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Re: Open Walled "Shed"

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Thor,

Once again, I recommend referring to the report:  "Wind Forces on 
Structures," 
published in ASCE Transactions, Vol. 126, Part II, 1961, page 1124.  Table 4 
on page 1160-1161 covers open shed roofs, such as may be used at railroad 
stations and includes the possibility of trains or stored material 
obstructing the wind.  Two roof slopes are considered; 10 deg and 30 deg.

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

Thor Tandy wrote:

>>A peer has sought my opinion on the lateral wind loads to a structure that 
is essentially a non-walled structure.  I.e. just a roof on a braced post and
beam assembly.

My opinion was that he should use the the exterior vector coefficients in the
code for the roof using the internal pressure coefficients for a building that
would have large openings open during high winds.  If the eave boards or beams
are deep enough they could also contribute?

That analysis provides a resultant vector addition according to the roof slope
(here 15 degrees) which would I believe be the main resultant lateral load to
the roof structure (together with some serious uplift).

He felt that the load calculated that way was too small, even using
corner/cladding coefficients.  I suggested using an elevated billboard of same
projected dimensions as an upper limit, but that gave a much higher number,
too high to be reasonable for what is essentially an aerofoil on stilts.

I think the simple vector addition of resultant roof pressures is sufficient.

What does the group think?<<