Missing bolts contributed to Mexico City metro collapse: Report | Infrastructure News

Missing bolts contributed to Mexico City metro collapse: Report | Infrastructure News

Poor welding additionally contributed to Metro Line 12 collapse that killed 26 folks in May, unbiased auditor finds.

A lethal Mexico City metro collapse in May was induced partly by lacking bolts within the beams of an overpass that already had deficiencies earlier than an vital earthquake, an unbiased auditor’s report launched on Tuesday by town authorities has discovered.

The 180-page evaluation by Norwegian firm DNV was the newest instalment of its technical opinion on the May 3 collapse – Mexico’s greatest prepare accident in years.

Twenty-six folks had been killed when an overpass and prepare carriage on Metro Line 12 immediately plummeted onto a stream of vehicles close to the Olivos station within the metropolis’s southeast.

The collapse put stress on shut allies of President Andres Manuel Lopez Obrador, in addition to on Carlos Slim, Latin America’s richest man whose development firm was chargeable for constructing the a part of the road that collapsed.

In the second section of DNV’s findings shared by metropolis officers, the agency mentioned deficiencies, together with a scarcity of practical bolts over a major stretch of the road, led to the buckling of north and south beams.

The deficiencies left the construction working as two unbiased girders that took on weight it was not designed to deal with.

“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 mentioned.

The agency mentioned different attainable components included deficiencies within the beams themselves and the design of the framework.

Sections of the collapsed overpass had been in “compromised condition” earlier than a critical 2017 earthquake that induced injury to components of the metro, the report mentioned. Poor welding practices had been additionally noticed by the auditor.

The metropolis authorities has already began engaged on rehabilitation of the road, and the report’s findings will likely be shared with a technical advisory committee, mentioned Jesus Esteva, head of Mexico City’s public works division.

“In the next few days we will be signing the agreements with the companies. They will be doing the work,” Esteva mentioned, with out including additional particulars.

The authorities of Mexico City has already began engaged on rehabilitation of Line 12, often known as the Golden Line [File: Marco Ugarte/AP Photo]

The metro was constructed by a consortium of Mexico’s ICA, Grupo Carso, an organization managed by Slim’s household, and French prepare maker Alstom SA.

Grupo Carso had no speedy touch upon the report, nor did ICA reply to a request by the Reuters information company for remark whereas a consultant for Alstom couldn’t be reached.

Carso would restore the road for gratis to the federal government in order that it may well reopen in a 12 months, Lopez Obrador mentioned in June.

DNV’s preliminary report discovered “six deficiencies in the construction process” that contributed to the accident and famous insufficient bolts and deformed structural helps.

The agency had been due to current its follow-up report on August 23 however requested a two-week extension to full its investigation. The firm continues to be anticipated to ship a 3rd section of its findings on what occurred.

Local media reported that the knowledgeable evaluation had value Mexico City greater than $1m.

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