166_CEG 4012 Notes Fall 2011 CEG 4012 Notes Fall 2011

166_CEG 4012 Notes Fall 2011 CEG 4012 Notes Fall 2011 - for...

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DF43 Drilled Shaft Toe Bearing: o be careful about sludge on shaft bottom! o also need to check soil/rock 1B to 2B under toe for voids and variability - use SPT or double tube rock core (~4" dia.) o for D/B > 3. c u ~ 5.0 ksf (250 kPa) Iqt = N~ C u I where N~ = 6.5 for Cu = 0.5 ksf (25 kPa) = 8.0 for C u = 1.0 ksf (50 kPa) = 9.0 for Cu ~ 2.0 ksf (100 kPa) C u = average C u for a depth of 2B below toe but if B> 75" (1.9 m) then must reduce qt as follows where F r = 2.5 S; 1.0 tp,B b + 2.5'11 2 lV 1 = 0.0085B b + 0.083(D/B b ) where 0 and B b in ft lV, = 0.0280B b + 0.083(D/B b ) where 0 and B b in m lV 2 = 0.014,JC: where C u in pst lV 2 = 0.065~ where C u in kPa o qt = 1.2N 60 < 60 ksf for qt in ksf qt = 57.5 N 60 S 2900 kPa
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Unformatted text preview: for qt in kPa where N 60 = the average SPT blow count (corrected to 60% energy) for a depth of 2 B b below the toe (S 50 blows per foot) it B &gt; 50&quot; (1.2 m) requires settlement of about 2.5&quot; (60 mm) at ultimate . 50&quot; h B&quot; h reduce qt If need less settlement: qtr =-q. were b In Inc es B b 1.2m h B' q'r =-B-q were b In m b o Rock o special topic. consider rock type. jointing, core recoveries, qu ROD = rock quality designation =[E(L&gt;4&quot;)]/length of run o conservatively use Terzaghi bearing capacity equation (typically '!trOCk&gt; 45 deg, and cohesion very high)...
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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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