March 11, 2026

242 - Learning from Earthquake Engineering with Negar Elhami-Khorasani and Justin Moresco

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Show Notes
Transcript

Being a part of broader civil engineering and built environment sciences, we have the unique opportunity to learn from other "sister" disciplines, rather than coming up with everything on our own. Especially, when those disciplines have 100+ years of experience in investigating stuff that has recently emerged as one of the leading challenges in our field.

The other discipline is Earthquake Engineering.

The interesting stuff - community resilience and managing safety across tens of thousands of buildings exposed to the same hazard.

Our field of application - Fire Safety of WUI communitites.

And most importantly, my diligent guests: Negar Elhami-Khorasani from University at Buffalo, and Justin Moresco from Applied Technology Council.

In this episode we discuss how earthquake engineering deals with hazards through four steps:

Hazard assessment,
System response (exposure)
Damage assessment (vulnerability)
Level of loss (consequences)

You will learn what are fragility functions and how they are applied. We will also discuss building archetypes and how we can use them to increase or decrease the level of detail in our analysis.

If you want more:

Recommended follow-up podcast episodes:

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WEBVTT

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Hello everybody.

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Welcome to the Fire Science Show.

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I always find it an amazing opportunity when we can learn something useful from experiences of other fields of engineering.

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It's not that we have to discover or come up with, uh, everything on our own, actually given the limited resources we have, that would be actually quite stupid if we tried to do that.

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And uh, there have been others who have been dealing with natural disasters and other things that threaten people in somewhat similar ways as fires in the past.

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We can take their knowledge, we can apply their knowledge to our problems.

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We can build on it and we can grow.

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And one of such fields is earthquake engineering.

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We have not talked about earthquake engineering, yet in the podcast, uh, fires are a big part of earthquake engineering because, uh, post earthquake fires are quite a thing and they're quite scary.

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Uh, regardless.

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Earthquake engineering deals with how structures respond to earthquakes and what happens to the whole cities and communities after earthquakes.

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And you can, you already see a ling in here because today we are talking about communities and societies and their resilience all the time In the fire, safety, engineering, and specifically in the wildfire, we engineering and I have found two guests that can confidently talk about transferring knowledge from the world of earthquake engineering into world of fire safety engineering, and those guests are.

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Professor Negar Elhami-Khorasani from university at Buffalo Negar is a structural engineer and she's been in the podcast a few episodes ago.

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She just won the Magnussen in the world at IFSS.

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And the second guest is Justin Moresco from Applied Technology Council, who's also uh, an earthquake engineer and who.

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who works a lot in transferring this knowledge from the space of earthquake engineering into the space of fire safety engineering.

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So in this particular episode, we will discuss about how.

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Earthquake engineering works with the disaster.

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What are the approaches that these guys are using?

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Uh, which of them are transferable to define safety engineering?

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What are the similarities?

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What are the differences?

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And basically what are the best things we can learn from earthquake engineers?

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And trust me, there is a lot of them.

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And they're not only applicable to wildfires, they're also applicable to normal building fires because some of this is, is.

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Pretty universal.

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They have a different views on stuff that we do.

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They definitely use a lot of probabilistic methods and risk in their assessments.

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I like it very much.

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So, yeah.

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Let's spin the intro and jump into the episode.

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Check their website@orconsultants.com And now let's head back to the episode.

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Hello everybody.

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joined once again by Negar Army, from University at Buffalo.

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Hey Nagar, welcome back.

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Hello.

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It's great to be back and I'm really happy to be here this time, uh, with a wonderful colleague.

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yeah, we've promised a quick return and, and we have delivered.

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And, uh, the interesting colleague is Justin MoCo from Applied Technology Council.

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Hey Justin, welcome to the Fire, sun Show.

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It is great to be here, so great to be on this panel with Nagar.

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Fantastic.

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And, uh, Nagar, you're already well known to the Fire Science Show audience.

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If you don't know Negar, there's an episode about structural fire engineering that you have to catch up just in, you're here for the first time.

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Maybe, uh, can you introduce yourself, what you're doing and what's Supply Technology Council doing

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Yeah.

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So I'm, I'm a structural engineer and an earthquake engineer.

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I'm, I'm with the Applied Technology Council.

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We're a nonprofit based in the San Francisco Bay area, and we develop tools, technologies, and resources to help communities be more resilient to natural hazards.

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Okay, and those natural hazards, I assume now evolve also wildfires.

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They do?

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Yes.

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Unfortunately.

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Yeah.

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we, we joined together, uh, Negar proposed to do this episode.

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and she got my attention by mentioning that you guys are trying to implement a lot of earthquake, uh, or earthquake engineering knowledge into improving resiliency of wildfire communities.

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And I found it very interesting, especially value those links between disciplines and, you know, learning from, from each other's.

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Maybe let's start with, uh, do you think, or why do you believe that, uh, engineering brings valuable lessons to, to wildfire, uh, resiliency?

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So, um, earthquake engineering, um, research has been going on for many, many years, similar to wildfires, but earthquakes focusing inside the built environment and looking at, structures as well as communities, response and recover.

