translated from Spanish: College of Engineers recommends not restarting operations; detects fissures

After the physical review of Line 12 of the Metro, the College of Civil Engineers of Mexico A.C., recommended not to restart the operation of the elevated section or the subway, until a more detailed evaluation is made.
In a press conference, he reported that cracks were found in columns, locks and heads; deformed support elements; shorter locks; separations in the elevated section, and leaks
Read: Construction deficiencies led to line 12 accident: preliminary expert report

In a first report, he disclosed that in 32% of the section analyzed – from Culhuacán to Tlaltenco, without intervening at ground zero – grade “B” affectations were found, which indicate vulnerabilities, damages or deficiencies that need to be addressed in more detail.
In this physical inspection there was no affectation classified within risk “A”, which implies the greatest danger.
It recommended priority attention on:

Review of the separation between the vehicular bridge of the Periférico and the columns of the elevated viaduct of the Metro.
Repair of cracks in columns.
Repair of fissures in pre-reinforced tablets with high level of leaks.
Repair of the heads damaged by the work of the seismic stoppers
Review of the reinforcement carried out in the section near the Nopalera station.

In a press conference, the coordinator of the Technical Committee on Structural Safety of the College of Engineers, Bernardo Gómez González, said that 68% of the elevated sections of Line 12 have grade “C” affectation, that is, they do not imply a severity and are common.
The goal of this assessment, he said, is to identify vulnerabilities at first glance in the work.
The integrated committee for this monitoring recommended initiating a strengthening and rehabilitation project to address the identified deficiencies.
Evidence 
These are some of the images of the deficiencies detected after the physical inspection.

Underground tunnel
According to the College of Engineers, the tunnel of Line 12 has no structural problems or deformations that put its stability at risk, although they did find problems of water filtration, which with an adequate treatment and an efficient system of collection and conduction of water is solved.
“However, it was agreed that for operational and maintenance reasons it is not possible to reopen it until the collapsed section is repaired,” the College said in the conclusions of the analysis of the underground section.
They recommended a thorough review of the drainage system, and a comprehensive project to solve the problems of leaks and runoff.

We continue with the live stream. https://t.co/VKMI6DmHpl
— @CICMoficial (@CICMoficial) June 17, 2021

According to the preliminary report of the opinion of the investigation of the Norwegian company DNV, contracted by the government of Mexico City, the collapse of a section of Line 12 of the Metro was due to a structural failure associated with several deficiencies in the construction process.
The company highlighted failures in the welding process of the bolts, lack of bolts in the locks, different types of concrete, as well as unfinished and / or poorly executed welds.
The collapse of a lock in the vicinity of Olivos station on May 3 left 26 people dead and 106 injured, as well as the indefinite closure of the entire Line 12, the newest and most modern of the STC.
The so-called Golden Line was inaugurated by the then head of government of the CDMX, Marcelo Ebrard on October 30, 2012.
The project director of this Metro line was Enrique Horcasitas, and the Construction Consortium was composed of Ingenieros Civiles Asociados, SA de CV (ICA), Alstom Mexicana, SA de CV, and Carso Infraestructura y Construcción, SAB de CV.
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Original source in Spanish