Technology

To completely eliminate the transportation constraints, modularize construction, and facilitate construction of taller towers, the Hexcrete tower has been developed at Iowa State University (ISU). This new concept uses easily producible (onsite or offsite) and transportable columns and panels, relies on high strength concrete and prestressing steel, and forms the tower with a hexagonal shape cross-section. In addition, it offers:

  • Multiple installation options
  • Increased lifespan for the towers
  • The possibility of using a deep foundation effectively, thereby reducing the decommissioning costs
  • Multiple design variables to reach newer heights
  • Thin panel thickness and base dimension comparable to that expected for steel tubular towers

Benefits of Hexcrete Tower

  • Improve the current state of wind tower construction
  • Provide for wind turbine tower designs which use high and ultra-high strength cementitious materials such as HPC, HSC and UHPC.
  • Provide a wind turbine tower suitable for use to provide hub heights of 80 meters or more.
  • Provide wind turbine towers which provide a cost-effective alternative to steel towers which provide numerous challenges especially for taller towers.
  • Provide a tower which is modular such that multiple pieces compose any given cross section and/or vertical segment.
  • Enable wind turbines to be supported cost effectively at hub heights of 80 meters and above while resisting the loads from wind turbine, gravity, wind forces, extreme loads such as due to earthquake, or combinations thereof.
  • Provide a reliable and cost effective means to elevate a wind turbine to a height sufficient to efficiently produce energy from the wind.
  • Provide a wind turbine tower with increased longevity relative to currently used steel towers with 20-25 year lifespan.
  • Provide a wind turbine tower that may be disassembled and reused at a different location.
  • Provide a wind turbine tower which uses less material than a regular strength concrete tower which generally requires much larger base dimension than steel tower.
  • Provide a wind turbine tower with reduced transportation and site development costs relative to normal concrete wind turbine towers.
  • Provide a wind turbine tower with the potential for reduced construction costs.
  • Provide a wind turbine tower with reduced transportation and site development costs relative to normal concrete wind turbine towers.
  • Provide suitable connections between the precast components of the tower that allow it to behave as one composite system when loaded.
  • Use modular components that can be either prefabricated and transported using standard trucks, or cast on site.
  • Increase the design life for wind turbine towers to 40-50 years (or more) instead of the 20-25 years as used currently.
  • Increase the design life for wind turbine towers to 40-50 years (or more) instead of the 20-25 years as used currently.
  • Increase the design life for wind turbine towers to 40-50 years (or more) instead of the 20-25 years as used currently.

Design Specifications

The wind turbine tower will have a height of at least 100 meters and include multiple vertical columns comprised of a concrete composition and a plurality of panels, with each of the panels extending between adjacent hexagonal-shaped vertical columns. The vertical columns may be, for example, circular, or of hexagonal shape to improve constructability. The vertical columns and panels are arranged to provide a hexagonal cross-section for the wind turbine tower. Connections between the panels and the hexagonal-shaped vertical columns may be bolted connections, ultra high performance concrete (UHPC) wet connections, or post-tensioned connections. The columns and panels may be formed of ultra high performance concrete (UHPC), High Performance Concrete (HPC) or high strength concrete (HSC).