Caveat: I am a student who has taken one *single* class on liquefaction and settlement analysis. What I am about to say may be super-basic knowledge you already have, or it may be incorrect.
Lateral displacement and settlement are factors of 1) soil type, 2) effective intergranular stress, 3) EQ magnitude, and 4) PGA. If I plug some numbers into my handy spreadsheet created using "Soil Liquefaction During Earthquakes" (Idriss & Boulanger, 2008), I see that a M9.0 EQ at 0.1 PGA can cause significant liquefaction effects if the soil (sand) is weak. Failure is dependent upon the number of loading cycles as well as the peak value of each cycle.
Short answer: talk to a geotech in your area...
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Kathleen Mitchell
Student Member, ASCE
Portland, OR
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Original Message:
Sent: 02-23-2017 09:33
From: Lee Keun
Subject: Lifuefaction induced by low PGA
Hi Everyone,
I am currently working on a foundation (a single CIDH) design under liquefaction and spreading for a railroad bridge project. The design PGA is very low, less than 0.1g. Do you have experience or reference on how much is liquefaction triggered due to the low PGA? It seems ODOT does not require liquefaction analysis if a PGA is less than 0.1g.
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Lee Keun Ph.D., P.E., M.ASCE
JACOBS
Denver CO
(720)934-3151
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