Liquefaction Triggering Screening (Seed-Idriss CSR)
Seed-Idriss screen: rd = 1 - 0.00233172 z (z <= 30.02 ft; per-meter 0.00765/0.0267 scaled by 0.3048), CSR = 0.65 amax (sv/s'v) rd, FS = (CRR/CSR) MSF, liquefiable if FS < 1. amax 0.30g, sv 2000, s'v 1200 psf, z 16.4 ft, CRR 0.20 -> CSR 0.313, FS 0.64, liquefiable; denser sand (CRR 0.40) -> FS 1.28. A level-ground screen; the geotechnical engineer of record governs.
Formula and source
rd = 1 - 0.00233172 z (z <= 30.02 ft) else 1.174 - 0.00813816 z; CSR = 0.65 amax (sigma_v/sigma'_v) rd; FS = (CRR/CSR) MSF; liquefiable if FS < 1.
The Seed-Idriss simplified liquefaction-triggering procedure (NCEER/NSF workshop consensus), by name.
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