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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How to verify loads graphically in RISAFloor
November 9, 2016

How to verify loads graphically in RISAFloor

RISAFloor does not record the applied area loads in a spreadsheet. To simplify modeling, it instead assumes a default area load over the entire diaphragm area. Additionally, you are free to apply area loads beyond the default loads. Whatever is drawn last will be considered the applied loading...

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Instabilities in RISA-3D with Flexible Diaphragms
October 19, 2016

Instabilities in RISA-3D with Flexible Diaphragms

In a model that contains both RISAFloor and RISA-3D data it is possible to define your diaphragms as either flexible or rigid for lateral design. You can do this from the Diaphragms spreadsheet in either program:

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Camber Design Rules in RISAFloor
July 12, 2016

Camber Design Rules in RISAFloor

RISAFloor has the ability to assign camber design rules which allow the user more control over which members are cambered. A camber is the slight upward curvature of a steel beam which is used to compensate for deflection. A user can assign a camber directly to a member or set up design rules to...

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Mechanically Graded Wood Design now Available
January 7, 2016

Mechanically Graded Wood Design now Available

Mechanically graded wood materials have been added for the AWC NDS 2015 design code per Table 4C, and CSA O86-14 design code per tables 6.3.2 and 6.3.3. This specification includes the updated MEL and MSR design values.

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Wood Design per AWC NDS 2015 Wood Code
December 22, 2015

Wood Design per AWC NDS 2015 Wood Code

The latest versions of RISA-3D and RISAFloor now incorporate the AWC NDS 2015. The new provisions have been implemented in RISA-3D v14.0 and RISAFloor v10.0 and can be utilized by selecting the AWC NDS-15: ASD from the Wood dropdown menu on the Codes tab of Model Settings.

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