Nonlinear inelastic force-displacement response envelopes of full-scale reinforced concrete bridge portal frames are predicted in this paper by representing the frame using strut-and-tie models. The nonlinear strut-and-tie analyses, which included the tension stiffening effect, were performed using the computer program Drain-2DX. Strut-and-tie analytical results were found to correlate satisfactorily with the experimental data and to provide superior prediction to that generated using conventional planar frame models.