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Home My WebLink AboutPINECONE PUD THE TOWER SHOPPES PRELIMINARY - 60 91L - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTI REPORT OF A PRELIMINARY SOILS AND GEOLOGIC INVESTIGATION FOR PARAGON DEVELOPNBNT CORPORATION FORT COLLINS. COLORADO PROJECT NO. 3792-79 RE: TIMBERLINE-HORSETOOTH SECOND ANNEXATION LARIMER COUNTY. COLORADO BY EMPIRE LABORATORIES. INC. 214 NORTH HOWES STREET FORT COLLINS. COLORADO 80521 3 0 Basements and Slabs on Grade In view of the depth to groundwater encountered at the site, it is our opinion that the majority of the property is suitable for basement construction. Moisture contents indicate that water levels may rise four (4) to five (6) feet at the site during periods of heavy runoff and/or irrigation. Thereforet all finished basement floor slabs should be placed four (4) to five (6) feet above existing groundwater elevations. This will necessitate raising basement floor levels and placing them in general no more than six (6) to seven (7) feet below existing grade. Due to the relatively shallow depth of groundwater encountered at the northeast corner of the site, this area is presently not suitable for basement construction. It is suggested that conventional garden-level9 slab -on -grade or crawl -space construction be utilized in this area or that the area be drained or that perimeter drains be constructed around the individual structures. The soils encountered near the surface site are adequate for supporting normal floor loads and may be used as fill material to sup- port slab -on -grade construction. It is suggested that slabs on grade at the upper levels be designed structurally independent of bearing members. All slabs on grade should be underlain by t minimum of four (4) inches of gravel or crushed rock devoid of fines. _ GENERAL COMMENTS It should be noted that this was a preliminary investigation and that the bearing capacities recommended in this report are based on preliminary tests. Due to variations in soil conditions and groundwater levels encountered at the site. it is recommended that additional test borings be monde prior to construction. Samples obtained from these test borings should be subjected to testing and inspection in the laboratory to provide a sound basis for determining the physical properties and bearing capacities of the soils encountered. w APPENDIX A. up :B B g uorzCzbLToorN riortkt�!, ABM _.�✓ GO NCR r 10 �F-954. A-2 FMCIRF IARnRATnRIF.%. INC __ KEY TO BORING LOGS TOPSOIL �••�� GRAVEL ® FILL '�`�: SAND & GRAVEL SILT i i�: SILTY SAND & GRAVEL CLAYEY SILT u ea COBBLES DSANDY SILT =,o SAND, GRAVEL & COBBLES ® CLAY ® WEATHERED BEDROCK SILTY CLAY PH SILTSTONE BEDROCK SANDY CLAY ® CLAYSTONE BEDROCK SAND 117-11 Pq SANDSTONE BEDROCK �/• i ... SILTY SAND ® LIMESTONE CLAYEY SAND ", K GRANITE LA SANDY SILTY CLAY Q SHELBY TUBE SAMPLE STANDARD PENETRATION DRIVE SAMPLER WATER TABLE 12 DAYS AFTER DRILLING C HOLECAVED T 5/12 Indicates that 5 blows of a 140 pound hammer failing 30 inches was required to penetrate 12 inches. A-3 EMPIRE LABORATORIES, INC. 5940 5935 5930 5925 5920 5910 LOG OF BORINGS �[ IJ e . l I.lo • 2 M. 23 his A-4 EMPIRE LABORATORIES, INC. LOG OF BORINGS 4945-- 12 4940 4935 5/12 i 29/12 tte J li /.I 1/1213 ; - 4920-- 4915 10/12 M Jl A-5 EMPIRE LABORATORIES, INC. APPENDIX B. BORING NO. DEPTH FT. % MOISTURE 1 3.0-4.0 20.1 7.0-8.0 18.6 14.5-15.5 8.0 2 3.0-4.0 17.9 4.0-5.0 23.0 7.0-8.0 20.7 n 14.5-15.5 9.6 J 3 3.0-4.5 26.7 8.0-9.0 24.5 14.5-15.5 19.4 4 3.0-4.0 14.0 7.0-8.0 23.2 8.0-9.0 14.5-15.5 11.5 ISUMMARY OF TEST RESULTS DRY DENSITY UNCONFINED COMPRESSIVE P.C.F. STRENGTH-P.S.F. i 93.2 94.2 2590 3230 WATER SOLUBLE SULFATES-% PENETRATION BLOWS/INCHES 5/12 3/12 25/12 5/12 5/12 39/12 1/12 3/12 6/12 7/12 7/12 14/12 EMPIRE LABORATORIES, INC. BORING NO. DEPTH FT. % MOISTURE 5 3.0-4.0 18.0 7.0-8.0 24.3 14.5-15.5 7.3 6 3.5-4.5 13.3 7.0-8.0 15.3 .8.0-9.0 14.5-15.5 21.9 7 3.0-4.0 14.0 7.0-8.0 19.5 14.5-15.5 15.6 8 3.0-4.0 24.3 4.0-5.0 21.3 7.0-7.8 21.2 14.5-15.5 23.5 SUMMARY OF TEST RESULTS DENSITY UNCONFINED