PSI - Issue 64

Maximilian Rohrer et al. / Procedia Structural Integrity 64 (2024) 1256–1263 Rohrer, Moeller, Lenzen / Structural Integrity Procedia 00 (2019) 000 – 000

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Figure 3: Aerial picture of the Floßgrabenbrücke.

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Figure 4: Schematic side view (left) and exemplary cross-section (right) of experimental bridge structure Floßgrabenbrücke.

3.2. Application of Measurement System In the first phase, four of the seven spans have been equipped with acceleration sensors. In each span, eight sensors are applied to the structure. The sensors are uniaxial IEPE acceleration sensors of type PCB393A03 . A weather station with five temperature sensors monitors the changing temperature, as well as wind, humidity, rain, and solar radiation. The scope of the first phase is to test the monitoring system for a long-time application and to obtain more profound insights into the dynamical behavior of the test structure. Depending on the results of the first phase, data handling, sensor placement, and other measurement parameters are optimized. In the second phase, the complete structure will be equipped with 56 acceleration sensors and included in the SHM concept. In the third phase, structural experiments will be conducted at the bridge. The structure will be experimentally and reversibly modified, to verify and test damage localization techniques and the monitoring concept. 3.3. Comparison Simulation to Measurement A basic FEM model, consisting of Bernoulli beam elements, was used to plan the initial experimental setup and to validate the results. In turn, the measurement results are utilized to check the simulation model for plausibility. Therefore, the simulation and the measurements are constantly used to cross-check the results. The comparability of the FEM model and the identified state space model can be derived from the identified mode shapes. Prior to the comparison, the Young’s modulus for the bending elements was manually adjusted to match the first eigenfrequency of the model with the identified eigenfrequency of the black box measurements. After this adjustment, the first six eigenfrequencies of the FEM model also matched the identified eigenfrequencies. Exemplary the mode shapes and frequencies of the first three identified modes are compared.