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Re: Wood Rafters, UBC ta

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Jay Crawford wrote,

. > I don't rely on the tables, since my live load are greater that those
. > specified int eh tables.  I calc my rafters and floor joists appling the
. > correct deflection requirement.

Yes!  Even when the tables *did* have L/240 and L/360 limitations, the L/240 
figures did not take into consideration the long term creep of wood.

If the dead load is more than 1/4 the live load, the L/240 limitation for DL 
+ LL deflection will control.  (This is assuming uniform loads and that the 
long term deflection under dead load will be twice the initial elastic 
deflection under dead load.)

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