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Home My WebLink About590105.tiff SUBSOIL INVESTIGATION AT THE SITE OF THE PROPOSED NEW WELD COUNTY LIBRARY ON 23rd AVENUE NEAR 20th STREET ROAD , GREELEY , COLORADO WOODWARD _ „i �;`� Av,40 % i 'r iienver ' ,G✓._o .. OMAL1A I. e. I. WOODWARD—( LYDE—S1ILRAEZD AND AssocI MIS C,OI'S1 I INC; LNCINEFRS son AKD FOUNDATION ENGINEERING !24O WE S' BAYAQS AVENUE PI 'UT%R i. c.CI OR ADC SHE AMAN a Coen SUBSOIL INVESTIGATION AT THE SITE OF THE PROPOSED NEW WELD COUNTY LIBRARY ON 23rd AVENUE NEAR 20th STREET ROAD , GREELEY ,COLORADO Prepared for : Einhorn & Nash, Architects 1002 9th Street Greeley, Colorado Job No. 2597 December 14 , 1959 SCOPE This report presents results of a subsoil investigation at the site of the proposed new :Veld County Library on 23rd Avenue near 20th Street Road , Greeey , Colorado. Factual data gathered during the feld and laboratory work are summarized in F _gs . I through 3 and Tables 1 and 2 attached . Our conclusions and recommendations , based on the results of our investigation and our experience in the area , are given below. As currently planned , the library is to be one story with no basement . It is to be of masonry type of construction with contin- uous wall loads of the order of 3-4 kips per lineal foot and column loads of approximately 15 kips . CONCLUSIONS AND RECOMMENDATIONS (1) Subsoil conditions at the site are uniform. Generally , 6 to 12 feet of soft to stiff sandy clay overlie medium dense sand and gravel. No water was encountered during the drilling. (2) Three foundation alternatives are feasible and satis- factory for the proposed structure: (a) belled piers founded on the sand and gravel strata at depth 6 to 12 feet designed for maximum soil pressure of 4 ,000 psf ; (b) conventional spread footings placed on the upper clays below frost depth designed for maximum soil pres- sure of 1 ,000 psf; (c) conventional spread footings on at least 2 .5 feet of compacted fill designed for maxi- mum soil pressure of 3 ,000 psf . The fill should be compacted to 95% of Proctor density , see appendix. (3) Foundation walls should be reinforced with a minimum amount equivalent to that required for a simply-supported span of 15 feet . -2- (4) Precautions should be taken against wetting of foundation soils during or after construction. Backfill around the building should be moistened and compacted , and the ex- terior should be well sloped . A slope of at least 12 inches for the first 10 feet is desirable . (5) The natural soils are adequate to support interior floor slabs . Fill to support slabs should be compacted to a minimum of 90% Proctor density at optimum moisture con- tent (see appendix) . (6) Ground water conditions are favorable for basement construction. (7) The results of the percolation test are shown in Table 2 . The average time required for the water in the test pit to drop 1" was 33 minutes . It is advisable that a soil engineer inspect the foundation materials exposed after excavation. WOODYARD-CLYDE-SHERARD AND ASSOCIATES By Everett A. Dye , P. E. Reviewed by Kal Zeff, P. E. EAD:vh (2 copies sent ) cc : John O. McNamara U21 2'21 --- !� 821 'LE 2 Ho' 3 J PROPOSED }IRE 5 I EUILDItdG ! - ' (V ! HOLE 4 *HOLE t fff i a w 1 I im PEACOLtTION TEST LOCATI ON - — — PROPERTY LINES 1 T1 7 '.. TEST HOLE LOCATION FLAN SCALE: 1• • 301 4825— HOLE 1 HOLE 2 HOLE 3 HOLE 4 HOLE 5 -4825 i ELEv.•u:+23.1a' ELEr.•L'_•22.0' ELEv.•4821.1' ELEv.•4821.6' ELEv.•4S22.2' __ J ci FJ �--r �� • ��,I Wc•18.5 I _° 'A ^ 3 i" 1--- 820 820 - . .,�I We-t6.