Shoreview Tower Disaster

In the Fall of 1971, in Shoreview, Minnesota, on a bright beautiful midmorning day, the most horrific construction accident occurred. The KSTP and WCCO 1350 foot television tower came crashing down, ending the lives of seven of its personnel. This was the most tragic construction accident in Minnesota history.

The tower was more than twice the height of the 53 story Minneapolis IDS tower where four of the men killed had worked with us before leaving to work on the television tower.

Ten miles to the south, in downtown Minneapolis, this consultant, along with his crew that was involved in installing the curtain wall exterior of the 52 story IDS building, viewed the unknown dust cloud to the north and soon heard over the radio of the sketchy reports of the collapse. Within minutes the team shut down their operation, taking cutting torches, lifting devices to aid in anyway needed. It was not known if the local rescue authorities were prepared for an event of this proportion.

As a result of increasing traffic in and around the scene, it took the team over an hour to arrive on the scene. Ironworker identification cards allowed them to pass through the police barricades. The ironworkers that came down with the tower had been removed and only the swarm of flies would mark the area among the twisted steel where they were extricated. The site was akin to what was described as a bombed out war zone. Workers' stainless steel thermoses were imbedded deep into the ground.

The men were not buried yet when the speculation began to flood the local papers as to how this tragedy could have happened. The following assessments were made by survivors of the event and also by persons that were on the scene shortly after the collapse.

1. Weldments on the tower sections were shop applied off site and when X rayed, signs of fracture were detected. These inspections were made only after the collapse. (This expert consultant's note is the tonnage and twisting of the collapse may have contributed to the fractures.)
2. It is not an unusual practice in steel erection with many connection points, that the sections are not fully bolted while proceeding with additional sections to keep the project moving, (This consultant's observation was that there were many unfilled bolt holes in members below where the men were working.)
3. The supervision for this project came from another similar tower project in Oklahoma that was still being worked on. The Oklahoma supervisors selected from their crew to come up to this site and hired skilled local tower people here. Two of the local people who became fatalities never had tower erection experience. Were the supervisors from Oklahoma the most skilled of that crew that had left Oklahoma? Is it possible they were depending on the skill level of the Minnesota ironworkers? Safety concerns were raised during the installation and were many times rebuffed by the Oklahoma supervisors. One issue was the erratic movement and sway of the tower platform 1300 feet above the ground.
4. The erection activity that was underway when the tower collapsed was a first time procedure that had not been attempted before. It would be the first of three vertical antennas that sat on the three points of a triangular base 1300 feet above. Each member was heavier than any other single piece that had been hoisted previously. The first one upon becoming airborne suddenly lurched and the tower began to implode upon itself and the deluge of bolts and steel came down jettisoning personnel off the tower with others trapped within. A brother of one of the victims who was on the ground working, leaped under a flatbed truck, which saved his life from the shower of bolts. He could observe his brother who was cut in two with safety belt still fastened to a steel member.
5. It was speculated that possibly the load line lifting the member had become hung up on a bolt or steel member on one of the three legs and the entire load was transferred to one leg, which did not allow the weight of the antenna to be distributed to all three legs.

In the final court settlements, the litigants of the victims families were cautioned or directed to not talk about the details of the court proceedings and causes along with who and what was responsible for this tragedy.

1. The items one through five were compiled by this consultant's interviews of witnesses and members of the victims' families. And as of today, no conclusive evidence has surfaced. This consultant's own opinion, based on this consultant's findings, are that it may not have been any one single factor but a combination of two, three or four. The ranking of those factors as to most important would be :
   • Experience or lack of it for this project. Example : Double time, Overtime money can make personnel take on unfamiliar projects and maybe depend too much on "On the job training." From the crew from Oklahoma, were they the most skilled in that group that left to seek skilled help in Minnesota? When the workers noticed the platform 1300 feet above shifted uncomfortably back and forth, they were told by the Oklahoma supervision that the movement was normal and not an issue.
   • The incomplete 100% bolting up of the members below where the men were hoisting the piece when it collapsed.
   • If as noted, the load line hoisting the final piece did somehow become wedged, hung up on one of the three legs somewhere in the mid span of one of the vertical legs, the weight of the load would have been transferred to just that one leg which stressed one leg taking support of it and transferring it to the other two, which could not support the entire weight along with the load they were hoisting.
   • Welds should have been tested at least randomly with each shipment of tower material that arrived on site. This had not been done.

To see the resume of the expert associated with this case study, see the link below.