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LRFD vs ASD

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LRFD is the best way to address the uncertainy of Loads and the Resistance of
materials to the load by adjusting the Factor for the load based upon the
accuracy of determination of the load.  The Design is further adjusted for the
uncertainy of the material's strength by introducing a strength reduction
factor.

ASD just does not address this  It is based upon applying a common strength
reduction factor to all load cases, regardless of the accuracy of the load.

We must remember that engineering is not that precise and our methods should
recognize those areas where we can be more accurate by imposing less stringent
design parameters.

For foundation design, If you recall, Terghazi's equation is at the strength
level.  We have been taught to design the soil bearing using ASD with
"allowable" bearing values commonly given in soils reports.  All we need to do
is ask the GE for the bearing strength of the soil.