COMPRESSIVE P.C.F. STRENGTH-P.S.F. 108.7 91.1 4370 M WATER SOLUBLE SULFATES-% PENETRATION BLOWS/ INCHES 5/12 5/12 29/12 8/12 6/12 9/12 9/12 9/12 15/12 6/12 1/12 10/12 EMPIRE LABORATORIES, INC. SUMMARY OF TEST RESULTS Swelling Pressures Boring Depth % Moisture Dry Density Swelling No. (Ft.) Before Test P.C.F. Pressure PSF 4 3.0-4.0 14.0 111.1 * 460 6 7.0-8.0 15.3 113.7 300 *Denotes remolded sample Atterberg Summary Boring Number 2 6 Depth (Ft.) 3.0-4.0 7.0-8.0 Liquid Limit 34.4 31.7 Plastic Limit 19.9 16.7 Plasticity Index 14.5 15.0 % Passing #200 Sieve 90.5 59.6 Group Index 9.8 6.9 Classification Unified CL CL AASHTO A-6(10) A-6(7) a TABLE OF CONTENTS Table of Contents ..........................:............... i Letter of Transmittal ...................................... it Report ..................................................... 1 Appendix A ................................................. A-1 Geologic Map and Teat Boring Location Plan ......009a0600 A-2 Key to Borings ........................................... A-3 Log of Borings ........................................... A-4 Appendix B................................................. B-1 Summary of Test Results .................................. B-2 Appendix C................................................. C-1 Soil Map ................................................. C-2 Soils Descriptions ....................................... C-3 APPENDIX C. ,i 0 l l_ P146 LL /,L-ND 7 • �. I \� - S,,W. GORNEJ� AC 29- 7-68_ rz • /-'�p � I--IORSE_.TOOT1=-1 RO/�� C-2 EMPIRE LABORATORIES, INC. Combined IIABC L/3/69 OAP T12 Fort Collins Clay Loom (2221-221CL) Rocource Area 60 Deep clay loam soils with excellent moisture holding capacity. Air, root and water penetration is somewhat slow. Surface soils are often calcareous. The depth of A and B horizons in much of the area has been reduced by land levelling or erosion. 7.. Land Capability Units Soil Group 6 Slope Irrigated Croup 0-1% Ilsl Class Its Irrigated Tnnd. Careful irri-gation is necessary to got Good water �'•' penetration. Slopes are less than one foot in 100 feet. 1 3% - I1e1 Class IIe Irritated Lnn3. Very careful $Irrigation is nocessary to get Cood •��Q water penetration and control erosion. Slopes range from 1 to 3 feet in 100 . ;. feet. 3•�,� IIIe2 Class Me Irrigated Land. Special cam C needed to got moisture penetration and control erosion. Slopes are 3 to 5 feet in 100 feet. Ivel Clnss Igo Irrigated Land. Extreme care D needea to control water and wind erosion on those slopes. _Slopes range-from-5-to — -- - 9 feet in 100 foot. Non -Irrigated 0-3% Ive6s Class IVe Non-Irrigatod L'ird. Precipitation . and wind.erosion hazard rats capability. Slopes on less than 3 feet in 100 feet. 3-9% vie Class VIe Non -Irrigated Lnnd. Steepness CD of slope limits capability* Ihis land best suited to pormanont vegetation. Slopes ran"e from 3 to 9 foot in 100 foot. Clayey P1aSn3 Range Site C-3 Combined II ABC 1� 1/22/68 OAP 3/5/68 CPP T2 Nunn clay loam (2221, 22J1) Resource Area 68 Deep clay loams with excellent moisture holding capacity. There may be underlying sands or gravels at depths of 40 to 60 inches. Air and root penetration is slow. The surface soils are sticky when wet and crust and crack when dry. Land Capability Units Soil Group 7 Slope Irrigated Group 0-1% Ilsl Class Its Irrigated Land.. Careful irrigation is A necessary to get good water penetration. Slopes are less than 1 foot in 100 feet. 1-3% I2e1 Class IIe Irrigated Land. Very careful irrigation is B required.to get good water penetration and prevent erosion. Slopes range from 1 to 3 feet in 100 feet: 3-5% -IIIe2 Class Me Irrigated Land. Special care needed to C control water erosion. Slopes range from 3.to 5 feet in 100 feet. Non -Irrigated 0-3% IIIs61 Class Ills Non -Irrigated Land. Capability is limited A,B by soil textures. Slopes are less than 3 feet in 100 feet. 3-5% -IVe70 Class IVe Non -Irrigated Land. Water erosion hazard C limits capability. Slopes range from 3 to 5 feet in 100-feet. Loamy.Plains Range Site. u Combined II ABC T2 Nunn clay loam (2221. 