Report blames poor welds for Mexico City subway collapse

MEXICO CITY (AP) — Poorly welded, badly located and completely missing studs that joined steel support beams to a concrete layer supporting the track bed were to blame for the May 3 collapse of an elevated segment of Mexico City’s metro that killed 26 people. The Mexico City government hired Norwegian certification firm DNV to find the causes of the deadly accident. Tuesday’s final report arrived at similar conclusions as the firm’s preliminary report in June. The sloppy installation of the studs created a situation where the elevated structure was working as “two independent parallel beams, a concrete beam and steal beam, that experienced loading conditions for which they were not designed.”