The URL can be used to link to this page

Home My WebLink AboutHAMPSHIRE SQUARE II PRELIMINARY SUBDIVISION - 31 92 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTi m LEWIS ENGINEERING COMPANY, INC. SUBSURFACE INVESTIGATION OF N. W. CORNER OF HAMPSHIRE & DRAKE FORT COLLINS LARIMER COUNTY STATE OF-COLORADO. FOR DOTY DEVELOPMENT CORPORATION 4901 EAST DRY CREEK ROAD, SUITE G-5 LITTLETON, COLORADO 80122 770-3700 1, G�tl 4OG�Ej,C��sS APRIL 24, 1990 PROJECT NO. 96-3909 H J DEPTH /N FEET LOG OF TEST HOLES FIGURE 2 SLOPE 12" IN 10' FEET MINIMUM INSIDE FOUNDATION WALL ASPHALTIC FILLER SLOPED. —A" CONCRETE SLAB a• ��Ir P ' J a Al 1/e q'• ROUND PERFORATED PIPE Z N CLEAN, FREE DRAINING (1 1/2" ROCK) GRAVEL - WITH TRENCH SLOPING TO OUTLET Y¢+PEa 4*9 FRENCH DRAIN - INTERIOR 1, , R c=Men& d Method of Constructirs Decorative Gravel or Bark Around Perimeter of Raise Roof (natter Downspout Extension. /v to Discharge Water Beyond Area Of Gravel or Bark Decorative �19�QU Wood oc Metal Enigi With 1/2'! M<nimn�'. Open Spam at Bottom a \\ �� A '. t, Concrete �� \� t P Foundation Wall to Allow Water to Fljway / �� ///�� ///� / S p• -� tV .AFrom Fbu deti \ Slope a Minima .•r f!o! r Unrestricted. �t of 12" in die - First 10 Feet From do ; -6A V ME djUA Foundation Wall. :oho `Q•�� lam Non-Wa+en, Geotextile Fabri Such as Typer or Mirafi May Be Used to Limit Weed Growth and.Still Allows Ibisture Evaporaticr. ILL 1. no Not place Plastic Material Under Gravel or Bark As It Will Remain Wet Under the Plastic. 2. Brick May Be Used In Lieu of the Wood or Metal Edging By mcing the Bricks Directly an the Ground With 1/2" Space Between Bricks. 3. Make 9uae the Ground Under the Decorative Gravel or Bark is a Minimum of 1" Abawe the Cann So That the Lawn Isn't Acting As a Dam and Preventing Water From Flowing Away From the Foundation Wall' FIGURE N O ' 4 No Text LEWIS ENGINEERING COMPANY, INC. 13048 NORTH HIGHLAND CIRCLE LITTLETON, CO 80125-9748 303-791-2633 April 24, 1990 Doty Development Corporation 4901 East Dry Creek Road, Suite G-5 Littleton, CO 80122 Dear Mr. Larry Doty: Enclosed is a copy of the Subsurface Investigation conducted on the site known as N. W. Corner of. Hampshire & Drake, Fort Collins, Larimer County, State of Colorado. If you have any questions regarding the contents of this report, or if we may be of any further assistance to you, please do not hesitate to contact our office. Si erely, Charles ewis CJL:vl Enclosures -3- n TABLE OF CONTENTS LETTER OF TRANSMITTAL SCOPE FIELD AND LABORATORY INVESTIGATION CONCLUSION AND RECOMMENDATIONS BUILDING FOUNDATION REINFORCING STEEL FLOOR SLAB WATER CONTROL LIMITATIONS FIGURE NO. 1 LOCATION OF TEST HOLES FIGURE NO. 2 LOG OF TEST HOLES FIGURE NO. 3 FRENCH DRAIN FIGURE NO. 4 RECOMMENDED METHOD OF CONSTRUCTING DECORATIVE GRAVEL OR BARK AROUND PERIMETER OF BUILDING FIGURE NO. 5 SWELL —CONSOLIDATION TEST RESULTS —2— SCOPE• This study was made to assist in determining the best type of foundation to use, ground water conditions, and types of soil encountered. FIELD AND LABORATORY: Two test holes were drilled on the site as shown on the attached Location Map (Figure 1) with soil samples taken at changes in the soils. The soils were classified during the drilling operation, based on cuttings delivered from the auger. Generally the top three and one-half feet consists of fill; with moist, soft, silty sandy clay found from the three and one-half foot to the eight -foot depth; with moist to wet, soft, silty very sandy clay found from the eight -foot depth to the sixteen and twenty -foot depth; with moist to wet, stiff, silt found below the sixteen and twenty -foot depth. Free water was encountered during the drilling operation at the twenty -foot depth. The silty sandy clay has a low swell potential and will consolidate if loaded too heavy. CONCLUSION AND RECOMMENDATIONS: A. BUILDING FOUNDATION: In our opinion, the foundation may be placed on reinforced footings on the undisturbed silty, sandy, clays below the fill level and (no fill) below frost depth. Design the footing for a maximum. soil pressure of 1,500 psf and a minimum dead -load of 500 psf. Continuous spread footings should be designed for a minimum footing width of 12 inches, and in general should be designed as narrow as is feasible to increase their minimum dead -load pressure. Isolated spread footing pads should have a minimum width of 24 inches to prevent a shear punch failure. The foundation walls should have a minimum of 2 #5 rebars in both top and bottom and there should be 2 #4 rebars around all windows and blockouts. There should be either a key -way or dowels, in the footing which will tie the footing to the foundation wall. The footing should be reinforced so it may bridge any soft spots in the soils. The footing should be a minimum of 48 inches below the finished grade of the soil round the foundation wall in order to be below frost heave. During the excavation of the footings the bearing soils will be disturbed. Prior to construction of the footings, these soils should be moistened and compacted to a minimum of 95% of the Maximum Dry Density as determined by the Standard Proctor Test (ASTM D-698-78). All concrete should have a minimum compressive strength of 3,000 psi in 28 days. Use sulfate resistant cements (Type II, Type II Modified or Type V cement) in all concrete exposed to the natural soils. B. REINFORCING STEEL: It is imperative for the reinforcing steel to be properly placed in the foundation walls. The following items should be adhered to: -4- 11111111 1. Rebars in top of foundation wall should be 3 to 4 inches below the top of the foundation wall. 2. Rebars in the bottom of the foundation wall should be 3 to 4 inches above the bottom of the foundation wall. 3. All splices should lap a minimum of 24 inches. 