This study investigated the application of concrete-filled steel tubes (CFSTs) in wharf piles. The deformation and mechanical characteristics of CFST piles under lateral loading were investigated through the finite element method. Furthermore, the mechanism of the steel tube effect was revealed. The findings of this study would provide a reference for the formulation of CFST pile design approaches and relevant specifications.
The concrete-filled steel tube (CFST) structure is one of the composite members made by filling a steel tube with concrete. Due to structural benefits, such as high bearing capacity, good plastic and toughness, and convenient construction and economic efficiency (Han et al., 2014), CFSTs have received increasing interest in recent decades. Fig. 1 shows the three typical CFST cross sections, including the circular, square and rectangular cross sections.
To promote the CFST application in civil engineering construction, various studies have been conducted on CFST members during their service life to study the mechanical properties, including the static performance in tension (Han et al., 2011a), bending (Han et al., 2004; 2006), and torsion (Han et al., 2007), the dynamic performance under cycle load (Hajjar and Tort, 2010; Denavit & Hajjar, 2012; Nie et al., 2013) and impact load (Bambach et al., 2008; Deng et al., 2012; Wang et al., 2013), the fire performance (Kodur, 2007; Han et al., 2003b; Huo et al., 2009), and the influence of concrete placement (Han and He, 2011b) and steel tube initial stress (Han and Yao, 2003a; Li et al., 2012) on the performances above. Based on these studies, a series of specifications such as the Eurocode 4 (2007), AIJ guide (2008), ANSI/AISC 360 (2016) and GB 50936 (2014) were proposed to provide guidance for the design of concrete-filled steel tubular members.
The wharf structure often uses the rock-socketed piles. The drilled shaft and CFST piles have been commonly used as rock-socketed piles (Chen et al., 2011), with the CSFT pile being more suitable for construction under offshore conditions for two reasons. One is that the structural benefits of CFST are helpful for the pile to resist the wind, wave, current load and other extreme loads, such as the ship impact load; the other is that it is unnecessary to use shuttering during concrete construction, reducing the offshore construction cost and time.
