Behavior Characteristics of CFST Columns-Steel Tube Foundations Socket Connection

In this study, finite element analysis was conducted to examine the behavioral characteristics based on design variables for a proposed foundation connection using Concret filled steel tube (CFST) columns and socketed steel tubes in relation to socket-type column-foundation connections. The parameters considered for the analysis included column embedded depth, socket steel pipe diameter-to-thickness ratio, reinforcing bar diameter, socket concrete strength, and the presence or absence of an annular ring. The results were then compared with the plastic flexural strength of the column as per WSDOT (2021) standards. Additionally, the flexural strength of the socket component in the Japanese Design Standards for Railway Structures and Commentary (2016) was compared with the outcomes of the finite element analysis outcomes The primary influential factors of the proposed structure were found to be the column embedded depth and the socket steel pipe diameter-to-thickness ratio. By analyzing the effects of these parameters and the resulting behavioral characteristics, the feasibility of applying the CFST column-socket type foundation connection structure using socket steel pipes was determined, and design guidelines were presented accordingly.