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HomeMy WebLinkAboutWESTBURY PUD, FIRST FILING - FINAL - 11-94A - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTI : MONITORING WELL # 2A Page 1 of I CLIENT Mark Linder ARCHITECT/ENGINEER Stewart & Associates SITE South Shields Street & West Harmony Road Fort Collins, Colorado PROJECT Westbury P.U.D. First Filing 0 U (L 4x ix 0 DESCRIPTION TOP OF CASING ELEV.: 89.1 ft. APPROX. SURFACE ELEV.: 86.4 ft. WELL DETAIL UV CL W 0 SAMPLES TESTS OCO W 0 W M 0 M z W 0- >. 0 W 0 0 W CY g z\ 1­:1 0 0. _j (n Co X W ca H 0 C zW Ix— U-0 ow U W Z�_ mcn h A A A A 0.5 6" TOPSOIL 85.9 LEAN CLAY WITH SAND Brown, moist, stiff Bentonite Silica sand 4.0 82.4 10— WEATHERFM CLAYSTONE/ SILTSTONE Olive, moist, soft Slotted pipe 8.5 77.9 CLAYSTONFISILTSTONE 10.0 Olive, moist, moderately hard 76.41 I SS 12" 12 13.7 2 SS 12" 34 13.8 BOTTOM OF BORING THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL. BOREHOLE DIA.: 6.25 in WELL DIA.: 2.0 In OBSERVATIONS WATER LEVEL OBSERVATIONS Empire Laboratories' Incorporated Division of Termcon BORING STARTED 5-25-94 WL 37 None W.D. None A].B. BORING COMPLETED 5-25-94 WI EhrsA.B. RIG CAff�:55 :T�005 FOREMAN DMIL r#20945 Water checked 24 APPROVED LRS JOB MONITORING WELL # 1A Page 1 of 1 CLIENT ARCHrrECT/ENGINEER Mark Linder Stewart & Associates SITE South Shields Street & West Harmony Road PROJECT Fort Collins,. Colorado Westbury P.U.D. First Filing SAMPLES TESTS WELL o DESCRIPTION DETAIL o 1.- o J U. E r W Z 2 v } x Z\ W HF ¢ TOP OF CASING ELEV.: 100.6 ft. W tUo M 0. W dJ O ZH a: CD APPROX. SURFACE ELEV.: 98.2 ft. 0 Z F- x to no E to 0.5 6" TOPSOIL 97.7 LEAN CLAY WITH SAND Brown, moist, stiff 2.5 95.7 on site backfill 1 SS 12" 5 18.2 SANDY LEAN CLAY 5 Red, moist, medium stiff 9.5 88.7 10— 2 SS 12" 6 9.2 4* SAND WITH GRAVEL low Red, moist to wet, loose Sz Bentonite 3 SS 12" 3 20.9 14.5 83.7 15 Silica sand SANDY LEAN CLAY__ Red, wet, stiff Slotted pipe 20 4 SS 12" 10 24.1 21.0 77.2 BOTTOM OF BORING THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BOREHOLE DIA.: 6.25 in BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL. WELL DIA.: 2.0 in WATER LEVEL OBSERVATIONS BORING STARTED 5-25-94 Empire Laboratories wL s 11.3' W.D.IT 11.31 A.B. BORING COMPLETED 5-25-94 Incorporated wL RIG CME-55 FOREMAN DMi. Division of Tersacon WL Water checked 24 hrs. A.B. APPROVED LRS JOB A 20945005 LOG OF BORING No. 6 Page 1 of 1 CLIENT ARCHTPECT/ENGINEER Mark Linder Stewart & Associates SITE South Shields Street & West Harmony Road PROJECT Fort Collins, Colorado Westbury P.U.D. First Filing SAMPLES TESTS c� 0 w z H� w a U DESCRIPTION } N Z\ = S W � i N F O Zz W!__j d cc F d fA U CO E W M O U 3 F-O rA H Yli ow UwU_ WHa FE\ Approx. Surface Elev.: 94.3 ft. W o cn w > z>_ > W o-� cnao o E oa ME mcncn cna F-HJ ¢H_j A A A w w O 5 6" TOPSOIL 93.8 1 SS 12" 13 14.1 1.0 LEAN CLAY WITH SAND 93.3 Brown, moist, stiff IK 2 BS 35/18/17 SANDY LEAN CLAY Red/tan, moist to wet Medium stiff to stiff 3 ST 12" 17.8 101 3190 5 4 SS 12" 6 13.5 5 SS 12" 5 14.7 10 3z 6 SS 12" 5 22.3 15.0 79.3 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 Empire Laboratories BORING STARTED 5-25-94 WL g None W.D.911.41 A.B. BORING COMPLETED .5-25-94 Incorporated Division of Terracon WL RIG CME-55 FOREMAN DML WL Water checked 24 hrs. A.B. APPROVED LRS JOB # 20945005 LOG OF BORING No. 5 Page 1 of 1 CLIENT ARCHITECT/ENGINEER Mark Linder Stewart & Associates SITE South Shields Street & West Harmony Road PROJECT Fort Collins; Colorado W ury P.U.D. First Film SAMPLES TESTS ►= X ►>. o 0 o U.J z z zX C.)DESCRIPTION } fA w CrzLL w 7 W ►H- _ LL.CD 2 a. 1—UE0.wU FO H YLL UwOLL CD Approx. Surface Elev.: 98.8 ft. w C] N w z} Z H w w w J Nm o 0 o_ 0. W0- z ►- to 7f_0- ".,.AAA 0.5 6" TOPSOIL 98.3 1 SS 12" 14 13.3 SANDY LEAN CLAY Red/tan, moist, medium stiff 2 ST 12" 12.2 101 1450 5 3 SS 12" 5 15.6 4 SS 12" 5 9.5 10 10.5 88.3 17� ww. SAND WITH GRAVEL. ': Red, moist, loose . * Q 5 SS 12" 6 16.5 1 15.0 83.8 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 BORING STARTED 5-25-94 wL s 14.1' W.D. s A.B. BORING COMPLETED 5-25-94 Incorporated Division of Terracon WL 1 13.0" D.C.I. RIG CME-55 FOREMAN DML WL Water checked 24 hrs. A.B. APPROVED LRS JOB N 20945005 LOG OF BORING No. 4 Page 1 of 1 JCLIENT ARCHITECTIENGINEER Mark Linder Stewart & Associates SITE South Shields Street & West Harmony Road PROJECT Fort Collins, Colorado ury P.U.D. First Filing SAMPLES TESTS I- o o J: er DESCRIPTION } N Ce z\ 0e z HF- 0: F1 �_• = F Uf W m W j O 1 N 3 H N O ZZ OW JU) Jfn ;n. D. W U W E O a >_ U W Y-O 0_J H O YLL WU UO:Ii ZF_Cn WWU. =Xco �i Approx. Surface Elev.: 93.0 ft. o :3 z H X N m E 51 5 w a w a a 0.5 6" TOPSOIL 92.5 LEAN CLAY WITH SAND Brown, moist, stiff %. 