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Home My WebLink AboutHARVEST PARK - Filed GR-GEOTECHNICAL REPORT/SOILS REPORT -c CTL/THOMPSON , INC . CONSULTING ENGINEERS GEOLOGIC AND PRELIMINARY GEOTECHNICAL INVESTIGATION RUFF PROPERTY SOUTHWEST COUNTY ROAD 9 AND HARMONY ROAD FORT COLLINS, COLORADO Prepared For: The Writer Corporation Northern Colorado Division PO Box 40 Windsor, Colorado 80550 Attention: Mr. Darwin Horan Job No. FC-1149 March 12, 1999 CTL./ ! HOMPSON, INC. CONSULTING ENGINEERS 375 E. HORSETOOTH RD. ® THE SHORES OFFICE PARK a BLDG.3.SUITE 201 • FT.COLLINS.CO 80525 970)206-9455 TABLE OF CONTENTS SCOPE 1 SUMMARY OF CONCLUSIONS 1 SITE CONDITIONS 2 PROPOSED DEVELOPMENT 3 SITE GEOLOGY AND GEOLOGIC HAZARDS 3 SUBSURFACE CONDITIONS 7 Natural Clays 8 Clayey Sands 8 Bedrock 9 Groundwater 9 SITE DEVELOPMENT 9 Grading 10 Slope Stability and Erosion 11 Underdrain 11 Utility Construction 13 Pavements 14 RESIDENTIAL CONSTRUCTION CONSIDERATIONS 14 Foundations 15 Slab-on-Grade and Basement Floor Construction 15 Basements 16 Surface Drainage 16 Concrete 17 LIMITATIONS AND ADDITIONAL INVESTIGATION 17 FIG. 1 - LOCATIONS OF EXPLORATORY BORINGS FIG. 2 - ELEVATION OF BEDROCK SURFACE FIG. 3 - CONTOURS OF BEDROCK DEPTH FIG. 4 - ESTIMATED GROUNDWATER ELEVATIONS FIG. 5 - CONTOURS OF DEPTH TO GROUND WATER FIGS. 6 THROUGH 9 -SUMMARY LOGS OF EXPLORATORY BORINGS FIGS. 10 THROUGH 16 -SWELL CONSOLIDATION TEST RESULTS FIGS. 17 AND 18 - GRADATION TEST RESULTS FIG. 19 - SEWER SUBDRAIN DETAIL TABLE I - SUMMARY OF LABORATORY TEST RESULTS APPENDIX A - GUIDELINE SITE GRADING SPECIFICATIONS L SCOPE This report presents the results of our geologic and preliminary geotechnical investigation for the Ruff property, located southwest of the intersection of County Road 9 and Harmony Road in Fort Collins, Colorado (Fig. 1). The site is planned for construction of single family residences, duplexes, townhomes, and a community area. Our investigation was performed to evaluate the site geology and subsurface conditions to evaluate how these conditions will likely impact development and residential construction at the site. The report includes descriptions of site geology, our opinions concerning the impact" of the geologic setting,on the proposed development, descriptions of the subsurface conditions found in our exploratory borings, and discussion of site development and construction as influenced by geotechnical considerations. The discussions in this report are based on our understanding of the planned development, conditions disclosed by exploratory drilling, review of geologic maps, site observation, results of laboratory tests, engineering analysis of field and laboratory data and our experience. The criteria presented in the report are intended fo,r planning purposes. Additional investigations will be required to design building foundations, floor systems and pavements. A summary of our conclusions is presented below. SUMMARY OF CONCLUSIONS 1.Subsurface conditions found in our borings generally consisted of up to 17 feet of moist to very moist,silty and sandy clays and 1 to 16 feet of medium dense to very dense, clayey and gravelly sands underlain by very hard, claystone bedrock at depths of 11 to more than 30 feet. Free groundwater was found at depths from 5 to 25 feet during drilling and when checked several days after drilling. 2.Swell-consolidation tests performed on selected clay and claystone samples from our borings indicated slight compression to moderate swell when wetted at an applied load of 1,000 psf. We anticipate all of the lots included in our investigation are characterized by low to moderate swell potential. THE WRITER CORPORATION RUFF PROPERTY 1CLT/T JOB NO. FC-1149 1 3. We found no geotechnical or geologic condition that would preclude development of the site for it's planned purpose. We believe the major geotechnical considerations at the site will be the potentially shallow groundwater and the low to moderately swelling soils and bedrock. We recommend basement floor elevations be set considering the groundwater bedrock elevations as discussed herein. 4.Preliminary information indicates spread footings with a minimum deadload pressure to resist swelling pressures of the soils and bedrock will be the predominant foundation type for townhomes planned in this development. We estimate less than 30 percent of the planned residences may require a deep foundation system such as drilled piers to resist uplift from the swelling soils and bedrock. A detailed soils and foundation investigation should be performed after overlot grading to determine the appropriate foundation type for each building and the design criteria. 5.Slab-on-grade basement floors are typically used on lots with soil conditions similar to those found at this site. Structurally supported floors are recommended in all ground floor finished living areas. Final design investigations may show structurally supported basement floors will be recommended in basements that will be finished within five years of completion. 6. . For planning purposes, we anticipate a composite pavement consisting of 4 inches of asphalt concrete over 6 inches of base course for local residential streets. For County Road 9 we expect 10 inches full depth asphalt or 6 inches HBP over 14 inches ABC. Alternatively, we anticipate 8 inches of Portland cement concrete pavement will be required on County Road 9. A detailed pavement and subgrade investigation should be performed in accordance with the City of Fort Collins standards after overlot grading is complete and utilities have been installed to confirm the appropriate pavement sections. 7.Control of surface drainage will be critical to the performance of foundations,slabs-on-grade and pavements. Surface drainage should be designed to provide rapid runoff of surface water away from the buildings. 8. We recommend installation of a subdrain system below sanitary sewers to help control rising groundwater in those areas with shallow ground water. Foundation drains should be anticipated for "crawl" spaces and basements. THE WRITER CORPORATION RUFF PROPERTY 2CLT/T JOB NO. FC-1149 1„ SITE CONDITIONS The site is approximately 105 acres located southwest of the intersection of Larimer County Road 9 and Harmony Road in Fort Collins, Colorado (Fig. 1). At the time of this investigation, the property was sparsely covered with native grasses and was being used for cattle grazing. The ground surface is relatively flat and generally slopes from west to east. Grading plans were not available at the time of this writing, however we anticipated minor cuts and fills of no greater than 2 to 3 feet. Land to the north and west is agricultural, with recently developed, completed and partially completed single family residences. Land to the east and south is generally agricultural land and rural houses. County Road 9 borders the site to