The purpose of this study is to investigate the effects of tension stiffening and softening of concrete in reinforced concrete beams and beam-columns. Analytical models of beams and beam-columns are prepared and the results compared to experimental results previously conducted by Berwanger et al. (1960) A layered model of the beams is developed and strains and stresses at various layers are computed. Moment-curvature relationships are then obtained from these. The stress-strain curves adopted are from El-Metwally and Chen (1989). The effects of tension stiffening and softening are included by adopting realistic stress-strain curves in both compression and tension. / Master of Science