August 27, 2014
What is a Rigid Link in RISA-3D?
A rigid link is a member element in RISA-3D that can be used for many advanced modeling procedures. It is so useful that it is included as one of the default member Section Sets, as you’ll see below.
October 9, 2013
What is the Tau b Factor and how does it affect my analysis?
When solving a RISA-3D model with hot rolled steel members under the AISC 360-05 (13th Edition) or AISC 360-10 (14th Edition) codes you may find references to a factor called Tau_b. To understand what this factor is you should first be familiar with the Stiffness Adjustment in RISA-3D, then see the...
September 6, 2013
Why Are The Steel Beam Deflections So Large?
When solving a RISA-3D model with hot rolled steel members under the AISC 360-05 (13th Edition), AISC 360-10 (14th Edition) or AISC 360-16 (15th Edition) codes you may find that your member deflections are roughly 20% larger than you would expect. To understand why see the AISC 360-10...
February 23, 2012
How Do I Resolve a P-Delta Instability?
Investigating P-Delta instabilities in RISA-3D (or RISA-2D) can be difficult. The first step is usually to solve the model without the P-Delta effect included to see if there are any obvious deflection problems that could cause issues with a P-Delta analysis. But, what can be done when this doesn’t...
December 29, 2010
What is P-Delta Analysis?
When a model is loaded, it deflects. The deflections in the members of the model may induce secondary moments due to the fact that the ends of the member may no longer be vertical in the deflected position. These secondary effects for members can be accurately approximated through the use of...
May 24, 2010
Define a Beam Eccentricity in RISA-3D
When you have a deep column, it is necessary to model the beam so that it connects to the face of the column. This results in an eccentricity at the joint. RISA-3D offers two ways to model this eccentricity.