Pre-cast Concrete Box Girder Wind Turbine Foundation
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Solution Overview
Problem
Conventional concrete foundations for wind turbines are resource-intensive, time-consuming, and prone to inefficiencies due to on-site pouring, logistical challenges, and thermal cracking, with abandoned foundations after the turbine's lifecycle.
Innovation Solution
Pre-cast concrete foundations with a hub and beams, fabricated off-site and assembled on-site using post-tensioning cables, reducing construction time and enabling easier transportation and assembly, while allowing for efficient reuse or decommissioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional on-site pouring of massive concrete foundations is used, then the foundation can support heavy cyclical loads, but the construction time increases to several weeks and resource mobilization becomes extremely complex
Solution Approach 1:
The foundation is divided into multiple pre-cast concrete segments that are manufactured separately off-site and then assembled together on-site. This segmentation allows parallel production of multiple segments, dramatically reducing overall construction time while maintaining the structural integrity and load-bearing capacity of the complete foundation assembly.
Solution Approach 2:
Concrete segments are pre-cast off-site in controlled manufacturing environments before being transported to the installation location. This preliminary action enables quality control, accelerates on-site assembly, and eliminates the time-consuming process of formwork construction and concrete curing at the final location.
2Strength
If on-site pouring of large volumes of concrete is performed, then the foundation achieves required structural integrity, but logistical coordination becomes extremely complex requiring multiple batch plants and numerous concrete trucks
Solution Approach 1:
The foundation structure is segmented into multiple pre-cast units that are manufactured independently at single batch plants. This eliminates the need for coordinating multiple batch plants and numerous concrete trucks, as each segment is produced separately and transported individually to the site for assembly.
Solution Approach 2:
Concrete segments are pre-cast off-site in controlled manufacturing environments, transferring the complex concrete pouring and curing operations away from the wind farm site. This preliminary action simplifies on-site logistics to primarily transportation and assembly operations.
3Strength
If steel rebar assemblies with extremely long bars exceeding forty feet are installed, then the foundation achieves required reinforcement, but special transportation logistics and crane equipment are required
Solution Approach 1:
The rebar reinforcement is integrated into pre-cast concrete segments during manufacturing. This eliminates the need to handle and install extremely long rebar bars at the site, as the reinforcement is already positioned and protected within the concrete segments before transportation and assembly.
Solution Approach 2:
Steel rebar assemblies are pre-installed into concrete segments at the manufacturing plant before the concrete is poured and cured. This preliminary action completes the reinforcement installation in a controlled factory environment, eliminating complex on-site rebar handling and assembly operations.
4Stability of the object's composition
If massive concrete structures are poured in one continuous pour to avoid cold joints, then the foundation achieves structural continuity, but thermal cracking risk increases due to overheating of the concrete mass
Solution Approach 1:
The foundation is divided into multiple separate concrete segments that are pre-cast independently. This segmentation allows each segment to be poured in smaller, manageable volumes that can be properly cured without excessive heat generation, eliminating thermal cracking risks while maintaining overall structural continuity through careful design of segment interfaces and connection details.
Solution Approach 2:
Concrete segments are pre-cast in controlled manufacturing environments where temperature and curing conditions can be carefully managed. This preliminary action allows proper curing of each segment without the thermal cracking risks associated with massive on-site pours, while structural continuity is achieved through engineered connections between segments.
5Strength
If conventional gravity foundations are used, then the foundation provides stable support, but the massive monolithic structure cannot be effectively reused or removed after the turbine lifecycle
Solution Approach 1:
The foundation is constructed from multiple discrete pre-cast segments rather than a single monolithic structure. This segmentation enables the segments to be disassembled and potentially reused in other applications after the turbine lifecycle, while the engineered connections between segments ensure stable support during operation.
Solution Approach 2:
The foundation transitions from a static monolithic structure to a dynamic, modular assembly that can be configured, disassembled, and reconfigured. This dynamic characteristic provides adaptability for reuse or relocation while maintaining structural stability through designed connection mechanisms between segments.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces construction time, minimizes logistical challenges, and prevents thermal cracking, resulting in more efficient and sustainable foundation solutions for wind turbines.
Implementation Method 1
The beams and the hub can be secured to one another and post-tensioned using a plurality of post tensioning cables
Data Source
AI summary
Concrete foundations for supporting towers and other structures under heavy cyclical loads are described. Some or all of the major concrete components, such as the beams and the hubs, that form the foundation are fabricated off-site and then transported to the intended use site for the foundation. The concrete components can be fabricated as pre-cast segments, sections, or pieces, with the pre-cast segments then being assembled in the field at the use site to form each component, and the components then being assembled together to form the foundation. In one embodiment, the beams used in the foundation may have a box-girder construction.