4. Rebar should be placed around all windows and blockouts in the concrete wall. 5. Rebar should be continuous around corner and across stepdowns, or have additional bent rebars extending 24 inches in both directions from the corner of the foundation wall. C. FLOOR SLAB: It should be realized that there is a chance for cracks developing in concrete slabs poured directly on existing ground. The probability of cracks developing increases as the soil becomes more expansive, or if non - expansive fill material exists beneath the slab, or if the slab can be heaved up by frost heave. If the contractor or owner wants to assume the risk, a floating slab, may be constructed and should be moderately reinforced with wire mesh and should be separated from foundation .walls by use. of expansion material placed 2 inches away.from the foundation wall at the bottom of the slab and touching the foundation wall at the top of the slab thus allowing the slab to move freely: Utility lines and structural members should be isolated from the floor slabs by wrapping the lines and columns with a non-bonding material and provide joints in concrete slabs around all lines and columns. All pipelines which pass through the slabs etc, .should be provided with flexible connections capable of moving at least 3 inches. When the furnace is placed on the floor slab it is necessary to provide a 3 inch collapsible connection between the furnace and duct work. If hot water heat is used, the piping should not.be placed beneath the concrete slab. The depth of slab control joints should be 1/4 the thickness of the concrete slab, and in 200 square feet maximum area, such as 10" X 201. A slab control joint located 3 feet from and parallel with the foundation wall is. also recommended. Non -bearing partitions constructed on the slab on grade floors. should be constructed with a 2 inch void space either above or beneath partitions. Door jambs, stairs, drywall, etc should not rest directly on slab -on -grade as the slab could move and cause damage to other portions of the structure. If any of the concrete floor slab will rest on fill material, it is necessary for the fill material to be compacted to a density of 85 to 90 percent of Standard Proctor'at 2 percentabove optimum moisture. -5- D. WATER CONTROL - RECOMMENDATIONS: 1. Poor drainage around buildings and along backfill has been the primary cause of heaving soil at foundation level, due to seepage of surface water into the subsoil. To help reduce the seepage of surface water, the finished grade shall have a slope of 12 inches for the first 10 feet away from the building. THIS IS MOST IMPORTANT. 2. Keep the excavated surface moist during construction by occasional sprinkling. 3. Do not place a gravel layer under the floating floor slab. The slab should rest directly on undisturbed natural soils, or on compacted fill soil. 4. The future owners should be cautioned not to install a sprinkler system next to foundation walls. If a sprinkler system is installed, the sprinkler heads should be placed so that the spray from the heads, under full pressure, does not fall within five feet (51) of foundation walls. Lawn irrigation must be controlled. Lawn, flowers, shrubs, etc., planted within five feet (51) of foundation walls should be hand watered and this watering must be minimized. 5. Extend roof downspouts'a minimum of 5 feet (5') beyond building and beyond the limits of backfill soil near the foundation walls. Sill cocks should discharge onto long concrete splash -blocks. 6. A French Drain is recommended. (SEE FIGURE NO. 3 FOR DETAIL) 7. Backf ill around the foundation walls should be compacted. Controlled puddling is satisfactory, providing it is done carefully so that too much water does not get beneath -the foundation walls. When this backfill settles, re -fill with dirt so that water runs away quickly. Particular care should be taken to compact disturbed, natural soils and any fills placed to support sidewalks, garage and driveway slabs. It is recommend that porches and patios be supported on haunches and or piers founded on suitable bearing soils. 8. The owner should be informed not to install decorative dams around the foundation, as it is necessary for water to flow away from the foundation as quickly as possible. CM LIMITATIONS: In any soil investigation it is necessary to assume that the subsoil conditions do not vary greatly from the conditions encountered in the soil investigation. Our experience has shown that variations do occur and that they become apparent at the time of excavation for the foundation system. If soil conditions appear to be different from those described herein, this office or a qualified soils engineer should be called to inspect the open excavation prior to any construction. This inspection is not a part of this report. dA2 i✓, r. s . LO I CArION CFTESTHOLES F/G W /