ASCE 7 22 Supplement 2

[struct_eeyore]

ASCE released a 'Supplement 2' for 7-22 middle of last year, and it flew completely under my radar. The changes to flood design are huge - as we're now looking at 500 year floods vs 100. I'm practicing in Florida, and we just adopted 7-22 last year. I was only starting to get comfortable with my shiny new book, when I came across this supplement last week. (FEMA likewise released their design guide based of this supplement only in April of this year). Of course, I've already got a project being built - which was in D&D when the supplement came out - but was signed and sealed afterwards. Needless to say, I cannot afford a 35% increase in height of my base flood w/o the structure failing (not to mention breaking waves, etc). I realize it's all a numbers game, but it's one with legal implications. I beat myself up over lots of "mistakes", but I can't get too excited over this one.

Any thoughts, opinions, un-official legal advice, etc, would be greatly appreciated.

Also, if the engineers around me actually start practicing by this supplement, it could very well put a huge damper on coastal development - or the owners/contractors will flee to someone who doesn't care / doesn't know.

 

[DaveAtkins]

Was there a regulatory body or official who approved the plans? If so, I think you are fine - Florida is transitioning from one code to another.

DaveAtkins

 

[TLHS]

This sort of thing super annoys me, so I looked briefly. The Florida Building Code specifically sends you to Chapter 5 of ASCE-7. The Supplement isn't written as an amendment and isn't chapter 5. It's an extra supplementary document. Unless there's some other way it's incorporated I don't think it's a part of the building code requirements until someone makes it one?

"1612.4 Design and construction.
The design and construction of buildings and structures located in flood hazard areas, including coastal high hazard areas and Coastal A Zones, shall be in accordance with Chapter 5 of ASCE 7 and with ASCE 24."

 

[Deker]

As far as I can tell, Chapter 35 of the Florida Building Code only references ASCE 7-22; no supplements. As opposed to, for example, Chapter 35 of the California Building Code, which references ASCE 7-16 with Supplements 1, 2, and 3. You may be able to wait until the next code cycle to incorporate the supplements unless the City or AHJ specifically adopts them.

 

[m7rhman]

It makes uplift check more sense though (0.9 Dead vs 0.6 now and fluid either 0.75 or 1.5), however, with changing MRI, results maybe will be worse than current combinations to check uplift. I tried to use it to design hydrostatic slab, but I thought will be difficult to convince Building Department with something not mentioned in chapter 35.

 

[struct_eeyore]

Thanks for the input everyone - will be getting some sleep tonight!

 

[lexpatrie]

Is it under construction? If not, you could inform the owner and see what they'd like to do in terms of using the "most modern" (perhaps not required by statute) design approach. These supplements tend to be a mixed bag, some things worse, other things better. But overall, more realistic to current understanding, therefore safer.

Standard of care is what your peers (competitors) do,

To my view, the breaking wave heights in Florida are generally from storm surge, if you've seen footage of actual storm surge, the heights of the waves involved appear less than the design wave height unless you are very close to the shoreline.

Take a look at Max Olson Storm Chasing on YouTube for Fort Myers Beach during Hurricane Ian.

 

[struct_eeyore]

Lex -

I have some issues with the standard of care around my parts - too many old engineers who keep on doing things they way they have been for the last 40 years, and largely ignoring new codes. Maybe that helps me... but you can always find a pro who could rip those guys (or myself) apart on the witness stand. Right now, I'm taking comfort in what Deker said about the California code specifically referencing supplements - we'll need to see similar language in the FBC before the supplement is legally binding.

 

[lexpatrie]

That would be my impression that it's not "in force" but you could still explore it with your client, as a supplemental. They could even view it as a potential sales tool down the line. "We are still compliant".

Testimony is another creature because you can argue all you want about some esoteric formula, but it's ultimately a Jury that has to find you (or rather, your retained expert witness carrying the spear for you) credible.

Failing to design to the current standard is where the Board is supposed to investigate.