The LRFD combinations in IBC 2006 are based on ASCE 7-05, and are given in Section 1605.2, Load combinations using strength design or load and resistance factor design. The template file is RamSteelIBC2006_LRFD.cmb. The basic load combinations are given in Section 1605.2.1:
|
1.2D + 1.6L + 0.5Lr
| (Formula 16-2) |
|
1.2D + f1L + 1.6Lr
| (Formula 16-3) |
|
1.2D + 1.6Lr + 0.8W
| (Formula 16-3) |
|
1.2D + f1L + 0.5Lr + 1.6W
| (Formula 16-4) |
|
1.2D + f1L + f2Snow + E
| (Formula 16-5) |
|
0.9D + 1.6W
| (Formula 16-6) |
where
|
E
| = | defined as (see Sec. 1617.1.1) E = ρ QE +/- 0.2 SDS D |
|
QE
| = | the Seismic force from the analysis |
|
ρ
| = | the Reliability/Redundancy Coefficient as explained previously |
The f1 factor may be specified as either 0.5 or 1.0 when the load combinations are generated.
The f2 factor applied to Snow loads when in combination with Seismic loads may be specified as described previously.
The generated load combinations can be viewed using the Reports – Load Combinations command.
