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HomeMy WebLinkAboutSoils Report_1.pdf irCTLITHOMPSON INCORPORATED SOILS AND FOUNDATION INVESTIGATION SINGLE FAMILY RESIDENCE 1414 MORAINE DRIVE LOT 7, FILING 1 DAUPHINAIS-MOSELEY SUBDIVISION VAIL, COLORADO Prepared For: 1414 MORAINE DRIVE LTD PO Box 6500 Vail, Colorado Attention: Brian Gillette Project No. SU01201-120 May 26, 2016 1790 Airport Road, Unit 2, Breckenridge, Colorado 80424 Telephone: 970-453-2047 www.ctlthompson.com TABLE OF CONTENTS SCOPE 1 SUMMARY OF CONCLUSIONS 1 SITE CONDITIONS 2 PROPOSED CONSTRUCTION 2 SUBSURFACE CONDITIONS 3 GEOLOGY 3 SITE EARTHWORK 4 Structural Fill 5 FOUNDATIONS 6 SLABS-ON-GRADE 7 FOUNDATION WALLS 8 Foundation Wall Backfill 9 SUBSURFACE DRAINAGE 9 CONCRETE 10 SURFACE DRAINAGE 11 CONSTRUCTION OBSERVATIONS 12 GEOTECHNICAL RISK 13 RADON 13 LIMITATIONS 14 FIGURE 1 —VICINITY MAP FIGURE 2 —LOCATIONS OF EXPLORATORY BORINGS FIGURE 3—SUMMARY LOGS OF EXPLORATORY BORINGS FIGURE 4—EXTERIOR FOUNDATION WALL DRAIN TABLE I — LABORATORY TEST RESULTS 1414 MORAINE DRIVE LTD 1414 MORAINE DRIVE LOT 7, FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL I THOMPSON PROJECT NO.SU01201-120 S:\PROJECTS\SU01201.000-1414 Moraine Drive\120\2.Reports\R1\SU01201-120 R1.docx SCOPE This report presents the results of our Soils and Foundation Investigation for the proposed residence at 1414 Moraine Drive on Lot 7, Filing 1 , Dauphinais- Moseley Subdivision in Vail, Colorado. We conducted this investigation to evaluate subsurface conditions at the site and provide geotechnical engineering recommen- dations for the proposed residence. Our report was prepared from data developed during our field exploration, engineering analysis, and experience with similar condi- tions. This report includes a description of the subsurface conditions observed in our exploratory pits and presents geotechnical engineering recommendations for de- sign and construction of the residence foundations, floor systems, and details influ- enced by the subsoils. The scope was described in a Service Agreement (SU-16- 0136, dated April 14, 2016). Recommendations contained in this report were developed based on our un- derstanding of the planned construction. If plans differ significantly from the descrip- tions contained in the report, we should be informed so that we determine whether our recommendations and design criteria are appropriate. A summary of our conclu- sions is presented below. SUMMARY OF CONCLUSIONS 1. Subsurface conditions encountered in our exploratory borings con- sisted of 2 to 6 inches of"topsoil" underlain by silty, sandy gravel with cobbles and boulders. Practical drill refusal was encountered at depths of 2 and 8 feet. The refusals were encountered on boulders or hard bedrock. Free water was not encountered in either boring during our investigation. 2. We anticipate that excavations for the new residence will result in natu- ral gravel and possibly bedrock being the predominant material at an- ticipated foundation elevations for the residence. The residence can be constructed on footing foundations supported by undisturbed, natu- ral soils and/or bedrock. Design and construction criteria are presented 1414 MORAINE DRIVE LTD 1 1414 MORAINE DRIVE LOT 7,FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL I THOMPSON PROJECT NO.SU01201-120 S\PROJECTS\SU01201 000-1414 Moraine Drive\120\2.Reports\R1\SU01201-120 R1.Eocx in the report. It is critical that we observe the excavation to check whether conditions are as anticipated, prior to placing footings. 3. Surface drainage should be designed to provide for rapid removal of surface water away from the building. 