static settlement vs Post-liquefaction settlement 2

[pelelo]

Hello,

Our local code limits footing settlement to 1 inch and mat settlement to 2 inches.

The same way there are static settlement limits for footings and mats, are there any for post-liquefaction settlement?, or when are post-liquefaction settlements considered to be ok or too high?

To my knowledge there is no relationship between static settlement and post-liquefaction settlement.

 

[EireChch]

You are correct, there is not relationship between static and post liq settlement, that I have seen.

Most of the time our clients spec say that liquefaction has to be mitigated and that there is no specific criteria on liquefaction induced settlement. And typically, the earthquake parameters we get (M, PGA) are ULS case. As such the settlement in the ULS case is irrelevant. For determining SLS liquefaction induced settlement you need SLS earthquake parameters which I have never seen provided.

But I have seen some that also say that liquefaction induced settlement should also be less than 25mm for ULS case, which is a bad approach as ive stated above.

 

[HTURKAK]

https://files.engineering.com/getfile.aspx?folder=7b22fdb5-b222-4fb1-a0c1-3c6b4af70b00&file=x2015_NEHRP_Recommended_DESIGN_EXAMPLES_FEMA_P-1051.pdf[/attach_link]