� '� �6/1z Bc 1,13k i u ;M jJ3/e6 00•tu5.1 Y, ! N� I •; \• r..y: r UC 1µ, G ,, ,�. Ir l,,' 4/13 We-15.0 �; RECOMMENDED 'jII15/12 y'� r DO•,1)., r% P. m BEAR 1 616 LAYER °;r�, 1 i1 } FAR BELLED PIERS =� 11 2 ` /• klrA ` {� YC•1,962 II/ } /1 1 ..1 k 4/12 �� r ..... i' 4815 ; ;:.4. : ., , ,t ,� —4ai5 .'^a -I k13112 I« �� r ✓:.t—r / i }1 f12 ir -1 ; • • , • • 12f12 J 4 II 6,• \ '•.,• JJ/ /t A a 10 t_� ~- e # 13/1. ;--11810 • a z4/12 i L iy �37/y 2 '°'� *144'125/9 s".'` 3 /12 �,' .� F . 1 LE SE fdt 'c_ --11805 11805—= ,—__ - ,' J TUP&tL, SANDY CLAY WITii SOME GRAVEL, MOIST, REFUSAL OCi --\jii SOFT, DARR mould. GRAVEL n{' ,1 „LAY ,;L) MEDIUM STIFF, SANDY, MOIST, CALCAREOUS, p SRELDY TUBE SAMPLE. 1/. OCCASICHALET SILTY, LIGHT BROWN. k%�`-' CLAY, VERY SANDY To SIti:O, VFW? cuv (OL—SC) `x'TLZ-; FL -. MEDIUM STIFF, QUITE MOIST, SOCIE GRAVEL• (1) :40 GROUND WATER ENCOUNTERED DURING ORILLINS. `' GRAVEL AND SAN:, (SC-SC) CLAYEY, MEDIUM DENSE TO An('. DENSE, MOIST, 'ABUT BROWN TO BLUFF. (2) HOLES WERE DRILLED OR UEc. 8, 1959 WITH A lj-INCH DIAMETER COIITINUOUS FLIGHT POWER AUGER. r1 CLAY (CL) SOFT, SANDY, MOIST, OCCASIONALLY \ SILT'r, LIGHT BROWN. (3) ELEVATIONS TAKEN FROM CON TO1:R MAP. _ (4) WC • WATER CONTFNt, PERCENT. • UNDISTURBED 2" [ROUT SAMPLE (CALIFORNIA) DD • DRY UFNSITY, PCF• NI DC • UNCGSFI:IED C:`:4PR E�E :SIVE STR :GTH, VF. 1 STANDARD L" PENETRATIOU SAMPLE. ill LOGS OF EXPLORATORY HOLES FORM NC WCS IA WOODWARD, CLYDE , SHERARD AND ASSOCIATES I ( T r n-r ! • I T I I r I I • ' - t T . T 1 I Nctural Dry Emit We.ght = 100.2 ;I,:` Natural Mo.s•ure Cur..ten+ 14.11 per,.e(..I . i ..;. ; ..• i••.4--•-• • .. . -.-- .. . ,. .. 1--4 +... • - I + I { r •••••. i W II a WATER ADDED I • "' •,.....s.,...o. 1 1 g! .. 1.... . : - . 1 - • f— ADDITIONAL J-NPNftSIION NDER C'NS1A!:T !R. ESSLBE as D'JE TO JET1INe ii Z. • i I ac a . •Z.. I I . . . .._ ._._..._1-•4 I _ , TYP I Ct.L SA TILE OF SAND( +iVAT FR::? HOLE 2 AT 0EPtH 2'-0" - I • . 11 • , Natu"ol Dry l:rit Weight - 115.1 pct Natural Moist ..re Content •_. 15.t' .‘e•rert` . I i ! • i ' W I ! 7 '\ WATER A�,ED i O C I a. V � 1 I 4"---ADDITI:RAL CO.$PRESSION UNDER CONSTANT PRESSURE rr o I DUE TO WETTING LLI Q T- O • . . U T1 F I r%A6 SAr1PLE r•r SANDY CLAY FROM 11:t.E 11 AT 0EPtH 3t-r 10 . APPLIED PRESSURE kaf ,-- ---r-t • . r J;r ' 117 1 . . :i • t . I ! i • I . ;� r{--.-- ..1 .. fi r•::.' t .. . I. ,• F t I I . ' I . I• ii• I • r.« ,+ r •• . . , .t i. I. 1 • I + I. I I. -'-- - 4._ . - f +I: t ' , , . . . .1 I � ' I j i ,1 F. .}. .. . ._ I . •... I . . . . . , -I I I NO .I . . • ! • II.. .. I t ..;•. . . 0 : 100 IC, GO 1.000 TIME - M ! NUTES S.LLL-;. :6i Lib, I1'... T. .--.• ;-....•.ELTS FIG. 3 JOB NO. 2597 FORM NO WCS-6 WOODWARD, CLYDE, SHERARD AND ASSOCIATES TABLE I SUMMARY OF LABORATORY TEST RESULTS NATURAL NATURAL DRYATTERBERG LIMITS UNCONFINED TRIAXIAL SHEAR TESTS HOLE DEPTH MOISTURE DENSITY LI0UID PLASTICITY COMPRESSIVE DEVIATOR CONFINING I S0IL TYPE (FE ET) (ova) (PSF) LIMIT INDEX STRENGTH STRESS 1I PRESSURE (%) (%o) (PSF) (PSF) (PSF) 2 2 . 0 16.2 103 . 2 1472 Clay , sandy 4 1 . 5 18. 5 104 .3 3434 Clay 3 . 0 15. 0 115 . 1 1962 Clay , sandy TABLE 2 PEPCO' AT t ON TEST (see Appendix for Procedure) TIME ELAPSED TIME :1ATES;I :3EPT`i ;7ATEl DROP AVG. PERCOLATION RATE SOIL 1 :23 6" 0 Clay,very sandy 1 :31 10 5. ,, y " 1 :44 21 5„ 1" 2 : 15 55 4" 2" 2 : 53 1 hr. 30 min. 3" 3" 3 :35 2 hr . 10 min, 2" 4" 4:05 2 hr . 