Vibration Assessment of a New Danube Bridge at Komárom
Construction of the bridge
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- 2.2 Monitoring system on the bridge
- Fig. 2
| 2.1 Construction of the bridge
The bridge was built by using the free cantilever method that is most commonly used for cable stayed bridges. The construction stage-10 can be seen in Fig. 2 with a can- tilever length of 209.40 m. Despite the fact, that the TMDs were tuned with respect to the dynamic properties of the completed bridge, the dampers were already erected and activated during the construction stages in order to avoid VIV prior to the deck closure. 2.2 Monitoring system on the bridge Monitoring system on structures are widely used [10] and was also utilized considering the slenderness of this unique bridge. The dynamic response of the Komárom Bridge as well as the wind velocity were monitored simultaneously by using sensors during the most critical construction period. The sensor positions at the cross section can be seen in Fig. 3. The wind velocity U and direction α were recorded on both sides of the stiffening girder by using sensors type Vaisala WINDCAP Ultrasonic Wind Sensor WXT532 mounted onto high steel masts. The accelera- tion sensors HBM B12 were installed to the cross sections at the TMD location. The vertical accelerometers were fixed to the top of the moving mass of the TMD (A TMD ) as well as to the bridge deck section (A bridge ). Thus, the ver- tical vibration of the bridge deck and the TMD could be measured at the same time. As the length of the stiffen- ing girder changed during the construction, the sensors Fig. 2 Free cantilever of the bridge (courtesy of Pont-TERV Ltd.) Fig. 3 Sensor positioning at the cross section Fig. 1 Bridge deck with the designer team (courtesy of Pont-TERV Ltd.) Szabó et al. Period. Polytech. Civ. Eng. |3 were repositioned (at one time only) in order to be closer to the end of the cantilever. Sampling rate for the wind sensors was 1 Hz, while that for the acceleration sensors was 20 Hz. The QuantumX MX840B universal measuring amplifier, the UPS, the PC for the data collection and the GSM communication were placed in a sealed box under- neath the deck, near the TMD elements. tải về 4.5 Mb. Chia sẻ với bạn bè của bạn:
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