CNN finds 90-degree stirrup hooks in Venezuelan towers that collapsed in June's earthquakes

In Caraballeda, 15 towers in five complexes collapsed during the magnitude 7.2 and 7.5 earthquakes. Each stood more than eight stories and held at least 240 apartments. Then-President Hugo Chávez commissioned them in 2011 through OPPPE, a special-projects office that reported to the presidency, and CNN reported they went up in about a year, with crews rotating through two or three shifts a day. Satellite images show 63% of the office's high-rises in the town fell.

A March 2012 inspection photo from the foundation of one tower at the complex called OPPPE 27 appears to show several stirrups with 90-degree bends. All four towers there collapsed, and experts told CNN that pictures of the ruins show at least some of those ties were never corrected. Of more than 40 verified images showing stirrups, CNN found few with a clearly correct bend. Structural engineer Kit Miyamoto, whose team of about 100 engineers is assessing buildings for the Ministry of Public Works, said the defect turned up throughout the rubble he examined. CNN also found bars set tight together without the bundling the code calls for, and heavy corrosion at three or more complexes.

The experts cautioned that a direct cause is hard to prove after shaking this strong. An AP investigation in September pointed to loose flood-deposited soil, building heights prone to resonance and one of the strongest ground motions on record. The government has not made its plans, soil reports or inspection files public, and former OPPPE director Francisco Sesto did not answer CNN's requests for comment.

A government commission is testing nearly 100 buildings. Nearby, five of the seven towers at OPPPE 25 survived but have been evacuated. A 2012 photo of that site shows the same 90-degree bends.