45 min. 1" 5" 33 min.iinch APPENDIX I (Suggested Minimum Specifications for Placement of Compacted Fill) General A Soil Engineer shall be the Owner's representative to control the backfill compaction. The Soil Engineer shall approve the material, the method of placing and compaction, and shall give a written approval of the completed Liii . Compacting Clayey or Silty Materials Preparation of Natural Ground. The excavated surface under the area to be filled shall be plowed or harrowed, moistened if necessary, and compacted in the manner specified below for the subsequent layers of fill. All topsoil shall be removed before beginning preparation of natural ground. Placing Fill. No brush, sod, frozen material, or other perish- able or unsuitable material, or stones of 6 inches or greater in maximum dimension shall be placed in the fill. The distribution of the material on the fill shall be such as to avoid the formation of lenses, or layers of material different substantially in characteristics from the surrounding material. The materials shall be delivered to the backfill surface at a uniform rate, and in such quantity as to permit a satisfactory construction procedure. Unnecessary concentration of travel tending to cause ruts and uneven compaction shall be avoided. before placing the successive layer, all ruts and other hollows more than 6 inches in depth shall be regraded and compacted. After dumping the fill material on the backfill surface, the material shall be spread by approved methods in approximately hori- zontal layers. These layers shall not be greater than 6 inches in thickness after compaction. Moisture Control. The material in each layer, while being compacted by rolling, shall contain the amount of moisture required for optimum compaction, as nearly as is practicable, as determined by the Soil Engineer, and the moisture content shall be uniform throughout the layers. The Contractor may be required to add the necessary moisture to the backfill material in the excavation if , in the opinion of the Soil Engineer, it is not possible to obtain uniform moisture content by adding water on the fill surface. Compaction. When the moisture content and condition of each spread layer is satisfactory, it shall be compacted by a method approved ey the Soil Engineer to al least 9U% of Proctor density for materials supporting floor slabs only, and to 93,, Proctor density for materials supporting i.,undatiuns. A Proctor test should be performed on each typical fill material and frequent density tests of the fill must be taken. Normally 4 to o passes of a sheepsfoot roller is suggested for the first trial . The feet of the roller shall extend approximately d inches in clear projection from the - 2 - roller' s cylindrical surface and shall be so spaced as to provide approximately one tamper foot per 100 square inches of roller area. The roller shall be provided with cleaner bars so designed and attached as to prevent the accumulation of material between the tamper feet . The roller shall be the type which can have its weight increased by the addition to the drums of water or sand, or both. The weight of the roller when fully, loaded shall oe not less than 4000 pounds per lineal foot of drum. Proctor Compaction Test ASTM D698-58T, Method A Essentially, Proctor Density is defined as the dry density obtained in the laboratory by compacting minus 1/4-inch soil at the optimum moisture for compaction, into a 1/30-cubic foot mold in three equal layers, using 25 blows of a 5 -pound 2-inch diameter hammer dropped 12 inches. Compacting Cohesionless Free-Draining Materials Where compacting cohesionless free-draining