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HomeMy WebLinkAboutNORTHERN COLORADO FEEDERS SUPPLY - FDP - FDP140031 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTNo fill material shall be placed, spread or rolled while it is frozen, thawing, or dur- ing unfavorable weather conditions. When work is interrupted by heavy precipi- tation, fill operations shall not be resumed until the Geotechnical Engineer indi- cates that the moisture content and dry density of previously placed materials are as specified. 14. NOTICE REGARDING START OF GRADING The contractor shall submit notification to the Geotechnical Engineer and Owner advising them of the start of grading operations at least three (3) days in advance of the starting date. Notification shall also be submitted at least 3 days in ad- vance of any resumption dates when grading operations have been stopped for any reason other than adverse weather conditions. 15. REPORTING OF FIELD DENSITY TESTS Density tests performed by the Geotechnical Engineer, as specified under "Den- sity Tests above, shail be submitted progressively to the Owner. Dry density, moisture content and percent compaction shall be reported for each test taken. 16. DECLARATION REGARDING COMPLETED FILL The Geotechnical Engineer shall provide a written declaration stating that the site was filled with acceptable materials, or was placed in general accordance with the specifications. EMPIRE CARPENTRY A-4 300 HICKORY STREET CTL I T PROJECT NO. FCG6533.125 Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction operations shall be continued until slopes are stable, but not too dense for planting, and there is no appreciable amount of loose soil on the slopes. Compaction of slopes may be done progressively in increments of three to five feet (3' to 5') in height or after the fill is brought to its total height. Permanent fill slopes shall not exceed 3:1 (horizontal to vertical). 10. DENSITY TESTS Field density tests shall be made by the Geotechnical Engineer at locations and depths of his choosing. Where sheepsfoot rollers are used, the soil may be dis- turbed to a depth of several inches. Density tests shall be taken in compacted material below the disturbed surface. When density tests indicate that the dry density or moisture content of any layer of fill or portion thereof is below that re- quired, the particular layer or portion shall be reworked until the required dry density or moisture content has been achieved. 11. COMPLETED PRELIMINARY GRADES All areas, both cut and fill, shall be finished to a level surface and shall meet the following limits of construction: A. Overlot cut or fill areas shall be within plus or minus 2/10 of one foot. B. Street grading shall be within plus or minus 1/10 of one foot. The civil engineer, or duly authorized representative, shall check all cut and fill areas to observe that the work is in accordance with the above limits. 12. SUPERVISION AND CONSTRUCTION STAKING Observation by the Geotechnical Engineer shall be continuous during the place- ment of fill and compaction operations so that he can declare that the fill was placed in general conformance with specifications. All site visits necessary to test the placement of fill and observe compaction operations will be at the ex- pense of the Owner. All construction staking will be provided by the Civil Engi- neer or his duly authorized representative. Initial and final grading staking shall be at the expense of the owner. The replacement of grade stakes through con- struction shall be at the expense of the contractor. 13. SEASONAL LIMITS EMPIRE CARPENTRY A-3 300 HICKORY STREET CTL IT PROJECT NO. FC06533-125 7. MOISTURE CONTENT Fill materials shall be moisture treated. Clay soils placed below the building en- velope should be moisture -treated to between 1 and 4 percent above optimum moisture content as determined from Standard Proctor compaction tests. Clay soil placed exterior to the building should be moisture treated between optimum and 3 percent above optimum moisture content. Sand soils can be moistened to within 2 percent of optimum moisture content. Sufficient laboratory compaction tests shall be performed to determine the optimum moisture content for the vari- ous soils encountered in borrow areas. The Contractor may be required to add moisture to the excavation materials in the borrow area if, in the opinion of the Geotechnical Engineer, it is not possible to obtain uniform moisture content by adding water on the fill surface. The