Performance based design is a term that is ill defined and is often used as an excuse to ignore the building codes.
From a code perspective PBD can be divided into two classes, those that comply with the normal building code provisions and those that violate one or more code provisions.
If your building would comply with the building code without PBD, what PBD methodology you implement is not a code issue but you still have to be concerned whether the methodology is appropriate and valid. This is likely true when your performance objectives are related to performance when subject to wind. When you consider seismic or other loadings then the world gets more interesting.
If the building regulations are formulated in terms of objective performance criteria and you can show compliance, you are code compliant.
If PBD is used to rationalize a building that would otherwise not comply with the building code then you have to ask what gives you the legal basis to ignore a code provision, what are the acceptable performance objectives, and how you will establish compliance. This is where the term PBD is frequently used to gloss over compliance with the code. Voodoo may be a politer way of describing some of the approaches taken.
ASCE 7-16 Section 1.3.1.3 contains some reliability criteria for PBD. While this criteria is interesting I suggest that most engineers would not know how to establish that their final design meets the established performance objectives.
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Mark Gilligan
Berkeley CA
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Original Message:
Sent: 11-12-2019 13:20
From: Danielle Schroeder
Subject: Performance Based Design
Starting in the early 20th century, if a building or other code was not available to prescribe the way design was to be performed, engineers designed structures based on their personal knowledge of materials and systems behavior and performance. This practice is called performance-based design (PBD) and there are several books on this topic on the ASCE Library. For example, one book released earlier this year was the "Prestandard for Performance-Based Wind Design" which can be viewed here: https://ascelibrary.org/doi/book/10.1061/9780784482186
Are you a believer in performance-based design? Have you used PBD on a past project?
Excited for a healthy discussion!
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Danielle Schroeder EIT, A.M.ASCE
Associate Engineer
Pennoni Associates
Philadelphia PA
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