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This paper demonstrates the concept of adaptive repurposing of a portion of a decommissioned Clipper C96 wind turbine blade as a pole in a power transmission line application. The current research program is aimed at creating a path towards sustainable repurposing of wind turbine blades after they are removed from service. The present work includes modelling and analysis of expected load cases as prescribed in ASCE 74 and NESC using simplified boundary conditions for tangent pole applications. Load cases involving extreme wind, concurrent ice and wind, extreme ice, differential ice, broken conductor, and broken shield have been analyzed and governing load cases for bending, shear, and torsion have been examined. Relative stiffnesses of different parts forming the wind blade’s cross section (i.e., shell, web, and spar cap) are determined. The corresponding stresses associated with each part under the governing loads are compared to allowable strength values which are determined from composite laminate theory and modelling of the known laminate structure of the E-Glass FRP material. Stresses and deflections obtained are compared with governing reliability-based design criteria and code requirements. The results of the structural analysis indicate that the wind blade can resist the expected loads with reasonable safety factors and that the expected deflections are within permissible limits. Recommendations are provided for detailing and modification of the wind blade for a power pole application in which crossarm and davit connections are highlighted, and foundation details are emphasized. 

The focus of this work is on the problem of the future waste to be generated by the decom-missioning of wind farms and especially the Fiber Reinforced Polymer (FRP) composite materials used in the wind turbine blades. The FRP composites used to manufacture the blades are not biodegradable and present severe problems with regard to waste management and their End-of-Life (EOL). The impact on polymers on the environment and society has become a major concern in many countries. With the increased awareness of the environmental impacts of climate change, decreased and more expensive natural resources, and greater global concerns for health, the barriers to FRP production and waste disposal are likely to increase. In the context of the circular economy the preferred method to manage FRP waste is to use it in new applications or processes. Recent structural analysis research conducted by the authors related to reuse of FRP composite material parts from decommissioned wind turbine blades in infrastructure applications is presented in this paper. 

Fiber reinforced polymer (FRP) waste is becoming an environmental concern due to the widespread use and non-biodegradable nature of FRP composites. Cutting FRP waste into discrete reinforce-ments (referred to as “needles” hereafter) as coarse aggregate in concrete has been suggested as a possible solution to FRP waste recycling. It has previously been observed in small specimens that FRP needles increase the tensile strength and energy absorption capacity of concrete. This paper presents an experimental investiga-tion into the effect of GFRP needles as coarse aggregate partial replacement in concrete on shear behavior of full-scale reinforced concrete (RC) beams. A total of 10 RC beams without steel stirrups in the critical zone were tested under four-point bending. The volume replacement ratio of the coarse aggregate and the surface type of GFRP needles were chosen as the test parameters. GFRP needles, with either smooth or helically wrapped surfaces, were added to the concrete mix to replace 5% or 10% of coarse aggregate by volume, respectively. All test beams failed in shear in a brittle manner with the ductility being slightly enhanced by the partial replace-ment of coarse aggregate using GFRP needles. An enhancement of 8%-10% in the load carrying capacity was observed in beams with helically wrapped needles, while beams with smooth needles showed a reduction in the load carrying capacity. 

The rapid increase in the wind energy sector has brought forward a challenging problem of disposing off a huge quantity of non-biodegradable, thermosetting fibre reinforced polymer (FRP) composite materials used in wind turbine blades. Most of the existing solutions are either not sustainable or not economical. This study focuses on re-use options. In this paper a design option for re-using decommissioned wind turbine blades in pedestrian bridges is presented. To demonstrate the concept, an 8.5 m long pedestrian bridge is designed using parts taken from two A29 (modified version of Vestas V27) windblades. A preliminary code-based structural analysis is carried out to assess practicality of the proposed design and to check strength and serviceability requirements given in the prescribed codes. The results show that proposed design full-fills the strength criteria and serviceability requirements recommended in the Eurocodes. The maximum strength utilisation of the blade components is found about 61% and deflection is limited to span/303. 

The rapid growth in wind energy technology has led to an increase in the amount of thermosetting FRP composite materials used in wind turbine blades that will need to be recycled or disposed of in the near future. Calculations show that 4.2 million tons of waste from wind blades will need to be managed globally by 2035, increasing to 16.3 million tons by 2055. Three waste management route are possible: disposal, recycling or reusing. Currently, most FRP composites taken out of service are disposal of in landfills or are incinerated. Recycling options consist of reclamation of the constituent fibers or the resins by thermo–chemical methods or recycling of small pieces of granular FRP material as filler material by cutting, shredding or grinding. Reuse options consist of reusing the entire FRP blade or large parts of the blade in new structural applications. This paper reports on the potential for reusing parts of wind turbine blades in new or retrofitted architectural and civil infrastructure projects. The paper introduces the geometry, materials, and laminates typically used in wind blades and provides a snapshot of the sizes of wind blades likely to be available from the inventory of active turbines. Because the materials and manufacturing of commercial wind blades are proprietary, generic blade geometries and materials are discussed. These come from the Sandia National Laboratory and National Renewable Energy Laboratory, in the United States, and from OPTIMAT in the European Union. The paper presents a method for generating the geometry and material properties of structural elements cut from wind blades, using the Numerical Manufacturing and Design Tool (NUMAD), published by the Sandia National Laboratory.