Costs of accident may be in tens of millions; Plaza offices off-limits

The cost of Thursday's crane accident is likely to run into the tens of millions, according to Tim Waters, a spokesman for the city of Bellevue.

One of the buildings hit, an office building called Plaza 305, has been red-tagged as unfit for occupancy. Engineers were hoping to shore up a sheared-off corner of the building by Monday or Tuesday, allowing employees to retrieve their work, said Mike Brennan of Bellevue's development-services division.

Two units in the Pinnacle BellCentre condominiums, crushed by the tip of the crane's boom, are also deemed off-limits. One of these units belonged to Matthew Ammon, the Microsoft lawyer who was killed Thursday. Two condo residents beneath Ammon's unit have been allowed to get their belongings but cannot stay in their homes, Brennan said.

Who will bear the cost is still being determined.

"Obviously, the insurance companies and the tower-crane manufacturer all have people doing their own investigations. There's a lot of eyes looking at why this particular failure happened," said Brennan.

Guy Conversano, a structural engineer hired by general contractor Lease Crutcher Lewis, said the problem may have originated near the base of the crane.

The crane, he said, was mounted on an unusual foundation of steel I-beams instead of the customary concrete slab. And the crane's tower was bent near the foundation.

"You've got to determine where the first failure occurred, whether in the crane or the foundation," said Conversano, a partner in Seattle-based DCI Engineering. Once the failure is pinpointed, Conversano said, he will look at the causes.

"We think the winds had something to do with it. We think the frequency of loading had something do with it. We think the design of the crane had something to do with it. We think the crane base may have had something to do with it," he said.

Jonathan Martin: 206-464-2605 or jmartin@seattletimes.com