Con- tractor may be required to rake or disk the fill soils to provide uniform moisture content through the soils. The application of water to embankment materials shall be made with any type of watering equipment approved by the Geotechnical Engineer, which will give the desired results. Water jets from the spreader shall not be directed at the em- bankment with such force that fill materials are washed out. Should too much water be added to any part of the fill, such that the material is too wet to permit the desired compaction from being obtained, rolling and all work on that section of the fill shall be delayed until the material has been allowed to dry to the required moisture content. The Contractor will be permitted to rework wet material in an approved manner to hasten its drying. 8. COMPACTION OF FILL AREAS Selected fill material shall be placed and mixed in evenly spread layers. After each fill layer has been placed, it shall be uniformly compacted to not less than the specified percentage of maximum dry density. Fill materials shall be placed such that the thickness of loose material does not exceed 8 inches and the com- pacted lift thickness does not exceed 6 inches. Compaction, as specified above, shall be obtained by the use of sheepsfoot roll- ers, multiple -wheel pneumatic -tired rollers, or other equipment approved by the Engineer. Compaction shall be accomplished while the fill material is at the specified moisture content. Compaction of each layer shall be continuous over the entire area. Compaction equipment shall make sufficient trips to insure that the required dry density is obtained. 9. COMPACTION OF SLOPES EMPIRE CARPENTRY A-`Z 300 HICKORY STREET CTL I T PROJECT NO. FC06533-125 0 SAMPLE SITE GRADING SPECIFICATIONS DESCRIPTION This item shall consist of the excavation, transportation, placement and compac- tion of materials from locations indicated on the plans, or staked by the Engineer, as necessary to achieve building site elevations. 2. GENERAL The Geotechnical Engineer shall be the Owner's representative. The Geotech- nical Engineer shall approve fill materials, method of placement, moisture con- tents and percent compaction, and shall give written approval of the completed fill. 3. CLEARING JOB SITE The Contractor shall remove all trees, brush and rubbish before excavation or fill placement is begun. The Contractor shall dispose of the cleared material to pro- vide the Owner with a clean, neat appearing job site. Cleared material shall not be placed in areas to receive fill or where the material will support structures of any kind. 4. SCARIFYING AREA TO BE FILLED All topsoil and vegetable matter shall be removed from the ground surface upon which fill is to be placed. The surface shall then be plowed or scarified to a depth of 8 inches until the surface is free from ruts, hummocks or other uneven fea- tures, which would prevent uniform compaction by the equipment to be used. 5. COMPACTING AREA TO BE FILLED After the foundation for the fill has been cleared and scarified, it shall be disked or bladed until it is fret, from large clods, brought to the proper moisture content and compacted to not less than 95 percent of maximum dry density as deter- mined in accordance with ASTM D 698 or AASHTO T 99. 6, FILL MATERIALS On -site materials classifying as CL, SC, SM, SW, SP, GP, GC and GM are ac- ceptable. Fill soils shall be free from organic matter, debris, or other deleterious substances, and shall not contain rocks or lumps having a diameter greater than three (3) inches. Fill materials shall be obtained from the existing fill and other approved sources. EMPIRE CARPENTRY A-1 300 HICKORY STREET CTL I T PROJECT NO. FC06533-125 APPENDIX A SAMPLE SITE GRADING SPECIFICATIONS TABLE SUMMARY OF LABORATORY TESTING BORING DEPTH (FEET) MOISTURE CONTENT (%) ATTERBERG LIMITS PASSING NO.200 SIEVE (%) DESCRIPTION LIQUID LIMIT PLASTICITY INDEX TH-1 24 17.9 43 23 55 CLAYSTO NE, SANDY i TN 2 4 4.1 I I I 6 SAND, SILTY, GRAVELLY (Sivi) NEGATIVE VALUE INDICATES COMPRESSION. EMPIRE CARPENTRY 300 HICKORY LANE CTLIT PROJECT NO. FC06533.125 Page 1 of 1 :. .. .. . .. . . ' SSSS��--- ----- -- --- ------ ----- — -- -- -- -- — Cm SII C � �CCS�GCC�S�� C.