The Government of Mexico City maintained that the third report of the Norwegian company DNV, on the expert opinion of the collapse of the Subway Line 12contains a series of inconsistencies and technical and scientific contradictions, which make it deficient.
At a press conference to explain the alleged errors in the report —which was not attended by the head of government, Claudia Sheinbaum, who revealed that there were dilemmas with DNV—, the head of CDMX Civil Protection, Myriam Urzúa, pointed out that among the The main inconsistencies are the use of Google Street View images “as a reference to reach conclusions in the structural analysis”.
On the subject, the Secretary of Works and Services of the Government of the capital, Jesús Esteva Medina, explained that the DNV company used Google to determine the buckling of longitudinal stiffeners in the beams, negative vertical deflection of the tracks and central deflection.
“How can it be that a company of this magnitude bases a technical conclusion of the highest precision, when Google itself warns of its limitations?” Esteva Medina questioned.
missing bolts
The local secretary explained in the first two reports of the Norwegian company the results of the analyzes indicated that the collapse occurred as a result of buckling of the north and south beams facilitated by the lack of functional bolts in a significant length which caused part of the elevated section lost its composite structure.
As well as contributing factors to the lack of functionality in the studs include poor welds, missing and misplaced studs, and cross frame design that did not meet applicable AASHTO design standards.
In other words, the North and South Beams were loaded in such a way that they were moving towards each other before failure, these deformations were not detectable in a simple visual inspection”, he detailed.
While he pointed out that there are also inconsistencies such as design flaws since, he explained, even if all the bolts were there they would have resisted only 14 years.
“Design Flaws: The fatigue strength of the bolts did not meet AASHTO specifications, even in a scenario where the bridge would have been built to specification (executive design), the most critical bolts failed after the passage of 1.25 million trains, or approximately 14 years of operation”, indicated Esteva when reading a part of the DNV report.
At the end, the local official expressed that “once again we want to thank the companies that are supporting the city and the victims, instead of entering into a long trial, with this they ratify their commitment to reinforce the structure and raise their level of structural safety based on the Current Construction Regulations of the Federal District”.
Maintenance
In the Report of the Technical and Scientific Inconsistencies and Contradictions of the Root Cause Results Analysis Report Prepared by DNV Phase III, capital government authorities also rejected the conclusions that the lack of inspections and maintenance contributed to the collapse of Line 12 was that the Root Cause is contradicted because, on the one hand, it indicates that the maintenance manual has deficiencies, but they also say that the inspections indicated in the manual should have been carried out.
Likewise, they highlight that in the latest Root-Cause report, DNV affirms that no routine inspections were carried out, but contradictorily acknowledges that the Government of Mexico City delivered documents that support inspections carried out in 2019 and 2020.
Meanwhile, the secretary of Comprehensive Risk Management and Civil Protection, Myriam Urzúa Venegas, recalled that the first and second DNV reports indicated that the incident on Line 12 of the Metro Collective Transport Service was due to the lack of bolts. and a failure in the construction of the work.
In addition, he said that in October DNV delivered its third report, but it contained inconsistencies, they did not deliver it in a timely manner and, he said, they were notified that they had to correct said document.
DNV denies conflict of interest and defends report
The company in charge of carrying out the expert reports on the collapse of Line 12, DNV, reiterated that the last report was prepared without the participation of any expert who could have a conflict of interest in the case, as indicated by the Government of the City of Mexico previous days.
Likewise, he said that the report was delivered within the contractual requirements and supported the methodology used, the findings and the conclusions of his report.
Regarding the complaints made against our employee Mr. Galindo Alvarado in the media, there is no conflict of interest. Mr. Galindo Alvarado has been an employee of DNV since July 2019”, the Norwegian firm added in a statement.
Likewise, it indicated that said collaborator has no authority, interference or decision-making power over the reports. He also did not participate in the investigation of the incident or in the writing of the deliverables at any time.
On the other hand, the Citizen Movement bench in the Chamber of Deputies pointed out that the disqualification of the document prevents the victims, relatives and citizens from knowing the reasons for the tragedy.
In the same way, he regretted that more than a year after the collapse there is still not a single person responsible and no public official has been prosecuted, “nor is there any progress in the rehabilitation that has left damages in terms of mobility in the eastern zone of CDMX ”.
Finally, given the questions raised by the report during the morning conference at the National Palace, the president, Andrés Manuel López Obrador, gave his support to Claudia Sheinbaum, head of government of the capital.
“She is a woman of integrity, upright, honest and who is also being subjected to strong pressure, but it is the season, it is what will have to come and it is natural for this to happen,” said President Andrés Manuel López Obrador in reference to the fact that The president of the capital is Morena’s candidate for the presidential candidacy heading to 2024.
(With editorial information)