2.0 91.0 1 ST 12" 13.5 105 4070 440 2 SS 12" 8 23.8 . i " SANDY LEAN CLAY 5 .; .. Red, moist, medium stiff 3 ST 12" 17.9 109 ,'• .r: r 4 SS 12" 6 15.9 '.r ` t 10.5 82.5 10 SAND WITH GRAVEL !fy.� Red, moist to wet, loose = R"W 14.0 79.0 SANDY T_.F__AN CLAY = 5 SS 12" 5 23.8 :J 15.0 Red, wei, medium stiff 78.0 15 BOTTOM OF BORING TiHE,STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL AND ROCK TYPES:. IN -SITU, THE TRANSITION MAY BE GRADUAL. WATER LEVEL OBSERVATIONS Empire Laboratories BORING STARTED 5-25-94 � n g 14.2' W.D• i 11.8' A.B. BORING COMPLETED 5-25-94 Incorporated Division of Termcon Eovr RIG CME-55 FOREMAN DML LWL Water checked 24 hrs. A.B. APPROVED LRS JOB x 20945005 LOG OF BORING No. 3 Page 1 of 1 CLIENT ARCHITECT/ENGINEER Mark Linder Stewart & Associates SITE South Shields Street & West Harmony Road PROJECT Fort Collins, Colorado Westbury P.U.D. First Filing SAMPLES TESTS \ > .� J J z HI_ DESCRIPTION } M Z\ z aEa H L)a U L)F-o }U_ IL Surface Elev.: 97.3 f. oMza°'Eas=Approx. � ain (no_ "^"^" 0.5 6" TOPSOIL 96.8 1 SS 12" 13 11.2 LEAN CLAY WITH SAND Brown, moist, stiff 2.0 95.3 2 ST 12" 13.6 121 SANDY LEAN CLAY Red, moist, medium stiff 3 SS 12" 8 18.3 5 4 ST 12" 11.0 Ill 1970 8.5 gg g 5 SS 1 12" 14 11.2 SAND WITH GRAVEL 10 Red/gray, moist, medium dense w M : w Sz 6 SS 12" 19 7.9 � 15.0 82'3 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 STARTED RTED 5-25-94 .r' Empire Laboratories WL g 14.30 W.D. LE A.B. BORING COMPLETED 5-25-94 Incorporated Division of Temcon WL 1 12.8' D.CL RIG CMri -55 FOREMAN DML WI. Water checked 24 hrs. A.B. APPROVED l,RS JOB q 20945005 LOG OF BORING No. 2 Page 1 of 1 CLIENT ARCHITECT/ENGINEER Mark Linder Stewart & Associates SITE South Shields Street & West Harmony Road PROJECT Fort Collins; Colorado Westbury P.U.D. First Filing SAMPLES TESTS X > o 0 '. o H DESCRIPTION y w Z\ � w IHj__ a E U Cn o}w zz o.)�w w 0 o o a. } w ~o n. d H o c a. c z r m w Approx. Surface Elev.: 98.7 ft. o Z f- Nm I= ca. ocna " " A 0 5 6" TOPSOIL 98_2 SAND 1 SS 12" 13 15.2 LEAN CLAY WITH 1.5 Brown, moist, stiff 97.2 2 ST 12" 23.4 101 2140 3 SS 12" 5 18.4 SANDY LEAN CLAY 5 Red/olive, moist to wet Medium stiff to stiff 4 ST 12" 19.7 105 2980 5 SS 12" 4 18.2 10 6 SS 12" 5 21.1 15.0'7 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 5-25-94 Empire Laboratories Incorporated Division of TenaCOn WL g None W.D.IT 13.1' A.B. BORING COMPLETED 5-25-94 WL RIG CME-55 FOREMAN DML WL Water checked 24 hrs. A.B. APPROVED LRS JOB Jt 20945005 LOG OF BORING No. 1 Page 1 of 1 CLIENT ARCHITECT/ENGINEER Mark Linder Stewart & Associates SITE South Shields Street & West Harmony Road PROJECT Fort Collins; Colorado West ury P.U.D. First Filing SAMPLES TESTS ►= t}- o o o 0 l~L E )I- W W M zS W L) DESCRIPTION > N o: z\ o: z Fig W •_ 2 W � I N F O zz -jo) CL t- o- fA c) CO E W a O L) 3 F-o rA H >-w ow C.)WLL J fA wwu_ of o � z z E o 0- � a y a n. Approx. Surface Elev.: 96.6 ft. cn ca Cn " " 0.5 6" TOPSOIL 96.1 1 SS 12" 15 10.5 LEAN CLAY WITH SAND Brown, moist, stiff to very stiff 3.0 93.6 2 ST 12" 8.5 106 3 SS 12" 7 10.6 SANDY LEAN CLAY 5 Red, moist, stiff to very stiff 85 4 ST 1 12" 11.9 1 122 5630 8.0 88.6 5 SS 12" 28 14.6 . 7;r 1 SAND WITH GRAVEL Red, moist to wet, medium dense 10 12.5 X7 84.1 SANDY LEAN CLAY Red, wet, medium stiff 6 SS 12" 5 26.3 15.0 81.6 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 BORING STARTED 5-25-94 g12.6' W.D. = 10.8' A.B. BORING CONfPL I'ED 5-25-94 LWL RIG CME-55 FOREMAN DML Division of Termcon Water checked 24 hrs. A.B. APPROVED LRS JOB N 20945005 IN 04*471 .1:, TIP. 000 r 7 17' z Ot 14 MW IA 13 7 C_ -1 : DRIVE V Empire Laboratories, Inc. A Division of The Terracon Companies, Inc. A 11 Linder Real Estate Terracon ELI Project No. 20945005 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 re- evaluate 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. 