Large dams |
The evolution of the Swedish dams industry
In the runup to the 91st ICOLD Annual Meeting to be held in Sweden this year, Rikard Hellgren and Maria Bartsch of SwedCOLD give an insight into dam development across the country
Above: Section through the Storfinnforsen embankment dam showing the new rock fill toe berm. The dam safety measures also involved installation of vertical chimney drainage consisting of drilled and sand-filled holes placed 7m downstream of the core through the support earth fill, new pore pressure sensors, downstream drainage with a seepage measurement system, and a monitoring programme
THE LONGSTANDING RELATIONSHIP BETWEEN ICOLD and the Swedish hydropower and mining industries via the Swedish national committee of ICOLD, SwedCOLD has been of exceptional significance to us. Since its foundation, SwedCOLD has successfully hosted three ICOLD events: the first Congress in 1933, the third Congress in 1948, and the Annual Meeting in 1981. This year, we welcome you to Gothenburg for the 91st ICOLD Annual Meeting in June.
In the run-up to this meeting, we would like to
provide you with a brief introduction to the Swedish dam industry and our dams. In this paper, we describe how the design of Swedish dams has evolved. This is exemplified by three Swedish dams built during different periods, Porjus, Storfinnforsen, and Trängslet. Then the focus turns to today, briefly describing the current dam inventory and our current challenges. Finally, we conclude with a presentation of SwedCOLD and welcome you to this year’s ICOLD meeting.
Right: Section through one of the buttress monoliths at Storfinnforsen, showing the improvements made to enhance the stability of the concrete dam, including pre-tensioned rock anchors through the buttress and insulation of the concrete buttress dam with the installation of heating, ventilation, lighting, and new inspection passages on two levels in the enclosed area. The dam safety measures also involved the renovation of all accessible concrete surfaces and new drainage in bedrock downstream of the front plate
The early large dams – 1890-1950s The use of dams in Sweden dates back to medieval
times when small dams were used to regulate water flow and power machinery in watermills. The mining
and hydropower industries were closely intertwined, and early mines were often powered by hydropower. Before the 20th century, Swedish dams were built of traditional materials such as wood, steel, brick, and natural stone or as embankment dams with a more or less homogeneous cross-section of materials available at the construction site - moraine, gravel, clay, and topsoil. In the late 19th century, Sweden’s electrification
led to a rapid expansion of hydropower stations throughout the country and the need to construct large dams. When larger dams were needed, Sweden quickly adopted the new building material, concrete, for hydropower facilities. Most early Swedish concrete dams were gravity dams. In the early 1920s, extensive damage and leakage
were discovered on many concrete dams in Sweden. This caused serious concerns about the suitability to use concrete for dams and prompted extensive investigations into the design and composition of concrete structures that could withstand high water pressure and Sweden’s climate. The research efforts resulted in the development of new cement types and more appropriate methods for concrete composition and proportioning. These efforts laid the groundwork for international cooperation on concrete research and were a strong contributing factor to Sweden becoming a member of ICOLD as early as 1931 and hosting the first-ever ICOLD Congress in 1933. Massive dams were the most common type of
concrete dams constructed in Sweden up to and including the 1940s. This was due to the experience gained from previously constructed massive dams, the relatively simple design calculations involved, and the wide Norrland rivers where large-scale hydroelectric plants were built, which made arch dams unsuitable. The introduction of vibration technology in the 1930s and the use of reinforced concrete led to a gradual transition from the massive dam to the buttress dam.
22 | May 2023 |
www.waterpowermagazine.com
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