Tips & Tricks

June 3, 2025

The Ultimate Guide to Instability Warnings in RISA-3D

Modeling instability can be one of the most frustrating errors to troubleshoot in structural software. Whether you're a new user or a seasoned pro, instability warnings in RISA-3D can bring your workflow to a halt if not properly diagnosed and resolved. This master article brings together all the most common types of instability, provides guidance on identifying the issue, and links to existing resources that walk you through the resolution process. To supplement this written guide, check out the Troubleshooting Mini Tutorial in the RISA Learning Center (RLC). Common Instability Types and How to Resolve Them Below are the five most common causes of instability in a RISA-3D model, along with diagnosis tips and links to deeper resources: 1. Member End Releases at Boundary Conditions Symptom: Instability warnings at the base of columns or ends of beams. Diagnosis: Look for members where moment releases are applied directly at nodes with pinned or fixed boundary conditions. Why It’s a Problem: This removes all rotational fixity at the connection, creating a hinge with no resistance to rotation. Resolution Resource: How do I avoid instability warnings in a RISA-3D model? 2. Pinned End Releases at Every Member Framing into a Single Node Symptom:…

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Calculation of Forces in Seismic Brace Connections
June 28, 2016

Calculation of Forces in Seismic Brace Connections

Seismic brace connections are a bit different from other connection types in RISAConnection. This is because the brace and connection elements must be designed for both tension and compression loading.

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SCBF Seismic Brace Connections
May 25, 2016

SCBF Seismic Brace Connections

Vertical Diagonal Brace connections and Vertical Chevron Brace connections may be designed as Special Concentric Braced Frame (SCBF) connections in RISAConnection v6.

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OCBF Seismic Brace Connections
April 19, 2016

OCBF Seismic Brace Connections

Vertical Diagonal Brace connections and Vertical Chevron Brace connections may be designed as Ordinary Concentric Braced Frame (OCBF) connections in RISAConnection v6.

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Improved Wall Panel Results
March 26, 2016

Improved Wall Panel Results

Wall Panel Forces Spreadsheet The power of RISA is the easy to access output. The Wall Panels have all the calculations and forces displayed in the Detail Report and now the new Wall Panel Forces gives you a quick way to get all the forces across the base of the wall. This new spreadsheet can be...

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How Do I Find A Failing Member in the Model?
March 18, 2016

How Do I Find A Failing Member in the Model?

You may find that when looking at the Code Check spreadsheet that a given member is failing in design. Here is an example where a steel brace is failing in bending.

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