Minimum area of reinf. for beams Rc (Abmin)

[javt75]

I want to know how the robot calculates the "Abmin" because it does not match my hand calculations according to equation (10-3) of ACI 318-02, since in some occasions gives 100% more in Robot, than calculation manually. Schedule an example with the following values​​: f'c = 21 MPa bw = 200 mm d = 244.1 mm fy = 420 Mpa According to equation (10-3) Asmin = 162.75 mm2 Robot and is: Abmin = 442.86 mm2. This is a very big difference, so I want you to help me clarify whether the "Abmin" Robot is calculated according to equation (10-3) of ACI 318-02 for RC beams, or a completely different variable . Thanks, Annex Image of Robot.

[javt75]

Annex pictures.

[Artur.Kosakowski]

PLease check http://forums.autodesk.com/t5/Robot-Structural-Analysis/Abmin-how-RSA-calculte-this-value/m-p/447599...

If this does not answer the question attach the rtd file with the beam please. Thank you.

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[javt75]

Thanks for the link, but perform the calculation according to equation (10-4) of ACI 318-08 section 10.6.4, and it gives me that I place a maximum spacing of 255mm reinforcement closest to the tension face, which in my example is not necessary, since my beam has a total width of 200mm. and is asking me twice Abmin which is calculated by the equation (10-3)
In short, if taking this Robot consideration of equation (10-4), it is possible that small sections for beams is not working properly.

[educm4]

I have the same issue. I can´t understand how Robot calculate the Abmin value. This value is much greater compared with hand calculations.

[Artur.Kosakowski]

Could you both attach the files with your beam sand your manual calculations of Amin please? Thank you.