�■�SS�C= CLAY (PLASTIC) TO SILT (NON -PLASTIC) ®Emrmm�,�® Sample of SAND, SILTY, GRAVELLY (SM) From TH - 2 AT 4 FEET EMPIRE CARPENTRY 300 HICKORY LANE CTL I T PROJECT NO. FCC8533-125 GRAVEL 35 % SAND 57 % SILT & CLAY 8 % LIQUID LIMIT % PLASTICITY INDEX % Gradation Test Results FIGURE 3 TH-1 TH-2 0 01 00, 3/ 12 5 00,00, D 4 30/12 10 .o ' =o 15 0 20 0 w w H tL w 0 5018 25 50/2 C 'n 30 'n 2 Z 35 c J A 40 45 EMPIRE CARPENTRY 300 HICKORY STREET CTL I T PROJECT NO. FC06533.125 LEGEND: IF ASPHALTIC CONCRETE (B-) CLAY, SANDY, MOIST TO VERY MOIST, SOFT, DARK BROWN (CL) SAND, GRAVELLY, WITH COBBLES, WET, MEDIUM DENSE, BROWN (SM, SP-SM, SW-SM) WEATHERED CLAYSTONE, SANDY, MOIST, FIRM, GRAY CLAYSTONE, SANDY, MOIST, FIRM TO HARD, BRAY (BEDROCK) DRIVE SAMPLE. THE SYMBOL 3112 INDICATES 3 BLOWS OF A 140-POUND HAMMER FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5-INCH O.D. SAMPLER 12 INCHES. LL SL WATER LEVEL MEASURED AT TIME OF DRILLING. S F a w O NOTES: 1. THE BORINGS WERE DRILLED ON MAY 9, 2014 USING 4-INCH DIAMETER CONTINUOUS -FLIGHT AUGERS AND A TRUCK -MOUNTED DRILL RIG. 2. THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN THIS REPORT. Summary Logs of Exploratory Borings FIGURE 2 APPROXIMATE SCALE: 1" = 50' 0, 25 50 LEGEND: TH-1 INDICATES APPROXIMATE LOCATION OF EXPLORATORY BORING WILLOX LN. SITE ICKORY ST. uj G,o Q n J � O U MULBERRY ST. (H 14) Ir ✓` - r'r '� �� F let. IN - r. VICINITY MAP FORT COLLINS AREA NOT TO SCALE TH-1 TH-2'r T'i , HICKORY STREET [i IF Locations of Exploratory Borings EMPIRE CARPENTRY FIGURE 1 300 HICKORY STREET CTL I T PROJECT NO. FC06533-125 We should observe footing excavations to confirm soils are similar to those found in our borings. Placement and compaction of fill, backfill, subgrade and other fills should be observed and tested by a representative of our firm during construc- tion. This report was prepared from data developed during our field exploration, laboratory testing, engineering analysis and experience with similar conditions. The recommendations contained in this report were based upon our understand- ing of the planned construction. If plans change or differ from the assumptions presented herein, we should be contacted to review our recommendations. We believe this investigation was conducted in a manner consistent with that level of skill and care ordinarily used by members of the profession currently practicing under similar conditions in the locality of this project. No warranty, ex- press or implied, is made. If we can be of further service in discussing the contents of this report or in the analysis of the proposed construction from the geotechnical point of view, please contact the undersigned. CTL I THOMPSON, INC. /J Thomas W. Finle/ Senior Geologist TW F:SAS (2 Copies) Via Email: empire@verinet.com Spencer Schram,"PE Project Manager EMPIRE CARPENTRY 7 300 HICKORY STREET CTL IT PROJECT NO. FC06533-125 SURFACE DRAINAGE Performance of foundations, flatwork and pavements are influenced by changes in subgrade moisture conditions. Carefully planned and maintained sur- face grading can reduce the risk of wetting of the foundation soils and pavement subgrade. Positive drainage should be provided away from foundations. Backfill around foundations should be moisture treated and compacted as described in Fill Placement . Roof drains should be directed away from buildings. Downspout extensions and splash blocks should be provided at discharge points. GEOTECHNICAL RISK The concept of risk is an important aspect with any geotechnical evalua- tion primarily because the methods used to develop geotechnical recommenda- tions do not comprise an exact science. We never have complete knowledge of subsurface conditions. Our analysis must be tempered with engineering judg- ment and experience. Therefore, the recommendations presented in any ge- otechnical 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 recom- mendations in this report are followed during construction. Home owners must assume responsibility for maintaining the structure and use appropriate practices regarding drainage and landscaping. Improvements performed by home owner after construction, such as finishing a basement or construction of additions, re- taining walls, decks, patios, landscaping and exterior flatwork, should be com- pleted in accordance with recommendations in this report. LIMITATIONS Although our borings were spaced to obtain a reasonably accurate picture of subsurface conditions, variations not indicated in our borings are possible. EMPIRE CARPENTRY t O 300 HICKORY STREET CTL I T PROJECT NO. FC06533-125 IT gravel leveling course between the vapor retarder and the floor slab. The placement of concrete on the vapor retarder may in- crease the risk of shrinkage cracking and curling. Use of concrete with reduced shrinkage characteristics including minimized water content, maximized coarse aggregate content, and reasonably low slump will reduce the risk of shrinkage cracking and curling. Con- siderations and recommendations for the installation of vapor re- tarders below concrete slabs are outlined in Section 3.2.3 of the 2006 report of American Concrete Institute (ACI) Committee 302, "Guide for Concrete Floor and Slab Construction (ACI 302.R1-04)". 