Superelastic SMA–FRP composite reinforcement for concrete structures

TLDR

Fiber‑reinforced polymers have long been considered for concrete reinforcement, yet their linear elastic behavior limits their use for structural damping or dynamic applications. This study investigates whether incorporating superelastic shape‑memory alloy wires into FRP bars can enhance the ductility and damping of FRP‑reinforced concrete. Cyclic tensile tests on SMA–FRP coupons were performed, and the data were used to calibrate a uniaxial analytical model, followed by parametric and case studies to evaluate the reinforcement’s performance and governing factors. The results demonstrate that SMA–FRP reinforcement can markedly improve ductility and damping while preserving the elastic behavior typical of FRP bars.

Abstract

For many years there has been interest in using fiber-reinforced polymers (FRPs) as reinforcement in concrete structures. Unfortunately, due to their linear elastic behavior, FRP reinforcing bars are never considered for structural damping or dynamic applications. With the aim of improving the ductility and damping capability of concrete structures reinforced with FRP reinforcement, this paper studies the application of SMA–FRP, a relatively novel type of composite reinforced with superelastic shape memory alloy (SMA) wires. The cyclic tensile behavior of SMA–FRP composites are studied experimentally and analytically. Tests of SMA–FRP composite coupons are conducted to determine their constitutive behavior. The experimental results are used to develop and calibrate a uniaxial SMA–FRP analytical model. Parametric and case studies are performed to determine the efficacy of the SMA–FRP reinforcement in concrete structures and the key factors governing its behavior. The results show significant potential for SMA–FRP reinforcement to improve the ductility and damping of concrete structures while still maintaining its elastic characteristic, typical of FRP reinforcement.