17 J� Terracon Linder Real Estate ELI Project No. 20945005 • 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. 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 1/II Portland cement is suitable for all concrete on and below grade. Foundation concrete should be designed in accordance with the provisions of the ACI Design Manual, Section 318, Chapter 4. GENERAL COMMENTS 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 have been 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 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 HNI I Linder Real Estate Terracon ELI Project No. 20945005 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. �4. 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 residences. 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. Landscaped irrigation adjacent to the foundation system should be minimized or eliminated. .r 15 I Linder Real Estate Terracon ELI Project No. 20945005 Aggregate base course ... 95 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. 6. On -site clay soils beneath pavements should be compacted within a moisture content range of 2 percent below to 2 percent above optimum. On -site clay soils beneath foundations should be compacted within a moisture range of optimum to 2 percent above optimum. '' • Slopes: For permanent slopes in compacted fill areas, the recommended maximum configuration for on -site materials is 2'/z to 1 (horizontal to vertical). `= If steeper slopes are required for site development, stability analyses should be completed to design the grading plan. • Compliance: Performance of slabs -on -grade, foundations and pavement elements RM 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. 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. If any excavation, including a utility trench, is extended to a depth of more than 20 feet, it will be necessary to have the side slopes designed by a professional engineer. . 14 Terracon Linder Real Estate ELI Project No. 20945005 • 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. Select granular materials should be used as backfill behind retaining walls. 3. Frozen soils should not be used as fill or backfill. 4. 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: Material . Minimum Percent Compaction (ASTM D698) On -site soils or approved imported fill: Beneath foundations ............................ 95 Beneath slabs ................................ 95 Beneath pavements ............................ 95 Utility trenches beneath construction 95 Utility trenches in open areas ...... .. ......... 90 13 Linder Real Estate Terracon ELI Project No. 20945005 6. All exposed areas which will receive fill, once properly cleared, should be scarified to a minimum depth of 6 inches, conditioned to near optimum moisture content, and compacted. • Excavation: 1. It is anticipated that excavations for the proposed construction can be accomplished with conventional earthmoving equipment. • Slab Subarade Preparation: 1. Where existing clay soils will support upper level floor slabs, the soils should be scarified, moisture conditioned and compacted to a minimum depth of 6 inches. 2. A minimum 4-inch layer of clean -graded gravel should be placed beneath upper level floor slabs. 3. A minimum 8-inch layer of free -draining gravel should be placed beneath basement floor slabs in conjunction with the underslab drainage system. • Pavement Subarade Preparation: 1. The subgrade should be scarified, moistened as required, and recompacted for a minimum depth of 6 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 j� of wet zones and replacement with granular materials may be necessary. Lightweight excavation equipment may be required to reduce subgrade pumping. Proof rolling of the street subgrade may be required to determine subgrade stability prior to paving. Use of lime, fly ash, kiln dust, cement or geotextiles could also be considered as a lit, stabilization technique. Laboratory evaluation is recommended to determine the effect of chemical stabilization on subgrade soils prior to construction. of 12 Linder Real Estate Terracon ELI Project No. 20945005 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. 