180 150 120 S 90 i 60 -- Displacement 30 -B- Differential STheoretical 0.0000 0.0010 0.0020 0.0030 Curvature (rads/in) Figure 5-20. Moment-curvature curves for specimen 1 180 150 120 90 30 -A-Differential 30 1i -e- Theoretical 0.0000 0.0020 0.0040 0.0060 0.0080 0.0100 0.0120 Curvature (rads/in) Figure 5-21. Moment-curvature curves for specimen 2 The theoretical M-D curve for specimen 2 agreed well with the displacement curve. The slope of the theoretical curve was approximately 25% higher compared to the slope of the displacement curve. The differential curve did not agree well with the displacement curve. The differential curve had a slope approximately 68% lower than the slope of the displacement curve. The experimental and theoretical M-D curves of specimens 3 and 4 (see Figs 5-22 and 5-23) were also calculated and plotted in the same manner as for specimens 1 and 2.