, Inc. High i RBD, Inc. EL/ Project No. 20935144 APPENDIX A SitePlan .............................................. Figure No. 1 Logs of Borings .......................................... Al thru A6 APPENDIX B Laboratory Test Data: Consolidation Test ......................................... B1 Summary of Test Results .............................. B2 thru B3 R-Value. Curve ..................................... ... B4 APPENDIX C GENERAL NOTES Drilling & Exploration .. ..................................... C1 Unified Soil Classification .................. ........ ... . ... C2 Bedrock. Classification, Sedimentary Bedrock ............................ C3 Laboratory Testing, Significance and Purpose ........................... C4 Report Terminology ..................................... .... C5 APPENDIX D Recommended Preventative Maintenance -Asphalt Concrete Pavements ......... D1 Recommended Preventative Maintenance -Jointed Concrete Pavements ......... D2 TABLE D2 RECOMMENDED PREVENTATIVE MAINTENANCE POLICY FOR JOINTED CONCRETE. PAVEMENTS Distress Distress Recommended Distress Distress Recommended Type Severity Maintenance Type Severity Maintenance Low None No Blow-up Polished Severity Groove Surface or Medium Full -Depth Patch/ Concrete P Aggregate l Levels Overlay High Slab Replacement Defined Low Seal Cracks No Comer Break Pop°uts Severity Levels None Medium Full -Depth High Concrete Patch Defined Low Seal Cracks No Underseal, Div ded Seventy Seal cracksroints - Medium Slab Pumping Levels and Replacement Defined Restore Load Transfer High Low None Low Seal Cracks Medium Full -Depth Patch Medium Full -Depth Durability Punchout Cracking Concrete - - High Slab Replacement High Patch Low None Low No Faulting Railroad Crossing Policy for this Medium Medium High High Grind Project Low None Scaling Low None Medium Medium Slab Replacement, Joint Map Cracking Seal Reseal Crazing Full -depth Patch, Hi 9. Joints High or Overlay Low Regrade and No Lane/Shoulder Fill Shoulders Shrinkage Severity None Medium Drop-off to Match Cracks Levels High Lane Height Defined Linear Cracking Low Clean & Low None Medium Longitudinal, Seal all Cracks Sparing Transverse and Medium (Comer) partial -Depth High Diagonal Concrete Patch Cracks High Full -Depth Patch Low None Low None Large Patching Sparring -- Medium Partial -Depth Patch and Medium Seal Cracks or (Joint) High Ut,Tity Cuts Replace Patch High Reconstruct Joint Low None Medium Replace Sman Patching Patch Empire Laboratories, IIIC. High -- A Division of The Tenacon Companies, Inc. _ GEOTECHNICAL ENGINEERING REPORT Terracon CITY OF FORT COLLINS LIGHT AND POWER 1 WOOD STREET CITY SERVICES CENTER EXPANSION FORT COLLINS, COLORADO ELI PROJECT NO. 20935144 INTRODUCTION This report contains the results of our geotechnical engineering exploration for the proposed garage structure to be located at the City of Fort Collins Light and Power Wood Street City Service Center at the northeast corner of Wood Street and Elm Street in north Fort Collins, Colorado. The site is located in the northeast quarter of Section 1, Township 7 North, Range 69 West of the 6th Principal Meridian, Larimer County, Colorado. The purpose of these services is to provide information and geotechnical engineering recommendations relative to; • subsurface soil and bedrock conditions e groundwater conditions a foundation design and construction 0 lateral earth pressures s floor slab design and construction e pavement design and construction i earthwork e drainage The conclusion. s 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 .J Based on information provided by Mr. Lloyd McLaughlin of RBD, Inc., the project will consist of construction of a garage structure having an approximate plan dimension of 100x.1.60 feet with associated parking and storage for the City of Fort Collins Light and Power facility. The site is located directly south of the existing City Services Center on Wood Street in northwest Fort. „_ Collins, Colorado. RBD, Inc. Terracon EL/ Project No. 20935144 Final site grading plans were not available prior to preparation of this report. Ground floor level is anticipated approximately three (3) to four (4) feet above existing site grade. Other major site development will include the construction of a parking lot surrounding the proposed garage structure. Two levels of traffic are anticipated for pavements to be constructed at the site. These include automobile parking and drive bays/truck access; Traffic criteria provided for pavement thickness designs include equivalent single -axle loads underlying the Equivalent Single Axle Loads (ESAL's) of 36,500 for automobile parking and 130,000 for drive bay/truck access. SITE EXPLORAT/ON The scope of the services performed for this project included site reconnaissance by a geotechnical engineer, a subsurface exploration program, laboratory testing and engineering analyses. Field Exploration: A total of six (6) test borings were drilled to depths of ten (10) to fifteen (15) feet below the surface on June 14, 1993 at the locations shown on the Site Plan, Figure 1. Three (3) of the test borings were drilled