Currently there are more than 38,000 bridges on German federal highways where 90% are made of concrete. A large number of these are now used for about 40-50 years. So more and more effort in restoration is necessary and a significant amount of money is tied up. Continuous observation is very important but nowadays it is only done on a regular basis every few years in an intense inspection where the date is independent of the results from the last observation. Since the overall traffic volume increased much faster in the last decades than foreseen, bridges might be damaged much faster than expected and an impending structural collapse might be overlooked. By adding sensors to the bridge and creating a continuous and fully automated monitoring the condition of the building can be estimated much faster and in more detail. Particularly temporary and extreme deviations from the plans like massive overloads, vibrations caused by small earthquakes or rust can be detected easily. Based on the monitoring, data inspections might be shortened since some measurements are no longer needed and as a consequence of the pre-known approximated bridge condition the inspection interval might become more flexible in both directions. So those bridges become of more interest where the current situation becomes quite worse and not where the last inspection was done a certain time ago.
However, this extreme resolution also implies substantial computational demands in order to investigate. The project is mainly divided into two parts: sensor network and data management. The sensor network has the mission to create lots of metric from different points at the bridge and collect them at a single point which is the connection to the outside world. Due to the large number of bridges and the fact that most bridges are not connected to any power source, the sensor network has to be almost energy independent. Some sensors which might be included completely in the structure (rust, gradient detectors ...) must be energy autarkic. So we aim at developing proper sensors but for the collecting node which will also send the data to a data centre we assume that an additional battery or something similar is necessary, at least for this project phase. This is based on the not yet existing energy independent node and the fact that in the test phase we will collect and handle much more data at the bridge than needed in a productive environment, therefore the energy consumption is probably much higher. After collecting the data it is send to/retrieved by a data centre, so the bridge's monitoring can be used in both directions. The sensor part is done by CMT, IMTEK and LITEF.
The second part in the project is the data handling and simulation. After the data is received or fetched from the bridge it is then stored in a hierarchical monitoring system which is quite flexible in adding different data sources and data types. Based on the configuration, new metrics are calculated automatically i.e. min/max/average values or some more complex metrics. The monitoring system can be easily extended if more bridges are added or more operations should be executed on the data. Based on these data time series the analysing engineer can see and compare the condition of bridges. Based on the same values a simulation about the future structural integrity of the bridge can be started and integrated in the analysis. This might even be possible with changed assumptions about traffic volume or detected movements of the ground. It is then also possible to compare similar bridges to find out if bridges of the same type are influences by a specific parameter like humidity nearby.
|Funding Agency||BaSt (Federal Highway Research Institute/Bundesanstalt für Straßenwesen)|
|Runtime||01.07.2012 - 31.12.2015|