ACI load factors

[Tdog67]

Fellers,

in 1990 from ACI the load factors were 1.4 for DL and 1.7 for LL, am I correct that now these are 1.2 for DL and 1.6 for LL?

please verify

 

[JPTStruct]

Yes, you are correct that the load factors are now the "standard" 1.2D and 1.6L. Note that when the load factors changed, the strength reduction factors changed as well. If you'd like to continue using the original 1.4D and 1.7L, you should look at Appendix C.

 

[BAretired]

The NBC reduced its load factors from 1.4 and 1.7 to 1.25 and 1.5 for dead and live load respectively. At the same time, they introduced a 'phi' factor which varied with material and with mode of failure, depending on the degree of confidence in the material and failure mode being considered. Structural steel in flexure has a phi factor of 0.9 whereas concrete strength has a phi factor of 0.6.

I do not know the ACI code, but in general, it is not safe to use old codes and simply adjust load factors. It is necessary to consider all of the aspects of the new codes.

BA