Is there a difference between the main bars and the additional bars in the beam "RC 2D Analysis and Design calculation"?

Question

Is there a difference between the main bars and the additional bars in the beam "RC 2D Analysis and Design calculation"?

Answer

The bottom reinforcement for the central zone of the beam is taken from the bottom bars in the first zone. This then cannot be edited for the central span, ie. if 2 x H16 are specified for the bottom bars in the first zone, this will be carried into the central zone and will not be editable.

 

If we then increase the number of bars in zone 1 to 4 x H16, this value will now be carried into the design of the bottom bars for the central panel.

 


If we wanted to increase the reinforcement provided to the central span without increasing the number of bars used in the first zone, the additional bars will allow us to do this. There is no difference in the provided area of reinforcement that these additional bars add to the design checks vs the ‘normal’ bars.

 

So adding the additional bars would allow you to reduce the reinforcement provided in the other zones and increase the local reinforcement for the central zone.