within the footprint of the proposed building, and three (3) of the test borings were drilled in the area of proposed parking lot construction. All borings.were advanced with a truck -mounted drilling rig, utilizing 4-inch diameter continuous -type, power flight auger drills. The location of test borings were positioned in the field by measurements from the south and west property lines. Elevations were taken of the ground surface at each boring location by measurements with an engineer's level and rod relative to a temporary benchmark (TBM) consisting of the edge of concrete at the northwest corner of the site. The TBM was established by RBD, Inc. and is assumed at an elevation of 59.0. The accuracy of boring locations and elevations should only be assumed to the level implied by the methods used to determine each. Continuous lithologic logs of each boring were recorded by the geotechnical engineer 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 each pavement boring. 2 IMP, Inc. Terracon ELI Project No. 20935144 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 penetration resistance is a useful index to the consistency, relative density or hardness of the materials encountered. Groundwater conditions were evaluated in each boring at the time of site exploration, and 24 hours after drilling. Laboratory Testin4: All samples retrieved during the field exploration were returned to the laboratory for evaluation by the project geotechnical engineer, and were classified in accordance with the Unified Soil Classification system described in Appendix C. Samples of bedrock were classified in accordance with the general notes for Bedrock Classification. At that time, the field 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. Selected soil and bedrock samples were tested for the following engineering properties: 0 Water content O Consolidation • Dry density a Plasticity Unconfined Compressive Strength • Soluble sulphate content • Expansion ® R-Value 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 test were performed in general accordance with applicable ASTM, local or other accepted stand.ards:. SITE CONDITIONS The site is currently an open, vacant tract of land situate at the northeast corner of Wood Street and Elm Street located south of the existing City Services Center. The site at one time was occupied by a concrete precast pipe manufacturing company. The City of Fort Collins has recently demolished and/or removed the structures associated with the concrete precast manufacturing company. Concrete debris and various filled areas were noted throughout the initial site investigation. At the time of the field exploration, fill material was being hauled to the site and placed on the northwest corner of the site. The site is sparsely vegetated consisting of relatively i J J 3 RBD, Inc. Terracon EL/ Project No. 20935144 short growth of grass and weeds. The property is relatively flat and exhibits minor surface drainage in the east to southeast directions. West of the site is Wood Street and residential property located beyond. South of the subject site is Elm Street with townhomes and residential property beyond. East of the site is the Colorado Northern railroad tracks and beyond to the east and to the north is the present City of Fort Collins City Services Center. SUBSURFACE CONDITIONS Geoioav: The proposed 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 two million (2,000,000) years ago), is a broad, erosional trench which separates the Southern Rock 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 seventy million (70,000,000) years ago), intense tectonic activity occurred, causing the uplifting of the Front Range and the 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 Pierre shale (sandstone/siltstone bedrock) underlies the site at approximate depths of nine (9) to eleven (11) feet below the surface. The regional dip of bedrock in this area is slight and in an easterly direction. Seismic activity in the area is anticipated to be low and from a structural standpoint the properties should be relatively stable. Groundwater underlies the subject site at depths of approximately two (2) to three and one-half (3'/:) feet below the surface. The property lies within the drainage basin of the Cache La Poudre River. Groundwater directional flow at this site is estimated to be in a northeasterly direction toward Cache La Poudre River which is located approximately one -quarter ('A) mile north of the subject site. SoiLand_Bedrock Conditions: The soil profile at the site consists of stratum of materials arranged in different combinations. In order of increasing depths, they are as follows: 1. Fill Material. The site is overlain by a one (1) to three and one-half (3'/z) foot layer of fill material. The fill consists of'a mixture of silty sand and/or clayey silty sand with gravel and brown sandy lean clay. Various concrete chunks and miscellaneous debris was encountered throughout sections of the fill material located at the site. It is not known a whether the fill has been uniformly or properly compacted; therefore, it should not be used 4 I