4. The design and construction criteria for foundations and floor systems in this report were compiled with the expectation that all other recom- mendations presented related to surface and subsurface drainage, landscaping irrigation, backfill compaction, etc. will be incorporated into the project and that home owners will maintain the structure, use pru- dent irrigation practices and maintain surface drainage. It is critical that all recommendations in this report are followed. SITE CONDITIONS The site is located at 1414 Moraine Drive in Vail, Colorado as shown on Fig- ure 1. The property is bordered by developed residential lots to the northeast and southwest, Moraine Drive to the northwest, and open space to the southeast. The ground surface in the building area slopes at 5 to 10 percent down to the southwest. The far southeast portion of the lot slopes steeply down to the southeast. Ground cover consists of grasses and weeds. Some disturbance to the ground surface was noted. PROPOSED CONSTRUCTION The proposed residence will be a two-story structure with an attached garage. The lower level and garage floors will be slab-on-grade. Wood frame construction will be used above grade with cast-in-place concrete foundation walls below grade. Required cuts for foundation excavations are not expected to exceed 5 or 6 feet. Foundation loads are expected to be about 1,000 to 3,000 pounds per linear foot of foundation wall, with maximum column loads of 40 kips or less. 1414 MORAINE DRIVE LTD 2 1414 MORAINE DRIVE LOT 7.FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL I THOMPSON PROJECT NO.SU01201-120 S\PROJECTS\SU01201.000-1414 Moraine Drive\120\2.Reports\R1\SU01201-120 RI.docx SUBSURFACE CONDITIONS Subsurface conditions were investigated by drilling two exploratory borings at the approximate locations shown on Figure 2. Our representative observed drilling, recorded the soils encountered and collected samples. Summary logs of the borings are presented on Figure 3. Subsurface conditions generally consisted of 2 to 6 inches of"topsoil" overly- ing silty, sandy gravel with cobbles and boulders. Practical drill refusal was encoun- tered at depths of 2 and 8 feet. Multiple refusals were encountered in each boring, as noted on Figure 3. The refusals were caused by either boulders or hard sand- stone bedrock. No free water was encountered in either boring during our investiga- tion. Samples obtained in the field were returned to our laboratory where field clas- sifications were checked and samples were selected for pertinent testing. Our labor- atory testing is summarized in Table I. GEOLOGY We reviewed the following geologic mapping showing the site. 1. Geologic Map of the Vail West Quadrangle, Eagle County, Colorado (Map MF-2369) by Scott, Lidke, and Grunwald with the U.S. Geologi- cal Survey, 2002. The site is mapped as Bull Lake Till (Qtb), consisting of unsorted, boulder gla- cial deposits. Bedrock of the Minturn Formation is mapped nearby. Our field inves- tigation and observations at the site generally support the mapping. We did not ob- serve geologic constraints on this site that would inhibit the planned construction. 1414 MORAINE DRIVE LTD 3 1414 MORAINE DRIVE LOT 7,FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL I THOMPSON PROJECT NO.SU01201-120 S'.\PROJECTS\SU01201.000-1414 Moraine Drive\120\2.Reports\R1\SU01201-120 R1 docx Covering the ground with houses, streets, driveways, patios, etc., coupled with lawn irrigation and changing drainage patterns, leads to an increase in subsur- face moisture conditions. It is critical that all recommendations in this report are fol- lowed to increase the chances that the foundations and slabs-on-grade will perform satisfactorily. After construction, the homeowner must assume responsibility for maintaining structures and use appropriate practices regarding drainage and land- scaping. SITE EARTHWORK Our subsurface information indicates that excavations for the residence will be mostly in gravel soils and possibly sandstone bedrock. We should observe the excavation to confirm whether subsurface conditions are as anticipated. We antici- pate excavation of the soils can be accomplished using conventional, heavy duty ex- cavating equipment. Hard cobbles and boulders should be expected. Some boul- ders may be large. A hydraulic hammer chisel (excavator attachment) or similar de- vice may be required to split large boulders. Sides of excavations need to be sloped to meet local, state and federal safety regulations. The soils will likely classify as Type C soils based on OSHA standards governing excavations, with a maximum allowable sidewall slope of 11%:1 horizon- tal:vertical. Some sloughing of the excavation face may occur as the