Answer:
Please check the design internal forces of the affected elements.
If the cross-section of an element is completely cracked, it is not possible to carry out a shear resistance analysis on this element in the RF-CONCRETE Surface add-on module. The result windows of the module will also display message No. 13 saying that the cross-section is completely cracked at these locations and the shear capacity is not designable.
Further information about the determination of shear capacity can be found in the manual of RF‑CONCRETE Surfaces in Section 2.4.4.1 Shear Force Resistance Without Shear Reinforcement, which you can download from our homepage.