Concrete Column Confinement with Mechanism-Based Composite Bistable Structures

Abstract

The application of fiber reinforced polymer (FRP) composites in civil engineering has advanced drastically in recent years, especially in the area of retrofitting concrete bridge columns. However, composite’s non-ductile (brittle) behavior is one of the concerns that have yet to be fully addressed. The objective of this research is to investigate a mechanism-based bistable composite structure as the wrapping system to improve the confinement in concrete columns. It consists of energy-absorbing “links”, main link and waiting link with the former being the primary load carrier and the latter as the secondary after the main link fails. A series of testing on cylindrical concrete members wrapped with the bistable structure made of hybrid carbon and glass FRP were conducted to investigate the effect of link geometry on the behavior. The results showed that a controlled failure was achieved in the structure and the ductility and energy absorption were enhanced. The effectiveness of the confinement was found to be affected by the number of links and the energy absorption relied on the size of the links.