soils dry out. Con- tractors should identify the soils encountered and ensure that applicable standards are met. Contractors are responsible for site safety and maintenance of the work site. No groundwater was encountered in our borings. Some seepage may occur during foundation excavation, particularly if it occurs during seasonal runoff. The 1414 MORAINE DRIVE LTD 4 1414 MORAINE DRIVE LOT 7,FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL THOMPSON PROJECT NO.SU01201-120 S\PROJECTS\SU01201.000-1414 Moraine Drive\120\2.Reports\R1\SU01201-120 R1.docx footing areas should be protected from any seepage and precipitation through the use of shallow trenches and sumps. Excavations should be sloped to a gravity dis- charge or to a temporary sump where water can be removed by pumping, if neces- sary. Structural Fill We do not anticipate that structural fill will be needed below foundations. However, removal of boulders, or over ripped bedrock sometimes requires place- ment of structural fill to re-establish subgrade elevation. The on-site soils, free of or- ganic matter, debris and rocks larger than 6 inches in diameter, can be used as structural fill. Care should be taken during fill placement so the larger rocks do not become nested or grouped together. If required, import fill should consist of CDOT Class 1 structural fill or CDOT Class 4, 5 or 6 aggregate base course or similar soil. Structural fill should have no rocks larger than 6 inches. We can evaluate potential fill materials upon request. Lean-mix concrete (flowable fill) could also be used to fill voids. The onsite soils with higher levels of silt or clay are moisture sensitive and it may be difficult to achieve proper compaction. Proper moisture content and pro- cessing is imperative to attain suitable compaction levels and reduce potential settle- ment. Structural fill should be placed in thin loose lifts, moisture conditioned to within +/-2 percent of optimum moisture content, and compacted to at least 98 per- cent of ASTM D 698 maximum dry density. Moisture content and density of struc- tural fill should be tested by a representative of our firm during placement. 1414 MORAINE DRIVE LTD 5 1414 MORAINE DRIVE LOT 7,FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL I THOMPSON PROJECT NO.SU01201-120 S:\PROJECTS\SU01201.000-1414 Moraine Drive1120\2.Reports\R1\SU01201-120 RI rlocx FOUNDATIONS The residence can be supported on footing foundations on the undisturbed, natural soils and/or bedrock. Prior to concrete placement, the footing areas should be moistened and compacted to provide a flat and level subgrade. Loose and dis- turbed soils should be removed or compacted. Structural fill, if required, should be tested by our representative and meet the criteria in the Structural Fill section. Our representative should observe conditions exposed in the completed foundation ex- cavation to confirm whether the exposed soils are as anticipated and suitable for support of the foundation as designed. 1. The proposed residence can be supported by footing foundations sup- ported on the undisturbed, natural soils and/or properly compacted fill. Soils loosened during the forming process for the footings should be removed or re-compacted prior to placing concrete. 2. Footings can be sized using a maximum allowable soil pressure of 3,000 psf. A coefficient of sliding friction of 0.45 may be used to resist sliding. Based on our experience in the area, we expect settlement of footings designed and constructed as discussed will be approximately 1 inch or less. 3. Continuous wall footings should have a minimum width of at least 16 inches. Foundations for isolated columns should have minimum di- mensions of 24 inches by 24 inches. Larger sizes may be required, depending upon foundation loads. 4. Grade beams and foundation walls should be well reinforced, top and bottom, to span undisclosed loose or soft soil pockets and resist lateral earth pressures. We recommend reinforcement sufficient to span an unsupported distance of at least 10 feet. Reinforcement should be de- signed by the structural engineer. 5. The soils under exterior footings should be protected from freezing. We recommend the bottom of footings be constructed at a depth of at least 42 inches below finished exterior grade. 