TY - JOUR

T1 - Fire behavior and design of steel columns reinforced by prestressed CFRP strips

AU - Hu, Lili

AU - Ghafoori, Elyas

AU - Pons, Stefano

AU - Feng, Peng

AU - Yang, Jian

AU - Azim, Iftikhar

N1 - Funding Information: The authors gratefully recognize the funding provided by the China Scholarship Council (File No. 201806210204) and Shanghai Sailing Program (No. 21YF1419500). The authors gratefully recognize the supervision of Prof. Dr. Mario Fontana, the help of Mr. Samuel Rebelo Garcia and Prof. Dr. Andreas Taras from ETH Zürich, Switzerland, and the support of Dr. Hanlin Qiang from Beijing Municipal Commission of Housing and Urban-rural Development, China. The authors also want to thank the technicians of the structural laboratory of ETH Zürich, Switzerland for their support in performing the experiments. Furthermore, the authors acknowledge the support of the S&P Clever Reinforcement Company AG through the provision of the CFRP samples. Publisher Copyright: © 2021 Elsevier Ltd

PY - 2021/11/1

Y1 - 2021/11/1

N2 - This study analyzes the behavior of steel columns reinforced by prestressed (PS) carbon fiber reinforced polymer (CFRP) strips exposed to fire. First, tests are performed to study the CFRP material degradation under high temperatures. The elastic modulus and strength of the CFRP decrease with increasing temperature. Second, a thermal–mechanical coupling analysis is conducted with finite element method (FEM) to study the behavior of composite members exposed to fire. Under compressive preloading, the columns are exposed to the ISO 834 standard fire curve. The fire exposure time of columns with different initial CFRP prestressing forces is obtained. All the specimens fail because of global buckling either due to the slacking of the concave side of the CFRP or the plastic deformation of the steel. Subsequently, parametric studies are performed considering different initial CFRP prestressing forces, preloadings and column slenderness values. Finally, a design method is proposed for steel columns with PS CFRP that are exposed to fire, followed by a design example. Columns with protections can achieve high buckling capacities at room temperature and long fire exposure time.

AB - This study analyzes the behavior of steel columns reinforced by prestressed (PS) carbon fiber reinforced polymer (CFRP) strips exposed to fire. First, tests are performed to study the CFRP material degradation under high temperatures. The elastic modulus and strength of the CFRP decrease with increasing temperature. Second, a thermal–mechanical coupling analysis is conducted with finite element method (FEM) to study the behavior of composite members exposed to fire. Under compressive preloading, the columns are exposed to the ISO 834 standard fire curve. The fire exposure time of columns with different initial CFRP prestressing forces is obtained. All the specimens fail because of global buckling either due to the slacking of the concave side of the CFRP or the plastic deformation of the steel. Subsequently, parametric studies are performed considering different initial CFRP prestressing forces, preloadings and column slenderness values. Finally, a design method is proposed for steel columns with PS CFRP that are exposed to fire, followed by a design example. Columns with protections can achieve high buckling capacities at room temperature and long fire exposure time.

KW - Design

KW - FEM

KW - Fire

KW - Prestressed CFRP

KW - Reinforced

KW - Steel column

UR - http://www.scopus.com/inward/record.url?scp=85112516413&partnerID=8YFLogxK

U2 - 10.1016/j.compstruct.2021.114516

DO - 10.1016/j.compstruct.2021.114516

M3 - Article

AN - SCOPUS:85112516413

VL - 275

JO - Composite structures

JF - Composite structures

SN - 0263-8223

M1 - 114516

ER -