Determination of the prestressing force
Determination of the prestressing force using 70% of yield limit relative to the tension cross section:
| FM | = | 0.7 · Rp 0.2 · As | [N] |
| F0.2 | = | Rp 0.2 · As | [N] |
Rp 0.2 |
for strength class 8.8 |
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| = | 640 N/mm² für d<16; | ||
| = | 660 N/mm² für d>16. | ||
Rp 0.2 |
for strength class 10.9 |
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| = | 940 N/mm² | ||
Rp 0.2 |
for strength class 12.9 |
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| = | 1,100 N/mm² | ||
Therefore: |
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| Δl | = | FM · δS | [mm] |