Wind Turbine Foundation Segmented Precast Stability
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Solution Overview
Problem
The manufacturing of wind mill foundations for large on-shore wind turbines is time-consuming and costly due to complex logistics and high manual effort, and existing precast concrete foundations face limitations in stability against overturning moments due to transport constraints and lack of a monolithic structure.
Innovation Solution
The introduction of bridging plates and a second reinforcement structure to extend the horizontal surface area for backfilling material to counteract overturning moments, along with a second reinforcement structure to connect precast concrete elements and simulate a monolithic structure, enhancing stability and load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If precast concrete elements are used to reduce on-site construction time, then productivity is improved, but the foundation stability against overturning moments deteriorates due to limited horizontal surface area
Solution Approach 1:
The foundation is divided into multiple precast concrete elements (pedestal segments and rib elements) that can be manufactured separately in controlled environments and assembled on-site. This segmentation enables parallel production and faster installation while maintaining structural integrity through carefully designed connection details between segments.
Solution Approach 2:
Bridging plates are introduced to extend the horizontal surface area of the foundation in the radial direction, creating additional leverage arm against overturning moments. This dimensional extension allows the foundation to resist higher moments without increasing the overall footprint or requiring larger precast elements.
2Ease of manufacture
If precast concrete elements are transported to worksite, then on-site formwork and reinforcement work is reduced, but transport constraints limit the dimensions of concrete elements
Solution Approach 1:
The foundation structure is segmented into smaller, transportable precast elements including pedestal segments and rib elements. These segmented components can be manufactured to manageable sizes for transport while being assembled to form the complete foundation structure, bypassing transport dimension limitations.
Solution Approach 2:
The design allows for nested assembly where rib elements are positioned between pedestal segments during construction. This nesting approach optimizes space utilization during transport and assembly, allowing complex geometries to be built from simpler, more transportable components.
3Ease of operation
If precast concrete elements are connected with screwed flanges, then assembly is simplified, but the monolithic structure is lost reducing load distribution capability
Solution Approach 1:
The connection system merges multiple functions into integrated connection assemblies that provide both mechanical attachment (screwed flanges) and structural continuity (embedded reinforcement bars). This combination maintains the ease of assembly benefit while restoring the monolithic behavior needed for load distribution across the entire foundation structure.
Solution Approach 2:
The connection detail combines different materials and mechanisms (steel flanges, concrete, embedded reinforcement) to create a composite connection system. This composite approach leverages the advantages of each material to achieve both easy assembly and monolithic structural behavior for optimal load distribution.
4Stability of the object's composition
If on-site concrete casting is performed, then continuous monolithic structure is achieved, but complex logistics and time-consuming operations are required
Solution Approach 1:
Concrete elements are precast in controlled plant environments before being transported to the construction site. This preliminary action allows for optimized manufacturing conditions, quality control, and parallel production of multiple elements, significantly improving construction efficiency while delivering complete structural components that require minimal on-site assembly.
Data Source
AI summary
A foundation for a wind mill includes a circular or polygonal pedestal for supporting a wind mill tower and a plurality of ribs radiating radially outwardly from the pedestal, wherein the pedestal is divided into a plurality of circumferential sections, wherein a circumferential section and a rib are each integrally formed with one another, or are each formed, as a precast concrete element, wherein the precast concrete elements are made from reinforced concrete including a first reinforcement structure, in particular reinforcement bars, embedded into the precast concrete elements, neighbouring precast concrete elements, in their sections radiating outwardly from the pedestal, are spaced from each other in a circumferential direction and the clearance between two neighbouring precast concrete elements is each bridged by a bridging plate.