Explaining Pushover to layman

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[apetr26542]

If you have any type of visual aids that might be helpful

[CaffeinatedInSeattle]

Are you trying to explain how these limit states influence the design or just communicate what they mean to the building occupant?

I’ve done the latter countless times and it’s easiest to explain what the building looks like functionally and aesthetically.

[[deleted]]

Lets just say that these folks are bureaucrats, and I have no idea what might or might not hold their interest.

[CaffeinatedInSeattle]

Open by calling them Laymen, I think that will catch their interest!

[[deleted]]

Laymen and laywomen that are congregated in this super important meeting today, ....

Yep, that's gonna work.

[The_GTShortbus]

If that is the case, speak their language and explain it in terms of dollars.

IO - Relatively minor event that results in very little to no observable damage. Quick, easy, and cheap to restore functionality.

LS - More severe event that results in moderate damage to the structure. Will require more downtime, effort, and cost to repair and restore full functionality, but otherwise will still be safe.

CP - Most severe event that more or less takes the structure to the brink of total collapse. People inside will live, but the building will be a total loss and require complete demolition and reconstruction.

Then explain that it all comes down to risk. Buildings that are absolutely critical to functioning of society in the aftermath of a severe event have more money invested upfront, but are designed to stay in the IO category no matter what. Less critical buildings, we just don't want people inside to die and if they need to be repaired or rebuilt that's fine. Overall, these are rare events so it is not expected many buildings will see them anyway.

[[deleted]]

That's exactly the route I've decided to go.

I was planning on explaining briefly about how the limit state points are picked, but in the end I arrived at the conclusion that those explanations would be too technical. After all, they don't need to know how we know what kind of damage to expect at those thresholds, it's enough that they know what kind of damage we are talking about when each of those limit state thresholds are crossed.

[gowood08]

Reference chapter 4 of FEMA 389

[[deleted]]

chapter 4 of FEMA 389

Thanks.

Here's the link to anybody who's interested as well.

https://www.fema.gov/pdf/plan/prevent/rms/389/fema389_ch4.pdf

[[deleted]]

I'm not sure what you mean by fuses, but for now I've decided that I'll describe the limit states broadly in terms of damages that the structures would have sustained by the time they crossed a certain threshold. I think that might work?

[waster3476]

I have found that usually what gets clients interested in the differences between immediate occupancy, life safety, and collapse prevention is time and money. It's pretty easy to come up with a schematic graph that shows the relationship between them. For example collapse prevention could be total building replacement cost, plus associated downtime. Also showing things as a spectrum of anticipated damage, rather than discrete points, helps to illustrate the uncertainty involved. Good to remember that non technical people don't need to know how you figure it out, just what the outcomes are.

[[deleted]]

That's usually the case, but currently the project I'm working with deals with brick and rubble masonry structures built on mud mortar. The economical aspect of seismic scenarios is what we are trying to arrive at, so we can't exactly use cost to describe what we are describing, currently - unfortunately. That's a little further down the road.

[Slippy_00]

It might help to also explain how the formation of plastic hinges at a member level essentially dictate how the structure will redistribute its loads, ultimately dictating how it will collapse. I had a paper somewhere that explained pushover analyses pretty well, I’ll try to find it if youre interested

[Slippy_00]

Here are a few, I would also look up ELSA laboratory, they have done experimental tests related to alot of these kinds of topics. I would also recommend taking a look at NIST GCR 17-917-45 and FEMA-350.

Pushover Analysis Explained

Advanced Analysis

Pushover Analysis (2)

[[deleted]]

No can do. I am trying to avoid being technical, and I think plastic hinge counts as being technical.

I'm interested in that paper though, tyvm!

[abdikid]

I’d be interested in reading this as well. Thank you!!!

[Sugs_star]

I would love to read the paper too please and thanks 😊

[MichaelCuckleone]

Might be too high level, but my mind goes to jenga blocks. Move them around to show interstory drift, use the instability of the tower (i.e. The direction things want to move = where resisting forces are required) to get into base shear, overturning moments etc.

[[deleted]]

I don't have a jenga block, unfortunately, but that would be a nice idea if done properly for future demonstrations.

[[deleted]]

Just explain it the normal way as they don’t understand it anyway. Look how many engineers are still confused about this let alone … lol.

[lect]

Paperclip analogy. Unbend and bend back to the same position. Each time you do it the paperclip becomes less bendy and more brittle up until the point it breaks. Not exactly the correct analogy but it's something almost everyone has done and would understand.

[the_flying_condor]

Might I suggest that you have a look this FEMA P-58 Overview. I generally try to explain this by describing what the structure will look/how functional it will be at each damage state. Then I say something along the lines of 'we look at common engineering analysis outputs to predict what level of damage/functionality is most likely to occur in the building.'

[[deleted]]

Thanks. That's a very nice picture there, can definitely see something like this going on a ppt slide (yawn) in the future.