What Are the Seismic Design Rules in RISA-3D

The Seismic Design rules can be found in RISA-3D on the Data Entry toolbar or in the Spreadsheets menu. Below is a quick-reference description of the entries required. For further information refer to the Online Help File > Seismic Detailing.

Label

The label can be any description - it does not affect the analysis/design.

Frame Ductility

• High - Meets the requirements for Special Braced and Moment Frames.
• Moderate - Meets the requirements for Intermediate Moment Frames.
• Minimal - Meets the requirements for Ordinary Braced and Moment Frames.

Overstrength

Check this box if this member type requires Overstrength Load Combinations. Note that only load combinations with Omega will then be used for Seismic detailing.

Moment Connection

• BFP - Bolted Flange Plate - Chapter 7 of the 2009 supplement to AISC 358.
• RBS - Reduced Beam Section- Chapter 5 of AISC 358.
• BUEEP - Bolted Unstiffened Extended End Plate - Chapter 6 of AISC 358
• BSEEP - Bolted Stiffened Extended End Plate -Chapter 6 of AISC 358.
• WUF-W - Welded Unreinforced Flange - Welded Web - Chapter 8 of the 2009 Supplement to AISC 358
• Other/None - All Other Frame types

Overstrength

Check this box if this member type requires Overstrength Load Combinations. Note that only load combinations with Omega will then be used for Seismic detailing.

Z Factor

The ratio between the plastic section modulus for the reduced beam section and the unreduced beam.

Hinge Location

The location of the assumed plastic hinge in inches from the face of the column.

Overstrength

Check this box if this member type requires Overstrength Load Combinations. Note that only load combinations with Omega will then be used for Seismic detailing.

KL/r

Check this box to apply Maximum slenderness to Specially Concentrically Braced Frames, K, V or inverted V braces for OCBF systems.