Picking up the pieces
07 March 2008
Just days after one of the worst bridge collapses in US history, St. Paul, MN contractor Carl Bolander & Sons was dispatched to the site to handle demolition and dismantling of the wrecked bridge.
Established in 1924, Carl Bolander & Sons specializes in self performing earthwork, underground utilities, demolition, and earth retention systems. The company owns four cranes that it uses for demolition and will rent additional cranes when needed. They also own a fleet of excavators and other equipment required for demolition projects.
Tedious and dangerous
For the Minneapolis bridge demolition project, removing the wreckage was a tedious and dangerous process, with an engineering team needed to determine how to rig, lift and load each piece of mangled concrete and steel. Evan Mackey, demolition division manager for Bolander and project manager for the job, says expert operators and engineers were needed to determine every lift.
“The bridge had collapsed in an uncontrolled manner, so there were different loads and stresses on everything,” he explains. “You had to know what you were doing and be selective in taking things apart. There were several engineers involved and the demolition was more or less the dismantling of each piece of the bridge.”
Bolander's scope of work was to dismantle the bridge from land abutment to land abutment, approximately 2,000 lineal feet of bridge and 456 feet across the Mississippi River itself. All materials were transported off site, with some pieces going to an evidence area established at the Bohemian Flats municipal park in Minneapolis and some pieces hauled to a site near Afton, MN. Mackey said some critical pieces were flown to Washington, D.C. for further inspection in the continual effort to determine the cause of the collapse.
“It was a lot of lifting and hoisting work,” he says. “The cranes did most of the work.”
Equipment on the $15 million demolition job included four 100-ton cranes and three excavators. Initially the company was involved in the recovery and removal of vehicles that were submerged when the bridge collapsed. The demolition and dismantling work began in late August.
Secured to a barge, Bolander employed its the sites where the mangled bridge material was delivered was an additional crane owned by Armstrong.
Land and river
Oftentimes, a supervisor would work from an access platform, giving instruction to the crane operators using a bullhorn microphone.
By late October Bolander had finished its work at the site and began doing pile driving work for Flatiron-Manson, general contractors awarded the contract to reconstruct the new bridge.