Industrialised, Integrated, Intelligent sustainable Construction - I3con

HANDBOOK 2 SUSTAINABLE CONSTRUCTION
Sensor signals are transmitted every hour to a reader, which is placed at the bridge. The reader box is
equipped with a solar panel in order to provide sufficient energy to receive and store the sensor
signals and subsequently transmitting the signals to an internet server by means of a GSM modem. In
that way the system is fully independent of the public electricity supply.
Figure 4. Left: Preparing repaired bridge deck for new waterproof membrane. Right: Sensor (black
box) with extra battery package (grey box)
Figure 5. Box out in bridge deck where the sensor and battery box are installed and a protection lid is
added on top. Right: Ready for applying the waterproofing membrane
Results from the first few weeks of operation are depicted in Fig. 6. A sampling frequency of one per
hour may not be suitable for real applications since the data amounts get huge and the battery is used
every time a signal is sent to the reader box. However, in the preliminary tests we were eager to obtain
proper data rather than optimizing battery life. Furthermore, the data signals from the sensor farthest
away from the reader box are not always picked up due to the signal conditions on the site in general
and on the signal distance of 30 m in particular. Thus, it is nice to have a rather high sampling rate so
that the data are sufficient for evaluation. In real applications a sampling frequency of once every
week may be sufficient.
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