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HomeMy WebLinkAboutPermit Notice 2005-3-11 Tax Map: Tax Lot: The building site at the above address is located on property that has soils prone to shrink-swell or other potential movement. Excavations, placement of fill materials and drainage for this site must be done under the direct supervision of a properly licensed Professional Engineer or Architect to verify the stability of the resulting building pad and the site. The owner, or the owner's qualified agent, is responsible to obtain the services of the appropriate professional engineer or architect (design professional). The design professional shall provide direction for the stabilization methods to be used for the building pad (and surrounding site, when site stabilization is also necessary). The geotechnical report, which was prepared for this subdivision, may be utilized to provide appropriate guidance for the methods of stabilization and required compaction "for the specific site. The engineer or architect shall prepare a report to be submitted to the City stating how the soil stabilization is being accomplished, including requirements not yet completed (if any). A signed and stamped report from the engineer or architect must be received and approved bv this office before footinfl or foundation inspection approval will be flranted bv the Citv Buildinfl Inspector. ACKNOWLEDGEMENT: The undersigned acknowledges the forgoing requirements for soil stabilization, including excavation, fill, soil compaction and drainage, as provided in the geotechnical report for the subdivision. The stabilization will be accomplished under the direction of a licensed professional engineer or architect as noted above. ") / Signatur~~ oatej/f)r- N ame~ r/ t:- J:..{;... ~ Ie Affiliation to owner . j-. GEOTECHNICAL INVESTIGATION prepared for HAYDEN ENTERPRISES, INC. for the JASPER MEADOWS SECOND ADDITION . SPRINGFIELD, OREGON. leXPIRES: 12/31/C 1 February 16, 2003 Prepared by: REC"FT"' TH'D' '- ' ..., -' _ v ;t:.:.., APR 1 8 2003 II BOIRE AssoclA. cS INC. BY: CI 5160 SW Beals Avenue . Corvallis, OR 97333 . Tel: 541.753.5344 . Fax: 541.753.5347 .. SoIRE ASSOCI~ ~s /NC.. . ..' Geotechnical Engineering Solutions Boire Associates Inc. 5160 SW Beals Avenue Corvallis. Oregon 97333 TEL 541.753.5344 FAX 541.753.5347 Mark Vukanovich Hayden Enterprises, Inc. 2622 SW Glacier Place, Suite 110 Redmond, Oregon 97756 February 16, 2003 Re: - Jasper Meadows Second Addition Geotechnical Investigation Springfield, Oregon Project 203,012 Dear Mr. Vukanovich: As requested, Soire Associates Inc. has completed a foundation investigation for the proposed Jasper Meadows Second Addition in Springfield, Oregon. This report provides a description of our work, a discussion of site conditions, and recommendations for site preparation, building pad development (residential foundation support) and pavement design for public streets. . , ' Our investigation of the property found high plasticity clay at many locations and depths that appears expansive. The clay is more extensive than found within previous development phases to the immediate north and we do not expect it will be practical to remove or segregate this material during mass grading; The planned development should be feasible; however, some special preparations of residential building pads would be required to mitigate clay that is potentially susceptible to shrink/swell beneath foundations. After grading, we expect limited over-excavation would be required beneath footings, slabs and/or pavements to remove the upper 1 to 2 ft of soil that would be most susceptible to future movement. Our recommendations for general grading are relatively strict to ensure compacted fills would be less expansive than native (in-plac~) soil. As an alternative to potentially restrictive earthwork procedures and practices, 'the use of post-tensioned slabs might be possible as discussed in the report. Expansive soils beneath streets have been given a lower priority as these structures are low risk and have a finite useful life. It has been a pleasure working with you again. Please contact us with any questions. Sincerely, Soire Associates Inc. ~'''' .-> , , I ' ?