The construction of the Trans-Alaska Pipeline System included over of oil pipeline, 12 pump stations, and a new tanker port. Built largely on permafrost during 1975–77 between Prudhoe Bay and Valdez, Alaska, the $8 billion effort required tens of thousands of people, often working in extreme temperatures and conditions, the invention of specialized construction techniques, and the construction of a new road, the Dalton Highway.
The first section of pipe was laid in 1975 after more than five years of legal and political arguments. Allegations of faulty welds drew intense scrutiny from local and national observers. A culture grew around the unique working conditions involved in constructing the pipeline, and each union that worked on the project had a different function and stereotype. Thirty-two Alyeska Pipeline Service Company employees and contract workers were killed during the project. The main construction effort lasted until 1977; the first barrel of oil was delivered on July 28 of that year. Several more pump stations, added as oil flow increased, were completed through 1980.
Survey and design Intensive geological sampling and survey work of the pipeline route started in spring 1970. Aerial photographs were taken, examined, and a preliminary route was detailed.Mead, p. 177 Small survey parties physically visited the route and hammered stakes into the ground. The work was difficult; animal dangers forced the crews to be armed, and they also had to cope with the remote area and limited infrastructure. In places, the foliage was so dense that trees had to be cut down and progress was limited to per day.Mead, p. 178 The surveyed route passed through several mountain passes: Atigun Pass, Isabel Pass, Thompson Pass, and Keystone Canyon.Mead, p. 179 In the latter location, surveyors had to rappel down cliffs in order to perform their work.
Surveyors and planners also had to deal with the Denali Fault, a major cause of earthquakes, and with large amounts of permafrost.Mead, p. 181 In 1969, the unincorporated Trans-Alaska Pipeline System group drilled a series of core samples north of the Brooks Range that demonstrated how ubiquitous the permafrost was along the route. This forced the design of an elevated pipeline, which was tested in a loop built near Barrow.Mead, p. 182 This elevation required the pipeline to be insulated, since extreme cold temperatures caused the metal to become brittle, even when hot oil was being pumped through the pipeline.Mead, p. 183
After ecological objections forced subterranean pipeline crossings (in order to allow caribou to cross), engineers developed a system by which the ground near the pipeline would be refrigerated by chilled brine. These refrigerated sections also would be placed in Styrofoam-lined trenches and covered with gravel for their insulation value. Altogether, of the pipeline was designed to be built underground in this way. In other places, a lack of permafrost meant it could simply be placed underground without a special refrigeration plant.Mead, pp. 187–188 Large amounts of gravel were needed for all sections of the pipeline as insulation to keep the heat of above-ground structures from melting the permafrost. Gravel also was needed to build the construction and maintenance road, and surveyors located 470 sites across Alaska where the needed of rock could be located.Mead, p. 189
The Pipeline Authorization Act required the pipeline to be able to withstand the maximum earthquake ever recorded in the area it was built. When crossing the Denali Fault, Teflon-coated sliders were designed to allow the pipeline to move side-to-side in an earthquake. To protect against forward-and-backward shocks and to allow for thermal expansion, the pipeline wasn't designed as a straight line. Instead, it was intended to be laid in an S-shape, and the bends would allow for expansion and movement without breaking.Mead, p. 192
Because most of the pipeline was built above permafrost, each of the pipes holding up the raised sections of pipeline contained a sealed tube of ammonia. As the permafrost below the pipeline warms, the ammonia absorbs the heat and rises to a radiator on top of each stanchion. The ammonia is cooled by the outside air, condenses, and falls back to the bottom of the tube, where the process repeats.Mead, pp. 192–193
The surveyed route crossed hundreds of streams and rivers. To cross these with the pipeline, engineers designed concrete "jackets" to surround the pipe and weight it down so it would sink to the bottom of the stream or river. Because oil is lighter than water, the pipeline would float without the concrete jackets. Dredging rivers and burying the pipeline in the streambed was not allowed due to environmental concerns. In several places—either out of fear of disturbing the river or because of the river's characteristics—pipeline bridges were constructed. The most notable of these are over the Yukon River and the Tanana River.Mead, pp. 192–194 To protect against corrosion in these wet environments, the pipeline was designed with cathodic protection.Mead, p. 195
In terms of spill prevention, the pipeline was designed with one-way valves (so oil moving ahead could not leak out of a hole behind a certain point), computer-aided leak detection, and other features. The pipeline was designed to be pressurized, so any leak would be instantly detected by a loss of pressure at one of the pump stations, which could sound an alarm and halt the flow of oil quickly.Mead, pp. 196–197
The original pipeline proposal called for an initial capacity of , then an increase to after two years, and then a further increase to at an indeterminate time thereafter. The events of the 1973 oil crisis caused a review of these plans, and the initial capacity was revised upwards to . This in turn required that eight pumping stations (instead of the originally-planned five) be ready at startup, greatly increasing the construction manpower required.Mead, p. 206
