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HomeMy WebLinkAboutHARMONY MARKET PUD, 8TH FILING, OUTBACK STEAKHOUSE - PRELIMINARY & FINAL - 54-87AB - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTr SUBSURFACE EXPLORATION REPORT PROPOSED OUTBACK STEAKHOUSE HARMONY MARKET CENTER FORT COLLINS, COLORADO EEC PROJECT 1942043 EARTH ENGINEERING CONSULTANTS, INC. [J I I Attn: Mr. Jamie Butler RE Subsurface Exploration Report Proposed Outback Steakhouse Harmony Market Center Fort Collins, Colorado EEC Project No. 1942043 Mr. Butler: Enclosed, herewith, are the results of the subsurface exploration you requested for the referenced project. In summary, the subsurface soils encountered in the test borings for this project included low plasticity cohesive soils with interbedded zones of granular and essentially granular materials. Based on the results of the field borings and laboratory testing, it is our opinion these soils can be used for direct support of footing foundations for the proposed lightly loaded structure. The near surface soils could also be used for direct support of floor slabs and pavements. Geotechnical recommendations concerning design and construction of the foundations and support of floor slab and pavements are presented in the text of the attached report. We appreciate the opportunity to be of service to you on this project. If you have any questions concerning the enclosed report, or if we can be of further service to you in any other way; please do not hesitate to contact us. Very truly yours, Earth Engineering Consultants, Inc. Principal Engineer cc: Eldon Ward, .Cityscape Urban Design (5 copies) Principal Engineer J 2600 Canton Ct, Suite A Fort Collins, CO 80525 (303) 224-1.522 FAX 224-4564 SUBSURFACE EXPLORATION REPORT PROPOSED OUTBACK STEAKHOUSE HARMONY MARKET CENTER FORT COLLINS, COLORADO EEC PROJECT 1942043 INTRODUCTION The subsurface exploration for the proposed Outback Steakhouse Restaurant to be constructed in the Harmony Market area of Fort Collins, Colorado, has been completed. Two (2) soil borings extending to depths of approximately 15 feet below present site grades were advanced in the proposed building area to develop information on existing subsurface conditions. One additional boring was advanced to a depth of approximately 5 feet in the proposed pavement area. Individual boring logs and a- diagram indicating the approximate boring locations are included with this report. We understand the proposed Outback Steakhouse will be constructed south of Harmony Road between Boardwalk and Lemay Avenues in Fort Collins, Colorado. The proposed restaurant will be a single story, slab -on -grade (non basement) structure with a plan area of approximately 10,000 square feet. Foundation loads for the structure are expected to be light with continuous wall loads less than 3 kips per lineal foot and individual column loads less than 50 kips. Floor loads will be light, less than 100 psf. Paved drive and parking areas will be constructed in conjunction with the new building. We expect those pavement areas will be used predominately by automobiles and light trucks and that traffic volume will be light. We expect cuts and fill of less than 2 feet will be required to develop site grades for the restaurant. _ The purpose of this report is to describe the subsurface conditions encountered in the borings, analyze and evaluate the test data and provide geotechnical recommendations concerning design and construction of foundations and support of floor slabs and pavements. I EXPLORATION AND TESTING PROCEDURES ® The boring locations were selected and established in the field by Earth Engineering Consultants, °�- Inc. (EEC) personnel. The field locations were determined by pacing and estimating angles from the references indicated on the attached boring location diagram. The locations of the ®' Earth Engineering Consultants, Inc. ® Proposed Outback Steakhouse June 2, 1994 Page 2 borings should be considered accurate only to the degree implied by the methods used to make the field measurements. The borings were performed using a track mounted, CME45 drill rig equipped with a hydraulic head employed in drilling and sampling operations. The boreholes were advanced using continuous flight augers and samples of the subsurface materials encountered in the borings were obtained using thin -walled tube and split=barrel sampling procedures in general accordance with ASTM Specifications D-1587 and D-1586, respectively. In the thin -walled tube sampling procedure, a seamless steel tube with a sharpened cutting edge is pushed into the soil with hydraulic pressure to obtain a relatively undisturbed sample of cohesive or moderately cohesive material. In the split barrel sampling procedure, a standard 2-inch O.D. split -barrel sampling spoon is driven into the ground by means of a 140-pound hammer falling a distance of 30 inches. The number of blows required to advance the split -barrel sampler is recorded and is used to estimate the in -situ relative density of cohesionless soils and to a lesser degree of accuracy, the