TY - GEN

T1 - An Innovative Hybrid Substructure for Offshore Wind Turbines

AU - Stümpel, Marina

AU - Marx, Steffen

AU - Schaumann, Peter

AU - Seidl, Günter

AU - Göhlmann, Joachim

N1 - Funding information: The research project “HyConCast - Hybrid Substructure of High Strength Concrete and Ductile Iron Castings” (Fkz.: 0325651) is funded by the BMWi - German Federal Ministry for Economic Affairs and Energy. The BMWi, the research partners Institute for Steel Construction, Ludwig-Franzius-Institute for Waterways, Estuarine and Coastal Engineering, and the industry partners SSF Ingenieure AG, grbv Ingenieure im Bauwesen GmbH & CO. KG, Siempelkamp Giesserei GmbH, and Max Bögl Bauservice GmbH & Co. KG are kindly acknowledged. The importance of renewable energy is increasing steadily. Among the different kinds of renewable energy, wind energy has particularly high potential. The most promising sites for wind energy, however, are located offshore. Northern European countries in particular are pioneers in the area of offshore wind energy: more than 91 % of the world’s offshore wind power is currently generated in Northern Europe (Global Wind Energy Council, 2016). In compliance with nature protection regulations, the German offshore structures are situated at a large distance from the coast, in water depths of up to 40 m. Many suitable sites are located in the Exclusive Economic Zone (EEZ) in the North Sea beyond the twelve-sea-mile zone. The technical requirements for construction of the foundation and tower, cabling, logistics, and maintenance are much more demanding than for OWTs located near landmasses (Bundesverband WindEnergie e.V., 2017). Offshore wind turbines in water depths greater than 20 m are mainly supported by monopiles and latticed steel substructures such as jackets (Bundesministerium für Wirtschaft und Energie, 2017). These types of substructures are also used in the offshore oil and gas industry. Therefore, many components and assessment procedures could be transferred to the design of jackets for OWTs. However, jackets have a large number of welded connections which have to be checked regularly during the life span of the turbine. In addition, protection against salt water is required to avoid corrosion. Compared to steel structures, concrete constructions offer advantages in terms of manufacturing and maintenance costs as well as durability. Therefore, combining both materials is the key to economical and durable constructions. The research project “HyConCast - Hybrid Substructure of High Strength Concrete and Ductile Iron Castings”, which is funded by the German Federal Ministry for Economic Affairs and Energy, deals with the design of a hybrid substructure for future OWTs in water depths of up to 50 m and with outputs greater than 6 MW. Combining the advantages of the materials concrete and steel, the substructure consists of large, thin-walled ductile cast iron joints connected to high-strength, lightweight precast concrete pipes. The overall objective of the project described in this paper was to assess the feasibility and applicability of the design concept and to investigate the necessary basics for planning, detailed design, and construction of this hybrid substructure.

PY - 2017

Y1 - 2017

N2 - In this paper, the concept of a hybrid substructure for offshore wind turbines (OWT) is presented. Within the nationally funded research project "HyConCast - Hybrid Substructure of High Strength Concrete and Ductile Iron Castings", the design concept of the substructure and its relevant design criteria have already been defined. The innovative design consists of large, thin-walled ductile cast iron joints connecting high-strength, lightweight precast concrete pipes. The most relevant design objective is to make optimal use of the properties of the employed materials. To ensure maximum cost efficiency, the entire process chain is examined, from the production of the individual components to land transport, preassembly, offshore transport, installation, completion, and operation of the finished structure. The relationships between the predefined design criteria and the developed hybrid substructure are presented in this paper.

AB - In this paper, the concept of a hybrid substructure for offshore wind turbines (OWT) is presented. Within the nationally funded research project "HyConCast - Hybrid Substructure of High Strength Concrete and Ductile Iron Castings", the design concept of the substructure and its relevant design criteria have already been defined. The innovative design consists of large, thin-walled ductile cast iron joints connecting high-strength, lightweight precast concrete pipes. The most relevant design objective is to make optimal use of the properties of the employed materials. To ensure maximum cost efficiency, the entire process chain is examined, from the production of the individual components to land transport, preassembly, offshore transport, installation, completion, and operation of the finished structure. The relationships between the predefined design criteria and the developed hybrid substructure are presented in this paper.

KW - Ductile cast iron

KW - High-strength concrete

KW - Hybrid substructure

KW - Jacket structure

KW - Offshore wind turbine

UR - http://www.scopus.com/inward/record.url?scp=85038895549&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:85038895549

T3 - Proceedings of the International Offshore and Polar Engineering Conference

BT - Proceedings of the 27th International Ocean and Polar Engineering Conference

PB - Society of Petroleum Engineers (SPE)

T2 - 27th International Ocean and Polar Engineering Conference, ISOPE 2017

Y2 - 25 June 2017 through 30 June 2017

ER -