1414 MORAINE DRIVE LTD 6 1414 MORAINE DRIVE LOT 7,FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL I THOMPSON PROJECT NO.SU01201-120 S:\PROJECTS\SU01201.000-1414 Moraine Drive\120\2.Reports\R1\SU01201-120 RI tlocx SLABS-ON-GRADE A slab-on-grade floor is desired. Based on our laboratory test data and expe- rience, we judge slab-on-grade construction supported by the undisturbed, natural or properly placed granular structural fill will have a low risk of damaging differential movement. Fill placed to attain subgrade elevations below floor slabs should be placed in accordance with the recommendations outlined in Structural Fill. We rec- ommend the following precautions for slab-on-grade construction at this site. These precautions will not prevent movement from occurring; they tend to reduce damage if slab movement occurs. 1. Slabs should be separated from exterior walls and interior bearing members with slip joints which allow free vertical movement of the slabs. 2. Underslab plumbing should be pressure tested for leaks before the slabs are constructed. Plumbing and utilities which pass through slabs should be isolated from the slabs with sleeves and provided with flexi- ble couplings. 3. Frequent control joints should be provided, in accordance with Ameri- can Concrete Institute (ACI) recommendations, to reduce problems as- sociated with shrinkage and curling. 4. We recommend a 4-inch layer of clean gravel be placed beneath the slabs to provide a flat, uniform subgrade. This material should consist of minus 2 inch aggregate with at least 50% retained on the No. 4 sieve and less than 2% passing the No. 200 sieve. To prevent water from collecting below the slabs, the underslab gravel should be con- nected to the perimeter underdrain system on the downhill side of the building. Typically this can be accomplished at the lower level frost wall footing step. We can provide additional recommendations for drain system layout upon request. 5. The International Residential Code (IRC R506) states that a 4-inch base course layer consisting of clean graded sand, gravel, crushed stone or crushed blast furnace slag shall be placed beneath below grade floors (unless the underlying soils are free-draining), along with a vapor retarder. 1414 MORAINE DRIVE LTD 7 1414 MORAINE DRIVE LOT 7,FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL I THOMPSON PROJECT NO.SU01201-120 S\PROJECTS\SU01201.000-1414 Moraine Drive\120\2.Reports\R1\SU01201-120 R1.docx IRC states that the vapor retarder can be omitted where approved by the building official. The merits of installation of a vapor retarder below floor slabs depend on the sensitivity of floor coverings and building use to moisture. A properly installed vapor retarder is more beneficial be- low concrete slab-on-grade floors where floor coverings, painted floor surfaces, or products stored on the floor will be sensitive to moisture. The vapor retarder is most effective when concrete is placed directly on top of it, rather than placing a sand or gravel leveling course be- tween the vapor retarder and the floor slab. Placement of concrete on the vapor retarder may increase the risk of shrinkage cracking and curling. Use of concrete with reduced shrinkage characteristics includ- ing minimized water content, maximized coarse aggregate content, and reasonably low slump will reduce the risk of shrinkage cracking and curling. Considerations and recommendations for the installation of vapor retarders below concrete slabs are outlined in Section 3.2.3 of the 2006 American Concrete Institute (ACI) Committee 302, "Guide for Concrete Floor and Slab Construction (ACI 302.R-96)". FOUNDATION WALLS Foundation walls which extend below-grade should be designed for lateral earth pressures where backfill is not present to about the same extent on both sides of the wall. Many factors affect the values of the design lateral earth pressure. These factors include, but are not limited to, the type, compaction, slope and drain- age of the backfill, and the rigidity of the wall against rotation and deflection. For a very rigid wall where negligible