The manufacturer of the clamping structures recommended investigating the clamping elements with respect to corrosion and possible wire ruptures after a certain service life of the structure (typically 5 to 10 years). In steel cables with a large diameter the visual examination of the object is even less reliable method. Too many information about the inner stress of the rope remains unknown during the purely visual inspection. Radiographic examination provides a much greater reliability, but is very time consuming and the radioactive substances are becoming less acceptable for use outside the laboratory.