Strength of concrete columns externally wrapped with composites under compressive static loading

This work describes the experimental results related to several series of circular cross-section concrete columns reinforced by composite materials glass/polyester. The columns have been wrapped externally with several plies, and subjected to classical static uniaxial compression loading, and a novel compressive technique consisting in repeated loading steps. The authors identify in particular two specific composite layups (bidirectional fabrics (0/90)2 and (+30/60)2), the first providing the highest time to failure, the second showing an increase up to 70% in strengthening efficiency compared with non-reinforced columns. Six hybrid composite jacket configurations have also been investigated. The authors also provide a cost analysis of the different types of layups used to wrap the columns, showing the enhanced mechanical/cost effectiveness of the reinforcements proposed in this article.