22J1) Resource Area 68 Deep clay loans with excellent moisture holding capacity. There may be underlying sands or gravels at depths of 40 to 60 inches. Air and root penetration is slow. The surface soils are sticky when wet and crust and crack when dry. Land Capability Units Soil Croup 7 Slope Irrigated Group 0-1% Ilsl Class Its Irrigated Land.. Careful irrigation is A necessary to get good water penetration. Slopes are less than 1 foot in 100 feet. 1-3% I2e1 Class IIe Irrigated Land. Very careful irrigation is g required -to get good water penetration and prevent erosion. Slopes range from 1 to 3 feet in 100 feet. 3-5% C 0-37. A9B 3-5% C 1/22/68 OAP 3/5/60 CPP -1IIe2 Class Me Irrigated Land. Special care needed to control water erosion. Slopes zange.from 3,to 5 feet in 100 feet. - Non -Irrigated IIIs61 Class Ills Non -Irrigated Land. Capability is limited by soil textures. Slopes are less than 3 feet in 100 feet. .IVe70 Class IVe Non-Irri ag ted Land. Water erosion hazard limits capability. Slopes range from 3 to 5 feet in 100 -feet. •Loamy:Plains Range'Site. 3 0 Emil Laboratories, Branch O/lies ��Jlliiil iJi�YV W Inc.lii 1242 B,amwood Place Longmont, Colorado 80501 MAT _RI. J FOUNDATION ENGINEERS P.O. Box 1135 214 ',o.1 Fort Collins, Colorado 80522 13031 776 3921 P.O. Sos 031 484.0359 3151 Nation Way Cheyenne, Wyoming 82001 Old9, 1979 P.O. Box 10076 (307) 632-9224 Pa Deveupnent CO&POAatLon to ah Cottege Avenue Su of Fla Mai, Cotmillo 805t5 At: ant Mlle Bob KLtt 4e. GE en: we ptemed to su[xLU owe Repast o6 a PueUAl =W SoZU and Oelatogta In 3attton pnepaned bat .the ptopoaed "AaenVW and comneu t A rent tocated do aoutheaat FoAt Cottdna, Coloudoe Th onrpanVtQ 3epoAt pueente owt d In .the sub+we6ace and owe ate :ukLWns bleed upon Am m "e: vc ttY YQUUjp Ek '.ABORATORIES, INC. s /off Zd Se=nq.iJteFAbw Oeotog" t 111111111 ilk, Snob, P. =_* 4803 is * _ _iA It r. N /, Ae 7 "� < AticWte to MEMBER OF ULTING ENGINEERS COUNCIL REPORT OF A PRELIMINARY SOILS NID GEOLOGIC INVESTIGATION Sc Is report presents the results of a preliminary soils and geo- lo avestigation prepared for the proposed single- and multifamily re tial and commercial development located on Timberline Road in so st Fort Collins. Colorado. The investigation was carried out by me- f test borings and laboratory testing of samples obtained from th arings. s obJectives of this investigation were to (1) determine the ge : characteristics of the site and (2) determine the suitability of site for construction purposes. SI IESTIGATION j field investigation, carried out on September 26, 1979, con- si of drilling, logging. and sanding eight (8) test borings. The la is of the test borings are shown on the Geologic Map and Test 00 vocation Plan included in Appendix A of this report. Boring logs yr d from the field logs are included in Appendix A. These logs sty ils encountered, location of sampling. and groundwater et-th — :U the investigation. A suamary of the test results is included in ;p< x Be 1 borings were advanced with a four -inch diameterg continuous- -41 ower-flight auger drill. During the drilling operationso a soils :n! r from Empire Laboratories. Inc. was present and made a con- :ir visual inspection of the soils encountered. A visual inspection :f site was made by an engineering geologist from Empire Labora- T Inc. on September 26, 1979. The field investigation was aug- Ma by topographic maps and general knowledge of the geology of the am -11- SITE LOCATION AND INVESTIGATION The site is located at the northeast corner of Norsetooth and Timberline Roads in southeast Fort Collins, Colorado. More partic- ularly, the site is described as the Timberline-Horsetooth Second Annexation being a part of the southwest 14 of Section 29, Township 7 North, Range 68 West of the Sixth P.M., Larimer County, Colorado. The site consists of irrigated farm land. The northern one-half of the site is vegetated with corn stubble and the southern one-half of the site is planted with alfalfa. Numerous small irrigation laterals cross the site in an east -west direction. The