Since I started looking at the new NYC Building Code with a topic that is tangential to my usual work, I might as well continue that way for a bit. A topic that was added to plain-vanilla IBC in its entirety by the New York City code committee is structural peer review. I don’t see it often because only one of the seven (old code) or eight (new code) reasons for it taking place is likely to crop up in my work. For anyone interested in the text, it was section 1617 in the 2014 code and it’s section 1618 in the 2022 code. Before I unleash a tidal wave of comments, New York City is not the only locality to add peer review to the IBC. It’s just the one I’m familiar with.
Six of the reasons peer review might be required can be described as “buildings that are structurally more daring” including being very tall or slender, having a single structural element that supports a large percentage of the loads, and having a lot of people in one place. Reason seven is “requested by the commissioner”, which in practical terms means requested by representatives of the commissioner, AKA the Department of Buildings. And the new-for-2022 reason eight is “Buildings designed by performance-based methods”, which is to say when the specific prescribed rules of the code have not been followed in favor of the newer performance-based design method. This is similar to the first six reasons in that it is a request for a second opinion when the structural analysis and design are outside the mainstream of practice.
Arguably, the biggest change to this requirement in the new code is that geotechnical peer reviews have been added. The requirements for 2014 included checking geotechnical issues in broad terms, but not a specific review of those issues. Geotechnical peer review is described in detail in the chapter on soils and foundations, in section 1818, but referenced in section 1618 to make sure it’s clear to people who might not refer to chapter 18 very often.
A single word that has caused some trouble has been clarified. In the old code, the peer reviewer is described as “a qualified independent structural engineer who has been retained by or on behalf of the owner.” In the new code, an entire paragraph has been added to explain what “independent” means. The short version: they can’t be involved with the project in another design or construction capacity.
The scope of review is much the same as it was before, while the list of required contents has become more specific. Because of the limits on which projects get reviewed, there have not been that many peer reviews here. I believe the total is in the low hundreds since the requirement was first added in 2008; since then, there have been more than 5000 new-building permits issued every year. In some places – California comes to mind – pretty much all buildings bigger than houses get peer reviewed. So the engineering community in New York needs more guidance, since this is not an ordinary part of our practice.
Part 1: Underpinning