Tandem lifts are not uncommon. They do go wrong from time to time. Lots of planning required. Every movement must be scripted to ensure the load is shared correctly.
The incident occurred approx. 5 p.m. on Jan 31. Winds above 20 mph call for reduced capacities at best. Booms do not tolerate lateral wind loading well.
https://www.idahostatesman.com/news/local/community/boise/article284971422.html[/URL]]Boise-based Inland Crane Inc. said in a Thursday statement that it was hired to provide its services for the project and began work Monday to help erect the steel structure with four of its cranes. By Wednesday afternoon, that work was “largely completed,” company Vice President Jeremy Haener said, with just one of its cranes still left at the job site
Yep, I’m sure that column base is as designed as a pin even though it’s maybe 3-4ft long. In a situation like this I would design the anchorage as fixed even with the frame designed with a pin. If this is in fact the initiating failure of the collapse, it should be a wake up call for the PEMB industry.
It would seem, that since the steel flange itself failed, that having had eight anchors instead of five, that this would NOT have made any difference whatsoever.
With the collapse occurring out in the main span somewhere, and the resulting total collapse of the bent, the anchors (and base plate) were subjected to a full rotation of the entire column section - not what they ever were designed for. This anchor bolt failure and tearing of the base plate is a result of the collapse, not a cause of it.
Would that failure be at the Heat Affected Zone? Looks like it was designed as a tear-off strip. Not likely the initiating failure, but still interesting.