3. If slab -bearing partitions are used, they should be designed and constructed to allow for slab movement. At least a 2-inch void should be maintained below or above the partitions. If the "float' is provided at the top of partitions, the connection between interior, slab -supported partitions and exterior, foundation supported walls should be detailed to allow differential movement. 4. Underslab plumbing should be eliminated where feasible. Where such plumbing is unavoidable it should be thoroughly pressure tested for leaks prior to slab construction and be provided with flex- ible couplings. Pressurized water supply lines should be brought above the floors as quickly as possible. 5. Plumbing and utilities that pass through the slabs should be isolat- ed from the slabs and constructed with flexible couplings. Where water and gas lines are connected to furnaces or heaters, the lines should be constructed with sufficient flexibility to allow for move- ment. 6. HVAC equipment supported on the slab should be provided with a collapsible connection between the furnace and the ductwork, with allowance for at least 2 inches of vertical movement. 7. The American Concrete Institute (ACI) recommends frequent con- trol joints be provided in slabs to reduce problems associated with shrinkage cracking and curling. To reduce curling, the concrete mix should have a high aggregate content and a low slump. If desired, a shrinkage compensating admixture could be added to the con- crete to reduce the risk of shrinkage cracking. We can perform a mix design or assist the design team in selecting a pre-existing mix. EMPIRE CARPENTRY 9 300 HICKORY STREET CTL IT PROJECT NO. FC06533-125 e ment cannot be tolerated, structural floors should be used. Structural floors can be considered for specific areas that are particularly sensitive to movement or where equipment on the floor is sensitive to movement. Where structurally supported floors are selected, we recommend a mini- mum void between the ground surface and the underside of the floor system of 4 inches. The minimum void should be constructed below beams and utilities that penetrate the floor. The floor may be cast over void form. Void form should be chosen to break down quickly after the slab is placed. We recommend against the use of wax or plastic -coated void boxes. Slabs may be subject to heavy point loads. The structural engineer should design floor slab reinforcement. For design of slabs -on -grade, we rec- ommend a modulus of subgrade reaction of 100 pci for on -site soils. If the owner elects to use slab -on -grade construction and accepts the risk of movement and associated damage, we recommend the following precautions for slab -on -grade construction at this site. These precautions can help reduce, but not eliminate, damage or distress due to slab movement. Slabs should be separated from exterior walls and interior bearing members with a slip joint that allows free vertical movement of the slabs. This can reduce cracking if some movement of the slab oc- curs. 2. Slabs should be placed directly on exposed soils or properly mois- ture conditioned, compacted fill. The 2009 International Building Code (IBC) requires a vapor retarder be placed between the base course or subgrade soils and the concrete slab -on -grade floor. 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 (10 mil minimum) is more benefi- cial below concrete slab -on -grade floors where floor coverings, painted floor surfaces or products stored on the floor will be sensi- tive to moisture. The vapor retarder is most effective when con- crete is placed directly on top of it, rather than placing a sand or EMPIRE CARPENTRY 8 300 HICKORY STREET CTL IT PROJECT NO. FC06533-125 4. The soils beneath footing pads can be assigned an ultimate coeffi- cient of friction of 0.4 to resist lateral loads. The ability of grade beam or footing backfill to resist lateral loads can be calculated us- ing a passive equivalent fluid pressure of 250 pcf. This assumes the backfill is densely compacted and will not be removed. Backfill should be placed and compacted to the criteria in the Fill Place- ment section of this report. 