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And, um, it started with life safety, basically saving lives, building the way that we can, resist the, earthquake.

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And then it has expanded in years and now days in the US to focus on, it's what's called functional recovery.

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Basically the idea is that after, uh.

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an earthquake, not, not for every, uh, extreme earthquake, but given an earthquake intensity, want to have a functional, community after the event, to a reasonable extent.

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So

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Hmm.

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even the, uh, way they've been thinking about it and given the tools that they have developed, we think that we don't have to reinvent the wool for other hazards.

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So, you know, other hazards such as floods, for example, have been following and now wildfire.

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So we can't, we don't need to start from scratch.

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Hmm.

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Wildfire is specific to itself, the, in terms of the dynamics of the fire and the details of, um, how it's present inside communities.

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But, uh, we can learn how, uh, the tools and decision making happen in the earthquake and bring some of that into wildfire.

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And I'll let Justin, add to that.

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Um.

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Yeah, no, I think what you said is spot on Nagar, that we've been fortunate, in the earthquake world in that we've had really, really well funded programs in the United States stretching back more than 50 years, where researchers and practitioners have been coming together to try to develop solutions to the problems of the hazard.

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And, and so then when we look over on, wooey Fires, uh, we see that a lot of these decision making tools don't seem to be there.

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And so we can then bring some of the learnings, um.

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Try to avoid the mistakes that were made over on the earthquake side and try to help move, um, Huey Fire, um, forward more quickly.

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so, so, okay.

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What's the similarities?

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What's the differences?

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I, I, I would assume that similarity is in, in the outcomes, in the damage, the differences that come immediately.

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My hand is kind of, not sure if you can predict earthquake, um, not an earthquake scientist, but my feeling is it's difficult, uh, whereas, uh, with wildfire, you perhaps have a warning shortly after a few hours a day, two days before.

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How, how do you feel about differences and, and, and, and similarities between the, the two fields

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in, in terms, well, I mean in terms of similarities, there's fundamentally, you have some sort of, you have a hazard, right?

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You have some, an intensity that can do damage, to the, the built environment.

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and so how you go about considering the interaction between that hazard and the built environment and then develop, estimates for what the outcomes of that damage may be.

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oftentimes it's, you know, expressed in terms of damage and fatalities and downtime, um, so that, you know, at, at the highest conceptual level, regardless of the hazard.

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I think that applies and we now have, like I said.

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Decades of experience demonstrating that we can do that and it can lead to informed decisions, right?

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So that communities can be more prepared and can hopefully reduce the expected losses, from, from future events.

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um, I think the, you know, at the highest level, that's where the, the similarities are.

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the, some of the, the differences are with wildfires.

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you do have a firefighting capacity,

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Hmm.

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that is, that is unique, um, at least to relative to the earthquake world.

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Um, you also have this, interaction between hazard and vulnerability.

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That is different, than the earthquake world.

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You, you could argue that you do have a similar pattern with other hazards like flood, for example, where you have debris that can be picked up and become part of the hazard.

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But on the wildfire side, you know, buildings that are highly vulnerable and therefore can become a source of the fire, um, create this sort of feedback loop that you don't get, over on the earthquake world.

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And then I think the other major difference that comes to mind for me is that you really have to be thinking at both the individual building level and the community level because.

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There is this, um, sort of herd.

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I, I like to use the term herd immunity concept, at least in my, in my, the way I conceptualize it.

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Where if you have a lot of buildings, if you take a typical, you know, say suburban neighborhood where you have a fairly dense, um, development, if some of those buildings catch fire and they're close to other assets, even if those other assets do have fairly fire resistant features, they're gonna be at a much higher probability of igniting themselves.

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And over in the earthquake world, you don't really have that phenomenon.

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You can, you can kind of largely sort of ignore the surrounding buildings.

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You can look at it more building by building, and, and still generate, you know, fairly accurate, expectations of loss.

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This is very interesting concept.

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And in terms of the, the background experience, do you consider this like a, a global perspective or is it more like a West coast US perspective from what, what you've been doing so far with the earthquake engineering

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Uh, from the earthquake side?

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No, I, I think at this point it's, it's global.

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There's, yeah, there's, there's research groups in, in Europe, Italy, um, Pavia comes to mind.

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Uh, London, uh, Japan has a lot of, um, advanced earthquake engineering, New Zealand Advanced Earthquake Engineering.

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there's probably, uh, south America, Chile is quite sophisticated and I think at this point, probably most people have more or less adopted, um, a, a pretty common methodology to how you think about risk from, from earthquakes.

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Yeah.

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concepts that we're discussing today in the world of earthquake engineering.

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Please, uh, forgive me my ignorance, but I, I literally don't know this space at all.

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Uh, are they like, well matured?

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Is it something being developed or, or like, how far ahead is earthquake engineering with those concepts, uh, ahead from us.

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It, it, it's, it's very well developed.

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Yeah.

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Okay.

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Yeah.

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Very well developed.

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Yeah.

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I will just add something perhaps quick.

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Uh, so I agree with what Justin mentioned, the similarities and, uh, differences.

