The demolition, being conducted by Veit and Company Inc., (Veit) concerns a well-built, decades-old dock on Lake Superior which extends 2,000 ft. (610 m) into the water (80 ft. [24.4 m] in height and 60 ft. [18 m] in width) and has a 700 ft. (214 m) section on land — a timber tressle with two separate railways. The dock was built to accommodate up to four cargo vessels specializing in the transport of iron ore.
Veit was awarded the contract in 2007 and work began in the fall of 2011 after all the demolition permits were secured. The job is expected to be completed this fall.
The base of the dock consists of wood pilings, followed by 80 ft. (24.4 m) of concrete rebar. The surface has a steel frame system where the tracks were placed, along with some wooden decking. Along the side are steel chutes where the ore was deposited by the trains and collected by the ships.
The first phase of the work led to the removal of the surface infrastructure and 28 ft. (8.5 m) of concrete.
“One major challenge was the permitting process,” said Steve Hosier, project manager and vice president of Veit’s Demolition Group. “We had to coordinate this with the Army Corps of Engineers, the Wisconsin Department of Natural Resources, Coast Guard and the city of Ashland. The dock sits in Chequamegan (Shawamagan) Bay, which is located in an area with major shipping lanes.
[quote_right]“There is 100,000 tons of structural concrete that we are demolishing and it is adjacent to water that is 28 feet deep due to dredging to provide access for the ships,” he added. “We only have a 60-foot surface to work on, which is pretty challenging.”[/quote_right]
In peak periods, about 11 workers are on site, while winter operations generally have five employees. Winter operations are suspended when it gets too cold.
For the first phase, completed in November 2012, Veit built four customized rail cars in order to utilize the existing tracks to begin the removal process at the end of the dock. The cars have train wheels that match the gauge of the track, thick and solid steel frames, and engines on the back. A 250 ton (226.8 t) hydro crane was employed to place two Caterpillar 336D excavators (90,000 lbs. [40,823 kg] each) on each car.
“We first took off the steel frame and wood and then the concrete,” said Hosier. “We had to build and place deflection panels along the sections we were working on so that concrete and debris would not fall into the water. The panels (angled steel frames) are attached to barges. This was important to minimize debris from falling into Lake Superior. As we moved towards shore, we would slide the panels along.
‘We also built a customized dump box on another set of wheels that could operate on the tracks,” he continued. “It has a frame and motor and when filled, could drive back to the end of the dock, dump its load and quickly return to demolition operations.”
For the custom-built vehicles, Veit purchased some used rail equipment from various suppliers. “After much research there were no options of purchase for this type of equipment to fit our needs,” said Ryan Olson, Veit demolition superintendent. At Veit’s in-house fabrication, they constructed the two carts in their Rogers facility and then shipped them up to Ashland for final assembly and use. Safety locks were designed in house then tested, installed and maintained daily on the site. According to Olson, crew safety was the key factor in their design. “After a few minor adjustments after initial set up, the carts and backhoes performed perfectly to our expectations,” he said.
Specially purchased equipment for the work had Veit secure LXP and GDR series shears and processors from Genesis Tools.
“We’re always purchasing new equipment to replace older machinery that is getting worn out,” said Hosier, “but on this particular project, we put our newer equipment on top because when you get to the top of the dock and are so far away from shore and so high up, you cannot afford for things to break down. We had two backhoes working next to each other simultaneously and if one goes down, the other cannot keep going because we had to take it down uniformly all the way back to shore. We had mechanics on site, but we’re fortunate to have the new equipment. Everything is working out well and we only have had to deal with typical issues that crop up — nothing major.”
The second phase — starting where the land portion ends — began in December 2012 and has crews using backhoes to remove the remaining 56 ft. (17 m) of concrete leaving the concrete base above the timbers.
For this work, the excavators can operate freely and now trucks can be utilized to remove the debris from the dock. Veit’s contract allows the firm to sell the recyclables and nearly 100 percent of the recovered material is being recycled. “All the concrete is going to be ground into road base,” said Hosier. “The steel has been brought to scrap yards or foundries and the wood has been sold. The wood, 16 inches by 20 feet, was banded and put in piles prior to being removed from the site. The steel was sheared on site. We do this work all the time, but not 80 feet over water.”
The last comment is crucial because safety concerns for the men and equipment continue to be a paramount factor for this project. “On the top of the dock it was 100-percent tie-off environment, which required Veit to install a fall protection system” said Hosier. “There was dilapidated wood and the railing and rusted railing along the top of the dock. We had to put up safety cables around the edges of the dock, as well as a safety cable/lifeline down the middle of the dock.”
Maintenance, be it in warm weather or in the winter, when machinery can be severely tested and on a project such as this demolition where every hour of work impacts the bottom line, is extremely crucial. “The operators and superintendent inspect the equipment daily and we have several mechanics roaming around from our corporate office to do scheduled maintenance and repairs,” said Hosier, who noted that this project has provided Veit with the experience it will need on similar harbor infrastructure. “Everything costs twice as much and takes twice as long. Once we had the permits to proceed, we spent about five months on our planning and fabrication for our specialty equipment. Nothing could be left to chance.”
When the demolition is complete, it is expected that more than 90,000 tons (81,646.6 t) of concrete, 6,000 tons (5,443 t) of steel and 2,500 tons (2,268 t) of wood will have been lifted and recycled. The dock served its purpose and via recycling, is once again serving the economy.