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25 Table 14. Ratio of measured to computed capacities. Method Specimen fy = 100 ksi Mast Eq. Ramberg-Osgood F1 1.47 1.12 1.07 F2 1.31 1.11 1.08 F3 1.54 1.08 1.01 F4 1.37 1.08 1.02 F5 1.35 1.19 1.14 F6 1.44 1.06 0.991 clearly demonstrate that the specimens reached and exceeded the target strains. Figure 8. Crack patterns and curvature in Specimen F4 Two strain gages were bonded to the concrete surface at the immediately prior to failure. midspan (i.e., in the constant moment region) to measure the compressive strain. The average strain was used to assess the performance of the specimens. The ratio of the peak strain to the target design strain is summarized in Table 15. The specimens developed a strain of at least 1.9 times larger than their target values prior to failure. At failure, the con- crete strain (tabulated in Table 15) ranged from 0.0025 to 0.0039 with an average value of 0.0033. The selection of a maximum concrete strain of 0.003 in a compatibility analysis of members reinforced with high-strength A1035 is rational. 2.3.5 Summary and Recommendations Considering the magnitudes of the strains in the longitu- dinal bars and concrete, the specimens performed adequately and met the design objective. The proposed strain limits of t = 0.008 or higher for tension-controlled behavior and t = (a) Specimens F1, F2, F3 0.004 for compression-controlled are appropriate. Moreover, well-established strain compatibility analysis techniques can (b) Specimens F4, F5, and F6 Figure 9. Load--midspan deflection. Figure 10. Measured and computed load-deflection relationships.