Safety Concerns Emerge in Hybrid Tower Construction
The wind energy sector's shift toward larger turbines has made hybrid concrete-steel towers a critical supporting technology, bringing both safety and economic considerations to the forefront. However, the application of high-strength concrete (C80 grade and above) in wind turbine foundations faces significant challenges due to the absence of standardized systems and insufficient performance data.
Xu Ruilong, Deputy Chief Engineer at Goldwind, noted that traditional C50-C60 grade concrete can no longer meet the demands of modern wind turbines with increasing capacity. While high-strength concrete has become more prevalent, the current design framework lacks unified standards, relying excessively on European specifications or empirical extrapolation. This approach introduces potential safety risks and design uncertainties that could lead to both structural vulnerabilities and resource inefficiencies.
Industry Calls for Unified Standards as Hybrid Tower Adoption Soars
Data from Cai Jifeng of the Renewable Energy Expert Technical Committee (REETC) reveals that hybrid towers were specified in more than one-third of newly tendered wind projects in 2024, with annual usage increasing by over 200%. This rapid growth highlights the technology's importance but also exposes critical challenges in cost management and safety assurance.
Wind turbine towers endure continuous dynamic loads, making fatigue resistance a paramount concern. The current lack of fundamental research in this area creates gaps in structural reliability assessments, emphasizing the need for comprehensive material studies.
REETC Initiative Aims to Establish Performance Database
In response to these challenges, REETC launched the "High-Strength Concrete Performance for Wind Turbines" research project in January 2025. This collaborative effort brings together turbine manufacturers, material suppliers, design institutes, developers, and third-party testing organizations to create a physical property test database and develop performance benchmarks specifically for China's wind energy sector.
The project represents REETC's first public technical cooperation initiative, reflecting the industry's urgent need for standardized hybrid tower solutions. Jiang Shaohui of the China General Certification Center presented interim findings, including preliminary analyses of mechanical property test data for C80+ concrete. The study examines critical parameters such as cube compressive strength, axial compression/tensile strength, splitting strength, elastic modulus, fatigue performance, and constitutive relationships.
Technical Breakthroughs Address Critical Performance Parameters
Several research teams shared specialized findings during the project's mid-term review:
Elastic Modulus Research: Wang Jian of Tianshan High-Tech presented methodologies for accurately measuring this crucial design parameter, which directly impacts structural stability. The research identifies key influencing factors and proposes optimization strategies.
Fatigue Testing: Huang Xiaogang of Chongqing University revealed performance degradation patterns in high-strength concrete under cyclic loading, providing essential data for durability assessments.
Material Variability: Li Xiangyu of the China Academy of Building Research analyzed fluctuations in fundamental material properties, emphasizing the importance of accounting for these variations in structural design.
Next Steps Toward Standardization
The project team has established preliminary consensus on mechanical property testing protocols and plans to complete batch testing protocols by late 2025. The initiative will culminate in publishing the "High-Strength Concrete Mechanical Performance Whitepaper 1.0" as part of a three-year research series.
This data-driven approach not only addresses current standardization gaps but also strategically positions the industry for future hybrid tower development. By establishing performance benchmarks and material databases, the project aims to support safer, more efficient wind turbine designs while contributing to broader advancements in concrete material science.