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RE: Snow load in combination with seismic

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In Utah we have adopted a statewide snow load study.  The equation for
snow included in seismic is:

% = (0.25+0.025*(Elevation-5000')/5000')

This is for Utah, Colorado may have a similar equation somewhere.

Jake Watson, E.I.T.
Salt Lake City, UT

-------------------
> Despite the fact that many engineers treat them deterministically,
> every load (with the possible exception of dead load) is strongly
> dependent on what happened in the past and on statistics.  Humans
are
> notoriously poor at predicting the future and even where rigorous
math
> is not used most people make decisions based on what seems likely to
> happen.  (Thus we don't carry eight spare tires in our cars.)
> 
> If we based our designs on what is possible (given the past) rather
> than what is likely the design loads for all locations on earth
would
> be something like the following:
> human live load = density of people in the black hole of calcutta
> snow load = based on glacial cover during an ice age
> wind load = several hundred miles per hour for direct tornado
> volcano load = hundreds of feet of ash, mud; high thermal loads from
> lava
> electrical load = direct lightning strike
> earthquake load = perhaps M10 at ground zero
> etc.
> 
> Once we decide to base loads on a specific service life or on a
level
> that is less than the maximum possible we should consider the
> statistics of the situation.  Once we decide that a given transient
> loading is appropriate, we have set our risk tolerance.  When
> combining multiple transient loads, it makes sense for the
combination
> to have the same likelihood of occurrence as we previously accepted.
> 
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
> Michael Valley, P.E., S.E.                   E-mail:
mtv(--nospam--at)skilling.com
> Skilling Ward Magnusson Barkshire Inc.             
Tel:(206)292-1200
> 1301 Fifth Ave, #3200,  Seattle  WA 98101-2699      Fax:       
-1201

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