Carpenters Local 2300: Online and On the Job
Generating powerful vibes
"The carpenters in this valley are the best tradesmen I've worked with."
Kieways May June 2000 cover story
This year, we have two summer students working here seven days a week as tour guides at the lookout site, Greg Dixon, Kiewit project manager, said, This has been a very popular attraction this summer.
What tourists are seeing is a magnificent power plant nestled within the most hydro-electrically developed river system in the world, the Columbia River Basin. The Columbia River flows 1,200 mi. from the base of the Canadian Rockies in southeastern British Columbia to the Pacific Ocean in Oregon. It is the third longest North American waterway to reach the Pacific Ocean. The river and its 10 major tributaries are home to more than 400 dams, tapping the majority of Columbias generating capacity . . . more than 21 million kilowatts.
The original Hugh Keenleyside Dam, completed in 1969, was one of three large dams constructed in Canada on the Columbia River during the 1960s and 1970s under the terms of the Columbia River Treaty. These dams offered significant benefits to the United States, both for flood control and for power generation optimization.
But it wasnt just Kiewits understanding of the risk that opened the door. The company's innovative design-build approach and creativity were also key factors. This project would not have happened if we would have built it using the conventional method, Sivertson said. Frank Margitan, Western Canada District area manager and sponsor of the Keenleyside Powerplant project, agrees. There is no doubt in our mind that this project would not have come to fruition without the use of design-build, Margitan said, Our contracting group and designers have provided the best ideas and their approach has led to the viability of the project. For the Keenleyside Powerplant project, Kiewit is serving as the general contractor; General Electric Canada Inc. of Lachine, Quebec, the turbine and generator supplier, and Harza Engineering Company of Chicago, Illinois, the projects designer, are both serving as subcontractors. Together, the project team has extensive experience in constructing, manufacturing and designing large-scale power plants.
A Birds Eye View
Work began in March 1999, and includes 4.5 million cu. m. (6 million cu. yd.) of excavation, including 3.9 million cu. m. (5.1 million cu. yd.) of overburden and 689,000 cu. m. (900,000 cu. yd.) of rock excavation. The job also includes 95,000 cu. m. (124,000 cu. yd.) of concrete for the power house and the approach channel; 8,500 tonnes (9,400 tons) of steel and rebar, and all the mechanical and electrical equipment associated with the 85 MW units.
Thirty, 12-in.-dia. deep wells are also being installed along the reservoir and across the approach channel mouth, which will allow the remainder of the channel construction below high water level to be completed in the dry.
|Approach Channel and Powerhouse Excavation
The approach channel is comprised of two different sections. The 24-m. (80-ft.) deep, 853-m. (2,800-ft.) long approach channel upstream of the existing dam is a v-shaped excavation and is concrete lined. The shorter 427-m. (1,400-ft.) section, downstream of the dam, consists of a concrete faced rock-filled dam that contains the south side of the channel, rock excavation that contains the north side of the channel and rock excavation that contains the powerhouse and tailrace channel.
The powerhouse itself is a 60 m. by 60 m. by 60 m. (200 ft. by 200 ft. by 200 ft.) deep excavation in solid rock. The 38.1-m. (125 ft.) excavation is separated from the Columbia River only by an 18-m. (60-ft.) wide rock plug. The plugs, which are located at the upstream end of the approach channel and the downstream tailrace, isolate the excavations from the reservoir and river during construction and will be removed upon completion of the powerhouse. Dixon said its been a challenge to dig a hole over 60 m. (200 ft.) down in solid rock.
"We envisioned a lot more problems, but weve been fortunate that we havent
The draft tube elbows are 12.2-m. (40-ft.) tall. Their unique shape will significantly improve the performance of the turbines, Dixon said.
The carpenters in this valley are the best tradesmen Ive worked with. The quality of work here is extremely high, Dixon said.
The formwork erection and stripping operations started in September 1999. Crews have been working three shifts since then to ensure that enough formwork is in place to keep the afternoon shift and night shift concrete pour crews busy. By the end of the summer, 75% of the first stage formwork will have been completed with only the upper intake structure remaining.
Powerhouse in Motion
The old dam stored water, but no energy was produced, Dixon said, Once the new 18-story power plant is operating, the old dam will become a relatively dormant structure. Bypassing the existing earth-filled dam, the 1.6-km. (one mi.) long approach channel diverts water toward the new powerhouse. To create power, the channel water enters the turbine scroll cases through six large intake gates. Water then passes through moveable wicket gates and down onto the variable pitch blades of the Kaplan runner. The runner shaft rotates, which in turn rotates the generator shaft and the generator rotor. The rotor, spinning inside the copper windings of the stator, creates a magnetic field which generates electricity. The water then exits through the tailrace.
Benefits to Surrounding Area
What has been an added plus is that 85% of the local people employed at Keenleyside live within 100 km. (62 mi.). Businesses in this area are also reaping the benefits as well, Wally Penner, director of community and regional affairs for Columbia Power Corporation, said, At first, we wondered if we had the labor force, but the workers here have experience in powerhouse construction because theyve built hydroelectric power plants before.
As an added bonus, 50% of the power plants profits will roll back into the valleys Columbia Basin Trust, allowing the government to give back to its constituents within the area and support regional objectives mandated in the Columbia Basin Trust Act.
Approximately 550,000 hours have been worked to date, and of that amount, 75% of the work has been self-performed by Kiewit. An overall rate of 0.6 incidents per 200,000 work hours has been experienced by the Kiewit project team.
Kiewit is adhering to the environmental requirements, which are very delicate issues, Lorne Sivertson, president of Columbia Power Corporation, said.
Enhancements are reflected in the design of the powerhouses tailrace. Weve oriented the tailrace so that the integrity of the existing eddies are maintained. The eddies create an environment that is good for fish, so weve replicated this existing habitat, Penner said. Reclaiming borrow locations from the previous construction of the Keenleyside Dam during the 1960s is another example of the construction teams environmental efforts.
As we complete areas, we immediately re-seed them. As the project proceeds, the regeneration and revegetation of the land continues, Penner said. Because of the areas environmental sensitivity, Penner said that extra attention is being given to re-vegetating areas with native grasses and shrubs. A total of 30 hectares (75 acres) will be hydro seeded with local grasses and 60,000 trees and shrubs will be planted to provide a scenic view of the reservoir. Were constructing a wetland area, which will be a great habitat for frogs, turtles, ducks and other water fowl, Penner said, An access trail for deer and elk has also been maintained.
One of the benefits of the projects enhanced design is the dramatic reduction of
To maintain a consistent water temperature, weve made the canal as deep as the reservoir in order to draw water of varying temperatures and depths, Penner said.
Its a well-thought-out, well-planned design and all measures have been put in place to build an environmentally friendly project that will avoid adverse effects, Penner concluded.
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