5. Exterior footings should be protected from frost action. We believe 30 inches of frost cover is appropriate for this site. 6. Foundation walls and grade beams should be well reinforced both top and bottom. We recommend the amount of steel equivalent to that required for a simply supported span of 10 feet. 7. We should observe completed footing excavations to confirm that the subsurface conditions are similar to those found in our borings. Occasional loose soils may be found in foundation excavations. If this occurs, we recommend the loose soils be treated as discussed in Item 1 above. Compacted fill should be tested for compliance. BELOW GRADE AREAS No below -grade areas are planned for the building. For this condition, pe- rimeter drains are not usually necessary. We should be contacted to provide foundation drain recommendations if plans change to include basement areas. FLOOR SYSTEMS In our opinion, it is reasonable to use slab -on -grade floors for the pro- posed construction. Any fill placed for the floor subgrade should be built with densely compacted, engineered fill as discussed in the Fill Placement section of this report. It is impossible to construct slab -on -grade floors with no risk of movement. We believe movements due to swell will be less than 1 inch at this site. If move - EMPIRE CARPENTRY 7 300 HICKORY STREET CTL IT PROJECT NO. FC06533-125 FOUNDATIONS Our investigation indicates soft clay and medium dense sand are present at the anticipated foundation levels. Spread footing foundations are considered appropriate for the conditions encountered. However, constructing the foundation on both materials will likely result in differential movement of the foundation and structure. Therefore, we recommend footings be either extended to the gravelly sand, or the clay removed and replaced to a minimum depth of 3 feet below foot- ings with compacted, granular fill. Design criteria for spread footing foundations developed from analysis of field and laboratory data and our experience are presented below. The builder and structural engineer should also consider design and construction details es- tablished by the structural warrantor (if any) that may impose additional design and installation requirements. Spread Footings Footings should be constructed on undisturbed natural gravelly sands or properly compacted granular fill (see the Fill Placement section of this report). All existing man -placed fill should be re- moved from under footings and within one footing width around footings and replaced with engineered fill. Where soil is loosened during excavation, it should be removed and replaced with on -site soils compacted following the criteria in the Fill Placement section of this report. 2. Footings constructed on the natural soils and/or engineered fill can be designed for a net allowable soil pressure of 2,000 psf. The soil pressure can be increased 33 percent for transient loads such as wind or seismic loads. 3. Footings should have a minimum width of at least 16 inches. Foundations for isolated columns should have minimum dimen- sions of 18 inches by 18 inches. Larger sizes may be required de- pending on loads and the structural system used. EMPIRE CARPENTRY 6 300 HICKORY STREET CTL I T PROJECT NO. FC06533-125 Site grading in areas of landscaping where no future improvements are planned can be placed at a dry density of at least 90 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). Example site grading spec- ifications are presentee in Appendix A. Water and sewer lines are often constructed beneath areas where im- provements are planned. Compaction of trench backfill can have a significant effect on the life and serviceability overlying structures. We recommend trench backfill be moisture conditioned and compacted as described in the Fill Place- ment section of this report. Placement and compaction of fill and backfill should be observed and tested by a representative of our firm during construction. Excavations The materials found in our borings can be excavated using conventional heavy-duty excavation equipment. However, some of the soils are soft and will be displaced if wheeled equipment is used in the excavations. We recommend wheeled traffic not be allowed in the excavations. Excavations should be sloped or shored to meet local, State and Federal safety regulations. Excavation slopes specified by OSHA are dependent upon types of soil and groundwater conditions encountered. The