TY - JOUR

T1 - Strengthening of steel beams with adhesively bonded memory-steel strips

AU - Wang, Sizhe

AU - Li, Lingzhen

AU - Su, Qingtian

AU - Jiang, Xu

AU - Ghafoori, Elyas

N1 - Funding Information: Support from the Key Research Project of Guangdong Province of China ( 2019B111106002 ), the National Natural Science Foundation of China ( 52278207 ), Natural Science Foundation of Shanghai ( 21ZR1466100 ), Fundamental Research Funds for the Central Universities of China , and China Scholarship Council (CSC) is acknowledged. The authors also acknowledge the support from re-fer AG, Switzerland, to provide the Fe-SMA material, and Sika AG, Switzerland, to deliver the structural adhesive for this study. In addition, thanks are due to the technicians at the Structural Engineering Laboratory of Empa for their assistance in conducting the experiments.

PY - 2023/8

Y1 - 2023/8

N2 - This study entails the development of a non-destructive prestressed strengthening solution for steel beams using adhesively bonded memory-steel (also known as iron-based shape memory alloy, Fe-SMA) strips. The Fe-SMA strip is activated via heating and subsequent cooling to generate prestress, while the two ends of the Fe-SMA strip are adhesively bonded as anchorages. The behavior of the Fe-SMA-to-steel bonded joints was investigated through lap-shear tests, from which an effective bond length of approximately 120 mm was determined. Subsequently, a strengthening solution for a 5.3 m span steel I-beam was designed based on finite element analysis. A 4200 mm × 100 mm × 1.5 mm Fe-SMA strip was bonded to the bottom of the steel beam with a bond length of three times the effective bond length, and a two-step activation strategy using torches was proposed. Furthermore, the designed strengthening solution was experimentally tested. With activation to the target temperature of 240 °C, the Fe-SMA developed a prestress level of approximately 280 MPa. A series of static and fatigue four-point bending tests were conducted. After 3 million cycles of fatigue loading, no debonding or degradation was observed for the adhesively bonded Fe-SMA-strengthened specimen; this demonstrated the reliable performance of the strengthening solution under service loads.

AB - This study entails the development of a non-destructive prestressed strengthening solution for steel beams using adhesively bonded memory-steel (also known as iron-based shape memory alloy, Fe-SMA) strips. The Fe-SMA strip is activated via heating and subsequent cooling to generate prestress, while the two ends of the Fe-SMA strip are adhesively bonded as anchorages. The behavior of the Fe-SMA-to-steel bonded joints was investigated through lap-shear tests, from which an effective bond length of approximately 120 mm was determined. Subsequently, a strengthening solution for a 5.3 m span steel I-beam was designed based on finite element analysis. A 4200 mm × 100 mm × 1.5 mm Fe-SMA strip was bonded to the bottom of the steel beam with a bond length of three times the effective bond length, and a two-step activation strategy using torches was proposed. Furthermore, the designed strengthening solution was experimentally tested. With activation to the target temperature of 240 °C, the Fe-SMA developed a prestress level of approximately 280 MPa. A series of static and fatigue four-point bending tests were conducted. After 3 million cycles of fatigue loading, no debonding or degradation was observed for the adhesively bonded Fe-SMA-strengthened specimen; this demonstrated the reliable performance of the strengthening solution under service loads.

KW - Adhesive bonding

KW - Fatigue

KW - Fe-Mn-Si shape memory alloy

KW - Memory-steel

KW - Prestress

KW - Rehabilitation

KW - Steel beam

UR - http://www.scopus.com/inward/record.url?scp=85162178966&partnerID=8YFLogxK

U2 - 10.1016/j.tws.2023.110901

DO - 10.1016/j.tws.2023.110901

M3 - Article

AN - SCOPUS:85162178966

VL - 189

JO - Thin-walled structures

JF - Thin-walled structures

SN - 0263-8231

M1 - 110901

ER -