materials such as sands and gravels, the materials shall be deposited in layers and compacted by treads of a crawler-type tractor, surface or internal vibrators, smooth or pneumatic rollers, hand or power tampers, or by any other means approved by the Soil Engineer. The thickness of the horizontal layers after compaction shall oe not more than 6-inches if compaction is performed by tractor treads, surface vibrators or similar equipment , or not more than the penetrating length of the vibrator head if compaction is performed by internal vibrators. The material may be ponded or flooded to aid in the compaction, if specifically approved by the Soil Engineer. The relative density (dry) of the compacted material shall be not less than 7u% as determined by the standard Bureau of Reclama- tion relative density tests for cohesionless free-draining soils. The relative density tests are completely different, and not to be confused with the Proctor test described above. The relative density tests will be made by the Soil Engineer. The relative density of a cohesionless free-draining soil, expressed as a percentage, is defined as its state of compactness with respect to the loosest and most compact states at which it can be placed by laboratory procedures. The relative density will be based on the following formula, wherein the maximum density is the highest dry unit weight of the soil, minimum density is the lowest dry unit weight of the soil, and in-place density is the dry unit weight of the soil in place. Rel. Den. (%) = max. den. (in-place den. = min. den. ) x 10( del. nT T den. = min. den. ) APPENDIX II PERCOLATION TESTS FOR SEPTIC FIELDS U. S . Dept . of 'lealtu 1. Excavate a hole 1 loot square and to the depth of the proposed disposal trenches. This depth , i,, most instances, will oe approximately 24 inches and should not exceed 36 inches. 2. Fill the hole with water to a depth of at least 6 inches, and allow this water to seep away . Judgment is required in determining how soil conditions aL time of Lest vary from year-round average conditions. Where soil appears exceptionally dr; , or where sell conditions are questiouaule . greater depths of WaLt.r may be used or the test may be re- peated. In no case should tests be made in tilled or frozen ground. Where fissured soil formations are ei ,untei'ed, tests should be made only as directed by and under the supervision of a representative of the State health department . 3. Observe the time in minutes required for the water to seep away completely. This time divided by the total number of inches of water placed in the hole gives the average time required for the water to drop 1 inch. With this information, the eitective absorption area required for each individual system may be determined from table 3 . TABLE 3. - Data for determining field requirements from percolation tests Effective absorption area required in Time required for water to bottom of disposal trenches in square fall 1 inch (in minutes) feet . _ Residences Camps Schools (per bedroom) (per person) (per person) 2 or less ,iO 13 9 3 60 15 1U 4 lo 16 12 h1) 2U 13 lu 100 24 IS 1b 130 32 21 30 sU in 30 6.; 2410 6u 4U Over GU Special design using seepage pits or sand lifter trenches. NOTE. A minimum of lbo square feet shnuid be provided for each indi- vidual family dweilinh unit . * ( INDIVIDUAL, SEWAGE DISPOSAL SYSTEMS - Recommendations of Joint Committee on Rural Sanitation, Reissued July 1534 uy U. S. Department of Health, Education, and Welfare , Public Health Service) Hello