the east and Fossil Creek Reservoir is located about a mile south of the southeast corner of the property. PROPOSED DEVELOPMENT We understand the property is planned for residential development that will include single family residences, duplexes, and townhomes as well as a community building area. A conceptual plan of the proposed development was provided. We anticipate the buildings will be one or two-story, wood frame buildings with partial or full basements. Walk-out and garden level basements are not anticipated. Foundation loads will be relatively light and may vary from 1,000 to 3,000 pounds per lineal foot of foundation wall. Paved streets, alleys and parking lots will be constructed to provide access. Sanitary and storm sewers, and water lines will be buried beneath streets. SITE GEOLOGY AND GEOLOGIC HAZARDS The site geology was investigated by reviewing geologic maps, field observations by one of our engineers and geologists, and by drilling of 18 exploratory borings. The approximate locations of our borings are shown on Fig. 1. THE WRITER CORPORATION RUFF PROPERTY 3 CLTIT JOB NO. FC•1149 This section is intended to discuss concerns related to a geologic hazards review that occurs during planning and zoning for land use changes. Specific requirements of Colorado House Bill 1041 "Areas and Activities of State Interest" and Colorado Senate Bill 35 "County Planning and Building Codes" are addressed. The geology and existence of geologic hazards on this parcel were evaluated by one of our engineering geologists using a review of available literature and field reconnaissance. Mapping by L. A. Hershey and P. A. Schneider (USGS Miscellaneous Geologic Investigations Map 1-687, Geologic Map of the Lower Cache La Poudre Basin, North-Central Colorado, 1972) indicates the surface of the site is mapped as pediment and alluvial fan materials including reddish clays, and arkosic gravel and sand. The underlying bedrock consists of the Middle and transition zones of the Pierre Shale, which generally consists of olive-gray, sandy, claystone-shale and fine-grained sandstone. The total thickness of the Pierre Shale is about 2,800 feet in this area. We believe the Pierre Shale dips gently to the east at about 5 degrees in the area. Our field exploration generally confirmed the conditions described by published mapping. Overburden clay soils and claystone(shale) portions of the bedrock are often expansive,which can result in damage to improvements or structures when moisture increase occurs. Engineered design of pavements,foundations, slabs-on-grade and surface drainage can mitigate the effects of expansive soils and bedrock. Our preliminary investigation shows samples of the overburden clays and claystone bedrock tested showed low to moderate swell potential when the samples were flooded under pressure. The site characteristics suggest swell potential will be variable over the site when the design geotechnical investigations are completed. Site soils and bedrock are not expected to be unusually corrosive to concrete or metal. Natural slopes are very gentle and stable. Significant faulting and structural discontinuities are not expected in the bedrock at this site. The soil and bedrock units are not expected to respond unusually to seismic activity. The area is considered by the most recent editions of THE WRITER CORPORATION RUFF PROPERTY 4CLTITJOBNO. FC•1149 Ei;;i3 the Uniform Building Code (UBC) as Zone 1, its least active zone designation. Maximum bedrock accelerations at 4 percent of gravity are probable during major earthquakes in the area. Only minor damage to relatively new, properly designed and built residences would be expected. Regarding the potential for radioactive substances on the parcel, it is normal in the Front Range of Colorado and nearby eastern plains area for radon gas to accumulate in poorly ventilated spaces (i.e., full-depth residential basements) in contact with soil or bedrock. The City of Fort Collins addresses the radon issue in Ordinance No. 45, 1997 and other publications that recognize radon as a health hazard. The amount of radon gas that can accumulate in an area is a function of many factors, including the radionuclide activity of the soil and bedrock, construction methods and materials,soil gas pathways and accumulation areas. Typical mitigation methods consist of sealing soil gas entry areas and periodic ventilation of below-grade spaces. Radon rarely accumulates to significant levels in above-grade living spaces. Fort Collins has addressed "Radon Reduction Systems" in their book of amendments to the 1997 Uniform Building Code. The site is probably not flood prone. There are no highly-developed, incised drainages on the site.The very gentle topography of the site indicates that very little, if any, water would be expected to flow onto the site from outside the boundaries. During peak precipitation events, some accumulation of surface sheet flow in drainages is expected. Development typically increases the relative amount of impervious surfaces, which can lead to drainage problems and erosion if surface water flow is not adequately controlled. Evaluation of flooding potential and surface drainage design should be performed by a civil engineer as part of the project design. Erosion potential on the site is considered low, due to the gentle slopes. Erosion potential can be expected to increase during construction,but should return to pre-construction rates or less if proper grading practices, surface drainage design and revegetation efforts are implemented. THE WRITER CORPORATION RUFF PROPERTY 5CLTITJOBNO. FC•1149 Groundwater was encountered in our borings at approximate depths of 5 to 25 feet during drilling and several days after drilling. Our field investigation occurred during the winter months when groundwater levels are typically low. Groundwater levels will likely increase in the wetter months and during wetter years. If groundwater levels increase to foundation levels, related problems will occur. The rise in groundwater to the foundation level will tend to soften the compressible soils, would cause expansion of soils with swell potential if present, and cause persistent wet or moist conditions in "crawl" spaces and basements. Mitigation includes underdrains or interceptor drains to lower the groundwater level, ground improvement techniques to increase the strength of soft soils, and special foundation selection and design criteria if swelling soils are present. We do not believe the site is located above underground mines or is located in a subsidence hazard zone. Site soils and bedrock are not considered subject to ground subsidence related to natural or mining processes. The bedrock below the site is the Pierre Shale formation which does not contain significant coal beds. There is no evidence of past mining activities on the site.We do not believe the site is