<S " ':'~~dd Boi~e, P.E. PROJECT INFORMATION The project consists of a new residential subdivision in Springfield, Oregon that will include developing 39 building lots and constructing approximately 2,000 lineal ft of new roC!dway. The proposed development would incorporate about 11 acres, immediately south of the' Jasper Meadows First Addition subdivision that is currently in the process of being built out. A vicinity map is shown on Figure 1. SITE CONDITIONS Site conditions were explored on February 6, 2003 by conducting a surface reconnaissance of the property and by excavating twelve exploratory test pits with a tracked hoe (excavator). . The explorations were located in the field by pacing from existing physical features and referencing these locations to a site plan provided to us. The approximate test pit locations are shown on Figure 2 of this report. The field explorations were. coordinated and monitored by a geotechnical engineer from our staff who recorded the subsurface conditions encountered, obtained representative soil samples, and described the soil by visual and textural examinations. Disturbed (bag) samples were obtained from representative soil strata 'by hand. All soil encountered was described using the Unified Soil Classification System (Standard Recommended Practice for Description of Soil, Visual- Manual Procedures). Narrative test pits logs are presented as an. attachment to this report. These logs represent our interpretation of subsurface .conditions identified during the. geotechnical explorations. Toooaraohv and Veaetation Topographic information provided to us indicates the site slopes from the east down to the west at a relatively gentle and . constant grade of about 16 (horizontal) to 1 (vertical). Along the eastern boundary of the development area, the slope increases to about 5 (horizontal) to 1 (vertical). A maximum elevation difference of about 40 ft is present across the development area. We understand grading would be limited in order to accommodate the existing topography. The site i$ currently undeveloped and contains mostly tall grass, weeds and bramble patches. There are no trees on the property. Soil Conditions Soil conditions within the project area are described in detail in the attached test pit logs. No fill or other foreign debris was found on the property. The native soil typically consists of 1 to 2 ft of medium to. high plasticity clayey silt followed by high plasticity clay. Explorations generally extended through the high plasticity clay below a depth of 3 to 5 ft into a variable mixture of . siltstone and/or sandstone with fragments of hard rock and intermediate layers of high plasticity .silt and clay. . Groundwater We observed subsurface seepage in test pits TP-1, TP-8 and TP-12 that was confined within upper soil layers as a result of perched runoff. No water was found at the bottom of any of the test pits. However, we expect an elevated groundwater table might develop within 10ft of the ground surface during the wettest months. Except for the sloping grade, we expect the site to be relatively poorly-drained during winter. CONCLUSIONS AND DISCUSSION Our investigation of the property suggests most of the site is underlain by high plasticity silts and . clays that are likely to be exposed within future building pad areas. Close examination of the native soil found the material often contains a fissured, slickenside and/or blocky structure suggestive of past soil shrink-swell. We conducted limited laboratory testing on two random specimens obtained from the test pits to quantify. the average soil plasticity. The test results, which are shown on Figure B-1, indicate the upper topsoil actually consists of high plasticity silt with an "MH" designation. The underling material consists of very high plasticity clay with a "CH" designation. Based on our .previous work in the area, we have determined the high plasticity soils are not atypical for the area. However, the native soils should be considered relatively expansive, especially above a depth" of about 2 to. 3 ft. Careful and specific earthwork procedures are recommended to minimize soil expansion potential (see below). . ~ t RECOMMENDATIONS The following section provides general recommendations for earthwork, building pad development, foundation