130_CEG 4012 Notes Fall 2011 CEG 4012 Notes Fall 2011

130_CEG 4012 Notes Fall 2011 CEG 4012 Notes Fall 2011 -...

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DF16 Concrete Piles: cylinder (dia. > 36") sections End Bearing: Unit end bearing at a given depth is based on the type of soil and the corresponding SPT blowcount. Figure 3 is a plot of mobilized unit end bearing versus blowcount for the four soil types. The empirically derived equations are as follows: Soil Type Description Mobilized Unit End Bearing Capacity (TSF) 1 Plastic clav Q = O.2226*N 2 Clay-silt-sand mixtures, very silty q=O.4101*N sand. silts and marls 3 Clean sands a = O.5676*N 4 Soft limestone, very q = 3.6*N/3 shelly sand Side Friction: Unit side friction at a given depth is also based on the type of soil and the corresponding SPT blowcount. Figure 4 is a plot of ultimate unit side friction versus blowcount for the four soil types. The empirically derived equations are as follows: Soil Type Description Ultimate Unit Side Friction (TSF) 1 Plastic clav f = O.5083*Ln(N)-O.634 2 Clay-silt-sand
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Unformatted text preview: mixtures, very silty f = O.3265*Ln(N)-O.2721 sand, silts and marls 3 Clean sands f = O.0188*N-O.0296 4 Soft limestone, very f = O.01*N shelly sand Pile Capacity: Database research at the University of Florida has indicated that, using the RB-121 methodology, it requires excessive pile movement to mobilize the calculated ultimate pile capacities. To better match the measured load test capacity values (using Davisson failure criteria) with calculated values, the "Mobilized End Bearing" has been set equal to 1/3 of the RB-121 ultimate end bearing value. The Davisson capacity equals the ultimate side friction plus the mobilized end bearing. The allowable pile capacity is taken as 1/2 the Davisson capacity. The ultimate capacity is then equal to the ultimate side friction plus 3 times the mobilized end bearing....
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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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