an economic source of gravel. No other economically important mineral deposits are expected on this site or are known to occur nearby. No geologic hazards which would preclude the proposed development were noted on the subject tract. We believe the geologic hazards can be mitigated with proper engineering design and construction practices, as discussed in this report. SUBSURFACE CONDITIONS Subsurface conditions were investigated by drilling 18 exploratory borings at the approximate locations shown on Fig. 1. Our borings were drilled using 4-inch diameter, continuous flight auger and a truck-mounted drill rig. The drilling operations were observed by our field representative who logged the soils and obtained samples for laboratory testing. Graphic logs of the soils found in our THE WRITER CORPORATION RUFF PROPERTY CIT/T JOB NO. FC-1149 6 i 1Q1 borings including results of field penetration resistance tests are shown on Figs. 4 through 7. Samples obtained during drilling were returned to our laboratory where they were visually classified by a geotechnical engineer and samples were selected for testing. The results of our laboratory testing are presented in Figs. 8 through 16 and are summarized on Table I. The subsoils found in our borings generally consisted of medium stiff to very stiff, natural sandy clays, medium dense to very dense sands underlain by claystone bedrock and occasional interbedded claystone/sandstone bedrock at depths of 11 to more than 30 feet . Ground water was measured at depths of 5 to 25 feet during drilling and when measured several days after drilling. Descriptions of the soils and bedrock found in our borings are presented in the following paragraphs. Natural Clays Two different natural, sandy clays were penetrated by our borings. The most predominant clay we encountered is a silty, moist, brown clay that occurred throughout the property. These clays were medium stiff to stiff judged from the field penetration resistance tests. Samples of this clay had liquid limits ranging from 35 to 54 percent, plasticity indices of 21 to 38 percent, and contained 84 to 90 percent silt and clay size particles (passing No. 200 sieve). We selected 2 samples of these clays for swell-consolidation tests. The samples swelled 0.4 percent and 2.5 percent when flooded under 1,000 psf. The dry densities were comparatively high and the moisture contents of the samples of the clays tested were relatively low indicating a tendency to swell. The second type of clay we encountered is a very sandy,reddish brown,moist to very moist clay. Field penetration tests indicate this clay is medium stiff to very THE WRITER CORPORATION RUFF PROPERTY 7CLTITJOBNO. FC-1149 stiff. Samples of the clay tested had a liquid limit of 39 and a plasticity index of 25. Two samples were selected for swell consolidation tests. One of the samples consolidated slightly and the other had no movement due to wetting. The samples had higher moisture contents as well, indicating less tendency to swell. Clayey Sands Discontinuous lenses of clayey sands and poorly sorted sands with gravel were penetrated at various levels in 13 of our 18 borings. The clayey and gravelly sands were judged medium dense to very dense from the field penetration resistance tests and are non-expansive. Samples of the sands contained 5 to 19 percent silt and clay size particles (passing the No. 200 sieve). Bedrock Claystone bedrock was penetrated in 15 of the 18 borings at depths ranging from 11 feet to more than 30 feet below the existing ground surface. The claystone was judged hard to very hard from the field penetration tests. The claystone was interbedded with sandstone lenses in some locations, but no cemented sandstone was found in our borings. Eight samples of the claystone were tested for swell/consolidation. The samples tested had swells that ranged from 0.5 percent to 3.6 percent. These results indicate it may be prudent to plan the site grading so that at least 4 feet of vertical distance is maintained between the bedrock surface and planned basement elevations. In such a case the claystone should not affect the planned construction. Our estimate of the elevation of the bedrock surface is shown on Fig. 3. Groundwater Free groundwater was measured in our borings at depths from 7 to 25 feet at the time of drilling and when checked approximately 5 days after drilling. Our estimate of the elevation of groundwater at the time of our investigation is shown on THE WRITER CORPORATION RUFF PROPERTY CLT/T JOB NO. FC-1149 1`, EQ3 Fig. 3. Groundwater levels will fluctuate with season of the year and after the site is developed and irrigation of lawns and landscaping starts. We recommend precautions be taken to reduce the potential impact of shallow groundwater as discussed in the next section of this report. SITE DEVELOPMENT The geotechnical concerns we believe will most influence this development are the shallow ground water and the expansive soils and bedrock. Other concerns of lesser magnitude include proper placement of site grading fill, erosion protection, and utility trench backfiH. Each of these concerns is discussed in the following sections. No geologic or geotechnical conditions were identified which, in our opinion, preclude development of this site. Grading The southeast quadrant of the property is the area that will present the greatest challenge from a site grading and geotechnical perspective. The hatched area on Fig. 2 illustrates the approximate area in which bedrock is sufficiently shallow that we expect it may influence the construction. If grades are raised using site grading fill, it should be designed so that basements or lower footings are a minimum of 3 feet above the bedrock elevation. Shallow ground water was also found near the southeast corner of this site. Site grading should be designed so that basements are a minimum of 4 feet above the maximum anticipated groundwater elevation. Alternatively, an underdrain system could be installed to lower the ground water area wide. An underdrain system will tend to control the area groundwater level at the invert of the underdrain. If such a system is selected,we recommend basement floor elevations be set at least 4 feet above the invert of the perforated underdrain pipes under the sewer lines in the streets. THE WRITER CORPORATION RUFF PROPERTY 9CLT/T JOB NO. FC-1149 Areas to receive site grading fill must be properly prepared. Prior to fill placement, all vegetation or organic topsoil should be removed. The stripped materials that contain organics should be discarded or placed in undeveloped areas or in areas which will not support structures, utilities or pavements. After stripping, the resulting subgrade should be scarified, moisture conditioned to 1 percent below optimum to 2 percent above optimum moisture content and compacted to obtain a firm platform for fill placement. Our borings