support and pavement construction. In many cases, our recommendations refer to specific material types or methods (shown in Italics) that are defined or described in the "Specifications" section. "!: 1 Striooina Most of the site is surfaced with tall grass, weeds and/or brambles. It should be expected that at " . least 2 to 4 inches of stripping would be required" in mostareas to removethesurface organics vegetation. Subarade Comoaction After stripping, the exposed Subgrade would likely consist of high plasticity silt or clay. We recommend this soil should be treated (prior .to covering) by processing/compacting the material to a depth a 12 inches to. a minimum of 95% relative compaction to a water content not less than 2% wet of optimum. In some cases, pumping of the soil might occur and it might be difficult to obtain the required density. We should be contacted in this event to evaluate site conditions. Generally, proper water content control would be given priority over soil density and/or stiffness. Mass Gradinq . In general, we would not recommend reusing the high plasticity silt or clay soils during grading due to poor workability and unpredictable engineering characteristics. However,. the clay is wide-spread over the site and would likely be difficult to avoid. Additionally, we believe the remolded soil would actually produce a soilless susceptible to soil shrink-swell (as compared to the native material) if prepared properly. If used as fill, the silt/clay should be placed in maximum 8-inchloose lifts arid .compacted to a minimum of 95% relative compaction to a water content not less than 2% wet of optimum. As indicated above, we expect pumping of the soil might occur in some cases due to high moisture contents. Workability is expected to be difficult. Buildino' Pad DeveloDment We have assumed foundations for new houses would be built on flat "push-outs" constructed during the general site grading. We recommend the native soil within push-out areas be prepared as recommended above for "Subgrade Compaction" and "General Grading." Following approved soil preparation, we recommend all areas that will support foundations and slabs be . . covered with a minimum of 12 inches of Coarse Granular Fill capped with 6 inches of Fine . Granular Fill. Foundations should be constructed directly on the completed fill. .~ Another alternative to mitigate potentially expansive soils within building pads would be to. treat spedfic foundation areas only. That is, after creating push-outs discrete trenches could be made to bypass the upper clay within isolated footings. If used, trenches should extend a minimum of 18 inches below the bottom of footings. The trenches may be made vertical but should extend a minimum of 12 inches beyond the sides of footings. Excavations should be made with a smooth bucket and the foundation soil left undisturbed. The exposed material should be kept moisten and immediately backfilled Fine Granular Fill to the surface of the push- out elevation. Footings should then be constructed directly on the trench fill. Foundation SUDDort Continuous wall footings for residential construction may be designed using allowable bearing capacity of 2,000 pounds per squareft (pst). We have assumed footings would be built on properly prepared building pads or over-excavated trenches, as discussed above. Prior to footing .construction, all foundation areas should be kept continually moist. Drainaae All house foundations should be constructed with a stan'dard perimeter foundation drain. Low point crawl space drains may also be used. If adequate drainage is not provided, it should be assumed that water would tend to accumulate in low areas. Post-Tension Slabs It might be possible to use post-tensioned slabs to avoid detailed .earthwork or. other special foundation preparations." The advantage of such a system is that the reinforced .slab resists . differential shrink-swell movement with very little special soil preparations required. The disadvantage is that some special design and construction procedures are required. The completed foundation would also consist of a finished concrete slab, which might not be preferable to all buyers. Pavement Desian Pavement structures are most influence or