
June 28, 2018
A Deeper Understanding of Deflection and Member Deflection Ratios
There are many different types deflection values calculated by RISA-3D. Let’s take a deeper dive into each.
When designing shear walls in RISA-3D, it’s common to add surface loads—whether to simulate lateral wind or seismic pressures, or even out-of-plane loads. But what happens when those loads intersect with openings in your wall panels? Let’s walk through exactly how RISA-3D handles this scenario behind the scenes, including how the program preserves total force and moment equilibrium—even when wall geometry gets complex. ⚙️ How It Works: Surface Load Redistribution at Openings When a surface load is applied to a wall panel that contains openings, RISA-3D uses a special algorithm to redistribute the portion of the load that would otherwise fall inside the opening. Rather than ignore that load entirely, the program converts the "lost" surface area into equivalent nodal forces along the edges of the opening. These loads are known as transient nodal loads. Here’s the step-by-step breakdown: Determine Centroid of the Loaded Region RISA calculates the centroid of the area made up of both the surface load region and the opening. Split the Load Across the Opening The surface load over the opening is divided into two halves, based on the centroid location. Distribute Equivalent Forces Along Opening Edges These two portions of the load are then “smeared”…
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There are many different types deflection values calculated by RISA-3D. Let’s take a deeper dive into each.
RISA-3D v16.0.4 introduces an enhancement that will allow for more control over the beam deflection ratio through Deflection Ratio Options. As part of the member properties, you can now designate the ends of single and multi-span beams as a cantilever or supported. This will determine whether the...
RISA-3D now includes improved behavior of the automesh feature as well as the newly added global model setting for Plate Local Axis. The new plate local axis options include both Nodal and Global. These options allow for more control over plates which can lead to clearer results in plate contour...
RISA is pleased to announce the release of the latest RISA-Revit Link which is compatible with Revit 2020. The RISA-Revit Link v19.0 allows seamless integration between RISAFloor, RISA-3D, and Autodesk Revit. The latest version now includes the ability to import beam reinforcement details from...
RISA-3D v16 now includes the added ability to view foundations designed in RISAFoundation. This feature proves useful as it gives a way for engineers to see if foundations have been sized appropriately for the loading from RISA-3D. For more information about how foundations can be shown in RISA-3D,...
In RISA-3D we now have the ability to design concrete shear walls for seismic forces.
In RISA-3D we now have the ability to:
In RISA-3D, you can define a boundary condition as Fixed (reaction will be calculated) or Fixed, (reaction will NOT be calculated).
The BS EN 1992-1-1:2004+A1:2014 has been implemented in RISA-3D version 16.0 and RISAFloor version 12.0. To select this code for your design, simply open the Model Settings and under the Codes tab select BS EN 1992-1-1:2004+A1:2014 for concrete:
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