Moderately Ductile Level Moment Resisting Frames

9.4. MOMENT RESISTING STEEL FRAMES WITH MODERATE DUCTILITY LEVEL

Steel frames with moderately ductile members that transfer loads and moments are expected to provide a limited amount of non-linear deformation of column panel zones and beam-column connections under the earthquake actions. Rules for the dimensioning of the steel frames with moderately ductile members are given below:

9.4.1. General Conditions

9.4.1.1 - The width-to-thickness ratios of elements should not exceed the limiting width-to-thickness ratios, λ_md, from Table 9.3, for members designed as moderately ductile members.

9.4.1.2 - Both flanges of beams shall be supported against lateral and torsional displacements based on the conditions specified in 9.2.8 for members with moderately ductility level.

9.4.1.3 - The rules given in 9.3.1.3 are valid to dimension columns of the moment-resisting steel frames with moderately ductile level.

9.4.1.4 - The rules given in 9.3.1.4 are valid to dimension beams of the moment-resisting steel frames with moderately ductile level.

9.4.1.5 - For moment-resisting steel frames with moderately ductile level, it is not mandatory to comply with the requirement given in 9.3.2 that columns must be stronger than beams.