Transmission And Substation Foundations - Technical Design Manual (TD06088E)

Solution P a

= 0.5K a g H 2

Equation 7-20

= 0.5 x 0.2 x 95 x 42 = 152 lb/ft = 0.5K p g H 2 = 0.5 x 3 x 95 x 42 = 2280 lb/ft

P p

P p - P a

= 2280 - 152 = 2128 lb/ft

Total lateral resistance

= 2128 x 25'-0 = 53,200 lbs

NOTE: In this example, more than 1” of movement will probably be required to fully mobilize the total lateral resistance. Partial mobilization requires less deflection.

DESIGN EXAMPLES

COEFFICIENTS OF EARTH PRESSURE (DAS, 1987) SOIL K 0 ' DRAINED K 0 ' TOTAL

K a ' TOTAL

K p ' TOTAL

Clay, soft 1 Clay, hard 1 Sand, loose

0.6 0.5 0.6

1

1 1

1 1

0.8

0.53

0.2

3

Sand, dense

0.4

0.35

0.3

4.6

Note: 1 Assume saturated clays.

Figure 7-34

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