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Four experts appointed by the Genoa Prosecutor’s Office to establish the causes of the Morandi bridge collapse, which occurred on August 14, 2018, presented their long-awaited report. The document is 476 pages long, divided into 14 chapters, and answers 40 questions. It was written by experts Gianpaolo Rosati, Stefano Tubaro, Massimo Losa, Renzo Valentini (the four engineers and university professors, two in Milan and two in Pisa) and it was presented to the investigating judge Angela Nutini.
As he wrote Republic, the report is “the most important document produced since the time of the disaster until today.” In their attempt to determine what happened to the bridge before August 14, 2018 and at the time of the collapse, the report – of which there are several excerpts in the newspapers – speaks of a corrosion process that had been going on for years and that they believe . It should and could have been identified and that was not the case due to poor maintenance and attention to signs.
The experience
According to experts, “the cause that triggered the collapse is the corrosion of the upper part of the tie rod of pile 9”, which “showed an obvious and very serious form of corrosion in the area of attack with the antenna”, a corrosion that “has was carried out in areas of cavities and non-injection formed in the construction of the bridge. ”The experts wrote that the corrosion process” began from the first years of the bridge’s life and progressed without stopping until the moment of collapse, causing a reduction unacceptable in the area of the resistant section of the cords that formed the core of the tie rods “. essential elements for the stability of the work”.
The document also says that since 1993, when the last concrete maintenance intervention was carried out on the bridge, “there have been no interventions that could stop the ongoing degradation process and / or repair the defects present at the ends of the bridge. the tie rods that, high up on the south side of Genoa of Pier 9, were particularly serious. ”And according to the experts, if the checks and maintenance had been carried out correctly,“ with high probability they would have prevented the event from occurring. ”They then added :
«The lack and / or inadequacy of the controls and the consequent corrective actions constitute the weak links of the system; if, in case of failure, they had been carried out and, if carried out, correctly executed, they would have interrupted the causal chain and the event would not have occurred ”.
About him Corriere della Sera, Andrea Pasqualetto summarized the “chain of causes” of the collapse as follows: “collapse due to tie breakage, high corrosion failure, corrosion due to poor maintenance and poor maintenance due to inadequate controls and inspections”.
However, at the origin of it all, the experts wrote that they also identified design, build and test shortcomings. According to experts, in fact, “the root causes” of the collapse “can be identified in: design deficiencies, which had not adequately taken into account the construction details, in reference to the difficulty of making the castings in the presence of very little interferences ; lack of adequate technical specifications on cable covers and injection methods; construction defects in the construction phase […]; deficiencies in the controls during the construction phase by the construction management and the commission of tests during construction; failure to carry out the specific investigations (demolitions located at the ends of the tie rods) necessary to verify the condition of the strands of the primary groups, as had been recommended since 1985; absence of restoration or repair work, which should have been carried out in time to repair the defective strap.
The document presented to the examining magistrate in Genoa explains that “the indications of the engineer Morandi himself have been neglected over the years with special reference to the degradation of the steels” that Morandi (the designer from whom he had taken the name the bridge) “had paid attention to the risk of cable corrosion” and that shortly after the opening of the bridge, which took place in 1967, both the director’s technicians and Morandi himself had “highlighted an already widespread state of deterioration and they proposed changes of intervention “.
– Read also: History and problems of the Morandi bridge
“If the maintenance interventions had been carried out correctly,” wrote the experts, “with high probability they would have prevented the occurrence of the event.” And, again according to the experts, those who had to be in charge of the bridge maintenance “should have had adequate knowledge of how the work was built, evaluating the correspondence with the design documents, which would have allowed identifying the serious construction defect in the last section of the tie rod, in correspondence with the upper part of the antenna, allowing to foresee and control the deterioration process ”.
And now?
The appraisal presented to the investigating judge – which follows August 1, 2019, which had already highlighted structural defects and lack of maintenance – is part of the second evidentiary incident in the investigations. The appraisal, in other words, is a test in all respects, even if the process itself has not yet started and we are only in the preliminary investigation stage. As explained Republic, now all parties involved “will have more than a month to study in depth each word of the document” since “the start of the discussion in the classroom is scheduled for February 1, 2021.”
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