Axial compressive performance of partially encased steel-concrete composite stub columns filled with lightweight aggregate concrete

• Published in: Engineering structures 2023-09, Vol.291, p.116422, Article 116422
• Main Authors: Qian, Zhenghao, Wang, Jingfeng, Liu, Yong, Xu, Qiuyu
• Format: Article
• Language: English
• Subjects: Axial compressive performance; Calculation method; Finite element analysis; Lightweight aggregate concrete; Partially encased steel-concrete composite stub column
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2023.116422

•This paper applied the lightweight aggregate concrete (LWAC) into partially encased steel-concrete composite (PEC) stub columns.•The axial compression test was conducted to explore the work properties of partially encased steel-concrete composite stub columns with LWAC.•The finite element models of the PEC-LC column were established to conduct a systemic parametric investigation.•The axial strength calculation method of PEC-LC columns was proposed considering the flange strength reduction and core concrete enhancement. This paper applied lightweight aggregate concrete (LWAC) in the partially encased steel-concrete composite (PEC) stub columns to achieve the advantages of lightweight and easy assembly. A total of 8 axial-loaded specimens were tested to explore the effect of concrete type, concrete strength, link spacing, longitudinal rebars, and height-to-width ratio on the compressive behavior of the partially encased steel-concrete composite stub columns with lightweight aggregate concrete (PEC-LC). Then, the finite element models of PEC-LC columns were established to conduct a systemic parametric investigation. The results demonstrated that the PEC-LC column experienced failure due to concrete crushing and local buckling of flanges, similar to the PEC column. Compared to the PEC column, the PEC-LC column exhibited a similar load-bearing capacity but poorer post-peak compressive performance, which could be improved by closer link spacing. Consequently, applying LWAC to reduce the self-weight of prefabricated members is a feasible option. Besides, the contact stress and the stress distribution at typical cross-sections were analyzed to reveal the confinement effect of H-shaped steel and links on the filled LWAC. Finally, A calculation method for estimating the axial compression capacity of the PEC-LC column was proposed, taking into account the reduction in flange strength and enhancement of core concrete. The accuracy of the calculation method was verified by comparison with experimental and numerical data. Overall, this research serves as a valuable reference for promoting the adoption of the PEC-LC column in assembled structures.