Transmission And Substation Foundations - Technical Design Manual (TD06088E)

Moment=Load*perpindicular distance Equation 7-5 Along the grid, the summation of moments would look like this (positive is resistance and negative is load):

∑ Moments =7.25ft*50kip*3piles+7.25ft*50kip*3piles-2000kip ft=175 kip ft

Therefore, the piles can resist an additional 175 kip-ft of moment with a FS of 2.0. For the corner to corner analysis, the summation of moments looks like this:

∑ Moments =(10.3ft*50kip*1 pile+5.1ft*50kip*2pile)*2-2000kip ft=50 kip ft

Therefore, the piles can resist the moment and axial loads in both directions. With the axial design completed, it is time to ensure the piles can take the shear loads. It is assumed that the piles will have a pinned pile head condition and the shear load is distributed to each pile evenly.

DESIGN EXAMPLES

Shear

Shear Force

40 kip 9 Piles

=

=

= 4.44 kip/pile

Pile

Number of Piles

This shear load as well as an axial load of 50 kips are input into L-pile along with the pile properties for R345001337 (found in the Drawings and Ratings section of this manual) and soil properties. See the Design Methodology section for assistance as well as the L-pile manual for assistance in using L-pile. The resulting deflection curve is included in Figure 7-18 and the moment curve is included in Figure 7-19.

Figure 7-18: Lateral Deflection vs Depth

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