boundary of the property is fenced. The area is relatively flat and slopes slightly to the north- east having positive drainage in this direction. SOIL AND GROUNDWATER CONDITIONS The soil profile at the site consists of strata of materials ar- ranged in different combinations. In order of increasing depths, they are as follows: (1) Silty Topsoil_: The site is overlain by a one (1) foot layer of silty topsoil. The upper six (6) inches of the topsoil have been penetrated by plant roots and organic matter and should not be used as a bearing soil or as a back -fill or till material. (2) Silty CigX This stratum underlies the topsoil and extends to depths five (5) to seven (7) feet below the surface. The silty clay is plastic and exhibits low to moderate bearing characteristics in its generally moist in situ condition. When wetted, the drier portions of the clay stratum exhibit slight swelling potentials. (3) Sandy Silty Clay: A layer of red sandy silty clay underlies the upper clay stratum.and extends to depths nine (9) to greater than fifteen and one-half ()%) feet below the sur- face. The lower red silty clay contains varying amounts of sand, is plastic, and exhibits low to moderate bearing char- acteristics in its moist in situ condition. (4) Silty Sand and Gravel: This gravel stratum was encountered in Borings 1. 20 49 5, and 8 below the upper clay stratum and extends to depths greater than fifteen and ohs -half (15h) feet below the surface, The sand and gravel contains varying amounts of silt, small cobbles. is poorly graded, and exhibits moderate bearing characteristics in its generally medium dense in situ condition, (5) Siltstone Bedrock: The bedrock was encountered in Boring 7 at a depth fourteen and one-half (141%) feet below the surface and extends to greater depths, The bedrock encountered is highly weathered and exhibits moderate bearing characteristics. (6) Groundwater: At the time of the investigation. free ground- water was encountered at depths seven and one-half (N) to twelve and one-half (12ss) feet below the surface. Water levels in this area are subject to change due to seasonal variations and irrigation demands on and adjacent to the site. Three (3) of the test borings were cased so that water levels could be monitored throughout seasonal variations and changes in irrigation demands. REC"ENDATIONS AND DISCUSSION It is our understanding that the site is to be developed for single - and multifamily residential and light commercial construction. Geology The proposed development is located within the Colorado Piedmont section of the Great Plains physiographic province. The Colorado Pied- mont, formed during Late Tertiary and Early Quaternary time (approxi- mately 65 million years ago), is a broad, erosional trench which sepa- rates the Southern Rocky Mountains from the High Plains. Structurally, the area lies along the western flank of the Denver Basin. During the Late Mesozoic and Early Cenozoic Periods (approximately 70 million years ago), intense tectonic activity occurred, causing the uplifting of the Front Range and the associated downwarping of the Denver Basin to the east. Relatively flat uplands and broad valleys characterize the present-day topography of the Colorado Piedmont in this region. The site is underlain by the Cretaceous Pierre shale. Alluvial and residual soils of Pleistocene and Recent Age overlie the Pierre shale at the site. The bedrock was encountered in the southern portion of the site at a depth thirteen and one-half (1h) feet below .the surface. It is — estimated that bedrock underlies the remainder of the site -at -depths— fifteen (15) to twenty (20) feet below the surface. The regional dip of the bedrock in this area is slight and to the east. From a structural standpoint, the site should be relatively stable. The property is relatively flat and therefore, geologic hazards due to mass movement caused by gravity are not anticipated. With proper site grading around structures and adequate drainage for all streets. erosion should be minimal. The site lies within the