MEXICO CITY — Development errors led to the Might collapse of an overpass in Mexico Metropolis’s subway system that killed 26 folks and injured scores extra, in accordance with the preliminary outcomes of an impartial investigation launched by town’s authorities on Wednesday.
The report, produced by the Norwegian threat administration firm DNV, means that severe issues with the welding and placement of metallic studs, linchpins of all the construction, straight contributed to the collapse.
“We are able to preliminarily state that the incident was brought on by a structural failure,” the report stated, citing “deficiencies within the building course of.”
The outcomes help the findings of a New York Times investigation that highlighted shoddy building on the metro line. A number of the studs holding the construction collectively appeared to have failed due to unhealthy welds, The Occasions discovered, an important mistake that in all probability precipitated the overpass to offer approach.
Engineers consulted by The Occasions pointed to the presence of ceramic rings, or ferrules, left in place after the welding course of, and to irregularly positioned studs as proof of subpar workmanship — findings that had been confirmed by the DNV investigation.
Its report documented a “failure to take away the protecting ceramic” across the studs, which “lowered the world of adhesion” with the concrete that held up the tracks. Too few studs had been used to fuse the construction collectively, and their placement was inconsistent, one thing that “contradicts the design” of the overpass, the report stated, echoing one other discovering of the Occasions investigation.
The investigators for the DNV additionally famous that several types of concrete had been used to construct the overpass, presumably as a result of staff needed to make changes on website throughout building. On the metal beam beneath the overpass, the report discovered poorly deliberate, problematic welding.
DNV stated its report was primarily based on “the sphere investigation and the laboratory testing of samples from the accident” and that it “solely comprises DNV’s speculation at this level.” The complete investigation will likely be completed later this 12 months, the corporate stated in a press release.
Mexico Metropolis’s authorities, which employed DNV to look at the causes of the crash, can also be conducting its personal investigation into the accident.
“We promised to supply complete care to the victims and to rent a specialised firm to know with technical professionalism and, primarily based on scientific proof, the basis reason behind this horrible tragedy,” Claudia Sheinbaum, the mayor of Mexico Metropolis, stated in the course of the presentation of the DNV report.
The outcomes of the impartial inquiry might spell hassle for 2 of Mexico’s strongest figures: Marcelo Ebrard, the international secretary, and Carlos Slim, one of many world’s richest businessmen.
Mr. Ebrard, the mayor of Mexico Metropolis when the road was constructed, needed it accomplished earlier than he left workplace in 2012, in accordance with a number of individuals who labored on the mission. He’s seen as a strong contender to succeed President Andrés Manuel López Obrador in Mexico’s subsequent presidential elections in 2024.
In response to the discharge of the preliminary report, Mr. Ebrard stated in a press release that figuring out the reason for the crash would require each a technical investigation and “an inquiry that critiques all the decision-making course of within the design, structure, supervision and upkeep” of the metro line.
Mr. Slim’s conglomerate, Group Carso, constructed Line 12 — the a part of the metro that collapsed — to broaden the corporate into the profitable rail business.
On Wednesday, Ms. Sheinbaum stated she would “contact the businesses that had been a part of the development consortium that constructed Line 12 to arrange a technical dialogue.”
In response to earlier questions from The Occasions, Antonio Gómez García, chief government of Group Carso, steered that upkeep failures could have been responsible for the subway’s collapse. Mr. Ebrard had beforehand stated that it was not possible to know whether or not his successor had “performed the entire upkeep” required after massive earthquakes.
However the preliminary report from DNV discovered that the tracks and their mechanical elements had been “in regular situations” and met with “routine upkeep protocols.” Mexico Metropolis metro staff additionally stated they carried out “day by day preventive upkeep actions,” in accordance with the report. Investigators will proceed to investigate whether or not the construction was subjected to irregular weight that might have precipitated the beams to buckle.
Carso is now constructing a major a part of the Tren Maya, a 950-mile railway supposed to bolster the economic system of southern Mexico — one of many nation’s poorest areas — and stand as Mr. López Obrador’s legacy mission.
Some engineers and designers engaged on the Tren Maya have complained of issues just like these confronted after they constructed the subway: a rushed, disorganized course of that has no grasp plan to information building. And Mr. López Obrador has insisted that he desires the Tren Maya to be completed earlier than he leaves workplace in 2024.