or very little deflection will occur, an "at-rest" lateral earth pressure should be used in design. For walls that can deflect or rotate 0.5 to 1 percent of wall height (depending upon the backfill types), lower "active" lateral earth pressures are appropriate. Our experience indicates typical below-grade walls in residences deflect or rotate slightly under normal design loads, and that this deflec- tion results in satisfactory wall performance. Thus, the earth pressures on the walls will likely be between the "active" and "at-rest" conditions. If on-site soils are used as backfill and the backfill is not saturated, we recom- mend design of basement walls at this site using an equivalent fluid density of at 1414 MORAINE DRIVE LTD 8 1414 MORAINE DRIVE LOT 7,FILING 1 ,DAUPHINAIS.MOSELEY SUBDIVISION CTL I THOMPSON PROJECT NO.5U01201-120 S:\PROJECTS\SU01201.000-1414 Moraine Drive\120\2.Reports\R1\SU01201-120 R1 Eocx least 50 pcf. This value assumes deflection; some minor cracking of walls may oc- cur. If very little wall deflection is desired, a higher design value is appropriate. Foundation Wall Backfill Proper placement and compaction of foundation backfill is important to re- duce infiltration of surface water and settlement of backfill. The natural soils can be used as backfill, provided they are free of rocks larger than 6 inches in diameter, or- ganics, and debris. The upper 2 feet of fill should be a relatively impervious material to limit infiltration. Backfill should be placed in thin loose lifts, moisture conditioned to within +1-2 percent of optimum moisture content, and compacted to at least 95 percent of ASTM D 698 maximum dry density. Backfill in landscape areas should be compacted to at least 90 percent of ASTM D 698 maximum dry density. Thick- ness of lifts will likely need to be reduced if there are small confined areas of backfill, which limit the size and weight of compaction equipment. Some settlement of the backfill should be expected even if the material is placed and compacted properly. In our experience, settlement of properly compacted backfill could be on the order of 0.5 to 1 percent of backfill thickness. Methods to reduce the risk of backfill settle- ment include conducting observation and testing during placement, using a granular material, and increasing the minimum compaction level. Moisture content and den- sity of the backfill should be tested during placement by a representative of our firm. Observation of the compaction procedure is necessary. Testing without observation can lead to undesirable performance. SUBSURFACE DRAINAGE Water from snow melt, precipitation and surface irrigation of lawns and land- scaping frequently flows through relatively permeable backfill placed adjacent to a residence, and collects on the surface of less permeable soils occurring at the bot- tom of foundation excavations. This process can cause wet or moist conditions in 1414 MORAINE DRIVE LTD 9 1414 MORAINE DRIVE LOT 7,FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL I THOMPSON PROJECT NO.SU01201-120 S'.\PROJECTS\SU01201.000-1414 Moraine Drive\120\2.Reports\R1\SU01201-120 R1 Eocx the lower level after construction. To reduce the likelihood water pressure will de- velop outside foundation walls and the risk of accumulation of water at the lower level, we recommend a foundation drain be installed. The drain should be installed along the entire lower level perimeter and at each level of excavation. The founda- tion drain will not prevent moist conditions in the lower level. The drain should consist of a 4-inch diameter, perforated or slotted pipe en- cased in free-draining gravel, and a geocomposite drain board or clean gravel layer extending to within 2 feet of exterior grade, adjacent to the walls. The drain should lead to a positive gravity outlet or sump where water can be removed by pumping. Sump pumps and gravity outlet locations must be maintained by the homeowner. A typical foundation drain detail for asement construction is presented on Figure 4. CONCRETE Concrete in contact with soil can be subject to sulfate attack. We measured the water-soluble sulfate concentration in a sample taken from the site at 0.06 