With the adoption of ASCE 7-22, the concept of a multi-period response spectrum has been added to seismic design requirements. While this provides more accurate hazard representation, it also means engineers need to generate and input additional site-specific data. This quick workflow shows how to gather that data from the ASCE Hazard Tool and use it in RISA’s site parameters table for seismic load generation.
Why This Matters for Engineers?
Multi-period response spectra reflect more realistic ground motion characteristics and will increasingly be required as jurisdictions adopt ASCE 7-22. By pulling site-specific values directly from the ASCE Hazard Tool, engineers can ensure compliance and avoid unnecessary assumptions.
The multi-period approach can result in higher or lower design forces depending on the building’s period and site class, but it always provides more accurate seismic representation than the traditional two-point method.
Download the latest versions of RISA that supports ASCE 7-22 below.
Step 1: Generate Multi-Period Spectrum Data
-
Go to the ASCE Hazard Tool.
-
Enter your project location (address, coordinates, or site description).
-
Select ASCE 7-22 as the building code.
-
Navigate to the seismic hazard results and download/export the Multi-Period Response Spectrum data.
Step 2: Copy Data Points into RISA
-
Open RISA and go to the Seismic Load Generation settings.
-
Select ASCE 7-22 as standard/code.
-
Select Multi-Period Response Spectrum
-
Locate the Site Parameters Table.
-
Copy the data points (period vs spectral acceleration) from the Hazard Tool output and paste them into the table.
Step 3: Verify Load Generation
-
Confirm that the values populate correctly.
-
Check the generated seismic load combinations to ensure the new spectrum is being applied.