Walking The Tightrope

During the week of Nik Wallenda’s tightrope walk across the Grand Canyon, my wife mentioned the stunt several times, so we ended up watching it on TV on June 23, 2013. The event itself sounded intriguing, but even more interesting was the description of the preparations. The producers devoted quite a bit of the program to showing how Wallenda got ready for the stunt. They also included a segment about installing the cable across the canyon. I was thinking that this looked like line work, and then I saw it: An International Brotherhood of Electrical Workers (IBEW) sticker on a piece of equipment. Subsequently, we noticed that many people were wearing NECA/IBEW T-shirts, and I saw the stenciling on the crates: O’Connell Electric. This was an electrical job, and the tightrope cable Nik Wallenda was going to walk on across the Grand Canyon was installed by an electrical contractor. Of course, I had to wonder: did someone have to prepare an estimate on this job?

I spoke to Vic Salerno and Randy Fletcher at O’Connell Electric Co., and, sure enough, they had to prepare an estimate (more of a budget, according to Fletcher). The first time they estimated a project like this was actually for Nik Wallenda’s Niagara Falls event last year. (For more details, see “O’Connell Electric Supports Nik Wallenda’s Walk Over Niagara Falls,” July 2012, www.ECmag.com.)

O’Connell Electric was qualified to do this project as the company had been doing line work for more than 40 years. Even with that experience, this was still a very different project. The first consideration was the cable. The electrical transmission lines they were accustomed to installing weighed between ¼ pound per foot to 1 pound per foot. The cable, provided by the Wallendas, weighed more than 7 pounds per foot! For Niagara Falls, that was about 13,000 pounds of cable to be installed in a single span. They needed a new game plan.

Getting it right

The engineering was of utmost importance. Nik’s great-grandfather Karl was killed on a tightrope walk where, according to the family’s analysis, faulty rigging was to blame. For this installation, the engineering and rigging had to be perfect. The Wallendas specified the cable, including weight, size and tensile strength (between 60,000 and 67,000 pounds of tension!). The span was also a new factor for O’Connel Electric. The company is used to working with spans between 400 and 700 feet. The span for the Grand Canyon was 1,400 feet, and for Niagara Falls, it was 1,800 feet. To handle the weight and tension of this cable, anchors were drilled to a depth of about 30 feet and reinforced with concrete.

The cable installation actually seemed sort of normal but on a much grander scale. A special lightweight synthetic pull rope was purchased. Since the pulling machine and the cable reel had to be on the same side of the canyon, they needed 3,200 feet of the rope, which weighed only 400 pounds and had a breaking strength of 73,800 pounds.

The pull required two machines. One was the actual pulling machine, and the other was a tensioning machine. For the Niagara Falls pull, just two machines in the country could handle the required tension. Since the Grand Canyon cable was a little shorter, there were more tensioning machines available. A helicopter flew the rope across the Grand Canyon, where it was threaded through a turning block and flown back to the other side.

A major difference between the two events was access to the two sides. For Niagara Falls, the team could drive from the United States over into Canada to get men and equipment to the other side. For the Grand Canyon, the “other side” was an island mesa. All of the manpower and rigging had to be taken across by helicopter. They actually lost one day because the helicopter was grounded due to wind.

More bid items

O’Connell Electric’s scope of work included two other items besides installing the cable. The first was the installation of pendulums on the cable to dampen sway and vibrations. The second was rescue. If Nik had fallen but managed to hang on to the cable, O’Connell Electric’s smallest men would have gotten into a basket suspended from the cable, pulled themselves down the cable and pulled Nik into the basket. Fortunately, that was not necessary. Would have been a change order?

I asked Fletcher how they could possibly prepare an estimate for something that was so far outside of their expertise. He told me that they took what they knew, studied the requirements and factored the labor up. Way up! For more information about this installation, there is a nice video at www.ElectricTV.net.

Congratulations to O’Connell Electric and the Wallendas. Job well done!

About the Author

Stephen Carr

Estimating Columnist
Stephen Carr has been in the electrical construction business since 1971. He started Carr Consulting Services—which provides electrical estimating and educational services—in 1994. Contact him at 805.523.1575 or steve@electrical-estimating.com .

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