did not indicate soft soils exist on the site; however, if soft soils are encountered,they should be stabilized prior to placing fill. Stabilization of soft subgrade soils can be accomplished by removal and replacement, scarifying and drying, "crowding" crushed rock into the subgrade, or utilizing geosynthetics until a firm surface is achieved. The properties of the fill will affect the performance of foundations, slabs-on- grade and pavements. On site soils are suitable for use as site grading fill. Clayey sands or sandy, low plasticity clays similar to the on site clays at this site can be imported for use as site grading fill. A sample of import materials should be submitted to our office for approval prior to hauling to the site. Fill should be placed in thin loose lifts and compacted to at least 95 percent of Standard Pr ctor maximum dry density (ASTM D 698). Fill should be moisture conditioned to 1 percent below optimum to 2 percent above optimum moisture content prior to compaction. Guideline specifications for overlot grading are presented in Appendix A. Placement and compaction of site grading fill should be observed and tested. Slope Stability and Erosion The site is comparatively flat and we expect no problems of slope instability or significant erosion in the investigated area. For the type of soils present at this site, we believe permanent slopes should be 3:1 (horizontal:vertical) or flatter. THE WRITER CORPORATION RUFF PROPERTY 10CLTITJOBNO. FC-1149 Surface drainage should be designed to prevent ponding of water at the top of slopes or water flowing down slopes. A swale at the top of slopes to collect surface water and convey it around and away from slopes is recommended. Erosion protection will be needed for steeper stretches of swales. Slopes should be seeded or mulched as soon as possible to reduce potential for erosion problems. Localized slopes enclosing the proposed retention/detention ponds should be designed by a qualified Civil Engineer with erosion control and slope stability concerns in mind. We believe the on-site clay soils and bedrock can be excavated with conventional large earthmoving equipment. Underdrain The shallowest groundwater we measured during our investigation in January, 1999 was 5 feet beneath the existing ground surface and occurred near the southeast corner of the property. Fig. 3 shows our estimate of the depth to ground water and the area in which groundwater levels will have the greatest effect on planned construction. Groundwater levels are likely to rise during wetter seasons and wetter years. In addition, with development and subsequent irrigation, soil moisture will increase and the chance of the shallower groundwater condition is greater. To feasiblely use basements in the southeast corner of the property, we believe it will be necessary to provide a drain system under sewer lines (underdrain system) to try to keep the water in the area below proposed basements. As a precaution,we recommend providing each building basement with a foundation and underfloor drain (see "Basements" section below). The underdrains should be provided with cleanouts so they can be regularly maintained. If the sewer district. will not maintain underdrains, the home owners' association should be empowered to provide maintenance and be provided copies of"as-built" plans. THE WRITER CORPORATION RUFF PROPERTY CLTIT JOB NO. FC-1149 11 CQ3 The underdrains should consist of 3/4-inch to 1.5-inch clean, free draining gravel surrounding a rigid PVC pipe. The pipe should be sized for anticipated flow. Recommended underdrain sizes are shown in Table B below. TABLE B UNDERDRAIN SIZING Slope= 0.005 (0.5 percent) Pipe Size (inches)4 6 8 10 Maximum Number of Residences 50 100 200 400 Slope = 0.01 (1.0 percent) Pipe Size (inches)4 6 8 10 Maximum Number of Residences 75 150 300 600 Slope = 0.02 (2.0 percent) Pipe Size (inches)4 6 8 Maximum Number of Residences 100 300 600 Note: Minimum slopes of the subdrain will govern pipe sizes and maximum number of residences serviced. The line should consist of smooth, perforated or slotted rigid PVC pipe laid at a grade of at least 0.5 percent. A gravel cross-section of at least 2 square feet should be placed around the pipe. A typical sewer underdrain detail is shown on Fig. 19. A positive cutoff collar(concrete) should be constructed around the sewer pipe and underdrain pipe immediately downstream of the point the underdrain pipe leaves the sewer trench. Solid pipe should be used down gradient of this collar to the daylight point. The underdrain should be designed to discharge to a gravity outfall and be provided with a permanent concrete headwall,vent and trash rack. If the underdrain discharges into a detention/retention pond, a contingency outfall should be planned so that at no time can the underdrain backflow into the basements of residences THE WRITER CORPORATION RUFF PROPERTY 1 ZCLT/T JOB NO. FC•1149 should their foundation drains be connected to the system. Underdrain systems should be designed and constructed according to current City of Fort Collins standards. Utility Construction The soils encountered in our borings were medium stiff to stiff clays and medium dense to very dense sands. Hard to very hard claystone bedrock was predominant below the soils, but no cemented bedrock was encountered. We believe the soils and bedrock can be excavated with conventional earth moving equipment with little difficulty. Clay soils were predominant in the near surface overburden. We believe the clay soils on this site can be classified as Type A and the sand soils as Type C based on the Occupational Safety and Health Administration (OSHA) standards governing excavations. Type A soils require maximum slope inclination of 3/4:1 horizontal:vertical) for short term excavations. Above groundwater levels,Type C soils require a maximum slope of 11/2:1 (horizontal:vertical). Below the groundwater elevation Type C soils will cave to very flat slopes unless dewatering is done in advance of excavation. The contractor should employ a competent person or agency to identify the soils encountered in excavations and refer to OSHA standards to determine appropriate slopes. Excavations deeper than 20 feet must be designed by a professional engineer. Water and sewer lines are usually constructed beneath paved roads. Compaction of trench backfill will have significant effect on the life and serviceability of pavements. We recommend trench backfill be uniformly mixed, placed in thin, loose lifts, moisture conditioned to 1 percent below optimum to 2 percent above optimum moisture content and compacted to at least 95 percent of Standard Proctor maximum dry density (ASTM D 698). The placement and compaction of fill and backfill should be observed and tested by a representative of our firm during construction. THE WRITER CORPORATION RUFF PROPERTY CLT/T JOB NO. FC•1149 