consistency of cohesive materials. All samples obtained in the field were sealed and returned to the laboratory for further examination, classification and testing. Moisture content tests were completed on each of the recovered samples. In addition, dry density and unconfined compressive strength tests were completed on appropriate samples. Swell/consolidation and Atterberg limits tests were also performed on selected samples to �. evaluate the potential for the near surface soils to change volume with variation in moisture ® content. Results of the outlined tests are shown on the attached boring logs. As a part of the testing program, all samples were examined in the laboratory by an engineer and classified in accordance with the attached General Notes and the Unified Soil Classification System, based on the soil's texture and plasticity. The estimated group symbol for the Unified ' Soil Classification System is shown on the boring logs and a brief description of that classification system is included with this report. �7 ■ 1. Earth Engineering Consultants, Inc. Proposed Outback Steakhouse June 2, 1994 Page 3 SITE AND SUBSURFACE. CONDITIONS The proposed Outback Steakhouse will be constructed south of Harmony Road, between Boardwalk and Lemay Avenues in Fort Collins, Colorado., The building site is located to the west of the Harmony Road entrance into the Harmony Market area. Surface drainage at this site is to the south with maximum difference in ground surface elevations across the building area. on the order of 2 feet. The project site is covered with grass and vegetation. Evidence of prior building construction was not observed at the site by our drill crew. An EEC field geologist was on site to direct the drilling activities and maintain a written log of the materials encountered in the boreholes. The field logs were prepared based on visual and tactual observation of disturbed samples and auger cuttings. Final boring logs included with. this report may contain modifications to the field logs based the results of laboratory testing and evaluation. Based on results of the field borings and laboratory testing, subsurface conditions can be generalized as follows. Approximately three to six inches of vegetation and/or topsoil was encountered at the surface at the boring locations. The topsoil/vegetation was underlain by lean clay which contain varying amounts of silt and sand. The predominately cohesive soils also contain occasional zones of granular and essential granular materials. The coloration of the cohesive materials ranged from dark brown to reddish brown and the granular materials were predominately brown and reddish brown. The cohesive soils were stiff to very stiff with the granular materials being loose to medium dense. Those materials extended to the bottom of the borings `at depths ranging from approximately five feet in the pavement area to fifteen feet in the building area. The stratification boundaries shown on the boring logs represent the approximate locations of changes in soil types; in -situ, the transition of materials may be gradual and indistinct. A Earth Engineering Consultants, Inc. Proposed Outback Steakhouse June 2, 1994 Page 4 WATER LEVEL OBSERVATIONS Observations were made while drilling after completion of the borings to detect the presence and level of free water. Free water was only observed in boring B-2 at a depth of approximately 14 feet, 24 hours after completion of the borehole. Longer term observations including the installation of piezometers which are sealed from the influence of surface water would be required to more accurately evaluate groundwater conditions. Zones of perched and/or trapped water may be encountered in the granular and essentially granular zones interbedded with the less permeable cohesive materials. The location and amount of perched water and the depth to the hydrostatic groundwater table can vary over time depending on variations in hydrologic conditions and other conditions not apparent at the time of this report. ANALYSIS AND RECOMMENDATIONS FOUNDATIONS Based on the materials observed at the test boring locations, it is our opinion the proposed lightly loaded building could be supported on conventional footing foundations. We recommend those foundations extend through all existing vegetation and/or topsoil and bear in the natural, medium stiff to stiff lean clay with varying amount of sand or natural, medium dense granular materials. For design of footing foundations bearing in the natural, medium stiff to stiff cohesive materials or medium dense granular materials, we recommend using a net allowable total load soil bearing pressure not to exceed 2,000 psf. The net bearing pressure refers to the pressure at foundation bearing level in excess of the minimum surrounding overburden pressure. Total load implies full dead and live loads. Exterior foundations and foundations in unheated areas should be located a minimum of 30 inches below adjacent exterior grade to provide frost protection. We recommend formed continuous footings have a minimum width