Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
GPS-based deflection monitoring
Major bridges are designed to accomodate specific levels of traffic and wind loading, as well as to withstand deterioration over time. As a result of these forces and thermal action, the large structures often move anywhere from a few decimeters to nearly a meter. Kinematic GPS (Global Positioning Systems) is ideal for monitoring large structures. GPS is a U.S. owned-and-operated satellite-based positioning system. The 28 satellites, orbiting Earth at an altitude of 20,000 km, transmit binary code modulated on carrier waves. Using the kinematic GPS, the roving receivers, whose coordinates are unknown, are positioned relative to reference receivers with known coordinates. Data processing can be carried out on the fly (OTF) in real time. The GPS-based system provides 3D coordinates with corresponding time, making it possible to derive the frequency of structural movements. Typically, the first natural frequency of long suspension bridges is 0.1 Hz; second- and third-order frequencies have been detected as well. You can analyze deflections in real time and compare them with the limitations of the bridge, and also analyze the frequencies of the movements and compare them with redicted values. GPS-derived data can be used to validate predictive models of the structure, and you can use the constant comparison of the models with the real movements to analyze structural health. The use of GPS was investigated to establish the magnitude and frequencies of a bridge's deflections. The field research was conducted on the Forth Road Bridge, near Edinburgh, Scotland, The bridge has an overall length of 2.5 km and a main span length of 1,005 m. Traffic over the bridge has steadily increased from 4 million vehicles in 1964 to more than 23 million in 2002. In addition, the heaviest commercial vehicles weighted 24 tons in 1964; the current limit is 44 tons. The project staff conducted trials at seven GPS-receiver locations on the bridge during a 46 hr. period. The bridge's GPS receivers were coordinated relative to two reference receivers located adjacent to the bridge, on the southern end viewing platform. The trials at Scotland's Forth Road Bridge have shown that it is feasible to use GPS to measure the magnitude and frequencies of the bridge's deflections in 3D. This is possible at a rate of as much as 10 Hz, and all the results are synchronized with one another. During the data-gathering exercise, it was evident that the bridge did move, and staff members saw a rippling effect on the bridge deck. On processing the data, movements of almost a meter and the rippling effect became evident in the data as well.
GPS-based deflection monitoring
Major bridges are designed to accomodate specific levels of traffic and wind loading, as well as to withstand deterioration over time. As a result of these forces and thermal action, the large structures often move anywhere from a few decimeters to nearly a meter. Kinematic GPS (Global Positioning Systems) is ideal for monitoring large structures. GPS is a U.S. owned-and-operated satellite-based positioning system. The 28 satellites, orbiting Earth at an altitude of 20,000 km, transmit binary code modulated on carrier waves. Using the kinematic GPS, the roving receivers, whose coordinates are unknown, are positioned relative to reference receivers with known coordinates. Data processing can be carried out on the fly (OTF) in real time. The GPS-based system provides 3D coordinates with corresponding time, making it possible to derive the frequency of structural movements. Typically, the first natural frequency of long suspension bridges is 0.1 Hz; second- and third-order frequencies have been detected as well. You can analyze deflections in real time and compare them with the limitations of the bridge, and also analyze the frequencies of the movements and compare them with redicted values. GPS-derived data can be used to validate predictive models of the structure, and you can use the constant comparison of the models with the real movements to analyze structural health. The use of GPS was investigated to establish the magnitude and frequencies of a bridge's deflections. The field research was conducted on the Forth Road Bridge, near Edinburgh, Scotland, The bridge has an overall length of 2.5 km and a main span length of 1,005 m. Traffic over the bridge has steadily increased from 4 million vehicles in 1964 to more than 23 million in 2002. In addition, the heaviest commercial vehicles weighted 24 tons in 1964; the current limit is 44 tons. The project staff conducted trials at seven GPS-receiver locations on the bridge during a 46 hr. period. The bridge's GPS receivers were coordinated relative to two reference receivers located adjacent to the bridge, on the southern end viewing platform. The trials at Scotland's Forth Road Bridge have shown that it is feasible to use GPS to measure the magnitude and frequencies of the bridge's deflections in 3D. This is possible at a rate of as much as 10 Hz, and all the results are synchronized with one another. During the data-gathering exercise, it was evident that the bridge did move, and staff members saw a rippling effect on the bridge deck. On processing the data, movements of almost a meter and the rippling effect became evident in the data as well.
GPS-based deflection monitoring
Roberts, Gethin Wyn (Autor:in) / Meng, Xiaolin (Autor:in) / Brown, Chris (Autor:in)
Sensors ; 23 ; 16-19
2006
4 Seiten, 5 Bilder
Aufsatz (Zeitschrift)
Englisch
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