Radar interferometry
The technology of the ground radar interferometry enables new possibilities in diagnostics, projecting, dimensioning, optimization and consecutive monitoring of bridges. In case of steel constructions, the technology has basically no requirements for installation and preparing and its character of contactless measuring of the whole construction with one device is suitable for long-term and repeated measuring of bridges or oversize load crossing.
Advantages
The method of radar interferometry is a new innovative measuring method that enables observing vertical deflections at several points at the same time. Bridge movements can be dynamically scanned at high scanning rate and it is possible to achieve the accuracy of 0.01 mm. Current diagnostic and measuring methods are not able to offer the above mentioned high accuracy or the following parameters:
Contactless determination of vertical deflections of bridges with accuracy of up to 0.1 mm in real time,
To record real-time oscillation of the monitored object with the frequency of up to 100 Hz and consecutive frequency analysis determine the main oscillation frequencies,
Deflections can be (in comparison with other measuring methods) determined via one device at more places of the bridge at the same time,
Installation of the device and preparation for the measuring is very simple and fast.
Disadvantages
Constructions (bridges) with low construction height, low underpass profile or way complex construction of the superstructure are not suitable for observing or monitoring via radar interferometry method. It is also necessary to find such a place for the radar enabling lucid measuring of the whole locality that is to be measured.
References of the radar interferometry
- D1-035 – Naháč bridge – monitoring of vertical deformations in regular traffic
- Rataje nad Sázavou – a railway bridge – monitoring of thermal expansion
- Červená nad Vltavou – a railway bridge – measuring of vertical deformation during static test
- Construction objects at 65-20-010 at Chotoviny while constructing the section Tábor – Sudoměřice – monitoring of horizontal deformation during dynamic test
- Specification of bridges diagnostics with radar interferometry
- D1, D1 highways – verification of radar interferometry for specification of diagnostics and fixing of bridges proposal
Usage
The technology of radar interferometry provides new information and offers new possibilities in diagnostics, projecting, dimensioning, optimization and consecutive monitoring of bridges. At the same time, it provides possibilities of immediate observation of the construction in real time, depending on its strain, climate effects, and the like. With respect to measuring that had already been done can be stated its real usage in measuring oversize load crossings or bridge load tests. The method can be used in solving long-term issues of construction behavior (bridges, scaffold bridges, and the like) while evaluating the reasons of their origin and consecutive solution.
