[AT] Snoow load

[carl gogol]

Farmer-
I'm just curious - can you tell how the trusses failed?  Did just a few of 
them collapse in the middle or did whole roofs flop or buckle.  I have been 
noodling around trying to understand the major ways that truss roofs fail 
and from what I see here, most of ours built 20 years ago are not adequately 
braced to stop several trusses from flopping over in the middle of longer 
barns.   It is not unusual to see only a 2x4 from the peak of each end 
nailed to the center lateral brace that runs the length of the barn on top 
of the lower cord.  If you look at the truss specifications today, they 
require some sort of bracing every 40 feet or so - this was typically not 
done until recently.  Also, without a ridged ceiling, most trusses should 
have lateral bracing every 4' along the lower cord and similarly any member 
of the truss that can come into compression that is longer than 4'-6".
Carl Gogol
Manlius, NY
(2) AC D-14, AC 914H
Simplicity 3112 & 7116
Kubota F-2400
>> I have noticed in driving around this last week that this part of Central
> Indiana has
>> lost a lot of barns and tool sheds this winter. That roughly 2 foot snow
> fall earlier
>> which is so rare here was just too much for a number of them. It was not
> windy when it
>> fell and it was a little sticky so it just piled up on the roofs. I did
> wonder a little
>> about a few of my roofs especially the 28'x64' tool shed which has one
> open face. It is
>> pretty flat and that shed was built with light framing (by a previous
> owner of that
>> property) about 1959. The 3 large barns all have fairly steep roofs and
> since they are
>> all metal roofs if the snow gets too heavy it generally slides off. They
> are also framed
>> heavy. A few of the tool sheds/pole barns that went down didn't look all
> that old. I
>> didn't see any that looked like the tractors and stuff stored inside had
> been uncovered
>> yet. Of course it rained during much of January on the days that it was
> not an icy/snowy
>> mess or zero temps.
>> I have promised myself that I will do a little work on that tool shed to
> make it a
>> little stronger before next winter.$100 or less worth of lumber can do a
> lot to beef up
>> the trussing (of which it has almost none) in the rafter area and is
> pretty cheap
>> insurance. I also want to tie the rafters down better with a few anchors
> all the way down
>> to the foundation. It seems like we have been getting a lot more high
> winds over the last
>> few years. Again very cheap insurance.