The Boise hangar that collapsed and killed 3 is going back up. What’s different this time?

BOISE (Idaho Statesman) — One year after the deadly Jackson Jet Center hangar collapse at the Boise Airport killed three and injured nine, the building is going back up.

The Jan. 31 collapse spawned national headlines and a federal investigation, which found that Big D Builders — the Meridian contractor hired to work on the building — ignored clear warning signs like bowing beams and exercised “appalling disregard” for safety before the collapse.

The U.S. Occupational Safety and Health Administration recommended nearly $200,000 in fines for Big D Builders and $10,000 for Boise’s Inland Crane, which was also working on the site. According to OSHA, the crane company exposed workers to hazards and failed to make sure the hangar was stable. The fines have yet to be finalized after the two companies appealed their alleged violations in August.

The collapse killed Nampa residents Mario Sontay Tzi, 32, and Mariano “Alex” Coc Och, 24. It also killed Craig Durrant, 59, one of the founders of Big D Builders.

“The tragic loss and pain suffered by so many is compounded by the fact that Big D Builders could have prevented all this from happening,” said David Kearns, Boise’s OSHA area director, in a July news release.

Despite an ongoing lawsuit from the victims’ families, Big D Builders is rebuilding the hangar. A considerable portion of the building is already standing at 4049 W. Wright St., with new designs and new steel supports.

According to Maria Ortega, a city of Boise spokesperson, the company submitted new, modified plans under the existing permit that the city reviewed and approved.

Those plans addressed the building’s footing design, exterior fire wall and plumbing, according to city records. Big D Builders submitted another round of modifications on Jan. 23 to the building’s base-plate design and anchor bolts.

When asked if there were any special requirements for the building after the collapse, Ortega said “the city followed our building code, and did not vary from those requirements. We were consistent with the permitting process and review.”

Big D builders declined to answer questions about the new hangar, new designs, timelines, the ongoing lawsuit and whether the company had pledged any financial support to the victims. Instead, Big D Builders issued a statement that said: “While this has been a difficult year for the families, employees, and friends of Big D Builders Inc., we are so grateful for the continued support, love and prayers provided daily by the local community.”

Jackson Jet Center did not return a request for comment.

Why did the building collapse at the Boise Airport?

One of the key problems before the building collapsed, according to investigators and those who were at the scene, was not enough structural support.

The company planned to build the 300-foot hangar in two 150-foot long sections and connect them with structural steel and bracing, according to Kearns. But the company made no plans to secure the hangar before starting construction.

Robert Hamilton, an associate professor of civil engineering at Boise State University, drove by the site and took pictures hours before it collapsed because he was curious about the skeleton of the building before crews put covering on the outside, according to prior Statesman reporting.

“I was very surprised it came down,” Hamilton said by phone a few days after the collapse. “Because any firm that constructs buildings like this understands you have to place a lot of temporary support until the entire system is put together.”

Tozo Yamamoto, a structural engineer with over 40 years of experience in metal buildings, told the Statesman by email Jan. 7 that the collapse was likely caused by insufficient lateral torsional bracing.

The Boise Airport hangar building with 300-foot clear-span frames is not a typical metal building, Yamamoto said, and required a greater number of supports.

As work continued, the metal began to bend. Workers reported bent rafters, crooked columns and snapped cables before the building collapsed, according to OSHA. The company left bolts loose and used straps rather than use extra support or industry-standard temporary lines meant to stabilize a structure.

Dennis Durrant, owner of Big D Builders and brother of Craig Durrant, who died in the collapse, told police that beams were bowing and that they’d reached out to the manufacturer, Steel Building Systems, because the supports for the frame weren’t adequate.

Big D Builders has switched manufacturers this time, going with Nebraska-based Behlen Building Systems.

“A new steel building manufacturer was provided for the same size, height and type of building with modifications to the design of the building and modifications to the design of the footing,” according to a city of Boise review of the new plans.

According to a certification, Behlen designed the new building in accordance with standards from the American Iron and Steel Institute and American Institute of Steel Construction.

Yamamoto, who reviewed the new plans on behalf of the Statesman, said the modifications call for greater bracing this time around.

Wind concerns plagued early theories of collapse

When the building first collapsed, some speculated that wind gusts at the Boise Airport could have contributed to the collapse — though the OSHA investigation did not prove that theory.

According to the certification from Behlen, “When properly erected, according to the Behlen plans, on an adequate foundation, this Behlen building has been designed to safely sustain [gravity, earthquake and wind] loads.”

However, the city required Jackson Jet Center to acknowledge that the building is designed to sustain maximum wind loads up to only 102 miles per hour when the doors are closed.

But 102 mph may be much higher than anything Boise has seen before. The greatest wind gust the National Weather Service has recorded in Boise was in July 1987, at 71 miles per hour.

“This building was designed to sustain maximum code wind loads only when the doors are closed,” wrote Jeff Jackson, CEO of Jackson Jet Center, in a letter to the city. “Failure to close them in high winds could result in structural failure and building collapse.”

“I take responsibility to assure the doors will get closed in time,” Jackson wrote.

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