Behaviour of reinforced concrete circular columns strengthened with iron-based and nickel-titanium Shape Memory Alloy (SMA) strips confinement / Syaza Nur Iylia Zulkifli

Concrete confinement has been proven to be effective in increasing concrete strength and ductility, where there are mainly two types of lateral confinement methods, namely, passive confinement and active confinement. The application of active confinement in practice is very limited due to practical limitations related to high cost, extensive labour, and excessive hardware requirement in prestressing conventional materials. This research work is proposing other sustainable material as an alternative strengthening material which is Shape Memory Alloy (SMA) material that has been utilized widely in another field. This research aims to investigate the axial behaviour of circular RC columns partially wrapped with Iron-based and Nickel-Titanium Shape Memory Alloy (SMA) materials by experimental work and validation of the results through finite element modelling. The main objectives of this research are to analyse the axial performance of both SMAs strip as the strengthening material to the plain circular RC column. A total of eight (8) concrete cylinder and eight (8) circular RC column specimens were cast and the experimental work is divided into two stages: concrete cylinder and circular RC column confinement. In the first stage of this research, concrete cylinder specimen was tested with both Fe-SMA and NiTi-SMA strip while in second stage of the experimental work, focus is more on to investigate the behaviour of circular RC column under axial loading. Both stages required to evaluate the feasibility and compressive strength enhancement of concrete cylinder and circular RC column with both SMAs strips confinement. The result has been thoroughly discussed includes the axial behaviour, covering the first crack, load carrying capacity, crack pattern and failure modes, load displacement behaviour as well as the stress-strain analysis then the experimental result was validated numerically with simulation by ABAQUS and lastly a fittest model were developed using MATLAB. All experimental SMAs partially confined specimens had managed to achieve the theoretical design load displaying the reliability of the results.