of 1.6 inches and isolated column foundations have I :1 I Cl Earth Engineering Consultants, Inc. Proposed Outback Steakhouse June 2, 1994 Page 5 a minimum width of 30 inches. Trenched foundations (grade beam foundations) could be used in near surface cohesive materials. If used, we recommend those foundations have a minimum width of 12 inches. No unusual problems are anticipated in completing the excavations required for the construction of the footing foundations. Care should be taken during construction to minimize moisture variations of the bearing materials. Bearing materials which become dry and desiccated or wet and softened should be removed prior to placement of reinforcement steel and foundation concrete. Any disturbed material should also be removed from beneath the footing foundations. We estimate the long term settlement of footing foundations designed and constructed as outlined above would be small, less than 3/4 inch. FLOOR SLAB AND PAVEMENT SUBGRADES All existing vegetation and/ topsoil should be removed from beneath the floor slab and pavement areas. After stripping and completing all cuts and prior to placement of any fill, floor slabs or pavements, we recommend the exposed subgrade be scarified to minimum depth of 9 inches, adjusted in moisture content and compacted to at least 95 % of the material's maximum dry density as determined in accordance with ASTM Specification D-698, the standard Proctor procedure. The moisture content of cohesive soils should be adjusted to be within the range of ±2 % of standard Proctor optimum moisture. Occasional zones of higher silt content soil's were encountered in the subgrade materials. It may be necessary to adjust the moisture content of the silty soils to a lower moisture content to increase the stability of these materials. Fill materials required to develop the floor slab and pavement subgrades should consist of approved, . low volume change material, free from organic matter and debris. Normally, cohesive soils with a liquid limit of 40 or less and plasticity index of 18 or less could be used for low volume change fill. If granular materials are used, we recommend those soils contain a minimum of 15 % fines, material passing a #200 sieve. The near surface cohesive soils Earth Engineering Consultants, Inc. Proposed Outback Steakhouse June 2, 1994 Page 6 encountered on the project site slightly exceed the general definition of low volume change soils; however, in our opinion could be used as fill beneath the floor slabs or pavements.' Fill materials placed beneath floor slabs or pavements should be placed in loose lifts not to exceed 9-inches thick, adjusted in moisture content as recommended for the scarified soils and compacted to at least 95 % of standard Proctor maximum dry density. Care should be taken after preparation of the subgrades to avoid disturbing the in place materials. Care should also be taken to maintain the recommended moisture content of the subgrades. If materials become dry and desiccated or wet and softened, it may be necessary to rework those materials prior to placement of the floor slabs or pavements. Disturbed materials will also need to be reworked prior to placement of the pavements or floor slabs. PAVEMENTS Based on previous work we have completed in this vicinity with similar soils, we estimate a Hveem R-value of 7 would be appropriate for design of the pavement sections. We also expect that traffic on those pavements would consist of low volumes of automobiles and light trucks. We recommend pavements for the drive and parking areas consist of at least 3-inches of asphaltic concrete overlying 6-inches of aggregate base. In strictly automobile parking areas, a thinner pavement section consisting of 21/2-inches of asphalt over 4-inches of aggregate base could be considered. The recommended pavement sections are minimums and, as such, periodic maintenance should be expected. Asphaltic concrete for use in the pavement areas should consist of SC-1 or SC-2 blends compatible with the City of Fort Collin. s standard criteria. The aggregate base should conform to Colorado Department of Transportation (CDOT) requirements for Class 5 or Class 6 base. The base materials should be placed and compacted as recommended for fill beneath the pavements. Earth Engineering Consultants, Inc. Proposed Outback Steakhouse June 2, 1994 Page 7 Consideration could be given to stabilization of the pavement subgrades to develop a stronger pavement subgrade and reduce the required pavement section. We recommend Class C fly ash be considered for stabilization. The Class C fly ash could be blended to a depth of 12-inches with the fly ash stabilized subgrade replacing the aggregate base course. We would be pleased to provide additional information concerning stabilization of the subgrades if desired. OTHER CONSIDERATIONS Positive drainage should be developed away from the proposed building and across and away from the pavement edges. Water allowed to pond adjacent to the building could result in wetting of bearing soils and floor slab subgrades and result