Geodetic monitoring and deformation analysis of a vertical lift bridge
Wegner, Jan Dirk ... [et al.]
A structure is subject to a continuous aging process due to acting loads. By monitoring this process, the engineering surveyor has an essential contribution to the short-term assessment of its functionality and safety. However, usually the monitoring activity starts after first damages have already occurred. Therefore, the properties of the structure before the damage took place are unknown. Such an unfavorable situation was prevented in the presented project by measuring and modeling the deformations due to regular influences. The object of interest was an old vertical lift bridge that will be replaced in near future by a new bridge, situated closely. Thus it will be possible to identify the additional influences of the construction works on the old structure and to assess its stability and functionality. The monitored object is a steel bridge situated in the harbor of Hamburg. It plays a major role in the road, rail and shipping traffic of the harbor. For this reason its functionality has to be guaranteed until the new bridge will be build up. Therefore, the monitoring activity was focused on the two towers and the superstructure, the most exposed components of the bridge, and aimed to measure and model their deformation due to temperature, tide, wind and traffic. In order to monitor long-term effects measurements were conducted for several weeks using GPS and inclinometers. All data was directly transmitted to a central PC deploying WLan. Thus, the modern concept of a wireless monitoring system was realized and implemented. For acquiring short-term deformations induced by vehicles and trains high frequency measurements were performed using a laser scanner set in profiler modus, inclinometers. Due to the fast observed effects the sensors needed to be synchronized.
Event: XXIII International FIG Congress : Shaping the change
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