Research Article
Prestress Force Identification for Externally Prestressed Concrete Beam Based on Frequency Equation and Measured Frequencies
Table 3
Measured frequencies and identified prestress force of the two-span beam.
| | Measured frequency (Hz) | Prestress force (kN) | | Mode 1 | Mode 2 | Mode 3 | Test value | Identification value | Error (%) |
| | 29.809 | 45.443 | 114.421 | 0 | — | — | | 30.141 | 46.062 | 116.129 | 71.52 | 75.31 | 5.30% | | 30.279 | 46.316 | 116.836 | 101.36 | 105.63 | 4.21% | | 30.466 | 46.659 | 117.790 | 139.71 | 149.27 | 6.84% | | 30.606 | 46.918 | 118.508 | 171.76 | 181.43 | 5.63% |
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