in unacceptable building performance. Water allowed to pond on or adjacent to the pavement could result in wetting of the pavement subgrades and premature failure of the pavement section. Care should be taken in completing on -site excavations to develop stable slopes of the sides of the excavations. We estimate slopes no steeper than 2 horizontal to 1 vertical would be relatively stable for short construction and shallow excavations. Longer term excavations or deeper excavations would require individual consideration. A portion of the near surface site soils have relatively high silt contents. Those materials would be subject to instability and strength loss when wetted. It will be necessary to closely monitor the moisture content of the site materials to avoid unstable subgrades. Placement of high silt content soils at dryer moisture contents could result in higher stabilities. Stabilization of the subgrades could also be considered to increase stability. Although the near surface soils at this site are not high plasticity materials, cohesive soils in general can experience volume change with fluctuations in moisture content. For low plasticity materials those volume changes are normally small unless moisture fluctuations are extreme. Care should be taken to minimize moisture fluctuations in the site subgrades and bearing materials. Earth Engineering Consultants, Inc. Proposed Outback Steakhouse June 2, 1994 Page 8 GENERAL COMMENTS The analysis and recommendations presented in this report are based upon the data obtained from the soil borings performed at the indicated locations and from any other information discussed in this report. This report does not reflect any variations which may occur between borings or across the site. The nature and extent of such variations may not become evident until construction. If variations appear evident, it will be necessary to re-evaluate the recommendations of this report. It is recommended that the geotechnical engineer be retained to review the plans and specifications so that comments can be made regarding the. interpretation and implementation of our geotechnical recommendations in the design and specifications. It is further recommended that the geotechnical engineer be retained for testing and observations during earthwork and foundation construction phases to help determine that the design requirements are fulfilled. This report has been prepared for the exclusive use of Outback Steakhouse for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranty, express or implied, is made. In the event that any changes in the nature, design or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the conclusions of this report modified or verified in writing by the geotechnical engineer. No Text OUTBACK STEAK HOUSE FORT COLLINS, COLORADO PROJECT NO. 1942043 DATE: MAY 1994 LOG OF BORING B-1 -SHEET-1 OF 1 RIG TYPE: TRACK.MOUNTED CME 4?'.>...'.. ,k: rF.::;, '.;,' .x;{#, :::: 5/25/94 WATER - DEPTH ELEV FOREMAN: SCK START DATE WHILE DRILLING- NONE AUGER TYPE: 4" CFA FINISH -DATE 5rism AFTER DRILLING NONE _SPT HAMMER: MANUAL SURFACE'ELEV 24 HOUR WA SOIL DESCRIPTION TYPE n (FEET) N (BLOWS/FT). au .- .(PSF) Me (%) 00 (PCF) AJ-IWS .200 (%) swaiL 1 LL PI PRESSURE %500 PSF r GRASS 3 TOPSOIL DARK BROWN SANDY CLAY (CL), moist, medium stiff _ _ _ _ 5 SS LIGHT RED SANDY CLAY (CL) moist, medium -stiff 15 10.9 DEEP RED CLAYEY SANDY SILT (ML), moist, medium stiff SS 14 12.8 10 BOTTOM OF.BORING 5' 6". 15 20 25 OUTBACK STEAK HOUSE FORT COLLINS, COLORADO LOG OF BORING B-2 I AUGER TYPE: 4"'CFA I FINISH DATE I 5n5/94 1AFTER DRILLING 14.0' �c nnmmc�c:._mt►nugcI -SOIL DESCRIPTION TYPE D (FEfiT) SUKFAGE-ELEV N (OLOW&IFT) OU (PSF) MC oD (PCF) 124,HOUR -AdSini -200 (%) 13.T SWELL LL PI PRESSURE % 600 PSF 6" WEEDS & TOPSOIL DARK BROWN SANDY CLAY (CL), moist, medium stiff SS _ _ _ _ _ 5 - 14. _ •3000 13.3 41 21 76.9 LIGHT RED SANDY CLAY (CL), Moist. medium stilt YELLOW SAND (SP), moist, medium dense SS 9 7.8 RED SANDY CLAYEY SILT (ML), moist, soft to medium stiff SS _ 10 5 "1500 23.6 1 23 8 _ _ 39.4 BROWN SANDY CLAY (CL), moist, soft to medium stiff SS _ 15 10 28.1 20 BOTTOM OF BORING 15' 6". • Calibrated Hand Penetrometer 25 OUTBACK STEAK HOUSE FORT COLLINS, COLORADO PROJECT NO: 1942043. DATE: MAY 1994 LOG OF BORING Ba SHEET 1-OF 1 RIG TYPE: TRACK MOUNTED CME � `;�.:^•..;: ;?.:ti'. , ' .;.,•� : ;#,:. 1.;.,# ' #,.. ; :;>:;..::f:^.: ;WATER. _ DEPTH ELEV FOREMAN: SCK START DATE 5125m WHILE DRILLING NONE- AU.GER TYPE:- 4" CFA FINISH -DATE ... _5125/94_ AFTERORILLING. NONE SPT HAMMER: MANUAL SURFACE ELEV 24 HOUR N/A SOIL DESCRIPTION TYPE.. o ETI IFE_ N .. _ (BLOWSIFJ)_ oU _-..IP$PI_. _. Mc _ _.. I%L. oo .. (PCF) A4ANTS •zoo I%1- swfi�� _.LL ._ . PI. PRESSURE. _ %500 PSF 6' WEEDS & TOPSOIL DARK BROWN GRAVELLY SANDY CLAY (CL-CH), moist, medium stiff to stiff SS _ _ _ _ _ 5 34 '8060 11.2 39 19 67 8000 sf 1.2% LIGHT RED SANDY CLAY (CL), moist, medium stiff to stiff SS SS RED SANDY GRAVEL (GP), moist, medium dense SS 6 42000 11.2 10 10 5.0 _ _ 15 8 23.9 _ 20 BOTTOM OF BORING 15' 6". • Calibrated Hand Penetrometer 25