Conclusions and Summary

Imposed deformations on fixed columns demand a big rotation capacity at the fixed ends. It can be seen from test results that the behavior of concrete is considerably more ductile than usually assumed. Especially with a strong lateral reinforcement, considerable compressive strains are possible without a significant reduction of the strength. Due to wide scattering of the material properties it is difficult to formulate an unique stress-strain relationship for concrete. Therefore, two extreme assumptions are made in this investigation. On one side a parabolic stress-strain diagram is used which accounts for a decrease in strength due to strain softening. On the other side a parabolic-straight diagram is used with no softening effect at all. Depending on the lateral reinforcement and other parameters the real stress-strain behavior of concrete lies between the two extreme assumptions.