The architect has handed you floor plates, and you need to figure out whether a moment frame system will work for seismic resistance. The problem? You don’t have member sizes yet. You don’t know the period. And without the period, you can’t pull loads from the response spectrum. Classic chicken-and-egg.
In our first two posts on Performance-Based Design (PBD), we covered the “what and why” – shifting from prescriptive codes to targeting specific building performance – and then we looked at the “who and how” of setting those crucial performance objectives. If you missed them, I’d suggest giving them a read first as we’re about to jump into the deep end of the pool.
Following An Introduction to Performance Based Design, this article focuses on how to actually run a PBD project in practice—who needs to be involved, what process they follow, and how performance objectives are defined.
On complex projects—tall buildings in Vancouver, essential facilities in higher seismic zones, or structures with unusual geometry—the prescriptive NBCC pathway can start to feel limiting. Performance-Based Design, or PBD, is the framework that lets us define how the building should behave and then design backwards from those objectives.
We spend a lot of time ensuring our structures are strong enough (hello, ULS!). But what about how they feel and perform day-to-day? That’s where Serviceability Limit States (SLS) come in. Sagging floors, cracked partitions, or that annoying bounce when someone walks by – these are all SLS concerns. The National Building Code of Canada (NBC) 2020 has brought SLS criteria more formally into the main body of the code (Article 4.1.3.4.), underscoring its importance.
Ever wonder how we landed on the structural design provisions we use today in Canada? The National Building Code of Canada (NBC) hasn’t always looked the way it does. It’s a living document, evolving with research, experience, and a continuous drive for safer, more reliable structures.
Navigating load combinations can sometimes feel like a complex dance. Get one step wrong, and the whole routine can fall apart. The National Building Code of Canada (NBC) 2020, specifically Article 4.1.3.2. and its associated tables, lays out the choreography for ensuring our structures are safe under various loading scenarios. Whether you’re getting to grips with principal and companion loads or double-checking a tricky overturning case, a solid understanding here is non-negotiable.
I’m Arun Kishore, a Professional Engineer based in Vancouver, BC. I specialize in structural engineering for LNG facilities, civic water infrastructure, and advanced buildings — with a passion for automating the tedious stuff so engineers can focus on what matters.
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