Dear Elisabeth_Biro,
for basic related information, I recommend to see ATENA Troubleshooting, 2.2.10 How can I take the bending and/or shear contribution of reinforcement bars into account?

You may also be interested in 2.2.12 How can I model a pull-out experiment?, 2.1.21 When I model the reinforcement, do the bars and stirrups have to be in geometric connection (with common intersection points) or they can be modeled according to their axis so that they do not touch one the other in geometric sense?, 2.2.6 How do I calculate the reinforcement ratio when defining smeared reinforcement? or 2.2.11 How can I take reinforcement bond into account?

If you seek advice specific to your particular analysis, please follow Troubleshooting, 2.1.1 to explain us what you are modelling (sending us also your current model if you already have one).

Regards.