Welding Wonders

Welding Wonder: The Trans-Alaska Pipeline

At 800 miles long, the Trans-Alaska Pipeline has been described as one of the most historic welding and construction projects in history. For three years, tens of thousands of welders braved the harsh climate and terrain of Alaska’s wilderness to weld together the 48-inch diameter of the pipeline. And since then, more than 17 billion barrels of oil have flowed from the Prudhoe Bay oil field in Northern Alaska down to Valdez Bay.

Construction of the massive pipeline began in 1975 – at a time where construction was in a slump throughout the United States. Because of this, the project attracted workers from all around the country. In fact, the men who welded the pipeline came all the way from the Pipeliners Local 798 Union out of Tulsa, Oklahoma. This group specialized in providing welders for large-scale pipeline projects, and the Trans-Alaska Pipeline was probably the largest up to that point.

Welding on the Pipeline

Two men weld together a portion of the Alaska pipeline.

Because of the immensity and importance of the Pipeline, the hiring process was very intense. Welders were first put through a certification process that involved several test welds. If the welder failed any of the test welds, they were not hired and were not allowed to be tested again for several weeks. The reason for the stringent hiring process was likely due to the fact that welders on the project were welding a new steel pipe thicker and larger than most of them had ever worked on before.

The first step to the pipeline construction involved clearing the 800-mile path laid out by surveyors. Workers slowly trudged their way through forrest, brush, and obstacles using chainsaws and bulldozers. Once the path was cleared and OKed by surveillance officers and engineers, holes were drilled and filled with gravel and water. These served as the foundations for the Vertical Support Members that held up the pipeline using semicircular supports. The VSMs were carried by crane in 40 or 80-foot segments, lowered into the holes, and then welded together. Quality control engineers inspected the welds using X-ray.

Quality control workers would indicate when a weld was x-rayed by writing on the support member.

Quality control workers would indicate when a weld was x-rayed by writing on the support member.

With several VSMs already in place, workers officially laid the first portion of the Trans-Alaska Pipeline on March 27, 1975.

Several 40-foot segments were places atop the supports, welded together, and coated in concrete. And so began the two-year long process of welding construction on the pipeline.

Welds on the pipeline were originally expected to meet an average impact value of 20 ft-lb and at least 15 ft-lb. The joints were made using submerged arc welding and a wire that contained 3% nickel. About 80,000 lb of that wire were used throughout the entirety of the Pipeline project.

Mid-way through the construction process, the U.S. Department of the Interior and a pipeline coordinating group representing the state of Alaska instituted more stringent requirements for weld toughness. Instead of the conventional electrode that was originally being used for the majority of field welds, new requirements necessitated a higher quality electrode using an E8010-G filler metal. This electrode had to be flown into Alaska from Germany. It was an electrode the most welders on the project had never used before.

Throughout the project, welders worked inside protective aluminum enclosures that shielded them from the wind and other harsh weather conditions. It also gave them the lighting they needed to work through the night. Similar to the VSMs, pipeline welds were also inspected using X-ray. Inspectors traveled alongside the welding crews in vans where X-ray film was automatically processed and inspected.

On May 31, 1977 the final pipeline weld took place. Pump station and terminal construction still needed to be completed, but the pipeline was able to be put into operation without them being completed. In a sense, the hard work had already been done, and just three months later the tanker ARCO Juneau sailed out of Valdez with the first load of oil that had traveled through the Trans-Alaska Pipeline.

So impressive was the project and the welding done on it, that in 2002 the American Welding Society declared the Trans-Alaska Pipeline an outstanding development in welded fabrication. The Alyeska Pipeline Service Company was presented with an award and congratulated on the immense project they helped create.

By law, Alyeska is required to remove the pipeline once oil extraction in the Prudhoe Bay is complete. Improvements in reducing flow-rates seem to suggest the oil could be flowing through the pipeline until at least 2075 – meaning this welding wonder could last 100 years.

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