Calcgeo | ASCE 7-22 Seismic Design Parameters

Disclaimer: This tool is approximate and may contain errors. Results depend on the USGS web service and on user inputs. Engineers must independently verify all output, for example with the USGS/ATC hazard tools (ASCE Hazard Tool, ATC Hazards by Location) and hand calculations, and must use professional judgment to select design values. Use is at the user's own risk.

1. Site Class (ASCE 7-22 Chapter 20)

Vs30 (ft/s)

Profile units: English (ft, ft/s) SI (m, m/s)

Top (ft)

Bottom (ft)

Vs (ft/s)

Thickness (ft)

Travel time (s)

Vs30 = 100 / Σ(d_i/Vs_i) over the top 100 ft (ASCE 7-22 Eq. 20.4-1). Layers below 100 ft are truncated; a profile shorter than 100 ft is completed by extending the bottom layer (flagged).

Vs basis

Profile contains > 10 ft of soft clay (PI > 20, w ≥ 40%, s_u < 500 psf) → Site Class E (§20.2.1 / Table 20.2-1 note)

Site Class F screening (§20.2.1) Soils vulnerable to potential failure or collapse under seismic loading: liquefiable soils, quick and highly sensitive clays, collapsible weakly cemented soils Peats and/or highly organic clays, H > 10 ft Very high plasticity clays, H > 25 ft with PI > 75 Very thick soft/medium-stiff clays, H > 120 ft with s_u < 1,000 psf

Override site class

2. Project & Location

Project / title Latitude (°) Longitude (°) Risk Category

Parameters are retrieved from the USGS Seismic Design Web Service (ASCE 7-22) through the Calcgeo server.

3. Seismic Design Parameters

Response spectra

Spectrum Format

1. Site Class (ASCE 7-22 Chapter 20)

2. Project & Location

3. Seismic Design Parameters

Response spectra

4. Report write-up