Experimental study on ultimate bearing capacity of short thin-walled steel tubes reinforced with high-ductility concrete

• Published in: Structures (Oxford) 2024-10, Vol.68, p.107109, Article 107109
• Main Authors: Chen, Rui-Sheng, Zhang, Hao-Yu, Hao, Xin-Kai, Yu, Han-Xi, Shi, Tao, Zhou, Hang-Sheng, Wang, Rong-Bing, Zhao, Zhi-Fang, Wang, Pengjie
• Format: Article
• Language: English
• Subjects: Axial load capacity; Bond strength; Engineered cementitious composite; High-ductility concrete; Thin-walled steel tubes
• ISSN: 2352-0124; 2352-0124
• DOI: 10.1016/j.istruc.2024.107109

Thin-walled steel short columns often suffer from local buckling and limited load-carrying capacity. To address this issue, this study uses high-ductility concrete to reinforce thin-walled steel tubes, aiming to enhance both their load-carrying capacity and ductility. However, the challenge lies in the low bond strength between steel and high-ductility concrete. Therefore, the paper aims to propose an appropriate bond interface treatment to ensure a reliable bond between these two materials. Subsequently, axial compression tests were conducted for twelve short thin-walled steel tubes, comprising three unreinforced steel tube columns and nine columns reinforced with high-ductility concrete. The effect of the following parameters on both unreinforced and reinforced thin-walled steel tubes was investigated: length-to-slenderness ratio, width-to-thickness ratio and the thickness of reinforced high-ductility concrete. The ultimate load-carrying capacity, failure modes and local buckling behavior of steel tubes are evaluated and high-ductility concrete can enhance the mechanical performance of thin-walled steel tubes. A design equation is proposed to predict the ultimate strength of short thin-walled steel tubes reinforced with high-ductility concrete, which provides design guidelines for the application of high-ductility concrete strengthening existing steel tube structures.