Development of a filamented finite element for the analysis of prestressed concrete poles.

摘要

The purpose of this study is the development of a finite element formulation capable of describing accurately the structural response of prestressed concrete poles. Prestressed concrete poles are used in many civil applications relating to infrastructure. Because of their excellent structural properties, these poles compete in efficiency and strength with steel poles, and in terms of durability, structural performance, and environmental impact with wood poles. The strength of prestressed concrete poles is usually determined by compatibility of strains and stress, whereas deflections are estimated by virtual work or moment-curvature analysis.; This study presents a methodology for the analysis of prestressed concrete poles, using a filamented finite element (FFE). FFE is a two-node beam-type finite element with the cross section discretized into individual filaments. FFE models allow the analysis of complex problems where material and geometric nonlinearities are expected. In analysis of prestressed concrete poles, material nonlinearities occur because of cracking and strain softening of concrete, prestressing steel hardening, and time-dependent effects. Geometric nonlinearities occur because of the interaction between vertical and lateral loads. This study suggests constitutive laws for concrete and prestressing steel that are appropriate for prestressed concrete poles. The FFE model is validated by comparison with other theoretical methodologies showing good agreement in the estimation of the moment capacity of the pole configurations studied. In addition, the FFE model is compared with experimental results of full-scale tests of poles reported in the literature. From this comparison, it is apparent that the FFE model is capable of predicting with great accuracy the overall structural response of prestressed concrete poles.; The FFE model is used in a parametric study to investigate a wide range of pole configurations. From the parametric study, it is apparent that an increase of prestress reinforcement results in a reduction of the ductility, whereas an increase of concrete strength results in an increase in ductility. A combined increase in concrete strength and prestress reinforcement may result in an increase or decrease in ductility. Finally, the parametric study suggests that ductility of prestressed concrete poles decreases as the reinforcement index increases.