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Uh, what else I can think of perhaps on the, The life safety part again for me.

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So earthquake, um, you, as you mentioned, you don't get much warning right.

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So, uh, you really need to design your structures to stand up, uh, once the earthquake happens.

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So life safety is pretty important.

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Consideration.

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Hmm.

00:12:56.736 --> 00:12:58.116
Um, it's the same thing for ui.

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Life safety is super important, but I think it's easier hopefully, to be achieved because of the warning that you have.

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If you think about the evacu evacuation routes, if you, they're, they're properly designed, or alternatives.

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I know that, um.

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We have not the, the, the, at least in the US the idea is to have the community evacuated, not staying back and fighting the fire.

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But some of the recent fires extremely, intense and I would say that led to fatalities.

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For example, the Lahaina fire, it happened so close to the community.

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It basically was at the border of the community

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Hmm.

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the warning was not, you know, It wasn't a lot of time, and then there was a gridlock and people couldn't get out.

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So, um, it actually led to fatalities.

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So in those cases, maybe the option of having a shelter, inside the community, some, you know, other options to be considered, uh, so that people can, uh, not necess, they don't necessarily need to evacuate outside the community, but if there's a nearby shelter that they can get in for safety.

00:13:59.730 --> 00:14:08.880
But potentially, for me, I think the life safety problem in the should not be as hard as the earthquake side.

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However, the damage side, you know, after an earthquake, yes, you may have collapsed structures, hopefully not, but you, you still have buildings that might be standing and you just need to have to go back and repair.

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Whereas after Hui, technically what, where we stand right now, we look at communities where tens of thousands of houses are gone.

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There's nothing left.

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So the level of destruction is pretty, intense after these recent w events we've had in, especially in the us.

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So that site then is pretty much rebuilding from scratch again,

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Hmm.

00:14:51.173 --> 00:14:54.682
um, makes it, um, harder on the WWE side than the earthquake side.

00:14:55.563 --> 00:15:03.033
Interesting about that aspect of, of, uh, wildfires, communities in a short notice and being able to escape.

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I had a really interesting, uh, interview with Eric Link and, and we've discussed, uh, NIST Escape Project, that, uh, I think that was campfire.

00:15:11.441 --> 00:15:12.791
It was campfire, yeah.

00:15:12.791 --> 00:15:15.910
So, so I would refer to, to that podcast episode.

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You'll find it in the shows.

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Of course, of course.

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You'll, uh, okay.

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Let's move, uh, so we know, uh, why should we learn from Meco engineering?

00:15:24.701 --> 00:15:30.431
And now you've convinced me that, uh, those people know some stuff that I'm potentially interested in hearing.

00:15:30.431 --> 00:15:31.961
So let's hear it out.

00:15:31.961 --> 00:15:37.461
What's, what's the paradigm of, building this resilience through the lens of, earthquake engineering?

00:15:37.461 --> 00:15:41.001
Where, where would we start in applying the knowledge from that space?

00:15:41.385 --> 00:15:53.206
So, in earthquake engineering, the risk, um, probabilistic risk assessment methodology that's pretty well established, um, basically relates to this performance based design.

00:15:53.206 --> 00:15:58.530
So they have a very systematic way of, defining the problem.

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in.

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Specific pieces and then connecting those pieces together.

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And then the beauty of the, I would say, methodology is that, each piece, um, has its own uncertainty.

00:16:11.004 --> 00:16:16.134
So because it's extreme event, we don't, we can't, it's, it doesn't make sense to do deterministic analysis.

00:16:16.134 --> 00:16:22.975
So each, I would say, piece of the process will have its own uncertainties and we then can quantify them.

00:16:22.975 --> 00:16:27.654
I'll mention the four pieces, and then I'll let Justin to continue

00:16:27.740 --> 00:16:31.250
I was, I was about to interrupt you and ask what the pieces are.

00:16:31.269 --> 00:16:31.840
the pieces?

00:16:31.840 --> 00:16:37.149
Okay, I'm gonna mention the four pieces and then let, uh, Justin expand on it.

00:16:37.149 --> 00:16:38.950
So the first piece is the hazard.

00:16:38.950 --> 00:16:42.970
So it's, if we think of these as boxes, the first box is a hazard box.

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Then, um, there is what we call system response.

00:16:46.333 --> 00:16:49.153
Basically, let's say right now, let's think of it as a building.

00:16:49.153 --> 00:16:51.494
You're looking at earthquake response of the building.

00:16:51.494 --> 00:16:56.774
So hazard is the earthquake, and then you have the building response to that, uh, earthquake.

00:16:56.774 --> 00:16:59.083
Then what we call damage assessment.

00:16:59.083 --> 00:17:00.374
So now you had a response.

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What was the level of damage?

00:17:01.903 --> 00:17:05.594
And then finally from that damage was the level of loss.

00:17:05.788 --> 00:17:09.048
and each of them would be considered from a probabilistic perspective.

00:17:09.482 --> 00:17:10.893
Each, yeah, each box.