4 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. • 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 fills, foundations or underground facilities are encountered during site clearing, such features should be removed and the excavation thoroughly cleaned prior to backf ill 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 Uoperations. 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. i� 4. 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 structures. 5. All materials derived from the demolition of existing structures should be removed from the site, and not be allowed for use in any on -site fills. 11 Terracon Linder Real Estate ELI Project No. 20945005 T 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. I Future performance of pavements constructed on the clay soils at this site will be dependent upon 1 several factors, including: • maintaining stable moisture content of the subgrade soils; and, ri • providing fora 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 7111, 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: • 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. 1 ��I 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. i. 10 J JTerracon Linder Real Estate ELI Project No. 20945005 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 D1559). 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 Transportation 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 D1'559). Where rigid pavements are used, the concrete should be obtained from an approved mix design with the following minimum properties: • Modulus of Rupture @ 28 days ........................ 650 minimum • Strength Requirements ....• • • .. ASTM C94 • 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 ; 1 • 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 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 N 9 Linder Real Estate Terracon ELI Project No. 20945005 soil was determined by correlation to the laboratory tests results. A modulus of rupture of 650 psi (working stress 488 psi) was used for pavement concrete. The rigid pavement thicknesses for each street were determined on the basis of the AASHTO design equation. Recommended alternatives for flexible and rigid pavements, summarized for each street, are as follows: Traffic Area Alternative Recommended Pavement Section Thickness (inches) Asphalt Concrete Surface Aggregate Base Course Subbase Plant -Mixed Bituminous Base Portland Cement Concrete Total Harmony Road A 5 12 12 29 B 4 9 13 C 8 8 Westbury Drive A 3 7 10 B 2 4 6 C 6 6 Mariposa Court A 3 4 7 B 2 3 5 C 6 6 Each alternative should be investigated with respect to current material availability and economic conditions. Aggregate base course (if used on the site) should consist of a blend of sand and gravel which 6 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 !i 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. i Linder Real Estate Terracon ELI Project No. 20945005 • A minimum 8-inch layer of free -draining gravel should be placed beneath basement floor slabs in conjunction with the underslab drainage system. • 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 Desian 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). Proposed pavements on the site will be divided into three categories based upon anticipated traffic and usage. Traffic criteria provided for pavement thickness designs include 18-kip equivalent single axle loads (ESALs) of 200 for Harmony Road, 12 for Westbury Drive and 5 for Mariposa Court. Based upon AASHTO criteria, Colorado is located within Climatic Region VI of the United States. 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. The AASHTO criteria suggests that these moisture conditions are prevalent for approximately 12- 1/2% of the annual moisture variation cycle. Local drainage characteristics of proposed pavement areas are considered to be good. 