# Why is there no warning when the capacity ratio is greater than 1.0?

*If* the *"Perform capacity ratio check using the fiber reinforcement concrete model"* option is activated *in the General Reinforced Concrete Settings *window, the capacity ratios are controlled thanks to the interaction curve calculated considering all combinations with the existing reinforcement placement of the element under the effect of axial force and biaxial bending.

*If the "Perform capacity ratio check using the fiber reinforcement concrete model" * option is activated, the capacity values are displayed on the 3D visualization screen. In cases where the capacity ratio is greater than 1, it is expressed in red.

*If the "Perform capacity ratio check using the fiber reinforcement concrete model"* option is not active, the capacity ratios are calculated with the fiber model, but it is not given as an error. An example of this situation is shown in the image below.

*If the "Check the capacity ratio using the fiber concrete model"* option is active, the capacity ratios are calculated with the fiber model and the ratios greater than 1 are given as inadequacy.

In order to prevent this inconsistency that may occur due to the method difference, it would be a suitable solution to calculate the "Calculate the required reinforcement using the fiber model" option in the elements.

Section capacities are calculated using the fiber model in ideCAD Structural. When calculating the section capacities, the section is divided into concrete and reinforcement fibers, as shown below. Then, a more detailed section calculation is made by using the Mander model, which is the material model defined in TBDY, and the conditions given in TS500. Then, moment-curvature analysis is performed using these fibers, and the bending moment strength of the section is determined by axial force and biaxial bending.

Section capacities are calculated using the fiber model in ideCAD Structural. Capacity ratios are also calculated according to the axial force and biaxial bending graph calculated by the moment-curvature analysis used in the fiber model.

Axial Force and Biaxial Moment Interaction for Columns

If the reinforcement ratio in the elements is *calculated when the "Calculate the required reinforcement using the fiber model"* option is not active, small reinforcement differences may occur due to the difference between the two methods.