00:17:10.893 --> 00:17:15.482
So the hazard you have, you don't have one earthquake, you have a suit of ground motions.

00:17:15.482 --> 00:17:17.282
Um, the system responds.

00:17:17.282 --> 00:17:22.863
Basically you are looking at how your building is shaking and then quantifying that.

00:17:22.863 --> 00:17:24.935
And then, the third one, damage.

00:17:24.935 --> 00:17:31.321
You typically, quantify the probability of exceeding a certain, um, damaged state.

00:17:31.321 --> 00:17:41.674
Um, you lump these things because, otherwise it's gonna be very hard to, Do this process for every, I mean, there are different level of, we can get into this.

00:17:41.674 --> 00:17:55.737
This is perhaps after we, there are different level of details of, uh, quantification that you can do if you do a inventory of buildings at the community level versus if you look at one, a single building, that's, there's a different level of detail.

00:17:55.737 --> 00:17:59.606
You can look into this and then, but there is a probability of exceeding a damage state.

00:17:59.606 --> 00:18:02.846
So that's again, a probabilistic uh, approach.

00:18:02.846 --> 00:18:05.787
And finally, from there you get the probability of loss, which is risk.

00:18:06.042 --> 00:18:15.323
I, I really love we're talking about frameworks and, you know, worked out stuff that that's potentially applicable, but yeah, please just expand on those.

00:18:16.034 --> 00:18:23.672
so gi given and, and there are different terms that are used in different, you know, sort of applications or we might call them industries.

00:18:23.672 --> 00:18:32.521
Uh, I mean the terms that I, I sort of came up with using our, our hazard exposure, vulnerability and then consequences.

00:18:32.521 --> 00:18:42.204
and one of the powers that this enables is that, like Nagar was saying, that there's, there's different, um, sort of levels and complexity.

00:18:42.204 --> 00:18:43.765
You can apply, right?

00:18:43.765 --> 00:18:54.921
And you can, depending on the need and also sort of the, the sort of capacity that somebody has in terms of time and budget, you can make things ratchet up the complexity or the simplicity.

00:18:54.921 --> 00:19:07.231
but you know, just to give one, one really powerful tool is to go back and, and look at what would happen if a well-known historical event were to occur again.

00:19:07.231 --> 00:19:14.601
you know, at least in California where I'm from, one of the most famous earthquakes was in 1906 that devastated San Francisco.

00:19:14.601 --> 00:19:33.128
And so there's been a lot of work that's done to say, okay, given the current inventory that we have information about the buildings and the people in the region, if that same earthquake were to occur today, what would the expected losses be?

00:19:33.128 --> 00:19:50.559
and that because there's so much sort of public awareness of that event, when you then do that sort of study, it automatically becomes, um, of high interest to the media and the public and, um, and that, you know, bring some awareness to the current risk.

00:19:50.559 --> 00:19:54.039
And it can help emergency managers and their planning.

00:19:54.039 --> 00:19:59.980
It can help policy makers justify investing more in earthquake safety and, and resilience.

00:19:59.980 --> 00:20:04.248
Um, so that, that's like one single scenario event.

00:20:04.248 --> 00:20:14.762
Um, but then you can make that ratchet up the complexity and you can say, well, we're not just gonna consider rerunning, one historical event.

00:20:14.762 --> 00:20:27.903
We're gonna consider all potential future events that we, that we think are likely, uh, and the most sophisticated models out there would then have tens of thousands of potential.

00:20:27.903 --> 00:20:29.772
Individual events.

00:20:29.772 --> 00:20:50.053
And these, these models would have that same information about the, the existing inventory that's out there, but then they run each one of those, um, they carry through the uncertainties in terms of the level of shaking caused by each one of those events, the amount of damage that would occur, and then the losses that result.

00:20:50.053 --> 00:21:12.103
Um, you do that for tens of thousands of events and, and then you can generate, um, statistics, probabilities on, okay, well what do we think the what, what are the what, what are the average annualized losses, from all those events Or, um, what, what is the probability of, of exceeding a certain level of damage in the future?

00:21:12.103 --> 00:21:17.247
communicating that kind of information becomes more complicated because it's probabilistic.

00:21:17.247 --> 00:21:25.751
Um, so the places where that kind of information gets used is, within the insurance industry, right?

00:21:25.751 --> 00:21:36.113
So they would, um, insurance companies would want to be able to demonstrate that, they have enough claims, paying capacity, considering all possible future events.

00:21:36.113 --> 00:21:41.172
it also enables true or benefit cost analysis, right?

00:21:41.172 --> 00:21:49.092
Because to do a real sort of, you know, rigorous benefit cost analysis, you don't wanna just consider one possible event.

00:21:49.092 --> 00:21:52.932
You want to consider all possible future events.

00:21:52.932 --> 00:22:11.614
and so you can imagine, you could say, okay, well, Here's this new building code or these new important changes that we'd like to make to the way, um, cities are developed or buildings are constructed, say, with with enhanced resistive capacities to, in this case earthquakes, but it could also be to, to other hazards.

00:22:11.614 --> 00:22:16.259
Um, if we were to make those changes, what would the benefits be?

