The collapse of a Bellevue crane that damaged three buildings and killed a Microsoft attorney as he sat in his living room was caused by...

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The collapse of a Bellevue crane that damaged three buildings and killed a Microsoft attorney as he sat in his living room was caused by a flawed engineering design of the crane base, a state report issued Friday concluded.

Two companies involved in the Nov. 16 crane collapse were cited and fined a combined $14,800 for workplace safety violations, the state Department of Labor & Industries reported at a news conference at Bellevue City Hall.

The report, the result of a six-month investigation, ruled out operator error and high winds as causes of the collapse at the Tower 333 project in downtown Bellevue.

The crane foundation, created by engineering firm Magnusson Klemencic Associates of Seattle, was designed to withstand only about one-fourth of the pressures the 210-foot tower crane required, said Steve Cant, assistant director of the L&I Division of Occupational Safety and Health.

The crane was anchored to a steel I-beam structure instead of a concrete pad set in the ground, the standard mounting system.

The L&I findings concluded that the cause of the collapse was “metal fatigue of the steel base frame, which was not strong enough to support the working crane.”

The toppled crane damaged three nearby buildings and killed Microsoft attorney Matthew Ammon, 31, who that evening was in his top-floor apartment at Pinnacle BellCentre on 108th Avenue Northeast.

Towering danger


Nov. 16

A 210-foot construction crane at an office development in downtown Bellevue collapsed and struck three buildings, killing a man inside a top floor apartment that was crushed. The crane was at the Tower 333 site at 108th Avenue and Northeast Fourth Street. The crane operator suffered minor injuries but was able to pull himself out of the cage, which was about 20 to 30 feet above the ground.

Dec. 1

Several vertical cracks were found in the tower of another crane in downtown Bellevue.

The 300-foot crane was dismantled two days later. State inspectors said the cracks were caused by water that accumulated inside the crane’s legs and then froze in the cold weather.

Dec. 5

A 225-foot tower crane in downtown Bellevue was repaired with welding torches after a 2-foot “hairline” crack was found near the top of the tower.

Jan. 21

A new crane is built at the Bellevue site where the crane collapsed in November.

April 10

Gov. Christine Gregoire signs a law that gives Washington some of the country’s strictest regulations of construction cranes and crane operators.

News researcher Miyoko Wolf

Magnusson Klemencic was cited for failing to ensure that the design specifications met the recommendations of the crane manufacturer and was fined $5,600, Cant said. The engineering firm said it would appeal.

In addition, Lease Crutcher Lewis, the general contractor at the Tower 333 site, was cited and fined $5,600 for failing to conduct periodic inspections. The contracting firm was also cited and fined $3,600 for attaching advertising banners to the tower crane that exceeded recommended size. The companies have 15 business days to appeal.

Four other companies were found to be without fault.

L&I described the fines as involving “serious violations,” but did not determine whether negligence took place.

Investigators said they didn’t know why the crane mounting base was engineered as it was, but speculated that it may have been done for reasons of time and money.

“Less time, less money, I think it’s all those factors,” said one of the investigators, Dan McMurdie, an L&I program manager, adding that “hindsight is 20-20.”

Magnusson Klemencic did not return calls for comment, but issued a brief statement in response to the report.

“The Department of Labor & Industries made several factual errors in its investigation and L&I refused to discuss these facts despite MKA’s repeated attempts to do so. MKA will immediately file an appeal,” said the statement issued by Jon Magnusson, chairman and chief executive officer of Magnusson Klemencic.

Bill Lewis of Lease Crutcher Lewis said he learned of the investigation results an hour before they were made public.

“It’s pretty fresh, and we need to study and fully understand it before we can comment,” he said.

Lewis said he was unable to explain why the base design was used. “We aren’t the designer,” he said.

Cant acknowledged that the amounts of the fines seem small, but added that state law was never expected to have to deal with such incidents and the state expects to review its fine structure.

“We never contemplated such a phenomenal catastrophe,” said Cant, adding that state laws involving tower-crane installations were revamped in the recent legislative session.

The state now has some of the toughest crane-installation laws in the country.

A replacement crane at the Tower 333 site was placed on a concrete base on the ground in January, while the collapsed crane was bolted to the I beams of a parking structure that had been installed in a project that went bankrupt years earlier.

The parking-structure design was used to “avoid creating holes through five levels of concrete,” Cant said.

Investigators interviewed people involved in the installation, reviewed documentation for the crane in downtown Bellevue, and did engineering tests and metallurgical examinations to determine the cause.

Preliminary findings in the investigation pointed to the steel base as the probable cause of the collapse, sources said early in the investigation.

“I think it’s obvious someone made some errors, and poor Mr. Ammon wasn’t who made them,” Matt Knopp, a Seattle attorney representing the Ammon family, said recently before the report was released. The family has not filed any lawsuits.

Ammon’s parents, who live out of state, issued statements through Mike Wampold, a second attorney representing the family, after the report was released Friday.

“There is little comfort in knowing what caused the tragedy that killed our only child, Matt,” said Kathleen Gaberson, Ammon’s mother. “The report shows that his death could easily have been prevented. This needless tragedy has devastated our family.”

Ammon’s father, Larry Ammon, said: “In this case, the engineers’ and contractors’ negligent decisions cost the life of our son, Matt, and we will miss him forever.”

Cant identified Doug Loesch, an engineer at Magnusson Klemencic, as the person who did the design for the tower base. “He was responsible as the signing engineer,” Cant said.

Cant said investigators did interview Loesch and other Magnusson Klemencic employees, but declined to say what explanation was given.

“We’ve done extensive interviews with him,” Cant said, who then referred questions about an explanation for the design to Magnusson Klemencic, one of the nation’s most well-known engineering firms.

Loesch also declined to comment on the L&I findings.

Peyton Whitely: 206-464-2259 or pwhitely@seattletimes.com.