13 Groundwater was at depths as shallow as 5 feet in our borings and was more shallow in borings drilled by others in the fall of 1993. Groundwater may be encountered in utility excavations. Where excavations in the clays penetrate groundwater only slightly,we believe the lower permeability of the clays will cause slower infiltration and the trench will likely be dewatered successfully by slope in the trench bottoms toward pits where water can be removed with heavy duty pumps. Where deeper utility excavations are required and where the trenches penetrate the saturated clayey and gravelly sands, caving will occur and the use of well points or other more extensive methods will be needed to dewater in advance of excavation. Pavements The surficial soils found on-site have fair pavement support qualities. Referring to Table I in section 2.03.04 in the City of Fort Collins "Design and Construction Criteria Standards and Specifications for Streets,Sidewalks,Alleys and Other Public Ways (July 1996)"we judge the subgrade clays in the Ruff property and on adjacent County Road 9 will prove to be medium to low swell as defined in Section 2.03.04. For preliminary planning purposes, we anticipate a composite pavement section consisting of 4.0 inches of asphaltic concrete over 6 inches of base course for local residential streets. Full depth asphalt pavement is generally not accepted for residential streets by the City of Fort Collins. Thicker pavements will be required for collector and arterial streets. For County Road 9 we anticipate a composite pavement section consisting of 6 inches of hot bituminous pavement over 14 inches of aggregate base course. Alternative pavement sections include 10 inches of full depth asphalt or 8 inches of Portland cement concrete. A subgrade investigation and pavement design should be performed according to the City of Fort Collins standards after overlot grading is complete and utilities have been installed to confirm the above estimates or determine the needed pavement section. THE WRITER CORPORATION RUFF PROPERTY CLT/T JOB NO. FC-1149 14 EQ3 RESIDENTIAL CONSTRUCTION CONSIDERATIONS The property is planned for single and multi family residential construction. Soil conditions will vary across the site, but will primarily include slightly consolidating to low swelling, medium stiff to stiff sandy clays and clayey sands near the surface. The following discussions are preliminary and are not intended for final design or construction. After grading is completed, a final detailed soils and foundation investigation should be performed for the design of each building proposed. Foundations We believe the final design investigation will show spread footing foundations designed with a minimum deadload to resist uplift from the expansive clays will be suitable for approximately 70% of the proposed buildings in this subdivision. Normally, 3 feet of soil cover is assumed for frost protection in the Fort Collins area. Care should be taken to properly moisture treat site grading fill when on site clays are used and to import clays similar to site clays or non-swelling soils so as not to introduce swelling soils at this site different from the existing natural clays. Slab-on-Grade and Basement Floor Construction Slab-on-grade basement floors are typically used on lots with soil conditions similar to those found at this site. Structurally supported floors are recommended in all ground floor finished living areas. Design investigations may show structurally supported basement floors will be recommended in basements that will be finished within five years of completion. Where slab-on-grade floors are used in basements,the following precautions will be recommended to reduce the potential for damage in the event movement of slabs-on-grade occur. THE WRITER CORPORATION RUFF PROPERTY CLT/T JOB NO. FC-1149 15 1:13—E1:1 1.Isolation of the slabs from foundation walls, columns or other slab penetrations; 2.Providing voids under interior partitions to allow for slab movement without transferring the movement to the structure; 3.Flexible water and gas connections to allow for slab movement A flexible duct above furnaces will also be required; and 4.Proper surface grading and foundation drain and underfloor installation to reduce water availability to subgrade and foundation soils. Basements Free groundwater was shallow in many of our borings drilled during this investigation. In addition, the groundwater elevation will tend to rise in wetter seasons and wetter years, and in response to future irrigation. Surface water can penetrate relatively permeable loose backfill soils located adjacent to residences and collect at the bottom of relatively impermeable excavations causing wet or moist conditions. Foundation drains will be necessary around all "crawl" spaces and basements. We suggest foundation drains be connected to a sewer underdrain system with a piped connection. A typical detail for a connection from the foundation drain to the underdrain is provided on Fig. 19.Sumps with pumps should be provided as a backup if underdrains do not perform as intended. The sump pumps will need to lift water for discharge on the ground surface. For preliminary design purposes, a typical basement wall should be designed to withstand an "at rest" lateral earth pressure designed using an equivalent fluid density of 45 pcf. Significantly higher pressures are possible due to potential swell if the wall backfill is not moisture treated and densely compacted. Surface Drainage. The performance of improvements in this development will be influenced by surface drainage. When developing an overall drainage scheme, consideration THE WRITER CORPORATION RUFF PROPERTY 16CLT/T JOB NO. FC•1149 should be given to drainage around each residence. Drainage should be planned so that surface runoff is directed away from foundations and is not allowed to pond adjacent to or between structures or over pavements. We recommend slopes of at least 12 inches where possible in the first 10 feet for the areas surrounding all residences or buildings. In areas between houses which are less than 20 feet apart, the slope should be at least 10 percent toward the swale used to convey water out of these areas. Slopes marginally less steep than those recommended may be necessary at the back of the houses on lots which drain to the front. Roof downspouts and other water collection systems should discharge well beyond the limits of all backfill around structures. Proper control of surface runoff is also important to control the erosion of surface soils. Sheet flow should not be directed over unprotected slopes. Water should not be allowed to pond at the crest of slopes. Permanent slopes should be seeded or mulched to reduce erosion. Erosion protection should be provided where runoff is channeled into detention/retention basins until vegetation is