affected by heavy truck traffic. With regard to construction traffic, we assumed each lot would generate 10 heavy truck trips. During the .design life, we expect the overall subdivision would receive less than 10 trucks per week for garbage collection and special deliveries. Cars and light trucks should have relatively little influence on the structural capacity of section. Construction plans were not provided to us butwe assume grading would be limited to shallow cuts and fills less than 2 ft total. Subgrade preparation and compaction, as well as placement and compaction of the aggregate base should be completed as recommended above. Where practical, we recommend that the bulk of.the aggregate base section consist of Coarse Granular Fill. , . ,~ A flexible asphalt pavement design was completed for local-type streets using the AASHTO procedure and a 20-year service life. We assumed a relatively low Modulus of Subgrade Resilience (MR) of 2,750 ponds per square inch (psi) to account for s,?i1 pumping resulting, possibly resulting from our recommended method of soil preparation (Le., compacting the soil wet of the optimum water content). The' calculated pavement sections are as follows: Section Option Table 1 PavementSection Options Asphalt Thickness 1 (inches) Aggregate Base Thickness2 (inches) 1 2 3 3 15 13 11 3Y2 4 Asphalt types and placement/compaction methods should conform to City standards. 2 We recommend the bulk of the material consist of Coarse Granular Fill capped with Fine Granular Fill. Utilities . We expect trench excavations would remain relatively stable when open due to the nature of the high plasticity soils. However, we recommend exercising extreme caution as unexpected caving and rapid failures of trench sidewalls might occur as a result of the blocky soil structur'e. It is imperative that shoring be provided in all cases in accordance with OSHA guidelines. Utility . contractors ,should also assume subsurface infiltration could occur from perched runoff if excavations are made early in the construction season. SPECIFICATIONS The following is a list of various materials types that have been used within this report but not previously defined. · Fine Granular Fill should consist of 1 i2 to %-inch minus, well-graded, clean, hard, angular, 'crushed rock with less than 5% material passing the No. 200 ~ieve. Place all Fine Granular Fill in maximum 12-inch loose lifts and compact to 90% relative compaction according to ASTM 01557. · Coarse Granular Fill should consist of 6 to 3-inch minus, well-graded, clean, hard, angular, crushed rock with less than 5% material passing the No. 200 sieve. Place all Coarse Granular Fill in maximum 12-inch loose lifts and. compaCt to 90% relative compaction , according to ASTM 0 1557. · Subgrade refers to the native grade after stripping (undisturbed or compacted) that is to receive fill. Note that general workability of high plasticity clay is expected to be difficult. LIMITATIONS AND USE OF THIS REPORT This report has been prepared for the exclusive use of Hayden Enterprise.s Inc. and their design consultants for the proposed Jasper Meadows Second Addition project in Springfield, Oregon. Information contained herein should not be construed as a warranty or guaranty: of site or subsurface conditions. Our explorations indicate soil conditions only at specific locations and only to the depths penetrated. They do not necessarily reflect soil strata or water level variations that may exist between or beyond exploration locations or limits. Soil and groundwater conditions at other locations or times may differ. Contractors using this report for bidding or quantity estimates,' or to determine construction difficulties, do so at their own risk. The scope of our services does not include services related to construction safety precautions, techniques, sequences or procedures, except as specifically described in our report for consideration in design. Our work, at the time this report was prepared, have been conducted in accordance with generally accepted principles and practices. No warranty or other conditions, expressed or implied, is made. ; " 1 ~'.! Mc~ENZ/E"./'\)~'.!;t,WY. __ ( -'--'-, . . h:l U) --, ~; ll')' Vi MT. VERNON RD. ,.",:.::=,,,,,,,,,,~~ \.:_~-..-;.