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RE: Single Family Housing Design

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James Cohen wrote:

. > Any comments to be offered on manufactured or modular housing?
. > 

I would stay away from them!  Although "modular" houses *have* to comply with 
the building code, *tremendous* liberties are taken in the design of 
"manufactured" homes.

I was called out to investigate a mobile home (manufactured home) that folded 
up while being transported.  (The 12" JR beams that comprised the frames 
buckled to the rear of the axle.)  There was no lateral bracing on the 
compression flange for these cantilevered beams.

Calculations that I made indicated that the maximum permitted stress for 
these unsupported beams was in the neighborhood of 6,000 psi.  (From 
memory.)  Calculations received from the manufacturer's structural engineer 
(a California SE) had the steel frame holding up the walls and the walls 
holding up the steel frame.  ASD calculations by the manufacturer's 
structural engineer showed that the maximum stress in the steel was "35,900 
psi < 36,000 psi, O.K."

If you like 1 X 3 wood studs in your walls, I guess manufactured homes are 
O.K.

HUD design requirements permit considering the "integrated" structure, 
whatever that means, which leads to some very creative engineering.

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