00:22:16.259 --> 00:22:25.184
And, and the way you would look at those benefits is you would say, okay, well let's, let's imagine that all these events occur under the status quo and now and get our.

00:22:25.184 --> 00:22:27.779
Expected annualized losses.

00:22:27.779 --> 00:22:37.767
and now let's, let's imagine that that a certain percentage of the buildings or all of the buildings and all of the communities are built to this higher standard.

00:22:37.767 --> 00:22:44.018
And then we, and now we, now we run the models again and, the losses should come down.

00:22:44.018 --> 00:22:53.198
And so you can compare the losses under the current status quo versus the expected losses under the, that enhanced sort of building practices.

00:22:53.198 --> 00:22:55.972
and there should be a, a big delta, we hope.

00:22:55.972 --> 00:23:04.041
Um, and then you can, and you can use that over, you know, you, you've gotta take into consideration the, the time value of money.

00:23:04.041 --> 00:23:09.855
but you can then arrive at a present day, cost benefit analysis, and, and.

00:23:09.922 --> 00:23:12.832
Yeah, I, I see the direct applicability of that approach.

00:23:12.832 --> 00:23:24.865
However, I also see like an imminent problem with it because, uh, the scenario definition, I believe for earthquake it would be just the earthquake, while the severity of the fire will largely depend on level.

00:23:24.865 --> 00:23:27.955
So you have an nasty feedback loop within there, right?

00:23:28.729 --> 00:23:29.298
Exactly.

00:23:29.355 --> 00:23:30.224
Right, right.

00:23:30.224 --> 00:23:37.664
So, so I'll, let me, um, dive in a little bit on the earthquake side and then bring it back to your question and the community side.

00:23:37.664 --> 00:23:43.424
So when we do this type of analysis, again, the level of, um, complexity, um, may vary.

00:23:43.424 --> 00:23:48.105
You may look at one structure or you may look at a whole inventory of structures.

00:23:48.540 --> 00:23:48.661
Hmm.

00:23:48.734 --> 00:23:50.144
you're looking at one structure.

00:23:50.144 --> 00:23:54.674
there's this concept of fragility function in earthquake engineering that quantifies damage.

00:23:54.674 --> 00:23:59.924
And that is a function of, um, XA is basically your hazard.

00:23:59.924 --> 00:24:09.105
Like your, either depends again, but it, it's a, it's a function of your hazard intensity or the impact of the hazard on your structure.

00:24:09.105 --> 00:24:13.305
So in earthquake, for example, drift, how much your structure is deforming, right?

00:24:13.305 --> 00:24:15.734
That's a function of your earthquake intensity.

00:24:15.734 --> 00:24:19.694
And then the Y axis is the probability of exceeding a damage state.

00:24:19.694 --> 00:24:25.724
And that again is lumped as is a slight damage, moderate damage, extreme damage or collapse.

00:24:25.724 --> 00:24:28.484
And when we say slight or moderate, then these.

00:24:28.484 --> 00:24:31.759
Have their own specific definitions.

00:24:31.759 --> 00:24:40.846
So slight damage is just, you know, crack some cracks, minor cracks, something that, doesn't really compromise safety all the way again to collapse, right?

00:24:40.846 --> 00:24:49.473
So, you look at these and you say, okay, this can be derived for individual structures as a function of your structural system.

00:24:49.473 --> 00:24:54.394
A steel moment frame will have a different and a high, and also number of stories.

00:24:54.394 --> 00:25:04.141
So a high-rise steel moment frame will have different set of fragility functions compared to a low rise, concrete structure with shoe roll

00:25:04.582 --> 00:25:04.801
Hmm.

00:25:04.951 --> 00:25:05.461
up something.

00:25:05.461 --> 00:25:05.760
Okay?

00:25:05.760 --> 00:25:17.683
So this is how we categorize an earthquake engineering, try to, Basically quantify again, the uncertainties, but then scale it up where you can look at the inventory of structures.

00:25:17.904 --> 00:25:18.384
Mm-hmm.

00:25:18.733 --> 00:25:27.617
Now, if I wanna tie back to your, uh, question on the, the one approach, again, it's, it's, it's conceptual.

00:25:27.617 --> 00:25:39.384
We haven't done it yet, but, it is not sufficient to look at these fragilities or develop these fragilities basically at the structural level, even if it's just a residential.

00:25:39.384 --> 00:25:46.494
You know, we categorize as this house has certain number of features with this level of vulnerability.

00:25:46.494 --> 00:25:50.343
So this is going to be the, the probability of exceeding certain damage state.

00:25:50.343 --> 00:26:11.691
But I think we may need to look again broader and think about, Community archetypes or neighborhood uh, representation of the conditions because of the dependence of your hazard intensity on the vulnerability because the houses become the fuel themselves.

00:26:11.691 --> 00:26:20.330
They start burning, they create the intensity for houses downstream, and therefore there's that feedback loop loop again.

00:26:20.330 --> 00:26:33.861
So if you have more vulnerable neighborhood, it means that there may potentially all catch on fire the amount of heat, energy and potentially fire spotting that other houses will receive, it's gonna go higher.