>" , l F"/RST ADDITION l' t Q \. I' I; ~ ~~ \. c- \,~ \\ "'0 \, ~ '..... -;0 \-;0 \.0 '\: \\.~ \\\.~. '- "\ . '. ;,,>.... ~ . . . .~ \\ '\z. \\ "\. " \. :;0 o )> CJ (T\ X -i (T\ Z If) o z ',% '.n '- ...t.. \~ \-:s:. t.'Y: \~ " C. \,tf'! ''Z. '\ \ ~, \ \. RO~O_~,... ~- " j \L \, II ':-'(. ... SCALE: N.T.S. ; , " .. .. . "- SOtRE VICINITY MAP FIGURE NO. ... . ASSOCtA TES JASPER MEADOWS SECOND ADDITION 1 Geotechnical Engineering Solutions SPRINGFIELD, OREGON " " ... , ~ , .. .. .. - - .. ..-' .. .. .. .. .. .. .. .. .. .. .. ,<"'" ""- ..' .. g 'il fa! ..~ S-i IUQtli !Eel ouq lQut~ .~,; .1 - --- ~-~ .. .. .. .. .. /' ,/ /' z o I- o o <( o z z 00 ()~ W 0: (/}o (/}9 3: w o ~ o~ <(8: Will ~ 0::: W a.. (/) <( ...., (f) p 6 ~ ~. ZO <( 0 ....J ....J a.. I- ~a: - I- (f) (f) ~ ~ " ~ z- b lIJ U . ... ~ U l/l d z .... 0:: G Ii: N -# \ 60 A TTERBERG LIMITS PLASTICITY CHART I - ! Inorgonic clays af , hi~h plasticitv Sample . / 5-3-1 / / o i ; .; ;,./,- ; " , I 50 I/' i ~ x l' ~ CH 1'/' " 'J..01 " 40 ! i r5 il: I I ' . ; I Micaceous or diatomaceous tine sandy and silty soils; elastic silts; arganic silts. cloys. and silty clays OH ~ 30 ~ 20 I ' I Iii J , Inorganic and organic silts I i and silty cloys of low i i plasticity; rock; flour; I i silty. or c~ayey, tine sa~ds I j i i I I I I I I I I MH I , I I ! I I I I i I I I I I 90 100 ! , 1 i I o o 10 20 30 40 50 Liquid Limit (LL) 60 70 I 80 ATTERBERG LIMITS TABULATED VALUES Sample Depth (ft) Water Content (%) Atterberg Limits LL PL PI USCS 8-3-1 2.5 42.9 82 27 55 CH S-12-1 1 40.0 63 30 27 CH ... ~ ,. '" .. '" .. '" ,. BOIRE LABORA TORY TEST RESUl TS FIGURE NO. ~ ~. ASSOCIA TES JASPER MEADOWS SECOND ADDITION 3 Geotechnical Engineering Solutions SPRINGFIELD, OREGON ~ ~ ... , ... , TEST PIT LOGS Project Name: Project Number: Project Location: Jasper Meadows Second Addition 203.012 . Springfield, Oregon 1! 1 TP-1 (Excavated on February 6, 2003) Elevation: .556 ft Deoth (ft) I Soil Profile Descriotion 0-2 Loosely structured SILT (MH); clayey, dark brown, moist, very friable, medium to high plasticity. Fine organics noted throughout. 2": 3 Stiff CLAY (CH); gray, moist, medium stiff to stiff, high plasticity. The soil has a biocky structure and shows evidence of past shrink/swell. . 3 - 6 Stiff SILT/CLAY; very sandy with rock fragments, rust brown (iron- stained), moist to wet. The soil appears to have weathered from rock (siltstone and/or sandstone). Pockets of high plasticity clay noted. 6 - 7 Weathered ROCK (siltstone/sandstone); silty and sandy with fragments of very hard rock, rust brown, damp. The consistency of the formation relative to soil is "hard." ;5 Notes: 1. Roots from surface vegetation extend downward about 4 inches. 2. Seepage from runoff perched between 3 and 6 ft. TP-2 (Excavated on February 6, 2003) Deoth (ft) Soil Profile Descriotion Elevation: 559 ft "" 0-2 Loosely structured SILT (MH); clay~y, dark brown, moist, very friable, medium to high plasticity. Fine organics noted throughout. Stiff CLAY (CH); gray, moist, medium stiff to stiff, high plasticity. The soil has a blocky structure and shows evidence of past shrink/swell. Stiff SILT/CLAY; very sandy with rock fragments, rust brown (iron- stained), damp. The soil appears to have weathered from rock (siltstone and/or sandstone). Pockets of high plasticity clay noted. Weathered ROCK (siltstone/sandstone); silty and sandy with fragments of very hard rock, rust brown, damp. The consistency of the formation relative to soil is "hard." 1 I 2-4% 4%-5% i 5%~6 Notes: 1. Roots from surface vegetation extend downward about 4 inch~s. . 2. No seepage or groundwater encountered. . TP-3 (Excavated on February 6, 2003) Deoth (ft) Soil Profile Descriotion Elevation: 562 ft 0-1 Loosely structured SILT (MH); clayey, dark brown, moist, very friable, medium to high plasticity. Fine organics noted throughout. Stiff CLAY (CH); some gravel, gray,. damp to moist, medium stiff. to stiff, high plasticity. The soil has a blocky structure and shows evidence of. past shrink/swell. Sample 5-3-1 taken from about 2% ft. Stiff SILT/CLAY; very sandy with rock fragments, rust brown (iron- stained), damp. The soil appears to have weathered from rock (siltstone and/or sandstone). Pockets of high plasticity clay noted. Weathered ROCK (siltstone/sandstone); silty and sandy with fragments of very hard rock, rust brown, dry. The consistency of the formation relative to soil is "hard." 1-3 3-5% 5% - 6% Notes: 1. Roots from surface vegetation extend downward about 4 inches. 