Non-destructive assessment of a historic masonry arch bridge using ground penetrating radar and 3D laser scanner

Applications of non-destructive testing methods such as ground penetrating radar (GPR), 3D laser scanners, accelerometer sensors and vibration detecting sensors amongst many others have been used to assess and monitor masonry arch bridge spans (brick and stone) in the past few years. This paper reports the application of high to low frequency GPR antenna systems (2000 MHz, 600 MHz and 200 MHz) and a 3D laser scanner on a historic masonry arch bridge (the Old Bridge, Aylesford - 860 years old) located in Kent, England. The position of different layers of the deck structure was established with the identification of the original stone base of the bridge and location of a number of structural ties (anchors - remedial work carried out previously). Results of the 3D laser scan of the bridge were crucial to initiate long-term monitoring of the structure.