loose lintel design

huangyhg

loose lintel design
i'd like some information on how to design a loose lintel using a single steel angle.  by loose lintel, i mean the headers that often frame over doors and windows to carry portions of the masonry facade above.  it seems odd that there is little information on the design of these members when it is such a frequently used application.
all i've been able do dig up as far as design examples are vague rules of thumb and prescriptive deflection requirements.  i realize that there is an aisc spec for the design of single angle members.  the problem for me is, since these lintels are laterally unsupported (i think), a lateral force of about 60% of the vertical load will go into the masonry.  
how can i account for this effect in the masorny?  also how should bearing be addressed at the lintel ends?  and how should i determine the capacity of the masonry wall below to carry the lintel reactions?  i'd really like to have some kind of refernce on this with explicit design examples.  any assistance that you could provide would be greatly appreciated.  thanks.
adam
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typically, loose lintle spans are rather small, therefore, not a large angle is required.  also, if there is enough masonry above, you get an arching effect of the masonry, and the lintle loads become rather small.  a typical lintel for a door opening in 4" veneer is l3 1/2x5x5/16 llv.  and thats overkill.  (galvanized, of course).  as for bearing, usually you can just bear the lintel on the masonry veneer.  its not much different than that bottom brick supporting hundreds above it.
for other lintels, i would design them just as you would for a beam.