How to Apply a Rigid Diaphragm in RISA-3D
In RISA-3D, rigid diaphragms can be added using the Diaphragm spreadsheet....
When you transfer a model from RISA-3D into RISAFoundation, you expect the reactions and design assumptions to carry over cleanly so foundations design the way you intended. If the workflow is not set up correctly, you can end up with soil bearing pressures, uplift, or foundation failures that don’t match what you saw in your RISA-3D results—and it’s not always obvious where the mismatch is coming from. This article walks through how the integration actually works, what transfers and what doesn’t, and a simple checklist you can follow to get reliable foundation results. 1. Understand What Transfers (and What Doesn’t) RISAFoundation reads joint reactions organized by load category, not by load combination. Those categories are defined in the Basic Load Cases spreadsheet in RISA-3D (DL, LL, WL, etc.). What comes across: Reactions grouped by load category (DL, LL, WL, etc.) Supports defined as Reaction or Spring Wall reactions represented as a series of point loads along the wall base (based on the wall mesh) What does not come across: Load combinations Fixed supports (these do not appear as foundations) Moving loads and non-linear/second-order effects on a per-combination basis Model Settings come over only the first time you transfer. If you…
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In RISA-3D, rigid diaphragms can be added using the Diaphragm spreadsheet....
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