contractor's "competent person" should identify the soils and/or rock encountered in the excavation and refer to OSHA standards to de- termine appropriate slopes. Stockpiles of soils, rock, equipment, or other items should not be placed within a horizontal distance equal to one-half the excavation depth, from the edge of excavation. Excavations deeper than 20 feet should be braced or a professional engineer should design the slopes. EMPIRE CARPENTRY 55 300 HICKORY STREET CTL I T PROJECT NO. FC06533-125 ty. None of these hazards considered will preclude proposed construction. The following sections discuss geologic hazards that pertain to the associated devel- opment. Seismicity This area, like most of central Colorado, is subject to a low degree of seismic risk. As in most areas of recognized low seismicity, the record of the past earthquake activity in Colorado is incomplete. According to the 2009 International Building Code and the subsurface conditions encountered in our borings, this site probably classifies as a Site Class D. Only minor damage to relatively new, properly designed and built build- ings would be expected. Wind loads, not seismic considerations, typically govern dynamic structural design in this area. SITE DEVELOPMENT Fill Placement The existing onsite soils are suitable for re -use as fill material provided debris or deleterious organic materials are removed. Areas to receive fill should be scarified, moisture -conditioned and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D698, AASHTO T99). Fill placed on the upper sandy clay may be difficult to compact and may require a laver of granular material be crowded into soft soils and stabilized prior to fill placement Sandy soils used as fill should be moistened to within 2 percent of optimum mois- ture content. Clay soils should be moistened between optimum and 3 percent above optimum moisture content. The fill should be moisture -conditioned, placed in thin, loose lifts (8 inches or less) and compacted as described above. We should observe placement and compaction of fill during construction. Fill place- ment and compaction should not be conducted when the fill material is frozen. EMPIRE CARPENTRY 300 HICKORY STREET 4 CTL I T PROJECT NO. FC06533-125 140-pound hammer falling 30 inches. This method is similar to the standard penetration test, and is typical for local practice. Groundwater measurements were taken during drilling. Summary logs of the borings, including results of field penetration resistance tests, are presented on Figure 2. Samples obtained during drilling were returned to our laboratory and visu- ally examined by the geotechnical engineer for this project. Laboratory analyses included moisture content, dry density, swell -consolidation, unconfined compres- sive strength, Atterberg limits, and water-soluble sulfate tests. Results of labora- tory tests are presented on Figure 3 and summarized in Table A -I. SUBSURFACE CONDITIONS Materials encountered at the surface consisted of 8 inches of asphaltic concrete. Underlying the asphalt, 71/2 feet of soft clay was encountered in one boring. Gravelly sand was encountered in both borings below the clay or asphalt to about 20 feet. The clay was not found in the second boring. Claystone was encountered in both borings underlying the sand to the depths explored. The clay was found to be soft based on penetration resistance. The sands are considered to exhibit good bearing characteristics. The claystone is at a depth that is not likely to influence shallow foundations. Groundwater was encountered in the bor- ings at 7 and 71/2 feet below the existing ground surface. Existing groundwater levels are not expected to significantly affect site development, but may affect deeper excavations and fill placement. Further description of the subsurface conditions is presented on our boring logs (Figure 2) and in our laboratory test results. GEOLOGIC HAZARDS We considered potential geologic hazards for this investigations, including unstable slopes, rockfall, expansive soils, collapsible soils, erosion, and seismici- EMPIRE CARPENTRY 3 300 HICKORY STREET CTL I T PROJECT NO. FC06533-125 compacted granular fill. Foundation design and construction rec- ommendations are presented in this report. 3. The presence of expansive soils and bedrock, and possibly collaps- ing soils, constitutes a geologic hazard. There is risk that slabs -on - grade and foundations will heave or settle and be damaged. We believe the recommendations presented in this report will help to control risk of damage; they will not eliminate that risk. Slabs -on - grade and, in some instances, foundations may be damaged. 