00:26:33.861 --> 00:26:42.849
So it won't be enough just to perhaps look at, and we can derive, we can develop these fragilities and it could potentially be maybe binary.

00:26:42.849 --> 00:26:46.434
I don't know how much in between damage we get for these timber.

00:26:46.434 --> 00:26:49.029
Yeah, pretty much, right?

00:26:49.029 --> 00:26:50.740
So either Yeah.

00:26:50.740 --> 00:26:58.329
But, um, at the neighborhood level, then we have to, um, and, and you don't have to come up with a fragility function.

00:26:58.329 --> 00:27:00.849
You can always come up with a fragility surface, for example.

00:27:00.849 --> 00:27:07.390
So you have multiple X axis in terms of ca, um, characterization of the community, like structure, separation distances.

00:27:07.390 --> 00:27:14.589
You know, you need to combine some of these, parameters that influence the hazard and the outcome.

00:27:15.500 --> 00:27:25.131
who's the user of that is so, so this tool in that sense is not perhaps guided towards a single house investor.

00:27:25.131 --> 00:27:26.300
Like, I'm building my house.

00:27:26.300 --> 00:27:33.500
I would like to understand how to build my house best, because then you just apply, you know, the best guidance that that exists.

00:27:33.500 --> 00:27:38.060
Uh, there are guidelines how to, um, your structure.

00:27:38.060 --> 00:27:40.701
I think that's the correct word, hardening, uh, structures.

00:27:40.701 --> 00:27:41.270
Yeah.

00:27:41.270 --> 00:27:46.851
But, uh, this is more guided towards community and, and, and like urban management.

00:27:46.851 --> 00:27:47.162
Right.

00:27:47.346 --> 00:27:47.675
Yes.

00:27:47.675 --> 00:27:59.294
So emergency management, the fire department, the, these commun communities, typically in the US they have their, wildfire protection plans, community, wildfire protection plans.

00:27:59.294 --> 00:28:20.739
And, um, the PE people around the table again include, um, the Fire Chief, the Office of Emergency Management, um, and they are trying to understand the risk to their community basically prepare for it, prepare if the risk is too high, they, they think they have to do something right.

00:28:20.896 --> 00:28:33.166
I'm asking this because, uh, you know, I, I assume that in earthquake engineering, this process is a part of designing a building and figuring out how I should do the PPD for this particular building, it's also done at community level.

00:28:33.236 --> 00:28:34.221
is also that community.

00:28:34.221 --> 00:28:34.436
Just,

00:28:34.734 --> 00:28:41.540
so on on, on the earthquake side, so for, the, the classic way is you're develop, you're designing right?

00:28:41.540 --> 00:28:52.385
An an individual building and, there are, within structural engineering, considering earthquakes, um, there, there, what's most commonly is to follow prescriptive methods.

00:28:52.385 --> 00:29:01.340
So it, it's important to emphasize that it's not that every building is being designed with performance-based design, but it, it's still a small percentage.

00:29:01.340 --> 00:29:20.151
However, what's been done over the years as those prescriptive designs have been tested, um, using this sort of risk framework that we were described to build confidence that those buildings following the prescriptive methods, achieve a certain reliability.

00:29:20.151 --> 00:29:26.593
That, that is, that they have a very small, probability of collapse, in a very extreme event.

00:29:26.593 --> 00:29:45.737
and so what, what comes to mind for me is that we now are seeing, and for, and I apologize, I'm most familiar with what's happening on the west coast of the us and, and I know your audience is much broader than that, but, um, but at least, in the west coast of the United States, there's now this growing interest in more hardened structures.

00:29:45.737 --> 00:29:53.397
And there, there is a, ICE International Code Committee, code, right, that can, that is being increasingly adopted.

00:29:53.397 --> 00:30:09.448
But I don't think any nagar you can say, but I, I don't think anyone can, could tell us, well, what is the expected performance of a community that designs its, its buildings, its communities to these prescriptive rules.

00:30:09.448 --> 00:30:13.448
And so one thing you could do then, if you have a.

00:30:13.448 --> 00:30:23.914
kind of tool, the beginnings of tools that Nagar was just talking about is we could start to test analytically, well, what kind of performance do, do we actually expect to get?

00:30:24.027 --> 00:30:24.537
what would happen

00:30:24.545 --> 00:30:24.755
Uh,

00:30:24.807 --> 00:30:25.527
had more

00:30:25.565 --> 00:30:25.835
yeah.

00:30:26.156 --> 00:30:27.416
buildings in our community?

00:30:27.416 --> 00:30:27.679
Not

00:30:27.743 --> 00:30:27.983
right.

00:30:27.983 --> 00:30:34.290
And then, yeah, and then that comes back to, you can say, okay, well, what's the performance that we'd expect under the status quo?

00:30:34.417 --> 00:30:34.538
Hmm.

00:30:35.101 --> 00:30:41.431
Um, under d And you'd have to be, you'd have to consider many different, um, ey fire scenarios.

00:30:41.431 --> 00:30:41.790
Right.

