Connecting the Load Path: Diaphragms Are More Than Just Deck and Fasteners

Open web steel joists and joist girders are often used to support the structure for steel deck and concrete floor diaphragms. The joists and joist girders not only provide gravity support but are often categorized as collector elements. After reviewing the methods for determining diaphragm capacity and force distribution, we will review the interaction of the diaphragm with the supporting joist structure to ensure a complete load path for the diaphragm forces.

Learning Objectives:

• Understand how shear stiffness analysis can be used in lieu of designing a diaphragm as rigid or flexible.
• Review component capacities and limitations for joists, deck and fasteners.
• Identify online tools that can be used to simplify the design process.
• Coordinate diaphragm design with connecting components and lateral resisting systems.