RISA-3D Concrete Beam Design vs CRSI Design Handbook

[ThorenO2]

Hello,

I am using RISA to design concrete beams and am comparing/verifying the analysis (moment capacity, shear capacity, & deflection) with CRSI. Does anyone have any experience with RISA-3D for concrete design and how the results may differ from other designs. Thank you,

 

[JoshPlumSE]

I have lots of experience with that (wink!) as I used to be a RISA tech support engineer. Some things to keep in mind:
1) Any concrete beam designed by RISA will be conservatively assumed to be singly reinforced for moment capacity calculations.... Even if there is top steel in the beam.
2) Any beam where the user has manually specified the reinforcement will take into account all layers of bars that were specified.
3) The calculations are usually pretty simple and can be verified to within 1 or 2% with a quick hand calculation.
4) The most common causes of "difficulty" matching the RISA calculation are input errors by the user. You can specify different stress blocks, different Fy for your bars, different types of concrete, et cetera.
5) When the differences are minor, it is likely due to a higher significant figure being used in the calculation of reinforcement area used by the program.

 

[ThorenO2]

JoshPlumSE, thank you for your input.