## 4 Experimental Results and Discussion
### Cyclically Tested Specimens
As with the monotonically tested specimens, no clear boundaries are visible between the individual areas of the M/\(\varphi\) ratio of the end section diagram, while in the other two sections these boundaries are more pronounced. The reason for this is again the loss of bond strength between the reinforcement and the concrete, where there is no sudden change in the slope of the diagram due to the loss of stiffness after crack formation. In cyclically tested specimens, the effect of the loss of bond strength between reinforcement and concrete on the decrease in stiffness during loading with horizontal force is not visible, as was the case with a monotonically tested specimen. The influence of the axial force on the displacement-force ratio is visible in the first four cyclically tested specimens. During the test, the specimens AB-NS-001-3 and AB-NS-001-4 were loaded with a lower axial force than the specimens AB-NS-001-7 and AB-NS-001-8, resulting in a lower cross-sectional load capacity. It should be noted that the compressive strength test showed that the first two sets of specimens had a concrete compressive strength one class higher than the other two (47.5/36.0 MPa). It can therefore be assumed that the differences would be even greater for the same concrete properties. Looking at the rotation of the cross-section when the failure is reached on the same specimens, it can be seen that for both specimens with a smaller value of the axial force, the rotation of the cross-section is higher. Specim AB-NS-001-9 was tested with an axial force of 125 kN. The load bearing capacity of this specimen is between the specimens tested with forces of 100 and 150 kN, while its rotation is lower than that of the other specimens tested in this series, which is also due to the lower compressive strength of the concrete. Figure 13: Moment to section rotation ratio of cyclically tested specimens: (**a**) end section; (**b**) 150 mm higher section; (**c**) 350 mm higher section. The specimens AB-NS-002-2 and AB-NS-003-2 were made with different amounts of reinforcement in the corners. The column AB -NS-002-2 column has a larger amount of reinforcement (4\(\Phi\)10) than the column AB-NS-003-2 (4\(\Phi\)8), so the load-bearing capacity is higher as expected. If we compare columns AB-NS-001-7, AB-NS-001-8, and AB-NS-004-2, we can see differences in the load-bearing capacity of smooth and ribbed reinforcement of cyclically loaded columns. These columns are made with the same amount of reinforcement, have approximately the same concrete properties and are loaded with the same axial force, but the column made with ribbed reinforcement AB-NS-004-2 showed a 30% higher load bearing capacity than the column made with smooth reinforcement. If we observe the rotation of the end cross-section of specimens with the same geometric properties and the same amount of axial force applied, we see that the specimen tested with ribbed reinforcement has a slightly lower rotation on failure than the specimens produced with smooth reinforcement. The difference here is not as pronounced as in the case of monotonically tested specimens. The results of measuring the relative deformations of the cross-section at a height of 150 and 350 mm from the bottom of the column and the corresponding values of cross-section rotation show the behavior of the column at the plastic joint. For the cross-section at a height of 150 mm from the bottom, we can see that in most of the tested specimens a third area, i.e., the area of plasticization, was present. At a height of 350 mm from the bottom, the two specimens reached the values where plastification takes place.