Circular Can-Shape Foundation for Wind Turbines
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Solution Overview
Problem
Existing foundation technologies for wind turbines and similar structures are inadequate in supporting heavy loads, particularly overturning moments, and are either costly, inefficient, or environmentally harmful due to their reliance on pre-stressed reinforcements, complex construction methods, and material limitations.
Innovation Solution
A circular can-shape foundation featuring a tubelike cylindrical structure with a solid cap and corbel concrete structure, utilizing cast-in-place reinforced concrete to transfer loads deep into the ground, combined with an anchor bolt system, and a trenching method for construction that eliminates the need for formworks and backfilling, allowing for efficient and cost-effective support of wind turbines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pre-stressed reinforcements and complex construction methods are used, then foundation strength and stability are improved, but construction costs and device complexity increase
Solution Approach 1:
The invention extracts and eliminates the complex pre-stressed reinforcement system from traditional foundation designs. By using a simple cast-in-place concrete monolith with conventional reinforcement bars instead of pre-stressed cables and anchorage systems, the patent achieves adequate strength while dramatically reducing construction complexity and cost.
Solution Approach 2:
The invention changes the construction methodology parameter from pre-stressed concrete requiring specialized equipment and multi-stage construction to simple cast-in-place concrete using conventional techniques. This parameter change maintains structural integrity while eliminating the need for complex pre-stressing apparatus and specialized construction procedures.
2Stability of the object's composition
If traditional foundation methods with extensive excavation and formworks are used, then structural stability is ensured, but construction time and material usage increase
Solution Approach 1:
The invention merges the foundation structure with the surrounding ground by eliminating formworks and extensive excavation. The tubular foundation is constructed in situ using the ground itself as the containing structure, combining the foundation with the earth and eliminating temporary formwork systems that extend construction time.
Solution Approach 2:
The ground surrounding the foundation trench serves as the retaining structure, eliminating the need for external formworks. The earth provides the containment and support that would otherwise require manufactured formwork systems, allowing the foundation to construct itself using the existing ground as a mold.
3Force
If pre-casted concrete sections with heavy reinforcements are used, then load-bearing capacity is improved, but construction cost and environmental impact increase
Solution Approach 1:
The invention segments the foundation into a tubular concrete structure with embedded reinforcement bars, eliminating the need for heavy pre-casted sections. By using conventional reinforcement distributed throughout the concrete volume rather than concentrated pre-stressed elements, the design achieves adequate load-bearing capacity with significantly reduced material waste and environmental impact.
Solution Approach 2:
The invention replaces expensive, heavily reinforced pre-casted concrete sections with simpler, conventionally reinforced cast-in-place concrete. This substitution uses more economical materials and construction methods that generate less waste, achieving sufficient structural performance without the overhead of pre-casting facilities and heavy material transport.
4Reliability
If conventional foundations are used to resist overturning moments, then structural reliability is maintained, but foundation size and material consumption increase
Solution Approach 1:
The invention transitions from conventional spread foundations that resist overturning moments through increased base area to a deep tubular foundation that resists overturning through deep embedment and skin friction along the tube walls. This dimensional change from horizontal expansion to vertical development reduces material consumption while maintaining reliability against overturning loads.
Solution Approach 2:
The tubular shape of the foundation provides superior structural efficiency in resisting overturning moments compared to conventional rectangular or circular spread footings. The curved tube walls efficiently distribute and transfer lateral and overturning loads to the ground through skin friction and end bearing, achieving high reliability with reduced material consumption.
Data Source
AI summary
Embodiments of the present foundation for onshore wind turbines comprise one solid cap structure, one tubelike upright cylindrical structure and a concrete corbel structure. All are constructed of high-strength cast-in-place reinforced concrete. The tubelike cylindrical structure has a purposely enlarged inner diameter than the wind turbine tower. The tubelike cylindrical structure has a wall thickness of 2 to 4 feet and embeds to the ground from 25 to 60 feet. The cap structure is constructed within the encompassed space of the tubelike cylindrical structure and seals the top of the tubelike structure. The anchor bolting system comprises anchor bolts, nuts, washers and embedment ring and is embedded in the reinforced concrete of the solid cap structure at the lower part and bolts the wind turbine tower flange to the solid cap structure. The corbel structure has a trapezoid shape in the section view with the top side is about 1 to 3 feet wider than the bottom side which is about 1 to 3 feet wide and is circumferentially arranged below the cap structure to reinforce the joints of the cap structure and the tubelike cylindrical structure. The ledge of the corbel starts from the outer edge beyond the embedment ring, and the lower part of the corbel structure extends to the tubelike cylindrical structure. A trenching method is tailored to construct the tubelike cylindrical structure, and guiding beams can be repeatedly used to direct the trenching, maintain the mud slurry level for trenching and provide a working mat for placement of the reinforcement cages, anchor bolting system and concrete. Other construction auxiliaries including mud slurry and water can be repeatedly utilized. The foundation constructed with the preferred embodiments can be used to support wind turbines and similar tower structures.