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Re: Structure Magazine Questions

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seaint(--nospam--at),Internet writes:
Can the safety factor for overturning of a retaining wall be reduced below
1.5 when
analyzed subjected to seismic forces (i.e. 1.5/1.33)?

I would say 'NO', it can not.  The loads from seismic forces are the maximum
probable load for a given return period.  They are not precise, and a factor
of safety is still required.  We design a structure to survive a seismic
event, for life safety reasons primarily.  Why would we want to reduce the
life-safety even further by reducing the factor of safety.  It would seem to
me to be a foolish move.   Allowable stresses are increased because for short
term duration a material can be taken to a higher stress before failure.  But
the laws of physics for overturning do not change for a short-term loading.


Richard Lewis, P.E.
Missionary TECH Team

The service mission like-minded Christian organizations
may turn to for technical assistance and know-how.