00:30:41.790 --> 00:30:55.279
Um, you can't just pick one individual scenario, but, but then you could also start to look at, well, yeah, if we start changing the way that we're designing our buildings and, designing our communities, how do the outcomes improve?

00:30:55.279 --> 00:30:58.789
And, and then you could also start to incorporate costs.

00:30:58.789 --> 00:31:00.200
I mean, I know all this is.

00:31:00.200 --> 00:31:02.153
There's a lot of hand waving that I'm doing right now.

00:31:02.153 --> 00:31:19.130
It it, it's not simple but you could imagine in the long run through some hard work, we could maybe get to the point where you actually could start doing that kind of analytical testing and then that could help to justify changes in the way that we develop our communities.

00:31:19.811 --> 00:31:20.791
That's an interesting concept.

00:31:20.791 --> 00:31:21.112
Yeah.

00:31:21.628 --> 00:31:21.898
Right.

00:31:21.898 --> 00:31:28.003
And I will just add, so, um, it, it's my experience for example, working in, uh, one community.

00:31:28.003 --> 00:31:30.740
they have limited resources.

00:31:30.740 --> 00:31:37.701
So for them, the questions that where do they want to spend their resources to have the maximum impact?

00:31:37.701 --> 00:31:48.701
typically, again, like a fire chief of a community, they have a good feeling based on their experience of where could potentially be their vulnerabilities.

00:31:48.701 --> 00:32:03.483
But once you start showing them the quantitative assessment and, potentially say, okay, we rerun the simulations, now we implement, and working with communities means that they actually, uh, bring to the table that these are our options.

00:32:03.483 --> 00:32:22.071
We can, for example, in terms of we doesn't have to be, uh, it, it, well structure hardening is, um, definitely something they want to consider, but, cutting vegetation inside the community, for example, that's something that might be easier for them to implement from the policy perspective.

00:32:22.071 --> 00:32:24.231
And it's, it's in their control.

00:32:24.231 --> 00:32:42.588
Uh, so they want to see the change in, let's say, The level of damage that they eventually get if they implement something like that, cutting vegetation in a specific neighborhood because they don't really have the resources to do it all across, for example, the community.

00:32:42.588 --> 00:32:46.578
So then you look at historically where could be the ignitions, right?

00:32:46.578 --> 00:32:48.499
So the hazard, the variability in the hazard.

00:32:48.499 --> 00:32:59.898
Whereas potentially the higher risk of having higher likelihood of having a fire an an ignition that will go outta hand.

00:32:59.898 --> 00:33:08.141
And during a season with a wind condition that will impact your community.

00:33:08.141 --> 00:33:23.508
and those are the things that I think, again, drawing parallels that will fall under the hazard box, where we start looking at ignitions and directional wind, blah, blah, blah, and then damage how much damage you're gonna have.

00:33:23.508 --> 00:33:34.133
And then the community stakeholders will decide that, okay, potentially we might, if we have X amount of dollars right now, this is where we're gonna go in and actually do something in this neighborhood.

00:33:34.682 --> 00:33:45.358
do you also involve calculations of ability to evacuate people, for example, like, firefighting operations in that, or you're just looking at from the damage layer perspective?

00:33:45.358 --> 00:33:45.608
That's it.

00:33:46.348 --> 00:33:51.058
um, ideally yes, we should include all of that again from the earthquake side.

00:33:51.058 --> 00:34:04.288
We look at things holistically with infrastructure, transportation, power, water, all of that on the we, so let me just expand a little bit on the earthquake side, the concept of fragility that I mentioned.

00:34:04.288 --> 00:34:09.253
We now have fragility functions for water pipelines for bridges.

00:34:09.253 --> 00:34:11.443
Right for transportation bridges.

00:34:11.443 --> 00:34:18.583
So, so you know your bridge type, you know, your bridge structural system, it's, it's a steel girders single span.

00:34:18.583 --> 00:34:35.983
So you have this fragility, you know, the potential earthquake scenario, and then you apply and say, okay, the, the likelihood of exceeding, you know, extreme damage for this specific bridge is such and such, which then means that, uh, because after an earthquake, again, the emergency response, they need to, it's chaotic.

00:34:35.983 --> 00:34:37.851
They need to, get to the community.

00:34:37.851 --> 00:34:53.692
If, if, uh, and I, for earthquakes, I've also had experience working with a community and they were worried about creating islands where they, if they have too many bridges and if those bridges get damaged, means that they could potentially have an island, like a neighborhood that may not be reachable.

00:34:53.692 --> 00:35:05.692
So these are the things that they look on the earthquake side, uh, on the side, I would say that, um, there's a lot of research, very excellent research going on, on the evacuation side.

00:35:05.692 --> 00:35:21.166
definitely, um, well, there's some research going on on the impact of fire on Water, but integrating them all together within a, I would say, community resilience assessment.

00:35:21.166 --> 00:35:23.152
We're not there yet

00:35:23.358 --> 00:35:23.978
That's another.

00:35:23.992 --> 00:35:29.387
have been doing research in pieces, but with the same community.