established. Attention should be paid to compact the soils behind curb and gutter adjacent to streets and parking areas and in utility trenches during development. If surface drainage between preliminary development and construction phases is neglected, performance of the roadways, flatwork and foundations will be poor. When considering landscaping of common areas, we recommend using landscaping that requires little initial or long-term watering. Concrete Concrete which comes into contact with the soils can be subject to sulfate attack. Sulfate concentrations of 0.04 to 0.35 percent were measured on samples from this site. Values in this range are considered moderate to severe using criteria of the American Concrete Institute. We suggest assuming for preliminary cost estimate Type II or Type V cement will be needed. A maximum water-cement ratio THE WRITER CORPORATION RUFF PROPERTY 7CLT/T JOB NO. FC-1149 i V of 0.45 should be used. We generally recommend use of deicing salts on exterior flatwork be minimized during the first year after construction. LIMITATIONS AND ADDITIONAL INVESTIGATIONS Our borings were widely spaced to obtain preliminary subsurface information to aid in planning and development of this site. Variations between the borings will occur. A representative of our firm should be present during site grading and utility trench backfilling to observe fill placement and perform compaction tests: Detailed investigations should be performed for design of foundations, slabs-on-grade and pavements after overlot grading has been completed. We should review the final grading plans prior to construction to look for potential geotechnical problems. We believe this investigation was conducted in a manner consistent with that level of care and skill ordinarily used by geotechnical engineers practicing in this area at this time. No other warranty, express or implied, is made. If we can be of further service in discussing the contents of this report or analyses of the influence of subsurface conditions on the design of the proposed development, please call. CTUTHOMPSON, INC L $ i Thom-: • . Chapel Proje .ngin.. -r Revi it,- . - i(,7/ c/`.'C/• ...mot it ,q C g 1 \ 1 /terf .6 fs,.-,,, Fran P . Ho day, E, i ia, . ' 1 e,, , Prin• pal En sine l i 1 TAC:FJH;blc 4/...pti- 6 copies sen FRANK J. KOLLIDAY THE WRITER CORPORATION RUFF PROPERTY 8 CLT/T JOB NO. FC.1149 HARMONY RD d pp Olt.m z 2 SIT SCALE: 1 m 6 6 m VICINITY MAP Fr.cams AREN NOSCALE TH-1 e TH,Z e e a PROPERTY UN aa b T TH B i eTH4 a711A a a I e cREIiEA' a 714-7 8 0 0 T1°H•1 7tF12 x T>+,o L co s a° TH-13 IH-14 al 0 0 e TH47 0 TH4s T11,81e 1"42'. aaa'4444%113;11PROPOSED DETENTION "• :• 4 Locations of ExploratoryWriterHomes RUFF PROPEMY Borings e Job No. FC-1149 Fig. 1 gf 1- 1—i LT] SCALE: 1`1 001 4800 4886 0 0®.o 0.a®®m®®®®®®OW®®o r01311Sil I PROPERTY e 1 8 8 1 RECREATION II- - -I fan 0 OM 1 4 L _ ] 14895 4890 • 1 a 1........., c__-,) ...... 48as I 4885 4880 a' LEGEND PROPOSED 4885 APPROXIMATE ELEVATION DETENTION -. ..: 4005 OONmoIAts ON BEDROCK SURFACE NOTE DATA FROM BORINGS AND OUR DXPERIDICE ViERE USED TO SUBJECTIVELYESTIMATE THE'ELEVATION OF BEDROCK SURFACE' Elevation of R Bedrock g Writer_, Surface e Job No. FC-1149 Fig. 2 L 4_, 411) SCALE: 1 500' 20 tea®®®®®gym o®®®®®m®iOli=a a=as TM.zo 1 PROPERTY 1 e i 201 16 11I Ir RECREATION AREA o 147 1:/ l 16'140°°°7 1.41P-..---„ f t/ i,/ LEGEND: 10 4" APPROXIMATE LOCATION OF lu CONTOURS OF BEDROCK DETENTION DEPTH I/ 1 S ATEMOT8OF BNNiawr aroac NOTE DATA FROII SAND OUR EXPERIENCE WERE USED TO SUBJECTIVELYESTIVATE THE'CONTOURS OF BEDROCK DEPTH' Contours of Bedrock Writer Homes 9 RUFF PROPERTY Depth i Job No. FC-1149 A9. 3 41f1) Eg SCALE 1, 001 401S ==" 2 4910 PROPERTY 10 b b •. 12 40124812 4912 6 4910 RECREATION 8 4910b. J 1 I b b c::: ),,,, N 4808%.,.....„........._ o LEGEND: AtAATE ELEVATION DETB TION -: ._ CONTOURS ON OROLA9yWATIN ELEVATION NOTE 01ITAF1 MBOAa106ANDOIEtEXPERIENCEDATAwERUB1O8t8YBCTNELYmaim 00lfTCURB OF C1tt0UI NfATBt E.EVATIOIP Coours of gi Groundntwater sWriter HOMSS Elevations k Job No. FG1149 Fig 4 L ji lir SCALE: 1°--500' 15 as a—4111=11111M0 MUm®®a®®o®ISM a®s s ems®. FOND1 PROPERTY 1 15 .. 1I 15 I 10 i1 AREA 1 1 m 15 25 10 1 i 1 t f 25 20LEGEND: iTfTi1 A tATELOCATIONOF 10 D 25A.Ma CONTOURS ON GROUNDWATER DEPTH 4// BHALiDW OIA YYA?T3t NOTE DATA FROM DORMS AND OUR T]PET ENCE WSW U813:11TO SU6ECTIVELYESTIMATE THE'CONTOURS OF DEPTH TO GROUNDWATER' Contours of Depth to Writer Homes N RUFF PROPERTY Ground Water 7 Job No. FC-1149 Fig. 5 V TH-4 4930 EL=4929 493.0 TH-1 TH-5 EL=4924 TH-2 TH-3 20/12 EL=4923 EL=4922 EL=4921 4920 114/12 J 10/12 4920 S 23/12 12/12 9/12 SZ e 12/12 i.']19/12 ft ,1Jb0/12 f20/12, psL 10/12 4910 320i12 n 2 / / 20/12 20/12 4910 - 25/12 =g/ J 5/12 i J3412 T 50/10 50/10 50/11 320/12 W 4900 50/4 = 4900 w 50/8 u. I - 50/10 J 20/12 s Z. o 50/6 0 H- H H H Q-Q ILI w 4890 4890 w 4880 4880 4870 4870 4860 4860 4850 4850 - SUMMARY LOGS OF EXPLORATORY BORINGS JOB NO. FC-1149 FIG. 6 W' 4930 4930 TH-8 EL=4925 TH-9 EL=4924 TH-10 TH-6 15/12 7 EL=4921 TH-7 EL=4919 10/12 49204920EL=4918 14/12 7 14/12 114/12 26/12 8/12 i J 12/12 / 14/12E Q= /. J11/12 4910 8/12 11/12 23/12 / / J14/12 Q`-7 4910 _ f Y 11/12SZ= ! 1- 150/12 mp28/12 / / 15/12 0 112/12 w 4900 50/4 150/6 4900 w tu. 34/12 z _ Pi 50/4 z H- 50/3 50/8 H j- r 50/4 111 4890 4890- WWW w 150/5 4880 4880 4870 4870 4.860 4860 4850 4850 SUMMARY LOGS OF EXPLORATORY BORINGS JOB NO. FC-1149 FIG. 7 v. 4930 4930 TH-14 EL=4924 7' TH-15 EL=4920 4920 TH-11 TH-13 I 4920 EL=4917 TH-12 EL=4917 r7 16/12 EL=4915 20/12 J7/12 5/12 8/12 4910 16/12 a J24/12 17/12 4910 8/12 I 11/12 / 14/12 / 25/12 44/12 J115/12 , 112/12 $ w-4900 a 20/1250/9 50/10 4900 w 1 mmJ_ 36/12 Z- MI 50/9 50/10 Jo H- H 50/6 w 50/6 4890—ww 4890 50/6 4880 4880 4870 4870 4860 4860 4850 4850 SUMMARY LOGS OF EXPLORATORY BORINGS JOB NO. FC-1149 FIG. 8 4930 • 4930— 4920 TH-16 4920- EL=4916 j TH-17 EL=4912 I 12/12 TH-184910 4910— Oi EL=4907 20/12 9i18 E 7 -- i- 45/12 15/12 y/ 15i12 1 4900 0 U / d 4900—W u. 30/12 f3 15/12 o 1 . cH- cc 50i5 50/12 J38i12 J—4890 4890=W W 50i6 iie 16/12 50/3 min 50"4 4880 4880- 4870 4870- 4860 4860— I 4850 4850 SUMMARY LOG OF EXPLORATORY EXCAVATION r JOB NO. FC-1149 51;i3.LEGEND: I CLAY, VERY SILTY, STIFF, MOIST TO VERY MOIST, LIGHT BROWN TODARKBROWN. 7.77 SAND, CLAYEY, MEDIUM DENSE, MOIST TO WET, TAN/BROWN. 7 CLAY, SANDY, SILTY, STIFF, MOIST, TAN/REDDISH BROWN. SAND, GRAVELLY, CLAYEY, VERY DENSE, MOIST TO WET, BROWN/TAN. WEATHERED BEDROCK (CLAYSTONE), VERY STIFF, MOIST, GRAY, A OLIVE, DARK GRAY. CLAYSTONE, VERY HARD, MOIST, RUST, BROWN, WITH OCCASIONAL INTERBEDDED SANDSTONE. DRIVE SAMPLE. THE SYMBOL 14/12 INDICATES THAT 14 BLOWS OF A 140-POUND HAMMER FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5 INCH O.D. SAMPLER 12 INCHES. V INDICATES GROUND WATER LEVEL MEASURED AT TIME OF DRILLING. T INDICATES GROUND WATER LEVEL MEASURED 5 DAYS AFTER DRILLING. N INDICATES GRADATIONAL TRANSITION TO UNDERLYING SOIL. NOTES: 1. THESE BORINGS WERE DRILLED ON JANUARY 26 THRU 28, 1999 USING 4-INCH DIAMETER CONTINUOUS FLIGHT POWER AUGER. 