§2.9 Frame Design
§2.9.1 Strength of Beams and Columns
Strong Column-Weak Beam should satisfy Equation 9-3 of the AISC 1997, Except that M*pb is based on the requirements of Section 3.2.6 in FEMA 350. Note that Cpr is always taken equal to 1.2 for this check.
§2.9.2 Lateral Bracing of Column Flanges
= | ||
= |
§2.9.3 Panel Zone Strength
This allows us to determine the panel zone demand from the beams at both sides of the column and design an appropriate web plate to carry the demand. Refer the FEMA 350 for an explanation of the parameters shown above. Note that Cpr is always taken equal to 1.2 for this check.
§2.9.4 Section Compactness Requirements
Beams should conform to the requirements of AISC Seismic Provisions. Per FEMA 350 Section 3.3.1.1 in the case of a beam with a reduced beam section the program considers the bf/2tf to occur at the ends of the center two-thirds of the reduced beam section (RBS). For this reason the engineer is required to input three dimensions to define the RBS, the distance face-of-column to start of RBS (a), the length of RBS (b), and the cut of the flange each side of beam (c). Refer to the v7.0 manual for more details on assigning reduced beam sections to members in the model.
For columns FEMA 350 stipulates that they should be compact unless a non-linear analysis shows that they do not yield. All of the building codes already require that the column is compact and as such no additional FEMA 350 compactness checks are performed for columns.