Preliminary Study on the Design of Structures with a Responsive External Post-tensioning System

Abstract

External post-tensioning has proven to be an effective solution to introduce intermediate supports in structures in order to decrease their spans and to allow a more efficient distribution of bending moments. This leads to important savings in terms of material. However, this increase in effectiveness is achieved only for a specific loading, which generally corresponds to the permanent load distribution. This paper introduces the possibility of expanding the benefits of this technique to situations where relevant live loads act through the use of a responsive external post-tensioning system. The responsive behaviour is materialized through an actuator located between the beam and the post-tensioning system. After a brief overview of the existing responsive structures, this research studies the static structural behaviour of responsive externally post-tensioned structures. Furthermore, the main design variables are parametrically analysed and the applicability of the system is evaluated with the construction of a small-scale prototype. Finally, results are discussed and the effectiveness of this approach in terms of material savings is claimed.