Otimização de torres eólicas de concreto armado

Abstract

Concrete wind towers over 100 m height have been presented as a more appropriated solution comparing to steel towers. The efficient design of these structures is important to ensure their feasibility and the use of optimization techniques can help reduce their costs and automate the design process. This paper presents an optimization model for reinforced concrete wind towers, aiming at the reduction of the weight of the tower considering concrete and reinforcement. Finite element analysis is conducted, and simplified strategies are investigated when considering physical and geometric nonlinearities and dynamic wind modeling for a more efficient optimization. The loading conditions and recommendations of NBR 6118 and IEC 61400-1 are used for the tower analysis. The design variables are the dimensions of the tubular section of the tower and the longitudinal reinforcement, all treated as discrete. The constraints are relative to geometry parameters, the ULS resistance, the excessive deformation in the SLS, the natural frequency of the tower and the longitudinal reinforcement ratio. The resistance is treated considering the approximate M-N interaction diagram of the resistant stresses corresponding to the ultimate deformed configuration. The optimization problem is solved by genetic algorithms and applications are made to towers over 100 m. Preliminary optimized solutions were obtained for the wind tower in an efficient manner, assisting the prior design stage of these structures.