2. BORING ELEVATIONS ARE APPROXIMATE AND WERE ESTIMATED FROM PRELIMINARY TOPOGRAPHY PROVIDED BY THE SEAR-BROWN GROUP. 3. THESE BORINGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS, AND CONCLUSIONS IN THIS REPORT. FIG. 9 1 5 4 EXPANSION UNDER CONSTANT PRESSUI DUE TO WETTING CO 0 0 1.4 t 0 cn Q Z 0 .6 r r_'i__r r r r r--____.-ram- cn cn W c a. .7 2 0 U 8 01 1.o 10 100 APPLIED PRESSURE -KSF Sample of CLAYSTONE NATURAL DRY UNIT WEIGHT= 110 PCF From TH-4 AT 24 FEET NATURAL MOISTURE CONTENT= 19.9 % Swell Consolidation JOB NO. FC-1149 Test Results FIG. 10 3 2 0 EXPANSION UNDER CONSTANT 1 PRR8SURE-DUE TO WETTT NG------.. O0 -----r- ---- --'-Y-_ -.. -------S----r-----t-1-r---1------------r-- -T-1-T--T CL _1 --_----1___----J____1_l__ -_-__--1___-L_____L_1_L__L 1 1 1 J 1 X w Fr) fn w IX -3 a 2 0 U 4 _ 0.1 1.0 10 100 APPLIED PRESSURE-KSF Sample of CLAY,SANDY(CL) NATURAL DRY UNIT WEIGHT= 117 PCF NATURAL MOISTURE CONTENT=From TH-7 AT 2 FEET 14.8 3 2 O ° E)cP,AN$IQN UNDER CONSTANT z e . PRESSURE DUE TO WETTING a -1 r, r, r X z -2 0 U) v) w 3 r--, r-, r--r, r, r a. 2 0 - a 0.1 1.0 10 100 APPLIED PRESSURE -KSF Sample of CLAY,SANDY(CL) NATURAL DRY UNIT WEIGHT= 105 PCF 1 From TH-7 AT 4 FEET NATURAL MOISTURE CONTENT 19.5 % Swell Consolidation JOB NO. FC-1149 Test Results FIG. 11 2 1 O.MOVEMENT_DUET-O WETTING-_.... 0 ° r i s X w e Z -2 • U) w IX -3 • a 2 0 U 4 0.1 1.0 10 100 APPLIED PRESSURE-KSF Sample of CLAY,SANDY(CL) NATURAL DRY UNIT WEIGHT= 99 PCF From TH- 11 AT 9 FEET NATURAL MOISTURE CONTENT= 24.0 % 3 2 . O °EXPANSION ODER CONSTANT z PRESSURE DUE TO WETTING x z -2 0 U cn tu ce U 0.1 1.0 10 100 APPLIED PRESSURE-KSF Sample of CLAYSTONE NATURAL DRY UNIT WEIGHT= 104 PCF From TH- 11 AT 19 FEET NATURAL MOISTURE CONTENT= 21.9 Swell Consolidation JOB NO. FC-1149 Test Results FIG. 12 3 2 EXPANSION UNDER CONSTANT 1 PRSSURE-DUE TO wE-TTNG- --•• O 0 r r-l-r---1-------t--- -T a r r JL L 1 L L 1_ __..A----1.._ -1-1-1..1. X Z• -2 r--, -r-. r-.. r w Y -3 a 2 O U q 0.1 1.0 10 100 APPLIED PRESSURE-KSF Sample of CLAYSTONE NATURAL DRY UNIT WEIGHT= 112 PCF From TH- 12 AT 14 FEET NATURAL MOISTURE CONTENT= 15.7 % 3 2 EXPANSIQN I;JNDER CONSTANT PRESSURE DUE TO WETTING O ° X Z .2 0 F cn cc -3 . r-- r, t r, r a. 2 V -4 0.1 1.o 10 100 APPLIED PRESSURE-KSF Sample of CLAYSTONE NATURAL DRY UNIT WEIGHT= 115 PCF From TH- 12 AT 29 FEET NATURAL MOISTURE CONTENT= 16.9 To Swell Consolidation JOB NO. FC-1149 Test Results FIG. 13 2 ADDITIONAL COMPRESSION UND.ER:CONSTANTP-RESSURE:----......--•- DUE TO WETTING 0 D r r r r r r------ r---- Q x CC -3 a O 0.1 1.0 10 100 APPLIED PRESSURE-KSF Sample of CLAY,SANDY(CL) NATURAL DRY UNIT WEIGHT= 102 PCF From TH- 14 AT 9 FEET NATURAL MOISTURE CONTENT= 24.2 % 3 2 II 0 °E 5PS Fl$1QN t.fri LR GONSTgNT PRESSURE DUE TO WETTING w z -2 1)2a.cc '3 er , r7r 0.1 1.0 10 100 APPLIED PRESSURE -KSF Sample of CLAYSTONE NATURAL DRY UNIT WEIGHT= 104 PCF From TH- 14 AT 19 FEET NATURAL MOISTURE CONTENT= 22.2 % Swell Consolidation JOB NO. FC-1149 Test Results FIG. 14 3, 2 EXPANSION UNDER CONSTANT PRESSURE-DUE*O WE-T-T NG-• --.. LITz -- - - r-1-r rT T i r r 1 1 i 1 L--11 ------ - --1-----11 w Ce _3 a 2 O a 0 0.1 1.0 10 100 APPLIED PRESSURE-KSF Sample of CLAYSTONE NATURAL DRY UNIT WEIGHT= 111 PCF From TH- 15 AT 14 FEET NATURAL MOISTURE CONTENT= 22.4 % 3 __.. 2 . 0 E rAN$1014 tINDER.CONSTANT co PRESSURE DUE TO WETTING z .2 O a. 0.1 1.0 10 100 APPLIED PRESSURE-KSF Sample of CLAYSTONE NATURAL DRY UNIT WEIGHT= 89 PCF From TH- 16 AT 9 FEET NATURAL MOISTURE CONTENT= 28.7 Swell Consolidation JOB NO. FC-1149 Test Results FIG. 15 7 6 - 5 4 3 2 r r r, EXPANSION UNDER CONSTANT P ASSURE DUE TO WETTING 1 F r--"-----T.----r 1 f r T f----- -r - 2 3 . z 0 4 z a W_g z O_fj _._.__.___r. r----r--T--r f r--_•__'r r'•____-.r,_ Cl, co cc a_.7 2 0 8 0.1 1.0 10 100 APPLIED PRESSURE -KSF Sample of CLAYSTONE NATURAL DRY UNIT WEIGHT= 111 PCF From TH- 17 AT 14 FEET NATURAL MOISTURE CONTENT= 12.5 To Swell Consolidation JOB NO. FC-1149 Test Results FIG. 16 V HYDROMETER ANALYSIS - I SIEVE ANALYSIS I HR. TIME READINGS U.S.STANDARD SERIES CLEAR SQUARE OPENINGS 5"6" 8' 5 MIN. 60 MIN.19 MIN. 4 MIN. 1 MIN. '200 '100 '50 '40'30 '16 '10'8 '4 3/8" 3/4" 1Ya 3" 5"6' 8" 0 0 1010 0202 30 wiIo 30i w a a 40 40 w z Ua 60 60 0 cc 70 0 80 80 90 1 0.002. .005 .009 .019 .037 .074 .149 .297 0.42. 590 1.19 2.0 2.38 4.76 9.52 19.1 36.1 76.2 12752 200 12/' 200 DIAMETER OF PARTICLE IN MILLIMETERS SANDS GRAVEL CLAY(PLASTIC)TO SILT(NON-PLASTIC) FINE I - MEDIUM 'COARSE FINE I. COARSE I COBBLES BBLES a ample of SAND,CLAYEY(SC) GRAVEL 33 % SAND . 62 % 29 % am TA- 1 AT 14 FEET SILT&CLAY 5 % LIQUID LIMIT NP % LIMIT 39 PLASTICITY INDEX NP °/a 25 HYDROMETER ANALYSIS I SIEVE ANALYSIS I 1 7 HR. TIME READINGS U.S.STANDARD SERIES CLEAR SQUARE OPENINGS I. 15 MIN. 60 MIN.19 MIN. 4 MIN. 1 MIN. '200 '100 '50 '40'30 '16 '10'8 '4 3/8' 3/4' 1W 3 5'6' 8' 5'S' 8' 0 0 20 w 40 1- w 40 w 5Q 62w w 6p.. _ cc cc 60 a too 0,002 005 009 .019 037 .074 .149 .297 0.42590 1.19 2.0 2.38 4.76 9.52 19.1 36.1 76.2 1 52200 12752200 DIAMETER OF PARTICLE IN MILUMETERS SANDS GRAVEL CLAY(PLASTIC)TO SILT(NON-PLASTIC) - FINE 1 MEDIUM I COARSE FINE I COARSE (COBBLES- BBLES ample of SAND,CLAYEY(SC) GRAVEL 24 % SAND 57 % 32 % roanTH 5 AT 19 FEET SILT&CLAY 19 % LIQUID LIMIT 36 %IMIT 38 PLASTICITY INDEX 23%24 % K Gradation 1149 Test Results Fig. 17 Fig. 18 1:g SANITARY SEWER 4"NON-PERFORATED CORRUGATED POLYETHYLENE PIPE(ASTM F 405) CONNECTION 4 . . . [ TO RESIDENCE va • . FOUNDATION DRAIN a PROVIDEMARAFI0 140Ne 6"MIN. 4 0 • °' v ,6"MIN. a • d 6"MIN • t d d A . v v : CI d v ca 4" 44" PVC PERFORATED SUBDRAIN PIPE SIZE VARIES SPECIFIED TRENCH 3/8"PERFORATIONS AT 5", WASHED ROCK 2 ROWS AT 60° FROM VERTICAL M SIZE: 1" WIDTH PVC PIPE AND FITTINGS MAXIMUM HAN 3% PASSING CONFORMING TO ASTM D 3034, LESS T THE NO. 200 SIEVE SDR 35 NOTE NOT TO SCALE a Sanitary Sewer Main Underdrain Job No. FC-1149 Fig. 19 0v lL O U w u- 0 O a. d z 0 71--_ N W O a Zwcoco0 JU n ( J (/) UJUUJJ J _J UV V J J VV} J }W W } >- >- } >- } W } >- 00000OWWW } } WWOWWOO} ZZ4ZZZZZZZZZZZZZ ZZZZ O O a < 000 zzaa °Zagagaagagaagaaaa _ Q cancan0Vcan000000UVUUUUU UUUU O 0 ZOW n (/) N0. W \ In a) v 0NO Cr) JWZ W m < w — u) v W O w H ; M 0 OVOv o 0 W W 0 z -s v W W W Z h O o o 0 0 ww a ti. co 0 Q Dpcn H v -I m ~X J J _ Z NN N N M 76 O O wnaJ. M m Wow ^ 0a Q ry o C) COS)COS) cd M Tt U) Z J ..a J M. a 2 O J O W -CO to 0 0cp 0O 0 OR to 0O Cl) M N cm666 , , ch — O O O J 0) c; v O. NOOOWOM vN003Nv , CO .- M N D Q' V O O 1 N O .- 0 .- 0 a 0 r r O O O 65 0 .- N O N ' HO .Z a , , .- rrrr . r rr1— . a ZW0 0_ a Q W Ma d' ., cOtn0) NmmtW orc 00,1r- ) NNNv1,, NLL( I1)a N NI-• O ON , , , NNN , , NNN . N N r ap co Z c a. vv rn v o) vrn 0 - 0 d va1 „ N , ON v N o) „ N O) „ , Or- .— OI—O W O 0)- O rTNNMv ,70 0c0N- WW ti Z to In t0 f 0 CC I = _ _ _ _ _ _ _ _ _ _ = 2. 