TESTS AND INSPECTION CHECKS BRIDGE LINE 1 M.N. - NAPLES

As part of a program of interventions envisaged and programmed in order to guarantee the necessary safety conditions of the entire Neapolitan railway infrastructure, a plan of inspection investigations of the traditional and diagnostic type was prepared for the metal bridge between sections 596.77 and 664.70 of the external line between Colli Aminei and Piscinola/Scampia of line 1 of the Naples Metro”.
The traditional investigations consisted of a sample check of about 650 bolts, while the diagnostic investigations envisaged the control of welds through combined magnetoscopic and ultrasonic investigations over a length of 15 m + 15 m distributed over the most stressed ashlars.
Specifically as regards welds, the examination with magnetic particles (MT) allows to detect surface and sub-surface defects in ferromagnetic materials, while with ultrasonic methods the aim is to locate any anomaly, such as splitting, present in the material that could impede the sonic beam path during weld exploration, and to accurately determine the thickness of the material so that the necessary sonic path lengths can be determined.
Finally, the checks of the tightening torque of the bolts were carried out using a Beta torque wrench matr.79118329820 equipped with a Beta torque multiplier, matr. 2018B10113.