Since the release of RISAFloor v15 and ADAPT-Builder v20, both which include the latest update to the ACI code (ACI 318-19), some customers have asked our support team why they're experiencing increased slab deflections. These increased deflections are the result of changes in the calculation of...
With the release of ADAPT-Builder v21, users now has the option to have the program automatically calculate long-term load factors using two different methodologies. Calculation of Long-Term Load Factors is available using all design codes but is implemented based on ACI 209. When calculating these...
As our team is hard at work updating and improving RISACalc based on customer feedback and requests. This latest release (Version 2.1) now includes two new features; deflection ratio checks for beam components and batch report printing.
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...
RISAFloor ES has the ability to check the Long Term Deflection with Creep and Shrinkage. The program uses an iterative method to adjust the plate stiffness until it converges upon a solution. You can setup all the necessary coefficients and factors in the Model Settings (as shown below).
After solving a model, you will see in the Member Deflections spreadsheet the following deflection ratios:
The deflected shape is really helpful to understanding your model’s behavior.
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...
Below is a model of a flat concrete slab made of plates. In order to ensure adequate serviceability of the slab, you may need to check the deflection of the slab between columns. However, RISA-3D only reports Member and Joint Deflections. There is no such thing as a “Plate Deflection”.
