Experimental validation of a shape memory alloy retrofitting application

Minarets are spread across urban nuclei. Their structural weakness could result in failures with heavy consequences. However, the retrofit solutions are limited due to their simple cantilever scheme. The use of metallic pre-stressed wires/cables is a rather consolidated technique. The use of shape memory alloy (SMA) wires has been recently investigated. In view of such an application, a series of reduced-scale tests was planned and realized. This paper synthesizes the full report on an experimental work performed to study the effect of SMA wires on the dynamic behavior of a single degree of freedom model built in laboratory to represent a 1/16th of a minaret actually built in Cairo, Egypt. The model was tested under free vibration for different values of the axial force, before and after adding SMA wires. The results showed enhancements in the stiffness when the SMA wires were added and when the axial force increased, while a decrease in damping ratios was detected when increasing the applied axial force or after providing SMA wires.