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Flexural strengthening of structural concrete with iron‐based shape memory alloy strips
Author(s) -
Michels Julien,
Shahverdi Moslem,
Czaderski Christoph
Publication year - 2018
Publication title -
structural concrete
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 34
eISSN - 1751-7648
pISSN - 1464-4177
DOI - 10.1002/suco.201700120
Subject(s) - shape memory alloy , strips , materials science , retrofitting , sma* , structural engineering , tension (geology) , structural material , flexural strength , alloy , composite material , deformation (meteorology) , ultimate tensile strength , computer science , engineering , algorithm
This paper presents a study on structural concrete retrofitting with iron‐based shape memory alloys (Fe‐SMA). Initially, the Fe‐SMA strip is prestrained at ambient temperature with a remaining deformation. Subsequently, it is applied on the structure as an end‐anchored strip. The shape memory effect, characterized by the material’s back transformation to its initial shape, is created upon heating at an elevated temperature of about 160°C. In this case, a mechanical end anchorage refrains the alloy to develop its recovery in strain and hence transforms it to a recovery stress, which results in a prestress in the concrete substrate. The ease of installation of the strip itself combined with an efficient and rapid direct fastening method render this strengthening technique highly competitive for the market. In this paper, material characteristics such as the ductile behavior of the alloy in tension as well as its activation by means of fast resistive heating are presented. The application on reinforced concrete beams is described and static loading tests are shown in order to demonstrate the efficiency of the technique. An improved structural behavior at service state proves that Fe‐SMA strips are an efficient and innovative method for structural strengthening. Finally, a site application is presented. It demonstrates that Fe‐SMA strips are a competitive solution for replacing existing, more pricy, and technically more complicated methods.