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, terminal serviceability indices of 2.5 and 2.0 were utilized for Harmony Road and the residential streets, respectively, along with respective reliabilities of 90 and 70%. An R-value of 11.2, determined from our laboratory testing, was used for the residential streets. An R-value of 5, supplied by others, was used for Harmony Road. Using the correlated `9 design R-values, appropriate ESALs per 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, rigid pavement design analyses were completed, based upon AASHTO design procedures. Rigid pavement design is based on an evaluation of the Modulus of Subgrade Reaction of the soils (K-value), the Modulus of Rupture of the concrete, and other factors previously outlined. The design K-value of 100 for the subgrade 7 I Terracon Linder Real Estate ELI Project No. 20945005 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. Basement Construction: The shallowest groundwater encountered on the site was at a depth of 10.8 feet in boring 1 near the west edge of the property. Full -depth basement construction is considered acceptable on the site, provided the basement excavations extend no deeper than 3 feet above the groundwater level. To reduce the potential for groundwater to enter the basement of a structure, installation of a perimeter drainage system is recommended. The drainage system should be constructed around the exterior perimeter of the basement foundation, and slope at a minimum 1 /8 inch per foot to a suitable outlet, such as a sump and pump system. The drainage system should consist of a properly sized perforated pipe, embedded in free -draining gravel, placed in a trench at least 12-inches in width. Gravel should extend a minimum of 3-inches beneath the bottom of the pipe, and at least 1 foot above the bottom of the foundation wall. The gravel should be covered with drainage fabric prior to placement of foundation backfill. Floor Slab Design and Construction: Low expansive soils will support the floor slabs. Some differential movement of a slab -on -grade floor system is possible should the subgrade soils increase 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 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. • Interior trench backf ill paced beneath slabs should be compacted in accordance with recommended specifications outlined below. • A minimum 4-inch layer of clean -graded gravel should be placed beneath upper level interior slabs. 6 ITerracon Linder Real Estate ELI Project No. 20945005 Zones of perched and/or trapped groundwater may also occur at times in the subsurface soils overlying bedrock, on top of the bedrock surface or within permeable fractures in the bedrock. The location and amount of perched water is dependent upon several factors, including hydrologic —j conditions, type of site development, irrigation demands on or adjacent to the site, fluctuations �j in water features and seasonal and weather conditions. The possibility of groundwater fluctuations should be considered when developing design and construction plans for the project. GROUNDWATER MONITORING WELLS Groundwater monitoring wells 1 A and 2A were installed in filings 1 and 2, respectively, on March 25, 1994 to aid in the design of a subsurface drainage system by other consultants. The monitoring wells were constructed with 2-inch diameter manufactured well screen and casing material. Monitoring wells 1 A and 2A were installed to depths of approximately 20.5 and 9.5 feet below site grade, respectively. Well construction details are shown on the groundwater monitoring well profiles in Appendix A. CONCLUSIONS AND RECOMMENDATIONS JFoundation Systems: Based on the soil characteristics encountered on the site, spread footing foundations bearing upon undisturbed subsoils are recommended for support of the proposed residences. The footings may be designed for a maximum bearing pressure of 1,500 psf (dead load plus half live load). 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.' Finished grade for perimeter footings is the lowest adjacent grade. 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 settlement resulting from the assumed structural loads are estimated to be on the order of %-inch 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. 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. 