ACI 318-02 default load combinations

This section provides information on the default load combinations (technically, loading combinations) that RAM Concept creates when you start a new ACI 318-02 file. The purpose and origin of each load combination are given. You can remove or modify any of these load combinations. You can also add load combinations. The load combinations are from ACI 318-02 / IBC 2003, unless noted otherwise.

The load and strength reduction factors changed significantly in the ACI 318-02 code. In general, the load factors were reduced and are now in agreement with the strength design of other materials. The strength reduction factors were generally reduced in order to provide similar design results as the previous code (ACI 318-99).

RAM Concept uses loading types to determine the appropriate factors in some load combinations. The factor on "L" in ACI 318-02 equations (9-3), (9-4), and (9-5) will be equal to 0.5 for Live (Reducible) Loading, 1.0 for Live (Unreducible) Loading, 1.0 for Live (Storage) Loading, and 1.0 for Live (Parking) Loading.

Note: Some load combinations in mat (raft) files are of the Lateral Group type and use a "Zero-Tension" analysis. Since a load combination using a "Zero-Tension" analysis does not use Alternate Envelope Factors, then such load combinations in mat files have been expanded into multiple load combinations. In some cases, the assumption that all gravity loads act in the same direction have been used to keep the number of load combinations to a minimum. See Specifying Load Combinations for further description.

Parent topic: ACI 318-02 Design

Related concepts
Specifying Load Combinations