2. No seepage or groundwater encountered. TEST PIT LOGS Project Name: Project Number: Project Location: Jasper Meadows Second Addition 203.012 Springfield, Oregon TP-4 (Excavated on February 6,2003) Elevation: .573 ft Depth Cft) I Soil ProfIle Description 0-% Loosely structured SILT (MH); clayey, dark brown, damp to moist, very friable, medium to high plasticity. Fine organics noted throughout. % ~ 6 Stiff CLAY (CH); gray, damp to moist, medium stiff to stiff, very high plasticity. The soil is highly fissured and shows evidence of past shrink/swell. Scattered large gravels and small cobbles contained within the soil matrix. Stiff SILT/CLAY; very sandy with rock fragments, rust brown (iron- stained), damp. The soil appears t6 have weathered from rock (siltstone and/or sandstone). Pockets of high plasticity clay noted. 6-8 Notes: 1. .Roots from surface vegetation extend downward about 4 inches. .2. No seepage or groundwater encountered. . TP-5 (Excavated on February 6, 2003) Elevation: 588 ft Depth Cft) I Soil P~ofile Description 0-2 Loosely structured SILT (MH); clayey, dark brown, damp, very friable, medium to high plasticity. Fine organics noted throughout. 2 - 3 Stiff CLAY (CH); some gravel, gray, damp to moist,. stiff, high plasticity. The soil has a blocky structure and shows evidence of past shrink/swell. . 3 - 4 Stiff SIL T/CLAY;very sandy witlJ rock fragments, rust brown (iron- stained), damp. The soil appears to have weathered from rock (siltstone and/or sandstone). Pockets of high plasticity clay noted. 4 - 5 Weathered ROCK (siltstone/sandstone); silty and sandy with fragments of very hard rock, light brown; damp. The consistency of the formation relative to soil is "hard." Notes: 1. Roots from surface vegetation extend downward about 4 inches. 2. No seepage or groundwater encountered. TP-6 (Excavated on February 6,2003) Depth Cft) Soil Profile Description. Elevation: 594 ft 0-2 Loosely structured SILT (MH); clayey, dark brown, damp, very friable, medium to high plasticity. Fine organics noted throughout. Stiff CLAY (CH); some gravel, gray, damp, stiff, very high plasticity. The soil has a blocky structure and shows evidence of past shrink/swell. Stiff SILT/CLAY; very sandy with rock fragments, rust brown (iron- stained), damp. The soil appears to have weathered from rock (siltstone and/or sandstone). Pockets of high plasticity clay noted. Weathered ROCK (siltstone/sandstone); silty and sandy with fragments of very hard rock, light brown, damp. The consistency of the formation relative to soil is "hard." 2-3 3-4 4-5 Notes: 1. Roots from surface vegetation extend downward about 4 inches. 2. No seepage or groundwater encountered. Project Name: Project Number: Project Location: TEST PIT LOGS. Jasper Meadows Second Addition. 203.012 Sprin9field, Ore9on TP-7 (Excavated on February 6" 2003) Elevation: 579 ft Deoth (ft) 0-1 1-2 2-5 5-5Y2 ." TP-8 (Excavated on February 6, 2003) Deoth (ft) Soil Profile Descriotion Elevation: 565 ft 0-2 Loosely structLired SILT (MH); clayey, dark brown, damp, very friable, medium to high plasticity. Fine organics noted throughout. Stiff CLAY (CH); some gravel, gray, damp, stiff, very high plasticity. The soil has a blocky structure and shows evidence of past shrink/swell. Stiff SILT/CLAY; very sandy with rock fragments, rust brown (iron- stained), damp. The soil appears to have weathered from rock (siltstone and/or sandstone). Pockets of high plasticity clay noted. Weathered ROCK (siltstone/sandstone); silty and sandy with fragments of very hard rock, dark brown to gray, dry to damp. The consistency of the formation relative to soil is "hard.a 2-3 3-4. 4-5 Notes: 1. Roots from :surface vegetation extend downward about 4 inches. 2. Perched water from runoff noted above 2 ft. TP-9 (Excavated on February 6,2003) Elevation: 565 ft Deoth (ft) I Soil Profile Descriotion 0-2 Loosely structured SILT (MH); clayey, dark brown, damp, very friable, medium to high plasticity. Fine organics noted throughout. 