TY - JOUR

T1 - A comparative study between Fe-SMA and CFRP reinforcements for prestressed strengthening of metallic structures

AU - Hosseini, Ardalan

AU - Michels, Julien

AU - Izadi, Mohammadreza

AU - Ghafoori, E.

N1 - Funding Information: The authors would like to gratefully thank the technicians of the Structural Engineering Laboratory and the Mechanical Systems Engineering Laboratory of Empa for their exceptional support and assistance in performing the small- and large-scale static and fatigue tests. Furthermore, supports from company re-fer AG (Switzerland) and S&P Clever Reinforcement Company AG (Switzerland) by providing the materials for the present study are acknowledged. It should be noted that all the commercial product names mentioned in this paper are only provided for the sake of factual accuracy and should not necessarily be interpreted as an endorsement of the products utilized. Publisher Copyright: © 2019 Elsevier Ltd

PY - 2019/11/30

Y1 - 2019/11/30

N2 - In the last two decades, carbon fiber reinforced polymer (CFRP) composites have been used for the strengthening of various civil structures. Since recently, iron-based shape memory alloy (Fe-SMA) has been introduced as a promising material, and Fe-SMA reinforcements have been utilized for prestressed strengthening of existing structures. This study aims to conduct a comparative analysis between the structural performance and cost of using Fe-SMA vs. CFRP reinforcements for the prestressed strengthening of existing civil structures. First, a comprehensive study is presented that compares Fe-SMA and CFRP at the material level, with the main focus on the relevant structural aspects, such as the static tensile behavior, high-cycle fatigue (HCF) performance, creep and relaxation, corrosion resistance, thermal compatibility with common construction materials (i.e., steel and concrete), and the behavior under high temperatures and fire exposure. Second, the application complexity and the structural performance of the two strengthening techniques, by using mechanically anchored prestressed CFRPs or thermally activated Fe-SMAs, are compared at the system level by performing sets of static and HCF tests on CFRP and Fe-SMA strengthened steel plates and girders. Finally, a cost comparison is carried out for a specific case, where normal modulus (NM) CFRP plates and Fe-SMA strips were used for the prestressed strengthening of a real-scale steel I-girder. The cost analysis revealed that although the current price of Fe-SMA strips is higher than that of the NM CFRP plates, both of the strengthening systems are financially equivalent, when the achievable prestressing force and the cost of clamping systems are taken into consideration.

AB - In the last two decades, carbon fiber reinforced polymer (CFRP) composites have been used for the strengthening of various civil structures. Since recently, iron-based shape memory alloy (Fe-SMA) has been introduced as a promising material, and Fe-SMA reinforcements have been utilized for prestressed strengthening of existing structures. This study aims to conduct a comparative analysis between the structural performance and cost of using Fe-SMA vs. CFRP reinforcements for the prestressed strengthening of existing civil structures. First, a comprehensive study is presented that compares Fe-SMA and CFRP at the material level, with the main focus on the relevant structural aspects, such as the static tensile behavior, high-cycle fatigue (HCF) performance, creep and relaxation, corrosion resistance, thermal compatibility with common construction materials (i.e., steel and concrete), and the behavior under high temperatures and fire exposure. Second, the application complexity and the structural performance of the two strengthening techniques, by using mechanically anchored prestressed CFRPs or thermally activated Fe-SMAs, are compared at the system level by performing sets of static and HCF tests on CFRP and Fe-SMA strengthened steel plates and girders. Finally, a cost comparison is carried out for a specific case, where normal modulus (NM) CFRP plates and Fe-SMA strips were used for the prestressed strengthening of a real-scale steel I-girder. The cost analysis revealed that although the current price of Fe-SMA strips is higher than that of the NM CFRP plates, both of the strengthening systems are financially equivalent, when the achievable prestressing force and the cost of clamping systems are taken into consideration.

KW - Carbon fiber reinforced polymer

KW - Civil structures

KW - Cost comparison

KW - High-cycle fatigue loading

KW - Iron-based shape memory alloy

KW - Prestressed strengthening

KW - Recovery stress

UR - http://www.scopus.com/inward/record.url?scp=85070226753&partnerID=8YFLogxK

U2 - 10.1016/j.conbuildmat.2019.07.169

DO - 10.1016/j.conbuildmat.2019.07.169

M3 - Article

AN - SCOPUS:85070226753

VL - 226

SP - 976

EP - 992

JO - Construction and Building Materials

JF - Construction and Building Materials

SN - 0950-0618

ER -