The pancake-style collapse on December 6, 2007, claimed the life of a laborer and injured 23 others. Atlanta-based Choate Construction Co. hired two forensic engineering firms, Wiss-Janney Elstner Associates, Inc., Atlanta, and Carl Walker of CW Consulting LLC, Kalamazoo, Mich., to review the design for the six-story, post-tensioned concrete garage that accompanies the Berkman Plaza II residential tower.

“Both studies independently conclude that the collapse was due to significant deficiencies in the design performed by the owner’s structural engineer, Structural Consulting Group LLC of Alpharetta, Ga.,” said the written release from Wm. Millard Choate, CEO of Choate Construction.

Choate didn’t immediately make available the full engineering reports.

Officials of the Structural Consulting Group could not be reached for comment. An employee who answered the phone in the firm’s office declined to comment.

Specifically, Choate’s statement says Wiss-Janney concluded, “The original design was deficient and inadequate to support the 50-psf design live load prescribed by the building code.” Mark Moore, a principal with Wiss-Janney, confirmed the accuracy of the statement but says he cannot comment further.

Neither the Will Janney or Walker report found any action or inaction by Choate to be the cause of the collapse, according to the Choate press release.

However, in June, the U.S. Occupational Safety and Health Administration cited Choate for three violations and proposed penalties totaling $56,700 against the contractor. OSHA also issued two willful violations with penalties totaling $125,000 against Southern Pan Services of Lithonia, Ga., the concrete formwork contractor.

Choate and Southern Pan each received a willful violation for failing to have a qualified person determine if the structure could support the additional three-quarters of an inch of wet concrete weight that was added to the 20-in floor slab. In addition, the agency proposed one willful violation against Southern Pan for failing to obtain a re-shoring drawing, including all revisions, for the reshoring design method used at the site.

Choate is vigorously contesting its citations, the release says, because the evidence shows Choate properly performed the work.

Mike Wald, a spokesman for OSHA, acknowledged that Choate has appealed the citations and declined to comment further.

The project’s developer, Harbor Cos., said in a statement that there was no surprise that Choate’s experts would point the finger at other project members. “Other experts will undoubtedly express very different opinions,” says Harbor’s statement. “The owner is committed to determining the true cause of the collapse and to making sure the responsible party or parties are held accountable for this tragic event, whoever they may be.”

Harbor says it won’t comment further until all investigations are complete. The developer has not set a date for resumption of construction and says it is taking steps to ensure no problems are encountered in completing the project and that the final product will be safe.