A Novel Tripod Concept for Onshore Wind Turbine Towers

A wind turbine tower assembly is presented, consisting of a lower tripod section and an upper tubular steel section, aiming at enabling very tall hub heights for optimum exploitation of the wind potential. The foundation consists of sets of piles connected at their top by a common pile cap below each tripod leg. The concept can be applied for the realization of new or the upgrade of existing wind turbine towers. It is adjustable to both onshore and offshore towers, but emphasis is directed towards overcoming the stricter onshore transportability constraints. For that purpose, pre-welded individual tripod parts are transported and are then bolted together during erection, contrary to fully pre-welded tripods that have been used in offshore towers. Alternative constructional details of the tripod joints are therefore proposed that address the fabrication, transportability, on-site erection and maintenance requirements and can meet structural performance criteria. The main structural features are demonstrated by means of a typical case study comprising a 180-m-tall tower, consisting of a 120-m-tall tubular superstructure on top of a 60-m-tall tripod substructure. Realistic cross-sections are calculated, leading to weight and cost estimations, thus demonstrating the feasibility and competitiveness of the concept.

Automated summary

The wind turbine tower assembly consists of a lower tripod section and an upper tubular steel section, allowing for very tall hub heights to optimize wind potential. The concept can be applied to both new and existing towers, with a focus on overcoming onshore transportability constraints and proposing alternative construction details to meet structural performance criteria. This innovative design approach demonstrates feasibility and competitiveness through realistic calculations of weight and cost estimations.