drainage basin of the Cache La Poudre River but does not lie within the flood plain of the stream. Minor amounts of silty sand and gravel underlie the site. These deposits are highly irregular and overlain by thick deposits of over- burden. In our opinion, these materials are not of economic value. The geologic conditions at the site necessary for the formation for coal, quarry rock, and limestone are not present to economic depths and therefore, the site should not be considered as an economic source for any of the above minerals. Site Grading and Utilities It is recommended that the upper six (6) inches of all topsoil below filled and paved areas be stripped and stockpiled for rouse in planted areas. The upper six (6) inches of all subgrade below filled areas should be scarified and recompacted two percent (2%) Met of opti- mum moisture to at least ninety percent (90%) of Standard Proctor Density ASTH D 698-70. Finished subgrade in cut sections should be scarified a minimum of six (6) inches and recompacted two percent (2%) wet of optimum moisture to at least ninety percent (90%) of Standard Proctor Density ASTM D.698-70. All fill should consist of the on -site soils or imported material approved by the soils engineer. The fill should be placed in uniform six (6) to eight (8) inch lifts and com- pacted two percent (2%) wet of optimum moisture to at least ninety-five percent (95%) of Standard Proctor Density ASTM D 698-70. All cut and ---fill slopes should be designed on grades no steeper than 3:1. All utility trenches dug in the upper soils four (4) feet or more in depth should be excavated on slopes no steeper than 1:1. The bedrock may be excavated on vertical slopes. Excavation of the bedrock may require the use of heavy-duty construction equipment. Where utilities are excavated below groundwater, dewatering will be required during placement of pipe and backfilling to insure proper construction. All piping should be bedded to insure proper load distribution and to elim- inate breakage during the backfilling operations. - r- All backfill placed in utility trenches in open and planted areas should be compacted in uniform lifts at optimum moisture to at least ninety percent (90%) of Standard Proctor Density ASTH D 698-70 the full depth of the trench. The upper four (4) feet of backfill placed in utility trenches under roadways and paved areas should be compacted at or near optimum moisture to at least ninety-five percent (95%) of.Stand- ard Proctor Density ASTM D 698-70, and the lower portion of these trenches should be compacted to at least ninety percent (90%) of Standard Proctor Density ASTM 0 698-70, Drying of the subsoils many be required to assure proper compaction. All stripping, grubbing, subgrade preparation, and fill and back - fill placement should be done under continuous observation of the soils engineer, Field density tests should be taken daily in the compacted subgrede, fills and backfill under the direction of the soils engineer, Foundation In view of the loads transmitted by the proposed construction and the soil conditions encountered at the sites it is recommended that the structures be supported by conventional -type spread footings and/or continuous grade beams. All footings and/or grade beams should be founded on the original, undisturbed soil a minimum of thirty (30) inches below finished grade for frost protection, The identification and undisturbed nature of the soil should be verified -by the soils engineer prior to placement of any foundation concrete. Based on pre- liminary soil tests, footings and/or grade beams founded at the above level may be designed for a maximum! allowable bearing capacities of one thousand (1000) to two thousand five hundred (2500) pounds per square foot (dead load plus maximum live load), To counteract swelling pres- sures which will develop if the drier upper clay soils become wetted* all footings and/or grade beams founded on the drier clays should be designed for a minimum dead load of two hundred fifty (260) to five hundred (500) pounds per square foot,