DIAGNOSING METHOD FOR CORROSION OF STEEL STRUCTURE

PURPOSE:To diagnose the present corrosion state and the remaining service life of a steel structure by measuring the remaining wall thickness of each part of the steel structure with an ultrasonic thickness meter and measuring the corroding speed of the same part with a corroding speed detector. CONSTITUTION:The corroding speed detector 2 of metal material is fixed on a steel pipe pile 3 used for the structure, for instance, a lading pier by a jig 4 and performs the automatic measurement by a program indication from a measuring system 1 and the arithmetic processing and figuring are performed by a calculation processing machine 5. The detector 2 catches a corrosion reaction of the metal as the impedance at the interface and calculates the reaction electric current quantity from the relation with the impressed voltage and converts it into the corroding speed. Then, first, the precise measurement of the remaining wall thickness is performed every four places in a circumferential direction of the steel pipe pile 3, for instance, with a 50cm pitch of the depth of water by the ultrasonic thickness meter and the corroding speed of the same place at the point of time is measured by the detector. Then, the necessary wall thickness for every depth of water is calculated from the designed load or the like to calculate the remaining life.