00:35:29.387 --> 00:35:33.376
Uh, we were looking at the level of damage and what resources you have.

00:35:33.376 --> 00:35:39.695
They actually had a separate study going on with a separate group, at their evacuation plan.

00:35:40.077 --> 00:35:40.737
Good, good, good.

00:35:40.737 --> 00:35:45.117
It's, I, I mean, I'm, I'm scouting, where are we and what's to be done?

00:35:45.117 --> 00:35:52.018
I know that evacuation part is growing and we had, uh, example, in podcast, um, mentioned multiple times.

00:35:52.018 --> 00:35:55.827
We had a Ty episode as well, which has, again in the show notes.

00:35:55.827 --> 00:35:58.947
Um, let's, uh, change the focus a little bit.

00:35:58.947 --> 00:36:02.097
You mentioned earlier the archetypes of buildings.

00:36:02.097 --> 00:36:13.077
Perhaps this is something interesting to discuss, and again, something that's not very familiar to me from my fire safety engineering experience, but perhaps something very obvious for earthquake engineers.

00:36:13.077 --> 00:36:17.128
So what do you mean by archetypes of buildings and how this concept can be used?

00:36:17.472 --> 00:36:33.474
The idea is that in order to try to do this sort of community scale risk assessments, that we're, it's not gonna be a realistic to define every single building, in great detail, right?

00:36:33.474 --> 00:36:40.135
And so we want to try to identify what are the features of these buildings that are most.

00:36:40.135 --> 00:36:47.050
Determinant of the building's response, um, and therefore damage, um, given ground shaking.

00:36:47.050 --> 00:36:58.630
And so over the years, there's been a lot of work done on this where the, the sort of key features that get distinguished are the, the structural system.

00:36:58.630 --> 00:37:09.713
is, is it steel and what are some of the, and then within steel there's, there's different types of, um, structural systems, braced frame or moment frame and, and, and others, is it reinforced concrete?

00:37:09.713 --> 00:37:11.994
Um, and then there's subcategories of that.

00:37:11.994 --> 00:37:12.893
Is it wood framed?

00:37:12.893 --> 00:37:14.454
And there's sub-categories of that.

00:37:14.454 --> 00:37:16.253
So that's the structural system.

00:37:16.253 --> 00:37:17.844
Then the height.

00:37:17.844 --> 00:37:20.829
Of the building is, is quite significant.

00:37:20.829 --> 00:37:31.865
and the, the vintage, um, and, and the, the reason the vintage is so important is because, um, that tells you what building standards it was designed and constructed under.

00:37:31.865 --> 00:37:43.028
And, and so, um, you can combine all that information with, you know, other studies that have been done, both experimental and um, um, numerical.

00:37:43.028 --> 00:37:49.186
to then, describe their potential for damage, um, their, their fragilities.

00:37:49.186 --> 00:38:18.871
and once you've built up enough of a catalog of these fragilities, um, you can, when you go into, um, analyzing a community or if it's an individual portfolio, um, going again, that, that could be say for an insurance company or if you just wanna look at schools within a community or hospitals within a community, having that catalog then allows you to more readily assign the fragilities, within that portfolio that you're looking at.

00:38:19.278 --> 00:38:23.869
Are you defining them primarily through the lens of how they are built?

00:38:23.869 --> 00:38:26.478
Do you take into account where they are located?

00:38:26.478 --> 00:38:35.239
Like for example, in wildfires, the terrain would have a significant, uh, impact on your potential damage.

00:38:35.239 --> 00:38:39.451
So here it's not just what's the building, but where is it?

00:38:39.451 --> 00:38:41.851
What's around, like how, how

00:38:41.918 --> 00:38:42.159
Yeah.

00:38:42.271 --> 00:38:44.221
translate this concept to, to wildfire?

00:38:44.637 --> 00:38:51.867
earthquake side, the, um, where, where it's built would be directly related to how it was built.

00:38:51.867 --> 00:38:57.637
um, and, and so that, that's gonna give you information about the, the codes that were in place.

00:38:57.637 --> 00:39:09.967
And, and then that, that in turn tell can help you understand, you know, how effective those codes are and therefore how effective the building is in, in resisting forces.

00:39:09.967 --> 00:39:13.744
the effect of the, the local site conditions.

00:39:13.744 --> 00:39:20.463
I'm not sure if that's what you were talking about, but at least within the earthquake world, and maybe there's an analogy here for, for Woo, we fire to pass it over to the guard.

00:39:20.463 --> 00:39:28.324
But in the earthquake world, if you have really soft soils, those then amplify the shaking,

00:39:28.349 --> 00:39:28.710
Yes.

00:39:29.197 --> 00:39:29.527
right?

00:39:29.527 --> 00:39:39.235
And so that, that local site condition affects the hazard, but it doesn't affect the capacity of that individual building to resist those forces.

00:39:39.235 --> 00:39:43.717
Uh, and so we're able to distinguish the two pretty cleanly.

00:39:43.717 --> 00:39:45.869

242 - Learning from Earthquake Engineering with Negar Elhami-Khorasani and Justin Moresco

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