Introduction

This final video in Lesson 3 covers torsional analysis results for both flexible and rigid diaphragm designs in the program. Under the flexible diaphragm assumption, loads are distributed based on the tributary area method, with the program applying a 5% accidental eccentricity per NBC Commentary J174. For rigid diaphragm analysis, the log file updates to include torsional rigidity in both X and Y directions, the center of rigidity, and the center of load, incorporating a 10% accidental eccentricity as required by NBC. The chosen capacity-based or deflection-based distribution setting impacts the torsional rigidity used in the analysis.

Learning Outcomes

By the end of this lesson, you will be able to:

• Explain the process of torsional analysis in shearwall design for both flexible and rigid diaphragm assumptions.
• Identify the accidental eccentricity requirements for seismic design based on NBC Commentary.
• Interpret the torsional analysis results in the Program, including torsional rigidity (J), center of rigidity, and center of load for different design settings.
• Differentiate between capacity-based and deflection-based distribution methods and their impact on torsional rigidity in seismic analysis.

Instructional Video (Part 4 of 4)

Video Run Time: 02:37 minutes

This video utilizes one project file and it is available for download below.