4. We believe a slab -on -grade floor is appropriate for this site. Some movement of slab -on -grade floors should be anticipated. We ex- pect movements will be minor, on the order of 1 inch or less. If movement cannot be tolerated, structural floors should be consid- ered. SITE CONDITIONS The site is located northeast of the intersection of Hickory Street and the Union Pacific Railroad in north Fort Collins, Colorado (Figure 1). An existing building is located at the footprint of the proposed building and is to be demol- ished. The lot is relatively flat and partly paved with asphaltic concrete. PROPOSED CONSTRUCTION Based on conversations with our client, we understand the proposed build- ing will be a 30-foot by 50-foot wood and steel -framed structure. No below grade construction is planned. INVESTIGATION Subsurface Investigation Subsurface conditions were investigated by drilling two borings to depths of approximately 25 and 30 feet. The approximate locations of the borings are shown on Figure 1. Our field representative observed drilling, logged the soils and bedrock found in the borings and obtained samples. Sampling was per- formed by driving a 2.5-inch O.D. modified California sampler with blows of a EMPIRE CARPENTRY 2 300 HICKORY STREET CTL I T PROJECT NO. FC06533-125 SCOPE This report presents the results of our Geotechnical Investigation for the proposed metal building in Fort Collins, Colorado. The purpose of the investiga- tion was to evaluate the subsurface conditions and provide foundation recom- mendations and geotechnical design criteria for the project. The scope was de- scribed in our Service Agreement (Proposal No. FC-14-0140, dated April 9, 2014). The report was prepared from data developed during field exploration, la- boratory testing, engineering analysis and experience with similar conditions. The report includes a description of subsurface conditions found in our explorato- ry borings and discussions of site development as influenced by geotechnical considerations. Our opinions and recommendations regarding design criteria and construction details for site development, foundation, floor system, slabs -on - grade, lateral earth loads, and drainage are provided. If the proposed construc- tion changes, we should be requested to review our recommendations. Our con- clusions are summarized in the following paragraphs. SUMMARY OF CONCLUSIONS Materials encountered at the surface consisted of 8 inches of as- phaltic concrete. Underlying the asphalt, 71/2 feet of soft clay was encountered in one boring. Gravelly sand was encountered in both boring and below the clay or asphalt to a depth of about 20 feet. Claystone was encountered in both borings underlying the sand to the depths explored. The clay was found to be soft based on pene- tration resistance. The sands are considered to exhibit good bear- ing characteristics. The claystone is at a depth that is not likely to influence shallow foundations. Groundwater was encountered in the borings at 7 and 71/2 feet below the existing ground surface. Ex- isting groundwater levels are not expected to significantly affect site development, but may affect deeper excavations and fill placement. 2. We believe the proposed structure can be constructed on a spread footing foundation placed on natural gravelly sand and/or properly EMPIRE CARPENTRY 300 HICKORY STREET CTL IT PROJECT NO. FC06533-125 r TABLE OF CONTENTS SCOPE 1 SUMMARY OF CONCLUSIONS 1 SITE CONDITIONS 2 PROPOSED CONSTRUCTION 2 INVESTIGATION 2 Subsurface Investigation 2 SUBSURFACE CONDITIONS 3 GEOLOGIC HAZARDS 3 Seismicity 4 SITE DEVELOPMENT 4 Fill Placement 4 Excavations 5 FOUNDATIONS 6 Spread Footings 6 BELOW GRADE AREAS 7 FLOOR SYSTEMS 7 SURFACE DRAINAGE 10 GEOTECHNICAL RISK 10 LIMITATIONS 10 FIGURE 1 — LOCATIONS OF EXPLORATORY BORINGS FIGURE 2 — SUMMARY LOGS OF EXPLORATORY BORINGS FIGURE 3 — GRADATION TEST RESULTS TABLE 1 — SUMMARY OF LABORATORY TESTING APPENDIX A — SAMPLE SITE GRADING SPECIFICATIONS EMPIRE CARPENTRY 300 HICKORY STREET CTL IT PROJECT NO. FC06533-125 CTLITHOMPSON GEOTECHNICAL INVESTIGATION PROPOSED METAL BUILDING 300 HICKORY STREET FORT COLLINS, COLORADO EMPIRE CARPENTRY PO Box 245 Belivue, Colorado 80512 Attention: Mr. Kevin Murray Project No. FC06533-125 May 21, 2014 351 Linden Street I Suite 140 1 Fort Collins, Colorado 80524 Telephone:970.206-9455 Fax:970-206-9441