Hybrid concrete-composite tower for a wind turbine and method of manufacturing

A method of forming a wind turbine tower, characterized in that:

• forming a foundation;
• forming a plurality of outer walls having a tapered cylindrical shape;
• forming a plurality of inner walls having a tapered cylindrical shape;
• joining each inner wall within one of the outer walls with a plurality of fasteners to define a plurality of shells such that an annular space is defined between the inner wall and the outer wall of each shell, each shell having a first end and a second end;
• mounting the first end of a first one of the shells on the foundation;
• disposing elongated tubes defining cable channels longitudinally within the annular space;
• introducing wet concrete into the annular space of the first one of the shells;
• after the concrete is cured, extending a plurality of post-tensioning cables through the elongated tubes and between the foundation and the second end of the first one of the shells and applying tension to the plurality of post-tensioning cables to connect the first one of the shells to the foundation;
• mounting the first end of a second one of the shells to the second end of the first one of the shells;
• disposing elongated tubes defining cable channels longitudinally within the annular space of the second one of the shells;
• introducing wet concrete into the annular space of the second one of the shells;
• after the concrete in the annular space of the second one of the shells is cured, extending a plurality of post-tensioning cables through the elongated tubes and between the foundation and the second end of the second one of the shells and applying tension to the plurality of post-tensioning cables to connect the second one of the shells to the first one of the shells and to the foundation;
• mounting the first end of a third one of the shells to the second end of the second one of the shells, the third one of the shells having no fill material within the annular space;
• disposing elongated tubes defining cable channels longitudinally within the annular space of the third one of the shells;
• and
• extending a plurality of post-tensioning cables between the foundation and the second end of the third one of the shells and applying tension to the plurality of post-tensioning cables to connect the third one of the shells to the first and second ones of the shells and to the foundation.

A method of assembling a wind turbine tower characterized in that:

• forming a foundation;
• forming a plurality of outer walls having a tapered cylindrical shape and further including shear transfer members formed on a longitudinally extending inside surface thereof;
• forming a plurality of inner walls having a tapered cylindrical shape and further including shear transfer members formed on a longitudinally extending outside surface thereof;
• wherein the shear transfer members are one of circumferentially extending ridges and circumferentially extending grooves;
• concentrically positioning and joining each inner wall within one of the outer walls to define a plurality of shells such that an annular space is defined between the inner wall and the outer wall of each shell, each shell having a first end and a second end;
• mounting the first end of a first one of the shells on the foundation;
• disposing elongated tubes defining cable channels longitudinally within the annular space;
• inserting temporary post-tensioning rods within the elongated tubes to temporarily secure the first one of the shells to the foundation;
• introducing wet concrete into the annular space of the first one of the shells;
• after the concrete is cured, extending a plurality of post-tensioning cables through the elongated tubes and between the foundation and the second end of the first one of the shells and applying tension to the plurality of post-tensioning cables to connect the first one of the shells to the foundation;
• mounting the first end of a second one of the shells to the second end of the first one of the shells;
• disposing the elongated tubes defining cable channels longitudinally within the annular space of the second one of the shells;
• inserting the temporary post-tensioning rods within the elongated tubes to temporarily secure the second one of the shells to the first one of the shells;
• introducing wet concrete into the annular space of the second one of the shells;
• after the concrete in the annular space of the second one of the shells is cured, extending a plurality of post-tensioning cables through the elongated tubes and between the foundation and the second end of the second one of the shells and applying tension to the plurality of post-tensioning cables to connect the second one of the shells to the first one of the shells and to the foundation;
• mounting the first end of a third one of the shells to the second end of the second one of the shells, the third one of the shells having no fill material within the annular space;
• disposing elongated tubes defining cable channels longitudinally within the annular space of the third one of the shells;
• and
• extending a plurality of post-tensioning cables between the foundation and the second end of the third one of the shells and applying tension to the plurality of post-tensioning cables to connect the third one of the shells to the first and second ones of the shells and to the foundation.