120_CEG 4012 Notes Fall 2011 CEG 4012 Notes Fall 2011

120_CEG 4012 Notes Fall 2011 CEG 4012 Notes Fall 2011 -...

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Unformatted text preview: DF11 Example 3 .. Driven Pile in Layered Soil (Clay over Sand): Determine the allowable (design) load tor the steel pipe pile (XS) shown below. Assume FS = 3, GWT at soil surface. Clay: $ 0', y,,, 105 pcl, q, 1400 pst Sand: $ 38', dense, y,,, 130 pcl = = = = = 1. Determine QS1 in clay layer: c, = (q, /2) = 1400/2 = 700 psf (= 0.700 ksf) ~ a = 1.0 + (0.7 - 0.5 kSf)( 0.5 -1.0 ) = 0.90 1.5 - 0.5 ksf 1,=C,=D.~olo.'k\')_ 0,&10 ,.s" '16n+ Q,,= If. A.I = c, InBD,) ) = O. (1r) (1,.1",/,>.,,/,,) ('J.b' - ~>..' K 20' Clay 15' Sa nd,,--,,-_ OD = 12.75" ID = 11.75" tWlIli = 0.50" As = 19.2 in 2 w = 65.4 pll &,,," 2. Determine Q" in sand layer: Apply critical depth from top of sand layer. not ground surface f, = KG', tanB use 0, = 20B = 20' and K = 1.50 (non-displacement). USACOE "" B = 0.67\' and tan B= Ian (0.67 x 38) = 0.47 McCarthy"" tan B = 0.20 smooth. 0.40 rough """""" use tan B = 0.30 Draw effective vertical stress and fs distribution along pile: 0\ = 0 0',,=:1..0' fs =t1o (,oS-I:;).<') pr( (.1 r = ~5J. ---+[;] Q,,= cr'v= 1.o'(lor-(,'1..") ~IS(,'Jo- n .,) = ,~" pt;,[ 1k (I f, dA,) = - P 0, = [383+840 PSf]( 1t(12.75")) (15 . )( 1000lb ) = f, 1 2 12" . ? 0 ' >.0 , K. ---.;.. J<.'fJ 3. Q, = {q, 1\1} = q, nB'/4 (assume plugged) q, = q Nq + 0.4 By Ny Ny = 78.6 from Terzaghi BC factors Nq = 83 from pial (use mid range) q = G', = 1866 psf at toe / " .... ,J ' .. Q, = [ ,nt." I h J) , b. 'I (". H'/'2'/I,) ( '" .. ,VI p,') (,s . )) " (1r ("." 'j" "/1-1-) 0 /-I) (, k/,"' 10 )' = L ,"/,~,I' >.,l"?] lo,IIt!)/" 1""1, 'I. 3" (tvo;"" j ,.. /I Nl'.rl_,.. ;,-... ) 6. Find pile weight: (assume plugged below ground surlace. use buoyant weighl) W = (,')US"'"I, (,,..) ltr.'lp/IJ' (W(,os",) '/5'("Of")["'-(II,1>//>' - 55"'(6?,~p'l)r-,r(".lS/");;'/J = )/J [p 'I , 1. H? ,OSo - fJ3 C It J' 6~.~" 7. P,=l:Q,,+Q,-W= (~1,1' Jo6'nj.~ -3.0= 3"13. It (= -l.' lo~,3 I< k) 8. P,=P,/FS='l0~.1/;, ...
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This note was uploaded on 02/10/2012 for the course CEG 4012 taught by Professor Staff during the Fall '08 term at University of Florida.

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