September 7, 2021
By Cassandra Garrison
MEXICO CITY (Reuters) – A deadly Mexico City metro collapse in May was caused in part by missing bolts in beams in an overpass that already had deficiencies before a major earthquake, according to an independent auditor’s report released on Tuesday by the city government.
The analysis by Norwegian company DNV was the latest installment of its technical opinion on the May 3 collapse – Mexico’s biggest train accident in years – that killed 26 people when an overpass and train carriage suddenly plummeted onto a stream of cars near the Olivos station in the southeast of the city.
In the findings shared by Mexico City’s civil protection agency (SGIRPC), DNV said deficiencies including the lack of functional bolts over a significant stretch led to the buckling of north and south beams.
That led to the structure operating as two independent girders that took on weight it was not designed to handle.
“This created conditions that led to the distortion of the central transverse frame and the initiation and propagation of fatigue cracks that further reduced the capacity of the structure to support the load,” the report said.
Sections of the collapsed overpass were in “compromised condition” before a major 2017 earthquake that caused damage to parts of the metro, the report said.
DNV had been due to present its follow-up report on Aug. 23 but requested a two-week extension to complete its probe.
The metro was built by a consortium of Mexico’s ICA, Grupo Carso, a company controlled by the family of Mexican tycoon Carlos Slim, and French trainmaker Alstom SA.
Grupo Carso had no immediate comment on the report. A spokesperson for ICA did not immediately respond to a request for comment and a representative for Alstom could not immediately be reached.
(Reporting by Cassandra Garrison and Raul Cortes; Editing by Bill Berkrot)
Source Link Missing bolts among issues that sparked Mexico City metro collapse, auditor finds
