Metallic constructions integrity assessment and maintenance planning method

A method for generating an optimal schedule for an maintenance of an extended metallic structure, comprising:

• localizing coordinates of the structure and detecting anomalies with localized coordinates within the extended metallic structure by using a non-contact remote technique based on measuring a value of the Earth's magnetic field at multiple locations in vicinity of the structure and identifying the anomalies by deviation of the Earth's magnetic field at each location from a background value, without applying an additional magnetic field during the measuring;
• selecting one anomaly to be a calibration anomaly;
• performing in-contact non-destructive mechanical stress measurement of the calibration anomaly of the structure;
• comparing of the mechanical stress value obtained by the in-contact measurement for the calibration anomaly with a measured data of the Earths magnetic field for the same anomaly and deriving a calibration coefficient, which transforms each Earth's magnetic field deviation value into mechanical stress data;
• calculating in a computer absolute values of a mechanical stress around all found anomalies in the metallic structure using the measured values of the Earth's magnetic field for each anomaly and applying the calibration coefficient;
• calculating risk-factors for the respective anomalies found based upon their absolute values of the mechanical stress;
• and
• creating short-term and long-term operational forecasts, including chronological and topological planning of necessary procedures required for the said structure maintenance and repairs;
• wherein the forecasts are created based on the anomalies by measuring the non-contact technique only once and without using a data from any previous measurement of the same anomalies by the same technique.