Welding unites metal. The Olympics unite people. The two may not seem to have much in common. However, in 1996 the lighting of the Olympic torch, or cauldron, at the opening ceremony bonded them. This year, the lit cauldron sat upon a 132-1/2 ft. welded steel structure. American Structural Metals (ASM), a metal fabrication shop located in Hugo, Minn., started building this large, complicated structure in July 1995 and finished in March 1996. The structure consisted of a cauldron, a tower, and a bridge which connected the tower and cauldron to the Olympic stadium.
“The tower and bridge were formed from 12,500 steel pieces that we MIG (GMAW) and Pulsed MIG (GMAW-P) welded together in our shop with Miller Electric Deltaweld power sources and 60 Series wire feeders,” says Fred Riermann, President of American Structural Metals. “After the pieces were welded, we brought them outside and started welding the structure together using Miller Big 40 and Trailblazer 250G engine-driven welding generators. We knew this part of the job would take a long time, so we hired a local contracting company, Amerect, to help us assemble the structure.”
The structure was designed by Siah Armajani, a structural artist from the Twin Cities in Minnesota. Since 1989, Riermann has worked on nine projects with Armajani, including the New York Staten Island tower and bridge; the Round Gazebo in Nice, France; the Irene Hixson Whitney Bridge in Minneapolis, Minn.; and many other bridges, walkways and gazebos around the world.
From Bridges to Gold Dust
ASM started business on August 2, 1972, building miscellaneous metal and light structural steel products. In 1983, the company began building and shipping large structural components, and it now specializes in large, complicated projects similar to the Olympic tower, bridge and cauldron.
Besides the projects Riermann worked on with artist Armajani, ASM has built 15 bridges in the Twin Cities area; a skyway system consisting of six bridges that are each 100 ft. long, in Rochester, Minn.; 52 sections of transporters designed to open up the Aloha Stadium in Honolulu; eight filters to separate gold dust in a gold mine in Russia; the Civic Center Skyway to downtown and the Cargill Ship Loading System in Duluth, Minn.; as well as 86 ShopKo stores, 26 Target stores and 16 K-Mart stores across the country.
The Race is On
Once the Olympic committee agreed that Armajani’s design was the structure it wanted to represent the 1996 Summer Olympics in Atlanta, Armajani hired a structural engineer. The engineer, Doug Iverson, determined the calculations to ensure the project would be structurally safe, and developed the design drawings. “Armajani then made a miniature model of the structure out of balsa wood,” says Riermann. “After that, the race was on to get the project finished in time for the Olympic Games.”
Arguably the most complicated portion of the project, the 22 ft. wide, 20-1/2 ft. tall cauldron burned natural gas, but ran on electricity. The cauldron included many electrical controls required to start-up and shut-down the flame, along with numerous safety features. It also contained back-up generators in case of a power failure.
“We started-up the cauldron at least 75 times before the Olympics and it never malfunctioned,” says Riermann. “I was confident everything would run smoothly.”
In addition to starting-up the flame, in April ASM burned the cauldron continuously for 48 hours. According to Riermann, “you could see it burning for miles and miles, and although it was still very cold here in Minnesota, hundreds of people came by to watch the immense flame.”
The cauldron, made of stainless steel, was welded together with Miller Deltaweld 451 and 452 power sources and 60 Series wire feeders. Because of the intense heat emitted by the flame, the welds had to be perfect.
“Perfect welds are not a problem,” says Riermann. “Because the majority of work we do involves structural welds, all 25 welding operators at ASM are certified for code work. In addition, I believe that weld quality depends on the welding power source, as well as the welding operator. That is why all my operators use Miller welders.”
Because Riermann and his crew were on a tight deadline, the welding power sources needed to withstand the rigors of high productivity. The Deltawelds are designed for such purposes and excel in situations involving long, hard hours of operation. Riermann added, “we wouldn’t have trusted any other brand of welding power source for this project.”
After the cauldron was built, it needed to be painted. Because the cauldron was designed with the front wall lower than the back, the inside required paint as well. This presented a small challenge. Regular paint would not adhere to the walls at such a high temperature. ASM located a company that manufactured special paint for high temperature applications. The paint, however, was a bit expensive, approximately $600 per gallon. Luckily only eight gallons were needed. The cauldron was then completed with Georgian red clay bolted to the outside of the rim.
Information courtesy of Miller Electric