11 5 Linder Real Estate ELI Project No. 20945005 SUBSURFACE CONDITIONS Terracon Soil and Bedrock Conditions: The following describes the characteristics of the primary soil strata encountered at the site in order of increasing depths. • Topsoil. A '/:-foot layer of silty topsoil was encountered at the surface of the test borings. The topsoil has been penetrated by root growth and organic matter. • Lean Clay with Sand. A layer of brown clay was encountered. below the topsoil and extends to depths of 1 to 4 feet below the surface. The lean clay is moist and contains moderate quantities of sand. • Sandy Lean Clay. A layer of red clay was encountered below the topsoil and/or brown clay and is interbedded with a granular stratum. The red clay contains substantial quantities of sand and is moist to wet with depth. • Sand with Gravel. The granular stratum was encountered in 5 of the 8 test borings between depths of 8 and 15 feet. The sand with gravel is relatively clean and is moist to wet with depth. • Claystone/Siltstone Bedrock. The bedrock stratum was encountered at a depth of 4 feet in the test boring for monitoring well 2A in the 2nd Filing of the subdivision. The upper 4'/z feet of the bedrock is highly weathered. Field and Laboratory Test Results: Field test results indicate that the clay soils vary from medium stiff to very stiff in consistency. The sand soils vary from loose to medium dense in relative density. The weathered bedrock is soft and the underlying bedrock is moderately hard. The soils at anticipated foundation bearing depths have moderate load bearing capability. Laboratory test results indicate that clay soils at anticipated foundation bearing depths have low expansive potential. Groundwater Conditions: Groundwater was encountered at depths of 11.3 to 14.3 feet in five the test borings at the time of field exploration. When checked one day after drilling, groundwater was measured at depths of 10.8 to 13.1 feet in five of the test borings. 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 and fluctuations in the flow of the Pleasant Valley and Lake Canal. 4 J Terracon Linder Real Estate ELI Project No. 20945005 Laboratory 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 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 and monitoring well cross sections for the project are presented in Appendix A. Selected soil and bedrock samples were tested for the following engineering properties: • Water content • Plastic limit • Dry density • Percent fines • Consolidation • Hveem stabilometer • Compressive strength • Grain size distribution • Expansion • Hydrometer analysis • Liquid limit • Water soluble sulfate 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, pavement and earthwork recommendations. All laboratory tests were performed in general accordance with the applicable ASTM, local or other accepted standards. The grain size distribution and hydrometer analysis were performed for Mr. Paul Clopper of Resources Consultants and Engineers (RCE) to aid in the design of a subsurface drainage system. SITE CONDITIONS The 1 st Filing of the Wesbury P.U.D. consists of approximately 8 acres of land on the south side of Harmony Road approximately 1/10 to 2/10 mile west of Shields Street in southwest Fort Collins, Colorado. The area is vegetated with low grass and a large cluster of small trees. The Pleasant Valley and Lake Canal runs along the southwest edge of the site. The 1st Filing is bordered by Harmony Road to the north, two single-family residences and the Gress Gallery to the east, the 2nd Filing of the Westbury P.U.D. to the south and a single-family residence to the west. The area exhibits slight surface drainage to the east. 3 J Terracon Linder Real Estate JELI Project No. 20945005 J Although final site grading plans were not available prior to preparation of this report, pavement subgrades and ground floor levels of the proposed residences are anticipated to be at or near. existing site grades. SITE EXPLORATION The scope of the services performed for this project included site reconnaissance by an engineering geologist, a subsurface exploration program, installation of two groundwater monitoring wells, IAboratory testing and engineering analyses. Field Exploration: A total of 8 test borings were drilled on May 25, 1994 to depths of 10 to 20 feet at the locations shown on the Site Plan, Figure 1. Four borings were drilled on planned residential lots and two borings were drilled in areas of planned residential streets of the 1 st Filing of the subdivision. One boring was drilled for a monitoring well in the 1 st Filing and one boring was drilled for a monitoring well in the 2nd Filing. All borings were advanced with a truck - mounted drilling rig, utilizing 4-inch diameter solid stem auger for the residential and pavement borings and 6-inch diameter hollow -stem auger for the monitoring well borings. J The location of borings were positioned in the field relative to the property lines. 