TY - JOUR

T1 - Stability of steel columns with bolted strengthening under preload

T2 - Experimental study

AU - Wang, Sizhe

AU - Su, Qingtian

AU - Jiang, Xu

AU - Ghafoori, Elyas

N1 - Funding Information: This work was supported by the Shanghai Engineering Research Center of High Performance Composite Bridges [No. 19DZ2254200 ], Key Research Project of Guangdong Province of China [No.2019B111106002], the Natural Science Foundation of Shanghai [Grant No. 21ZR1466100], and the Fundamental Research Funds for the Central Universities of China. The first author also acknowledges the support of the China Scholarship Council (CSC). Publisher Copyright: © 2021

PY - 2022/3

Y1 - 2022/3

N2 - Strengthening of steel columns is usually conducted with existing loads, so there is a need to study the effect of the preload (the existing load during strengthening) on the stability of strengthened columns. This study presents an experimental work, in which H-shaped steel columns were strengthened with bolted steel angles. Specimens strengthened under different preload levels were tested. The test results showed that the preload had an influence on column behaviors including deformations, strains, and stresses. In particular, the preload had an effect on the ultimate load capacity. The (normalized) ultimate load capacities of the specimens slightly increased and then decreased with the increasing preload. The effect of the preload on the ultimate load capacities was generally insignificant (no more than 8% in the study), and the effect could be either favorable or unfavorable depending on the case. This varying effect of the preload could be interpreted by the combined effects of the equivalent initial deformation and initial stresses. In addition, specimens with different steel angle properties, strengthening length ratios, and slenderness ratios were tested. The test results indicated that all these variables affected the behaviors and ultimate load capacities of the strengthened specimens.

AB - Strengthening of steel columns is usually conducted with existing loads, so there is a need to study the effect of the preload (the existing load during strengthening) on the stability of strengthened columns. This study presents an experimental work, in which H-shaped steel columns were strengthened with bolted steel angles. Specimens strengthened under different preload levels were tested. The test results showed that the preload had an influence on column behaviors including deformations, strains, and stresses. In particular, the preload had an effect on the ultimate load capacity. The (normalized) ultimate load capacities of the specimens slightly increased and then decreased with the increasing preload. The effect of the preload on the ultimate load capacities was generally insignificant (no more than 8% in the study), and the effect could be either favorable or unfavorable depending on the case. This varying effect of the preload could be interpreted by the combined effects of the equivalent initial deformation and initial stresses. In addition, specimens with different steel angle properties, strengthening length ratios, and slenderness ratios were tested. The test results indicated that all these variables affected the behaviors and ultimate load capacities of the strengthened specimens.

KW - Bolting

KW - Buckling

KW - Compression test

KW - Preload

KW - Stability

KW - Strengthening

UR - http://www.scopus.com/inward/record.url?scp=85123195338&partnerID=8YFLogxK

U2 - 10.1016/j.jcsr.2021.107119

DO - 10.1016/j.jcsr.2021.107119

M3 - Article

AN - SCOPUS:85123195338

VL - 190

JO - Journal of Constructional Steel Research

JF - Journal of Constructional Steel Research

SN - 0143-974X

M1 - 107119

ER -