Numerical Modeling of Unreinforced Masonry Walls Strengthened with Fe-Based Shape Memory Alloy Strips

Abstract

This study presents a new way to improve masonry wall behavior. Masonry structures comprise a significant part of the world’s structures. These structures are very vulnerable to earthquakes, and their performances need to be improved. One way to enhance the performances of such types of structures is the use of post-tensioning reinforcements. In the current study, the effects of shape memory alloy as post-tensioning reinforcements on originally unreinforced masonry walls were investigated using finite element simulations in Abaqus. The developed models were validated based on experimental results in the literature. Iron-based shape memory alloy strips were installed on masonry walls by three different configurations, namely in cross or vertical forms. Seven macroscopic masonry walls were modeled in Abaqus software and were subjected to cyclic loading protocol. Parameters such as stiffness, strength, durability, and energy dissipation of these models were then compared. According to the results, the Fe-based strips increased the strength, stiffness, and energy dissipation capacity. So that in the vertical-strip walls, the stiffness increases by 98.1%, and in the cross-strip model's position, the stiffness increases by 127.9%. In the vertical-strip model, the maximum resistance is equal to 108 kN, while in the end cycle, this number is reduced by almost half and reaches 40 kN, in the cross-strip model, the maximum resistance is equal to 104 kN, and in the final cycle, this number decreases by only 13.5% and reaches 90 kN. The scattering of Fe-based strips plays an important role in energy dissipation. Based on the observed behaviors, the greater the scattering, the higher the energy dissipation. The increase was more visible in the walls with the configuration of the crossed Fe-based strips.

Application of Shape Memory Alloys in Retrofitting of Masonry and Heritage Structures Based on Their Vulnerability Revealed in the Bam 2003 Earthquake

“…Rezapour et al [ 63 ] analysed the performance of URM reinforced with iron-based SMA strips. As seen in Figure 12 , the SMA-based strips were mounted in the shape of crossings and verticals in walls and subjected to post-tension force with mortar as the connector between the wall and strips.…”

“…The SMA strips network, which can improve the performance of the URM walls, is employed in order to enhance the strength, stiffness, and energy dissipation capacity of the wall during an earthquake. As the crossing network has shown better behaviour [ 63 ], in this scheme, the same pattern is proposed. The network might be helpful to prevent shear, sliding, and rocking failure of the URM wall.…”

“… Numerically studied SMA-reinforced walls [ 63 ]; ( a ) 2 vertical stripes; ( b ) 4 vertical stripes; ( c ) 8 vertical stripes; ( d ) 2 cross-strips; ( e ) 6 cross-strips; ( f ) 14 cross-strips. …”

Sustainability of Civil Structures through the Application of Smart Materials: A Review

“…Rezapour et al [81] investigated the performance of URM strengthened with ironbased SMA bars. Figure 19 shows SMA-based strips installed in the configuration of crossovers and parallels in brickwork and exposed to post-tension stress with cement as the interface between the wall and the stripes.…”

Optimized Neural Network Prediction Model of Shape Memory Alloy and Its Application for Structural Vibration Control

“…Dehghani and Aslani developed hooked-end pseudoelastic shape memory alloy fibres (PSMAF) which can provide re-centring and crack-closing behaviour in cementitious composites [ 7 ]. Rezapour et al investigated the effects of SMA post-tensioning reinforcements on originally unreinforced masonry walls using Abaqus soft [ 8 ]. Siddiquee et al evaluated the seismic performance of concrete frame buildings reinforced with superelastic SMA rebar in terms of the collapse margin ratio, and the results are compared with that of a reinforced concrete structure with regular steel rebar only [ 9 ].…”