per- cent. For this level of sulfate concentration, ACI 318-08 Code Requirements for Structural Concrete indicates there are no special requirements for sulfate re- sistance. Superficial damage may occur to the exposed surfaces of highly permeable concrete, even though sulfate levels are likely relatively low. To control this risk and to resist freeze-thaw deterioration, the water-to-cementitious materials ratio should not exceed 0.50 for concrete in contact with soils that are likely to stay moist due to surface drainage or high water tables. Concrete should have a total air content of 6 percent ± 1.5 percent. We advocate all foundation walls and grade beams in con- tact with the subsoils (including the inside and outside faces of garage and crawlspace grade beams) be damp-proofed. 1414 MORAINE DRIVE LTD 1 1414 MORAINE DRIVE LOT 7,FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL I THOMPSON PROJECT NO.SU01201-120 S-.\PROJECTS\SU01201 000-1414 Moraine Drive\120\2.Reports\RI\SU01201-120 RI docx SURFACE DRAINAGE Surface drainage is critical to the performance of foundations, floor slabs and concrete flatwork. Recommendations in this report are based on effective drainage for the life of the structure and cannot be relied upon if effective drainage is not maintained. We recommend the following precautions be observed during construc- tion and maintained at all times after construction is completed: 1. The ground surface surrounding the exterior of the building should be sloped to drain away from the building in all directions. We recom- mend providing a slope of at least 12 inches in the first 10 feet in land- scape areas. There are instances where this slope cannot be achieved. A slope of 6 inches in the first 10 feet should be used as a minimum. We recommend a slope of at least 3 inches in the first 10 feet in paved areas. A swale should be provided around the uphill side of the building to divert surface runoff. 2. Backfill around the exterior of foundation walls should be placed as de- scribed in Foundation Wall Backfill. Increases in the moisture content of the backfill soils after placement often results in settlement. Settle- ment is most common adjacent to north facing walls. Re-establishing proper slopes (homeowner maintenance) away from the building may be necessary. 3. Landscaping should be carefully designed to minimize irrigation. Plants used near foundation walls should be limited to those with low moisture requirements; irrigated grass should not be located within 5 feet of the foundation. Sprinklers should not discharge within 5 feet of the foundation and should be directed away from the building. 4. Impervious plastic membranes should not be used to cover the ground surface immediately surrounding the building. These membranes tend to trap moisture and prevent normal evaporation from occurring. Geo- textile fabrics can be used to control weed growth and allow some evaporation to occur. 5. Roof downspouts and drains should discharge well beyond the limits of all backfill. Splash blocks and/or extensions should be provided at all downspouts so water discharges onto the ground beyond the backfill. We generally recommend against burial of downspout discharge. Where it is necessary to bury downspout discharge, solid, rigid pipe 1414 MORAINE DRIVE LTD 11 1414 MORAINE DRIVE LOT 7,FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL I THOMPSON PROJECT NO,SU01201-120 S.\PROJECTS\SU01201.000-1414 Moraine Drive\12012.Reports\R1\SU01201-120 R1.tlocx should be used and it should slope to an open gravity outlet. Buried downspout discharge pipes should be heated (with thermostat) during winter months to prevent freezing. Downspout extensions, splash blocks and buried outlets must be maintained by the homeowner. 