2 - 3 Stiff CLAY (CH); some gravel, gray, damp, stiff, very high plasticity. The soil has a blocky structure and shows evidence of past shrink/swell. 3 - 4 Weathered ROCK (siltstone/sandstone); silty and sandy wi~h pockets of high plasticity clay, dark brown to gray, dry to damp. A large boulder or outcrop of hard rock at 4 ft prevents continued excavation. Notes: 1. Roots from surface vegetation extend downward about 4 inches. 2. No seepage or groundwater encountered. TEST PIT LOGS Project Name: ProjeCt Number: Project Location: Jasper Meadows Second Addition 203.012 Springfield, Oregon r ~ TP-10 (Excavated on February 6,2003) Deoth (ft) Soil Profile Descriotion Elevation: 575 ft 1-3Y2 Loosely structured SILT (MH); clayey, dark brown, damp to moist, very friable, medium to high plasticity. Fine organics noted throughout. Stiff CLAY (CH); gray, moist to wet, medium stiff to stiff, very high plasticity. The soil is highly fissured and shows evidence of past shrink/swell. Scattered gravels contained within the soil matrix. Stiff SILT/CLAY; very sandy' with rock frC)gments, rust brown (iron- stained), damp. The soil appears to have weathered from rock (siltstone and/or sandstone). Pockets of high plasticity clay noted. ~ ~ , 0-1 3Y2 - 6 Notes: 1. Roots from surface vegetation extend downward about 4 inches. 2. No seepage or groundwater encountered. TP-11 (Excavated on February 6, 2003) Elevation: 586 ft Deoth (ft) I Soil ~rome Descriotion 0- 1 Loosely structured SILT (MH); clayey, dark brown, damp, very friable, medium to high plasticity. Fine organics noted throughout. 1 - 2Y2 Stiff CLAY (CH); some gravel, gray, damp, stiff, very high plasticity. The soil has a blocky structure and shows evidence of past shrink/swell. Stiff' SILT/CLAY; very sandy with rock fragments, rust brown (iron- stained), dry to damp. The soil appears to have weathered from rock (siltstone and/or sandstone). Pockets of high plasticity clay noted. Weathered ROCK (siltstone/sandstone); silty and sandy with fragments of very hard rock, dark brown to gray, dry. The consistency of the formation relative to soil is "hard.. '.~ c ! ~ 2Y2;.... 3 3-4 ' Notes: 1. Roots from surface vegetation extend downward about 4 inches. 2. No seepage or groundwatar encountered. TP-12 (Excavated on February 6,2003) Deoth (ft\ Soil Profile Descriotion Elevation: 572 ft 0-2 Loosely structured SILT (MH); clayey, dark brown, wet, very friable, medium to high plasticity. Fine organics noted throughout. Sample S-12- 1 taken at about 1 ft. Stiff CLAY (CH); some gravel, gray, damp, stiff, very high plasticity. The soil has a blocky structure and shows evidence of past shrink/swell. Weathered ROCK (siltstone/sandstone); silty and sandy with pockets of high plasticity clay, dark brown to gray, dry to damp. A large cobble or rock outcrop at 4Y2 ft prevents continued excavation. 2-3 3-4Y2 Notes: 1. Roots from surface vegetation extend downward about 4 inches. 2. The area is located near a ditch and the ground surface is very wet. ~+ ~ '8 \ '8-a;<j ~, ~~"""V, ~~~.01~ "'. .., ~ - 'NG "AGEWAY -----. . . . 4' \11 'I/IDn\ 60.00' PUBLIC DRAINAGE . EASEMENT PER CC&R'S ~ 9H_ iL- ~Y LINE :g ~ g. ~.~ ~8 g~ 2l~ ~~ 8S 2l ;ISTERED ESSIONAL St:lRVEYOR ~?d/: r 18, 1981 W. BAKER 1978 12/31/05 0: 5/6" REBAR :sr NO. 10954 e ^v .............-........... ...... (ii' . ; EXlSTINC.-l 7.00'P.U.E. \ -- COMMON AREA '\ 7.00' P.U.E. ~\ DEDICATED HEREON ~-::P \ ~ '" "', " , lOT 144 74,OJ2 S.F.. 160.00' PUBLIC - DRAINAGE EASEMENT PER CC&R'S COMMON AREA \5 N89'48'06"E '" 0. 15.60' 208.04' ~CA'c1(tj~".211~~~c1 ~~,,~ ~'&a ",'?' .~.~ I " C11 I CI2 I CI3 I CI4 I CI5 I. C16 I C17 I C18 I CI9 I C20 I C21 I C22 I C23 C24 C25 i C26 ~. C27 '1- ~ ~ ." I C3J 0 I C32 b I C33 .,,; I C34 a '" ,I C38 ~ I C39 I C40 I C41 I C42 I C43 I C44 I C45 I C46 C47 I C48 I C49 I C50 1 C51 I C52 I C53 I C54 I C55 L C56 (A < ~ VI II> VI II> -g 4 177.06' ~ N69'46'D6"E OR CH 1.0 Ul 'Ul in Ul 0 0 0 0 0>0 <00 <0 0 <0 O' 0>..1 lOT 116 0 ..I lOT 117 0 ..I lOT 116. oJ <... ...... (, ~.. b ....... o ,...A~ ... ... 6.096 S.F. 0'" 6,120 S.F. 0'" 6.120 S.F. 0 '" . .... '~ ' .... ' .... '" '" '" '" r o o VI 60.00' i6.00' 60.00' N69'46'06"E . 66.00' 60.00' 56.26.-.... 56.26' 329.76' 67.50' 60.00' VI O. <00 ",..I Ul' o <00 P :: lOT 122 ~ ~ lPD~<o g lOT 124 Ul <0 0 o 0 (, ..I .;. .... "'. lOT 121 lOT 129 . 