A structural failure caused by at least six serious construction errors caused a section of Mexico City’s metro to collapse in May, killing 26 people, according to the preliminary accident report presented by the municipal government on Wednesday.
The document, which was prepared by the Norwegian company DNV with international experts at the request of the government of Mexico, revealed multiple problems with the screws, beams and planks used in the structure.
It further describes in detail the weld defects of the bolts which have not been fused as they should have been to prevent them from eroding from water and use.
He also points out that bolts were missing in the beams that make up the bridge, that different types of concrete were used and that some welds were not completed or were poorly done.
Mexico City Mayor Claudia Sheinbaum told the press conference that they would continue to investigate and monitor “not only because of our legal obligation, but because of our ethical, human and moral commitment.”
The city’s public works secretary, Jesús Antonio Esteva Medina, said that in order to prepare the report, they carried out visits to the accident site, adding that laboratory tests are still needed to determine, for example, if incorrect or defective materials were used.
Esteva noted that they found warped beams in the section where the metro was curving at the time and other beams had slipped from their positions.
Marcelo Ebrard, the current Minister of Foreign Affairs and mayor of Mexico during the construction of the “Golden Line”, defended Wednesday his management of the project and reiterated his willingness to collaborate with the authorities.
“I support the carrying out of the expert and technical investigations necessary to determine the causes of the accident and define the responsibilities that may arise from it,” said Ebrard, one of the most important political figures in the current administration, in a statement. letter posted on Twitter. .
Ebrard said decisions regarding the layout, design, construction and supervision of the metro line were made in consultation through committees and there is extensive documentation.
Wednesday’s report found that different concrete was used where the crucial Nelson bolts were placed – which were not evenly spaced, “which is not in accordance with the design,” Esteva said. . These bolts were also not driven well into the beams and fewer bolts were used than necessary.
“In the area of the fault, the necessary reinforcements in the columns were not observed and the foundation was shallow” in the columns, Esteva said.
The report states that information on repairs carried out after the end of construction of the railway line, as well as daily maintenance tasks on this section of the metro, still need to be analyzed.
The company DNV maintains that its goal, beyond clarifying the causes of the incident, is to determine if there are systemic problems, in order to prevent them from occurring in other sections of the metro.
It was on May 3, shortly before 10:20 p.m. local time, that a line 12 elevated bridge collapsed between Olivos and Tezonco stations, causing one of the country’s biggest rail tragedies.
In addition to the 26 people who died, nearly a hundred were injured. The head of government of the capital, Claudia Sheinbaum, has promised a thorough investigation to find out what happened.
Noticias Telemundo Investiga had access to a report published by the city congress in May 2019 to the metro management, which deals with delays in service and its administrative and financial situation. The document reports on the use of defective parts to repair trains and unqualified employees, such as ticket agents, performing maintenance work.
Mexico City’s metro carries around six million people every working day and is one of the busiest in the world. But several groups of citizens criticized the precariousness of the facilities and the lack of maintenance that causes frequent interruptions of metro service.
A second phase of the report will be delivered on July 14 and phase 3 will be delivered on August 30.
A version of this story was first published in Noticias Telemundo.
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