dh series jois

huangyhg

dh series joist
hi all,
we are modifying a building that was constructed around 1972.  fortunately we have existing drawings.  unfortunately, following joists are specified:
-28dh9 with 3 1/2" bearing shoe, 50' span
-18dh8 with 3 1/2" bearing shoe, ~30' span
also specified are:
-18h6 with 3 1/2" bearing shoe
-32lh12 with 5" bearing shoe
we do have the sji 50 yr catalog and cannot find a "dh" series.  of course, there are "h" series and "dlh" series.  has anyone heard of the "dh" series before or know where to find more information?
nothing specific, but i did run across an undated great west steel joist catalog out of canada (5th edition, 1st printing) that did refer to a "deep hat section" on page 2.  
great west steel is no longer producing steel joistsi believe it was bought out by canron some years ago.
if anyone has an earlier catalogue edition, maybe the "dh" nomenclature is there.  just thinking...
good hunting.
mike mccann
mccann engineering