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. 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. A representative bulk sample of subsurface materials was obtained from one of the pavement borings. 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 measurements were made in each boring at the time of site exploration and one day after drilling. 2 I I I J Terracon GEOTECHNICAL ENGINEERING REPORT WESTBURY P.U.D., 1ST FILING HARMONY ROAD AND SHIELDS STREET FORT COLLINS, COLORADO ELI Project No. 20945005 June 3, 1994 INTRODUCTION This report contains the results of our geotechnical engineering exploration for the proposed project to be located south of Harmony Road and west of Shields Street in southwest Fort Collins, Colorado. The site is located in the NE'A of the NE'/. of Section 3, 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 and bedrock conditions • groundwater conditions • foundation design and construction • • basement construction floor slab design and construction • pavement design and construction • earthwork • drainage 1 E 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 Based on information provided concerning construction, the 1 st Filing of the Westbury subdivision will consist of 19 single-family residences on individual lots. Mariposa Court and a portion of Westbury Drive (designated as residential streets) will be constructed across the site. Pavement for West Harmony Road north of the site (designated as an arterial street) will also be upgraded. A subsurface drainage system will be designed by other consultants. The design will be based, in .part, on information obtained from groundwater monitoring wells and associated laboratory testing by Empire Laboratories, Inc. 4 Linder Real Estate ELI Project No. 20945005 Terracon Other design and construction details, based upon geotechnical conditions, are presented in the report. We appreciate being of service in the geotechnical engineering phase of this project, and are prepared to assist you during the design and 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. ] -R. SC16-e ; 4 a R. Schoenfeld, P.E. ] Geotechnical Engineer Reviewed �by: Chester C. Smith, P.E. Division Manager LRS/CCS/dmf l aqunnnnnn� SCHO =-o• 237 J •�_' - � 02- e ° AI`11E�'��`��,,� 9 Copies to: Linder Real Estate (3) Mr. Paul Clopper/Resource Consultants and Engineers (1) Empire Laboratories, Inc. A Division of The Terracon Companies, Inca 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. June 3, 1994 Linder Real Estate 3500 J.F.K. Parkway, Suite 221 Fort Collins, Colorado 80525 Attn: Mr. Mark Linder Re: Geotechnical Engineering Report, Westbury P.U.D., 1st Filing Harmony Road. and Shields Street, Fort Collins, Colorado ELI Project No. 20945005 Empire Laboratories, Inc. (ELI) has completed a geotechnical engineering exploration for the, proposed project to be located south of Harmony Road and west of Shields Street in southwest Fort Collins, Colorado. This study was performed in general accordance with our proposal number D2094182.1 dated May 24, 1994. The results of our engineering study, including the boring location diagram, laboratory test results, test boring records, groundwater monitoring well cross sections and the geotechnical recommendations needed to aid in the design and construction of foundations, pavement and other earth connected phases of this project are attached. The subsurface soils generally consisted of brown, lean clay with sand overlying red, sandy lean clay. The lower clay stratum is interbedded with a layer of sand with gravel. Claystone/siltstone bedrock was encountered below the clay layer in monitoring well 2A located in the second filing of Westbury. The information obtained by the results of field exploration and laboratory testing indicate the soils at the site have low expansive potential. The soils at anticipated foundation bearing depths have moderate load bearing capability. Based on the geotechnical engineering analyses, subsurface exploration and laboratory test results, we recommend that the proposed residences be supported on