6. The design and construction criteria for foundations and floor systems were compiled with the expectation that all other recommendations presented in this report related to surface and subsurface drainage, landscaping irrigation, backfill compaction, etc. will be incorporated into the project. It is critical that all recommendations in this report are fol- lowed. CONSTRUCTION OBSERVATIONS This report has been prepared for the exclusive use of 1414 Moraine Drive LTD and the design/construction team for the purpose of providing geotechnical de- sign and construction criteria for the proposed project. The information, conclusions, and recommendations presented herein are based upon consideration of many fac- tors including, but not limited to, the type of structure proposed, the geologic setting, and the subsurface conditions encountered. The conclusions and recommendations contained in the report are not valid for use by others. Standards of practice evolve in the area of geotechnical engineering. The recommendations provided in this re- port are appropriate for about three years. If the proposed project is not constructed within about three years, we should be contacted to determine if we should update this report. We recommend that CTL I Thompson, Inc. provide construction observation services to allow us the opportunity to verify whether soil conditions are consistent with those found during this investigation. If others perform these observations, they must accept responsibility to judge whether the recommendations in this report re- main appropriate. 1414 MORAINE DRIVE LTD 12 1414 MORAINE DRIVE LOT 7,FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL'THOMPSON PROJECT NO.SU01201-120 S'.\PROJECTS\SU01201 000-1414 Moraine Drive112012.Reports\R11SU01201-120 RI tlocx GEOTECHNICAL RISK The concept of risk is an important aspect with any geotechnical evaluation primarily because the methods used to develop geotechnical recommendations do not comprise an exact science. We never have complete knowledge of subsurface conditions. Our analysis must be tempered with engineering judgment and experi- ence. Therefore, the recommendations presented in any geotechnical evaluation should not be considered risk-free. Our recommendations represent our judgment of those measures that are necessary to increase the chances that the structure will perform satisfactorily. It is critical that all recommendations in this report are fol- lowed during construction. The homeowner must assume responsibility for main- taining the structure and use appropriate practices regarding drainage and land- scaping. Improvements performed by the owner after construction, such as finishing a basement or construction of additions, retaining walls, decks, patios, landscaping and exterior flatwork, should be completed in accordance with recommendations in this report. RADON Radon is a gaseous, radioactive element that comes from the radioactive de- cay of uranium, which is commonly found in igneous rocks. Indoor radon levels in Eagle County are commonly above the recommended action level of 4 pCi/L as rec- ommended by the Environmental Protection Agency (http://county-radon.info/CO/Eacile.html). Testing for radon gas at the site is beyond the scope of this study. Due to the many factors that affect the radon levels in a specific building, accurate testing of radon levels is usually only possible after con- struction is complete. Typically, radon mitigation systems in this area consist of ven- tilation systems installed beneath lower level slabs and crawlspaces. The infrastruc- ture for such a mitigation system can normally be installed during construction at a relatively low cost, which is recommended. The building should be tested for radon 1414 MORAINE DRIVE LTD 13 1414 MORAINE DRIVE LOT 7,FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL I THOMPSON PROJECT NO.5U01201.120 S'\PROJECTS\SU01201.000-1414 Moraine Drive\12012.Reports\R1\SU01201-120 RI.docx once construction is complete. If test results indicate mitigation is required, the in- stalled system can then be used for mitigation. We are not experts in radon testing or mitigation. If the client is concerned about radon, then a professional in this spe- cial field of practice should be consulted. LIMITATIONS Our exploratory borings were located to provide a reasonably accurate pic- ture of subsurface conditions. Variations in the subsurface conditions not indicated by the borings will occur. A representative of our firm should observe placement of and test structural fill. We should observe the completed foundation excavation to confirm that