2 2 2 2 2 2 2 2 2 r 1 0 0 APPENDIX A GUIDELINE SITE GRADING SPECIFICATIONS RUFF PROPERTY Southwest of County Road 9 and Harmony Road Fort Collins, Colorado a THE WRITER CORPORATION RUFF PROPERTY CLTIT JOB NO. FC•1149 s a 1: 1;;ij GUIDELINE SITE GRADING SPECIFICATIONS RUFF PROPERTY FORT COLLINS, COLORADO 1. DESCRIPTION This item shall consist of the excavation, transportation, placement and compaction of materials from locations indicated on the plans, or staked by the Engineer, as necessary to achieve preliminary street and overlot elevations. These specifications shall also apply to compaction of materials that may be placed outside of the project. 2. GENERAL The Soils Engineer shall be the Owner's representative. The Soils Engineer shall approve fill materials, method of placement, moisture content and percent compaction, and shall give written approval of the completed fill. 3. CLEARING JOB SITE 4 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 provide the.Owner with a clean, neat appearing job site. Cleared material shall not be placed in areas to receive fill where the material will support structures of any kind. 4. SCARIFYING AREA TO BE FILLED All topsoil and vegetable matter shall be removed to a depth of about 12 inches from the ground surface upon which fill is to be placed. The resulting surface shall then be plowed or scarified to a depth of 12 inches, moisture treated to 1 percent below optimum to 2 percent above optimum moisture content, and compacted until the surface is free from ruts, hummocks or other uneven features 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 free from large clods, brought to the proper moisture content, (1 percent below optimum to 2 percent above optimum) and compacted to obtain a firm, non-yielding platform for fill placement. 6. FILL MATERIALS Fill soils shall be free from vegetable matter or other deleterious substances, and shall not contain rocks having a diameter greater than six (6) inches. Fill materials shall be obtained from cut areas shown on the plans or staked in the field THE WRITER CORPORATION RUFF PROPERTY CLT/T JOB NO. FC•1149 A-1 4 by the Engineer or imported to the site. Concrete, asphalt, and other deleterious materials or debris shall not be used as fill. Import materials shall be similar to on site soils. A sample of import materials shall be submitted to the Engineer for approval prior to hauling to the site. 7. MOISTURE CONTENT Fill materials shall be moisture treated to within 1 percent below to 3 percent above optimum moisture content as determined by the Standard Proctor Compaction Test (ASTM D 698). Sufficient laboratory compaction tests shall be made to determine the optimum moisture content for the various soils encountered in borrow areas or imported to the site. The Contractor may be required to add moisture to the excavation materials in the borrow area if, in the opinion of the Soils Engineer, it is not possible to obtain uniform moisture content by adding water on the fill surface. The contractor will be required to rake or disk the fill soils to provide uniform moisture content through the soils. The application of water to fill materials shall be made with any type of watering equipment approved by the Soils Engineer, which will give the desired results. 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 a 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 95 percent of Standard Proctor maximum dry density(ASTM D 698). Fill materials shall be placed such that the thickness of lose material does not exceed 8 inches and the compacted lift thickness does not exceed 6 inches. Compaction, as specified above, shall be obtained by the use of sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or other equipment approved by the Soils Engineer for soils classifying as CL, CH, or SC. Granular fill shall be compacted using vibratory equipment or other equipment approved by the Soils 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. 9. COMPACTION OF SLOPES Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction operations shall be continued until slopes are stable, but o 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 THE WRITER CORPORATION RUFF PROPERTY CLT/T JOB NO. FC-1149 A-2 i i 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 Soils Engineer at locations and depths of his choosing. Where sheepsfoot rollers are used, the soil may be disturbed to a depth of several inches. Density tests shall be taken in compacted material below the disturbed surface. When density tests indicate the density or moisture content of any layer of fill or portion thereof is below that required, the particular layer or portion shall be reworked until the required density or moisture content has been achieved. Observation by the Soils Engineer shall be full time during the placement of fill and compaction operations so that they can declare the fill was placed in general conformance with specifications. All inspections necessary to test the placement of fill and observe compaction operations will be at the expense of the Owner. 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,a 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 All construction staking will be provided by the Civil Engineer or his duly authorized representative. Initial and final grading staking shall be at the expense of the owner. The replacement of grade stakes through construction shall be at the expense of the contractor. 13. SEASONAL LIMITS No fill material shall be placed, spread or rolled while it is frozen, thawing, or during unfavorable weather conditions. When work is interrupted by heavy precipitation, fill operations shall not be resumed until the Soils Engineer indicates the moisture content and density of previously placed materials are as specified. 14. NOTICE REGARDING START OF GRADING The contractor shall submit notification to the Soils 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 advance of THE WRITER CORPORATION RUFF PROPERTY CLT/T JOB NO. FC-1149 A-3 A 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 made by the Soils Engineer, as specified under"Density Tests" above, shall be submitted progressively to the Owner. Dry density,moisture content and percentage compaction shall be reported for each test taken. 16. DECLARATION REGARDING COMPLETED FILL The Soils Engineer shall provide a written declaration stating that the site was filled with acceptable materials, or was placed in general accordance with the specifications. 17. DECLARATION REGARDING COMPLETED GRADE ELEVATIONS. A registered Civil Engineer or licensed Land Surveyor shall provide a declaration stating that the site grading has been completed and resulting elevations are in general conformance with the accepted detailed development plan. r r4 THE WRITER CORPORATION RUFF PROPERTY A-4 CLT/T JOB NO. FC-1149