Work in the State Park of Tahquamenon Falls on the Upper Peninsula of Michigan allows universal access to a rustic island nestled on a river and a visualization platform put on a hill overlooking the upper falls: the largest waterfall in Michigan, an attraction that attracts 500,000 people to the park annually.
The two projects, with some works completed and some ongoing, are only about $ 4 million at cost, but were not easy to perform, as the primary need to protect a sensitive natural environment.
The crews could not use a crane, so they installed a helicopter aluminum bridge over the Tahquamenon river to access the island of losses. Using only manual tools, they also removed an existing wooden staircase to build a fiberglass promenade. They are also building a observation platform on a slippery, abrupt hill on the edge of the upper falls.
The first project involved expanding a seafront of 2,000 feet more than 340 feet and installing a pedestrian bridge over the Tahquamenon river to connect an island on the river with the continent.
“There was no existing bridge previously,” says Zane Hyrkas, project manager for OHM Advisors, who designed the two projects. “To access the island, visitors should go up the river.”
Its firm was challenged to design a bridge that could be located by the helicopter in order to protect the natural environment of the area.
A helicopter was needed to place segments of a bridge that connects an island of the river with the continental part.
Photo courtesy of Ohm Advisors
Gather the weight limits of the seafront
The crews used the old wooden promenade to access the place where the new promenade and bridge were installed.
“We were limited to about 1,500 to 1,700 pounds [on the wooden boardwalk] Since we did not know how much the seafront would be, “says Steve Olsen, project manager with contractors of the Olsen & Olsen Building contractor in Manistique, Mich. All the material had to be four wheels or wheel hut at the location.”
To allow a compact loader to meet the weight limit, the team pulled the front bucket and the front arms.
“It took six to eight boys to return it so we could have this machine to use on the island and for other things,” says Olsen.
The installation of the new bridge required to pour two concrete tablets, one on the island and one on the continental part.
In order to achieve concrete on the island, Olsen created a cable and goat system on the river.
“I looked for a quick speed cabor, but I couldn’t find it, so I actually made it,” says Olsen. “I used a boat goat and usually where you would have put the handle, I removed it and I welded it and I used it to return the empty material container.”
A crew prepares concrete foundations on an observation platform that is being installed in the upper falls.
Photo courtesy of Ohm Advisors
Installation of the bridge
The biggest challenge of the project was to install the bridge, which required use a helicopter that struck a 150 -foot cable to wear the four segments of 8,000 pounds one by one.
“We had to get a large enough helicopter to collect 8,000 pounds,” says Olsen.
The park was closed for a day so that the bridge segments could be glued to the helicopter in a car park. Each trip was about half a mile and required precise calculations that included the amount of fuel needed.
“We had to get a large enough helicopter to collect 8,000 pounds.”
—Theve Olsen, project manager, Olsen and Olsen buildings contractors
“They had to calculate the right amount of fuel so that they could take it to the place, give it time to set the segment and return and land the helicopter,” says Olsen.
The crew had to place the bridge in a day or risk -to pay the cost of hiring a helicopter again.
“There was only a small window of opportunity to collect, configure and mount this thing,” says Olsen.
It was a windy day when the bridge was placed, which turned out to be an advantage because the bridge segments were long and heavy and the descending pressure of the rotor washing machine, which pulls air from above and pushed down to create lift, helped to put the load down.
“The wind was actually a blessing because it gave them a better lift,” says Kevin Dennis, the park manager.
The wind had disappeared when the last segment was placed, which turned the experience into a nail for the crew of land that he expected to do -in his place.
)[The pilot] He tried to lift his helicopter, but he could not because the helicopter wind pushed so much the piece of the bridge that he could not lift, “says Olsen.” He had to go back and add 100 feet of cable so that he had a greater distance between the bridge and the helicopter. When he did, he was able to establish the last section. “”
Olsen calls that moment “the nerve, so that we could not establish the last section, he would have had to look for a larger helicopter. They made larger helicopters, but would have cost significantly more.”
Olsen had a crew attached to the bridge sections to the helicopter and another on the river that joins the sections.
“We had to put it well because if the bridge had a little gap, we couldn’t have set this last section,” he says.
Olsen says that this is the only time his company has used a helicopter in a project and that he is not sure he wants to return.
“We [usually] Set up things with cranes and cranes, you can slowly define it as a quarter of an inch at a time. You can really manipulate it, “he says.” But here, the pilot fought against the winds and fought against the elevators. Therefore, it had to be a kind of fast process. “”
Before the bridge was installed, the visitors had to climb a boat from the continental part to the island.
Photo courtesy of Ohm Advisors
Upper falls
As with the Bridge and Boardwalk project in Lower Falls, another project that is being built in higher falls requires the use of manual tools: the replacement of a 94 -step scale that went down the hill in almost a straight line. In its place, an ada fiberglass seafront will be zigzag on an expansive pattern of the hill to which an observation platform will be replaced with views of falls. The promenade will have five switches with landings and benches.
“Sometimes you sit and rest and reflect on and are surrounded by nature and only take everything.”
—Lex Kish, project manager, Asi Environment
The project is a challenge, says Alex Kish, Ludington’s head of projects, based on Mich., Asi Environmental, because “there is no flat place to gain foot. And there is no way to make the machinery a lot of work at hand and, at some of these points, work on 10 inches from Muck. The terrain is trying to remove the boots while taking a step.”
“It is a very steep and dynamic mountain and has pockets of wetlands,” agrees Hyrkas. “And by dynamic, I mean, the mountain material is slowly dragging from the top to the bottom, as gravity would.”
The construction equipment is installing 425 feet for the ramp, 18 to 24 inches in diameter. To deal with the dynamic mountain, the crew uses two types of foundation: sonotubes, which are cylindrical tubes that are used to form concrete columns and helical batteries, which are installed in the upper third of the seafront.
“The concrete foundations are anchored directly to bed to resist the descending movement of the material,” says Hyrkas.
Work continued during the winter on the project, which began in October and will be held in late July.
Using a bewilderment device with a circulating hose with an antifreeze that circulated and covering it with thermal blankets, the equipment kept the ground warm enough on the foot and the foundation holes so that the concrete can be cured during the winter months.
The team eliminated the previous observation cover, but maintained the existing scale that was built in the 1970’s in place to maintain access to the area. The new observation cover will have a cantilever 11 feet at 12 feet in length supported by steel beams.
The cantilever is needed, says Hyrkas, because the waterfall causes the stoneware bottom on which it flows to erode. He says he has eroded 13 feet on the slope since 1974.
The crews install a helicoidal stack for a new ramp that will lead to an observation platform overlooking the upper falls.
Photo courtesy of Asi Environmental
“The new platform is designed with a steep steel beam superstructure so that the erosion and the supporters club are produced -it is wound and approaches the foundation, they will be able to throw the visualization platform and establish it in new foundations. They can move it back as they need,” says Hyryrkas.
Dennis says that the project is even more complicated because “its work area is as wide as the footprint of the seafront.
“If we only let them work Willy-Nilly, we could have a beautiful seafront, but in the end the mountain would have all kinds of problems with erosion.”
Although Kish says the project has been brutal, it has also been beautiful. “It has taken a long time, this is what we have achieved, some very resistant crews and hard boys who stick day after day,” he says.
It helps when “sometimes you sit and rest and reflect and you are surrounded by nature and you only have everything,” he adds.