the exposed soils are suitable for support of the footings as designed. This investigation was conducted in a manner consistent with that level of care and skill ordinarily exercised by geotechnical engineers currently practicing under similar conditions in the locality of this project. No warranty, express or implied, is made. If we can be of further service in discussing the contents of this report, ft() C1E074% CTL J THOMPSON, INC. r . �..c Revi- vc,1e Brendan P. Moran, El Gee r;- :enecke "' �1�9••• �` Staff Geotechnical Engineer Division Manager, ,i ,atilt + BPM:GWB (2 copies) cc: brian gillette(c�gillettellc.com 1414 MORAINE DRIVE LTD 14 1414 MORAINE DRIVE LOT 7,FILING 1 ,DAUPHINAIS-MOSELEY SUBDIVISION CTL I THOMPSON PROJECT NO.SU01201-120 S:IPROJECTS1SU01201.000-1414 Moraine Drive112012.Reporis1R11SU01201-120 R1.docx 4:11) T Not to scale 1,5 i` e Simb al 0c9' Conti G`�0* a a a Nv \,0°4 c1 Q;�a�P ?0 �utkehr Cree�P <)°.1/4\5Q�°P ,. r, Timber Ridge Village ■ - • `a�Q`.00Ct P - / `O(\ •' i Oa mUS Post Office m 0-.le' * I 0 0 42P 1 • `� Atwater on Gore Creek n . . . tions N' ' 'SO 4�1i , L eons Rage L50 �` V Property Location Eagle Point,,Resort •�� by BeaverXCreek ... `7' U`' Wes thavec% Donovan Pavilion it �e cD Wesfh 3 -vert Cir ri��� - `� Gore Cre' x,a r. _> /' m GQCe Yi May Palace -'f } EAGLE VAIL AIRPORT .�'/7 y LIMOUSINE._ : ..-2f�,`/ y / i ec�VVVVV O� � O�OS Oi � doba Mexican Eat" s,./<<k/<Ci 1 �G� A�Q�� VICINITY MAP Project No. SU01201-120 Figure 1 jr T Scale: 1 inch = 40 feet FOUND 5/8"RFBAR W/PLAS. CAP(P.C. Ivo, "*r,.. &P.L.S N0. 26626)(rep.) 0) ..,,,,, tz nOr v 4=1574'58" '-0"t i 1�C. R=221.86' \ RP L=59.70' '�', - \ �� CB=5510102"W - CH=59.51' LOT 4 *,Qrr / / N \ ck ,,,„.. LOT 5 T' - s'rzs,. `ss. N4 \ ,. , .''.'7?<? Si, — O. C-,\ ,moo, 1000 Nor \ LOTB rn �1 OT ` ' \ ,823 , . 51.' N FOU :"R :A�W N�. -488) CA- .5 LOT 9 \ 5 /.0 8090, „:2Z-------7--Z-7 / / \._,._, \ %; /\ LOCATIONS OF EXPLORATORY BORINGS Project No. SU01201—120 Figure 2 TH-1 TH-2 ELEV.=8133' ELEV.=8132' 8,135 8,135 fro 22/12 e fs7 we=11.2 irl DD123 -200=33 L n"I a 8,130 7ss o.Dc 8,130 m V' 24/12 0 fr wrmRefusals of I', DD=121.2 1S and 2' O -200=28 o z o 8,125 8,125 w Refusals at 7' twice and 8' 8,120 8,120 LEGEND: TOPSOIL; clayey sand, with roots, slightly moist, dark brown. 04 GRAVEL; silty, sandy, with cobbles and boulders, moist to very moist, medium dense to dense, Et% red—brown (GM) - Drive Sample; The symbol 50/12 indicates 50 blows of a 140—pound hammer falling 30 inches were - required to drive a 1i—inch I.D. sampler 12 inches. Disturbed bulk sample. Practical drilling refusal encountered at depth indicated. Refusals on boulders or bedrock. NOTES: 1. The borings were drilled on April 27, 2016 using 4—inch diameter continuous flight augers and a truck—mounted CME 45 drill rig. 2. No free water was observed in the borings at the time of drilling. Groundwater levels can fluctuate. 3. Boring locations as shown on Figure 2 were measured from site features and should be considered approximate. 4. Boring elevations are estimated from topography shown on Figure 2 and should be considered approximate. Relative elevations were checked by hand level. 5. These exploratory borings are subject to the explanations, limitations and conclusions contained In this report. i SUMMARY LOGS OF EXPLORATORY BORINGS Project No. SU01201-120 Figure 3 .................. .................. .................. SLOPE PER REPORT • •GEOCOMPOSITE WALL DRAIN OR 12 INCHES OF DRAIN GRAVEL. EXTEND TO WITHIN 1 TO 2 FEET ::: :•......::::::::� BELOW—GRADE WALL OF FINISH GRADE. DO NOT T ':.'" " `' EXTEND TO GROUND SURFACE SLOPE OR BRACE PER OSHA l:•:::•:::•: — BACKFI VAPOR RETARDER 6" MIN. / ' ' RECOMMENDED BY IRC. fr .,`.:: L './.:::•:•:••::•::•::::• SLIP JOINT COVER ENTIRE WIDTH OF , :..;•. ::,'::.:. :.' ::•; GRAVEL WITH NON—WOVEN -• ••• ' ' / LAB 0 GR D GEOTEXTILE FABRIC (MIRAFI r: ... . "t.• ••••• ............ :::: 140N OR EQUIVALENT). _ _ _y:_ _ ROOFING FELT IS AN f.:. ::.:: : ::::::: 0 DII if W / 00 0 Z0W pya « r < ) CO r ; o § 7 1- § (kyr & � DO o $ — m - OZ ( \ x § q H ] Cr) o0 25 - & E ) \ � . [ 3 \ Z > < _ � � & ( \ a & = I - - _ } \ ® m m mza / § S ( � a , / \ \ < z — a k gyre I § X 0 §