Cyclic load behaviour of reinforcing steel

Abstract

The stress–strain behaviour of mild steel under cyclic loading is examined. The results of tests are described in which a variety of loadings were applied to reinforcing bars to study a range of initial strains and loading and unloading sequences from tension and compression. The tests emphasize that when postelastic stress reversals take place the stress–strain relationship for steel becomes non–linear over much of the loading range owing to the Bauschinger effect. It is found that a Ramberg–Osgood type function gives good agreement with the loading portions of the experimental curves except at very large strains. The empirical constants in the function were determined from the experimental results by least squares analyses and were found to depend on the plastic strain in the previous loading run and the number of previous loading runs.