RE: Plaxis: Site response facility

원호 정 — Thu, 14 Apr 2022 07:56:48 GMT

Thanks for your valuable response.

RE: Plaxis: Site response facility

Sean Johnson — Tue, 09 Nov 2021 23:24:35 GMT

Generally, whenever you generate a 1D column model using the SRA script the Lysmer criteria will be met unless you have materials that fit well outside the bounds of material stiffness. The reason being is that the Lysmer criteria is based on nodal spacing and the Finite Elements are already sub-divided among many nodes. Therefore, in nearly all practical applications you should be able to run the SRA without doing a element size calculation. However, I would still recommend doing it regardless as a habit of good engineering practice. (As a reminder:)

The mesh elements should be small relative to wavelength (Kuhlemeyer and Lysmer, 1973) and the shear wavelength should be coupled with element size:

Element Size ≤ λ / 8 = v_{s, min} / (5 ÷ 10) f_max

λ = wavelength
v_{s, min}= minimum shear wave velocity
f_max = maximum frequency component

The answer to part 2 depends on if you are using a compliant base as your dynamic y(min) boundary. In that case, the input value is only the upward propagating motion (half the within motion). This is typically in a SRA because you are only trying to capture the upward propagation component of the motion (1/2 of total).