LRFD Load combinations with positive and negative numbers
LRFD Load combinations with positive and negative numbers
(OP)
I have number of fixed end moments on a roof truss. (due to dead, live, snow and wind) Some of the wind moments are negative. Do I just combine the negative numbers straight into the load combination with the positive moments for example from Eq 16-6 in IBC 2015...
0.9D + 1.0(-W) + 1.6H
Is that correct? It makes sense in my head. I can expect positive moment due to dead load (or anything else) to counter-act the negative moment due to wind. (And obviously H is zero in my example)
0.9D + 1.0(-W) + 1.6H
Is that correct? It makes sense in my head. I can expect positive moment due to dead load (or anything else) to counter-act the negative moment due to wind. (And obviously H is zero in my example)






RE: LRFD Load combinations with positive and negative numbers
If you know that a certain combination will not give max forces the you can omit this combination
But generally you need to consider whatever gives the extreme forces
Positiv or negativ is sometimes difficult to see in a bigger structural model
best regards
Klaus
RE: LRFD Load combinations with positive and negative numbers
RE: LRFD Load combinations with positive and negative numbers
there is no general answer
best regards
Klaus
RE: LRFD Load combinations with positive and negative numbers