spread footing and/or grade beam foundation systems. Slab -on -grade maybe utilized for the interior floor systems provided that care is taken in the placement and compaction of the subgrade soil. Offices of The Terracon Companies, Inc. Geotechnical, Environmental and Materials Engineers 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, Fort Worth ■ Utah: Salt Lake City ■ Wyoming: Cheyenne QUALITY ENGINEERING SINCE 1965 I Linder Real Estate ELI Project No. 20945005 Terracon TABLE OF CONTENTS (Cont'd) JAPPENDIX A Site Plan ...............................................Figure No. 1 Logs of Borings Al thru A8 J APPENDIX B.............................................. Consolidation Test 61 Swell -Consolidation Test .......................................... B2 Gradation Curves ............................................... B3 R-Value Curve .................................. B4 Summary of Laboratory Test Results ........................... B5 thru B7 J APPENDIX C: GENERAL NOTES Drilling & Exploration ........ C1 Unified Soil Classification ......................................... C2 7 Bedrock Classification, Sedimentary Bedrock .................. . ......... C3 Laboratory Testing, Significance and Purpose C4 Report Terminology ............................................. C5 APPENDIX D Recommended Preventative Maintenance -Asphalt Concrete Pavements ......... D1 l Recommended Preventative Maintenance -Jointed Concrete Pavements ......... D2 H F Linder Real Estate ELI Project No. 20945005 TABLE OF CONTENTS Terracon Page No. Letter of Transmittal................................................... i INTRODUCTION..................................................... 1 PROPOSED CONSTRUCTION ........................................... 1 SITE EXPLORATION .................................................. 2 Field Exploration ............................................... 2 Laboratory Testing .............................................. 3 JSITE CONDITIONS.................................................... 3 SUBSURFACE CONDITIONS ............................................ 4 Soil and Bedrock Conditions ....................................... 4 Field and Laboratory Test Results . 4 Groundwater Conditions .......................................... 4 GROUNDWATER MONITORING WELLS .................................... 5 CONCLUSIONS AND RECOMMENDATIONS . ......... .:.:................. 5 Foundation Systems 5 Basement Construction ........................................... 6 J Floor Slab Design and Construction .................................. 6 Pavement Design and Construction .................................. 7 Earthwork................................................... 11 General Considerations ..................................... 11 Site Clearing ............................................ 11 Excavation............................................. 12 Slab Subgrade. Preparation ................................... 12 pPavement Subgrade Preparation ............................... 12 Fill Materials ............................................ 13 Placement and Compaction .................................. 13 Slopes................................................ 14 Compliance............................................. 14 Excavation and Trench Construction ............................ 14 Drainage.................................................... 15 Surface Drainage ......................................... 15 Subsurface Drainage ....................................... 16 Additional Design and Construction Considerations ...................... 16 Exterior Slab Design and Construction .......................... 16 Corrosion Protection..............I......................... 16 GENERAL COMMENTS ................................................ 16 GEOTECHNICAL ENGINEERING REPORT WESTBURY P.U.D., 1ST FILING HARMONY ROAD AND SHIELDS STREET FORT COLLINS, COLORADO ELI PROJECT NO. 20945005 Prepared for. LINDER REAL ESTATE 3500 J.F.K. PARKWAY, SUITE 221 FORT COLLINS, COLORADO 80525 ATTN: MR. MARK LINDER Y Empire Laboratories, Inc. A Division of the Terracon Companies. Inc. GEOTECHNICAL ENGINEERING REPORT WESTBURY P.U.D., 1ST FILING HARMONY ROAD AND SHIELDS STREET FORT COLLINS, COLORADO ELI PROJECT NO. 20945005 A Division of The Terracon Companies, Inc.