Introduction

This video, the second in a four-part series, explores flexible diaphragm design in Shearwalls, building on the previous discussion of flexible vs. rigid diaphragm distribution. It explains that while some Canadian and US codes permit flexible-only assumptions (e.g., ASCE 7-16 for light-frame structures), NBC Part 4 requires both analyses. Engineers can determine flexibility based on diaphragm deflection exceeding twice the shear wall story drift, though the Program does not calculate this directly. A demonstration using a sample building shows how to toggle between flexible, rigid, or worst-case scenarios in Shearwalls. Running a flexible diaphragm analysis distributes forces based on tributary areas, with results guiding structural design. The next video will introduce torsional analysis in shearwall design.

Learning Outcomes

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

• Differentiate between flexible and rigid diaphragm distribution assumptions and their impact on shearwall design.
• Identify when flexible diaphragm distribution is permitted based on Canadian and U.S. building codes, including ASCE 7-16 and CSA O86.
• Utilize Shearwalls Program to select and analyze different diaphragm distribution methods.
• Assess shearwall deflections in the program and compare them with manually calculated diaphragm deflections to determine flexibility.

Instructional Video (Part 2 of 4)

Video Run Time: 03:51 minutes

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