Valdez Marine Terminal The Valdez Marine Terminal, the southern end of the pipeline, was planned for a site across the Port Valdez fjord from Valdez proper. Initial studies predicted bedrock would be six feet below the surface of the ground, but when excavation began, it was discovered that bedrock was actually sixty feet down, requiring the removal of of overburden. The terminal itself was designed to be built with four tanker berths and space for a fifth, should it become necessary. Holding tanks were planned that had a capacity equal to that of the pipeline, allowing the whole pipeline to be emptied if required.Mead, p. 201 As required by the Pipeline Authorization Act, a ballast-water filtration system had to be designed as well. This system removes oil from tankers' ballast water so it is not released into Prince William Sound—something fishermen feared when the pipeline was proposed.Mead, pp. 202–203
Preparation
Shortly after the permit was signed, convoys of equipment on snow tractors began heading north, using hardened snow roads and an ice bridge over the Yukon River to reach the seven construction camps that had been dormant since 1970. In the 83 days from mid-January to the time the snow and ice melted in mid-April, 680 workers moved to the seven camps, and built five more camps and five temporary airstrips.Roscow, p. 96
In February, as the ice bridge and snow road were carrying tracked vehicles north, Alyeska awarded a contract to design the construction and maintenance road, Michael Baker, Jr., Inc., a firm in Pennsylvania, was awarded the contract.Mead, p. 207 For the road and pipeline to cross the Yukon River, the state of Alaska designed the E. L. Patton Yukon River Bridge and paid two-thirds of its cost. The remaining third was paid by Alyeska, and the bridge was built by Manson-Osberg-Ghemm.Roscow, p. 97 On April 5, the contracts to build the road were picked. In total, the new Dalton Highway cost $185 million to build, and four companies shared that cost. Construction of the Dalton Highway started on April 29, and at the peak of the effort, Alyeska and the four subcontractors had more than 3,400 workers deployed from the Yukon River to Prudhoe Bay. A massive airlift was created to supply the road construction effort; more than 700 flights per day—170,000 in total—were required before the road was finished on September 29. In just 154 days, a 360-mile gravel road had been built. Final grading had to be done and more than 20 small permanent bridges had to be built, but by November, the road was open to traffic crossing the Yukon River on another ice bridge.Roscow, p. 99
Management To supervise the construction of the pipeline, Alyeska appointed two construction management contractors to oversee all the other subcontractors in the project. Bechtel Corporation, from San Francisco, was named the management contractor for the pipeline itself. Fluor Alaska Inc., a division of Fluor Corp., was named the management contractor for the pumping stations and Valdez Marine Terminal, which was the most complex single section of the pipeline, since it involved the transfer of oil from the pipeline to seagoing oil tankers.Roscow, p. 100
Neither of those two companies actually did the construction work. That job was handed off to a series of subcontractors, each of whom had responsibility on one (or two) of six sections of the pipeline (seven, if the marine terminal is included). Bidding on the subcontracting jobs opened at the end of March, and the contracts were announced on June 12, 1974.
On Section One, which ran from Valdez to the Sourdough pipeline camp, River Construction Corporation, a division of Morrison–Knudsen, was given the contract. For Section Two, which covered from Sourdough to north of Delta Junction, Perini Arctic Associates, a joint venture of Perini Corporation, Majestic Construction, Wiley Oilfield Hauling Ltd., and McKinney Drilling Company. Section Three covered from Delta Junction, past Fairbanks, and almost to the Yukon. The contract for this section was given to H.C. Price, a group formed by H.C. Price Company (usually known as PPCO), R.B. Potashnick, Codell Construction Company, and Oman Construction Company.
Section Four was from south of the Yukon to Coldfoot. It was contracted to Associated-Green, a group formed by Associated Pipeline Contractors, Inc. and Green Construction Company. The group also was one of the main contractors for construction of the Dalton Highway.Roscow, p. 101 Section Five covered the distance from Coldfoot to Toolik pipeline camp, and Section Six went from Toolik to Prudhoe Bay. Together, the two sections covered , and they both were under the supervision of Arctic Constructors, a venture of Brown & Root Inc., Ingram Corporation, Peter Kiewit Sons Inc., Williams Brothers Alaska, Inc., and H.B. Zachry Company.
In Valdez, where Fluor had supervision, the work also was divided among several contractors. Site preparation work was done by Morrison-Knudsen. Chicago Bridge & Iron Company built the tank farms, the tanker berths were built by Kiewest (a venture of Peter Kiewit Sons and Willamette-Western Corporation), and General Electric insulated the pipes.Roscow, pp. 101–102 Fluor also had supervision of the construction of the pumping stations, which were generally built by the contractors working on a specific section of the pipeline.
Pipeline camps
When the contracts were announced, Alyeska already had 12 pipeline construction camps either built or under construction. These camps were all north of the Yukon, however, and camps had to be built along the entire length of the project. Alyeska planned for 29 construction camps, but 31 were created.Cole, p. 66 Seven were built along the pipeline south of the Yukon, and one was built at each of the 12 pump stations along the length of the route.