Inspection using ground penetration radar (GPR) to locate metal elements in the base and masonry stereotomy detection.
The inspection of the base of the statue of King José I, located in the Commerce Square in Lisbon, aimed to detect the metal spikes that hold the stones and the statue, as well as verifying the geometry of some stone elements. The inspection was conducted using a GPR equipment and antennas with different frequencies.
Tests were performed with equipment from MALA (RAMAC / GPR) using three antennas with different frequencies (1600 MHz, 800 MHz and 500 MHz) in order to try to achieve the goals and desired thickness. The profiles were performed with antennas made in various faces of the statue.
The most relevant results of this inspection work were the definition of the internal geometry of the stones and the probable number and location of metallic elements. Connecting clamps were found in stones as well as vertical spikes, while no other metallic internal structure was detected.