Soil category

This tab works on the solution chosen in Inversion.

Vs,eq and category

Choose NTC 2018 or NTC 2008 and enter the foundation depth, measured from ground level.

• NTC 2018: V_s,eq = H / Σ(h_i/V_s,i). H is the depth of the bedrock with V_s ≥ 800 m/s; if there is none within 30 m, H = 30.
• NTC 2008: V_s,30 over the 30 m below the foundation. Probabile suolo di tipo E flags the condition that velocity alone cannot establish.

If the value falls exactly on a boundary (100, 360 or 800 m/s), or the foundation is in the bedrock beyond 30 m, the code table assigns no category and the app says so in words instead of picking one.

Layer parameters

For each layer: G₀, E_d, K, E and ν. These are dynamic moduli at small strain: do not use them directly in settlement calculations.

NSPT (Ohta and Goto) and Q_c (Jamiolkowski) are empirical correlations inverted from V_s: choose composition, age factor and soil type. Beyond 100 blows or 5000 kPa the app shows N/D. The half-space has no such estimates.

Transfer function

The chart shows the 1D response of the profile, with 1 % damping, and the frequency of the maximum. With such low damping the peaks are very high: it indicates resonance frequencies, not a design amplification.

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