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Higher resolution scanning of structures

Fugro Aperio are amongst the first specialists in Europe to take advantage of a new high resolution radar antenna which enables improved imaging through a wide range of structures.

Systems developers, such as GSSI in the United States, provide a range of radar antennas to enable investigation from depths ranging from millimetres to several metres. GSSI’s latest antenna for structural investigation operates at a frequency of 2600 MHz – considerably higher than the earlier 1500 MHz model. This higher frequency means a shorter wavelength signal that can penetrate gaps –between rebars for example – that would have represented a boundary to alternative systems.

Working on a range of concrete and masonry structures, Fugro Aperio’s investigation team has been impressed with the quality of data delivered by this new generation antenna. It can reveal defects such as delamination and voids which previous systems would have missed, as well as structural features such as very closely spaced rebars or small diameter wall fixings. Other applications include pavement investigation, where benefits include improved characterisation of internal layers and detection of delamination.

In a recent investigation of reinforced concrete structures in Peterborough, a Fugro Aperio survey team compared data from identical positions using the new high resolution antenna and its earlier equivalent. They found that in places the older antenna could detect the presence of a metallic layer within a concrete bridge deck but could not provide any more detail on its arrangement, whereas the new antenna could resolve individual bars even where they were lapped or bunched.