A preliminary report by specialists to the collapse of a Mexico City raised subway line which killed 26 people put much of the blame Wednesday on weak welds in studs which combined steel support beams into a concrete coating behind the trail bed.
The town authorities hired Norwegian certification company DNV to examine the probable causes of the May 3 mishap, where a span of this line buckled into the floor, dragging down two subway cars.
The report also stated that there were seemingly insufficient figurines, as well as the cement poured over them might have been faulty; the welds between stretches of metal beams seem to have been poorly done.
“The studs revealed deficiencies in the welding procedure,” the report says.
The report based on physical and photos review that revealed that metal studs welded to the surface of steel reinforcement beams had broken or sheered off , indicating the welds were faulty.
The beams couldn’t take the burden of this track bed by themselves. The claws projecting upwards from the beams have been covered with a poured concrete slab intended to help carry the weight.
However, the studs were discovered to be still carrying ceramic rings which coated the welds. Employed as a security and management method to include the wrought iron, the rings have been assumed to have been pumped off following welding therefore inspectors could observe the welds themselves. The truth they were abandoned in position may indicate the welds weren’t properly inspected.
That would match with reports that the job had been hurried to end therefore the Number 12 subway line might be inaugurated by present Foreign Relations Secretary Marcelo Ebrard until he left office as mayor at 2012.
The section was constructed by a business owned by telecom and building magnate Carlos Slim, now Mexico’s richest person and after the world’s weakest.
Any proposals his company did shoddy job on the subway could be a critical blow to his standing as a type of elder statesman of the Mexican business community.
The $1.3 billion Number 12 Line, the newest section of a vast subway system opened in 1969, was ill-fated from the start. The so-called Gold Line cost half again as much as projected, suffered repeated construction delays and was hit with allegations of design flaws, corruption and conflicts of interest.