ON THIS DAY: February 5, 2007, Convention Center floor collapses onto 10th Street after beam fails

PITTSBURGH — The David L. Lawrence Convention Center had only been open a few years when a 6-inch thick, 30-by-59-foot section of the second floor loading dock collapsed. No one was injured, but the section was directly above the 10th Street passageway and its water feature. A high-lift fell 30 feet down onto the roadway and a tractor-trailer became wedged in the gap over the missing section.

The break occurred just outside one of the exhibit halls while the truck was being unloaded for the auto show. It was an area designed for trucks and was built to take the weight. Temperatures were rapidly falling at the time and contributed to the collapse by weakening welds.

Fortunately, no one fell through the hole and the debris did not strike anyone on the street below, which was right outside the main entry to the Convention Center and happened around 2 p.m.

The driver of the truck was trapped in the cab for 30 minutes. Rescuers had to remove the windshield to pull him to safety. About 150 people were safely evacuated from the building.

The annual auto show was canceled in the wake of the collapse.

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Built in three phases between 2000 and 2003, the $332-million Convention Center already

had a series of mishaps prior to the 2007 collapse.

The collapse was near an area where caissons shifted in November 2001, which necessitated unexpected repairs.

Three months later, on Feb. 12, 2002, a 90-ton steel truss collapsed just before the first phase of the Convention Center was scheduled to open. Ironworker Paul Corsi, Jr. was killed and two other workers were injured by the falling truss. Improper bolts that were insufficiently tightened, caused it to collapse.

Allegheny Coroner Cyril Wecht had recommended that homicide charges be filed against Dick Corp., which was building the center, but District Attorney Stephen Zappala did not believe there was enough evidence.

The 2007 collapse was ultimately blamed on a compromised expansion joint that seized and stressed adjoining welds already weakened by the cold weather.

Engineers investigated the entire design of the building and determined that all structural connections throughout the building needed to be retrofitted with improved connectors. When it was built, precast concrete sections were supported by steel beams, with the ends of each beam connected to a support member with bolted web clip angles, which failed in the collapsed section.

The repairs consisted of one-foot-square steel seats with Teflon pads, a structural element that was on early blueprints for the building, but never installed.

The Sports & Exhibition Authority settled claims over the floor collapse with steel fabricator ADF Group, Rafael Vinoly Architects and Dick Corp. for $4.78 million in 2009.

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