6,443 S.F. 60.00' 60.00r .60.00' 60.00' 60.00' 60.00' 529.39' 76.60" 60.00' 60.00' )47.42' 156.22' LOT 136 \ 6.203 S.F. ~ gZ ~ ~ i5 ~ Z lOT 143 '1. \~ \ 0> 0 (D (D 0 (D 0 0> 0 0> 0 0> g 9197 SF \.:i ~ :: lOT 137 <0:: lOT 13B !O:: lOT 139 !":: LOT 140 !":: lOT 141 !O:: lOT 142 !" ..I 1 ,.,0'06' '" . '\:.; "! ~ 5.360 S.t. ~ ~ 5.367 S.F. ~ ~ 5.374 S.F. e; ~ 5,361 S.F. ~ ~ 5.366 S.F. g; 'i. 5.J95 S F ~ ~ 21~00' ,"f, . .'v'" 5 1..." ~ ~ loD'2..'L ~ l.oO'?::iO ~ lDeAlD ~ \.ot)'Ot) ~ lcO..DlD .;, \.oD':l2.';' 1i"1l11~~~.~~' .,.".~ot> If.\ .!'~~~~.9' '- 39.7L J iO.oo' _ _ iO.oo' _ _ iO.oo' _ _ .,.!O:2Q' _ _ iO:2Q' _ _ :o~80' _ €~3..o~_- . ~o, ~.t. .~. L ~ C40 :~' ."(- 7.00' P.U.E. N69'46'Oi;"E 412.02' I \ . . D~~I~:~D 457.50' QUARTZ AVE. C41 . . N69'46'06"E 665.54' ... PU8l1C TEMPORARY TURNAROUND EASEMENT PU8l1C SLOPE ASEMENT 15.03' (CHORD DISTANCE) (( I L 30.00' N69'46'06"E ~ 45.64' ~U~O".l.A'm:."e:- ,2258.21' 796.60' FOUND: 5/6. REBAR PER CSF NO. 10954 , -~. 'J 1 c3 engineering . K & A Engineering, Inc. P.o. Box 23624, Eugene, OR 97402 . 521 Market St., Suite B, Eugene, OR 97402 (541) 684-9399 Voice (541) 684-9358 FAX January 6, 2005 ,.' Project: 74.04 . c Hayden Homes 2464 SW Glacier Place, Suite 110 Redmond, OR 97756 Subject: General Foundation Drainage Recommendations jasper Meadows Subdivision - 2nd Addition . Springfield, Oregon .' PURPOSE AND SCOPE - . . This letter provides additional recommendations for drainage for the construction of single-family residences at the subject new subdivision. These are intended to supplement recommendations provided in the original geotechnical report provided by Boire Associates, which included general construction criteria for development of the project site. SITE CONDITIONS. As documented in our summary report of September 20, 2004, the gently sloping site had from 1 to 3-feet of gray plastic silts' over weathered yellow/tan tuffaceous sandstone. . . . . . . EXcavation for the foundation pads consisted of benches cut into the slope with cuts as high as 4-feet. K & A Engineering, Inc. witnessed excavation and provided on-site recommendations so that all foundation cuts were made to suitable subgrade soils or bedrock. . . . After excavation and grading of sUbgrade to undisturbed soils/rock,: 10 to 24-inches of granular fills were placed on the' foundation subgrade and compacted." . Groundwater was not encountered in any of the excavations except at the lower elevation of the project in the . road subgrade~ FOUNDATION DRAINAGE RECOMMENDATIONS . . Since a significant amount of low penneability, dense granular fill will support foundation loads on the underlying native soils and rock,. if groundwater were present above the excavation grade it is likely that the granular fill 'could trap and isolate water in the foundation excavation. ConventionaHooting drains would not remove this water because it would be below the footing grade. . . ( : .. K & A Engineering, Inc. As a precaution to avoid the possibility of trapping water below the foundation, we recommend that low point drains be installed in the crawlspaces with the inlet at subg~de level. This will effectiveJydrai~ the entire foundation. This low point drain can replace the recommended conventional footing drains. ' The low point drain should be constructed at the base of a small well excavated in the granular fill. The sides of the well should be uniform with a slope not exceeding 2 horizontal to 1 vertical. The inlet pipe should be covered with some sort of grate or galvanized screen to prevent fines from entering into the drain system. The low point drain should be located in the crawlspace as close to the downhill side of the foundation as possible. Additionally, we recommend that the final grading at the surface between houses slope to a gentle swale that routes surface runoff away from the foundation to the street or to an approved stann drain collector. The swale should have a total drop of at least 1-foot. Thank you for the opportunity to be of service. Please call if you have any questions. Sincerely, Michael Remboldt, P.E. K & A Engineering, Inc. Project: 74.04 Jasper Meadows Subdivision Phase II, Springfield, OR Client Hayden Homes Page 2 of 2 January 6, 2005 .. ';' ...