Article
Behavior of an Internally Confined Hollow Reinforced Concrete
Column with a Polygonal Cross-Section
Sungwon Kim , Hyemin Hong and Taekhee Han *
Citation: Kim, S.; Hong, H.; Han, T.
Behavior of an Internally Confined
Hollow Reinforced Concrete Column
with a Polygonal Cross-Section. Appl.
Sci. 2021, 11, 4302. https://doi.org/
10.3390/app11094302
Academic Editor: João Carlos de
Oliviera Matias
Received: 6 April 2021
Accepted: 5 May 2021
Published: 10 May 2021
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4.0/).
Coastal Development and Ocean Energy Research Center, Korea Institute of Ocean Science and Technology,
385 Haeyang-ro, Yeongdo-gu, Busan 49111, Korea; swkim@kiost.ac.kr (S.K.); hyeminhong@kiost.ac.kr (H.H.)
* Correspondence: taekheehan@kiost.ac.kr
Abstract:
The new supporting structure, internally confined hollow reinforced concrete (ICH RC),
was suggested by former researchers. It maintains the material saving effect, which is the advantage
of the hollow concrete structure, and it solves the brittle fracture problem of the inner wall by the inner
steel pipe to make it into the 3-axis confinement state. However, until now, its design and analysis
model has been limited to a circular cross-section. In this study, to expand the applicability, research
and development of an ICH RC structure with a polygonal cross-section were performed. The
material model was developed by defining the constraint stress in the members of the concrete and
deriving a reasonable stress-strain relationship. For the column model, it was developed to predict
the behavior of the polygonal ICH RC columns by analyzing the axial force-moment correlation,
moment-curvature, and lateral force-displacement relationship. Each model was verified not only by
comparing with the results of previous experiments but also by analyzing the results according to
parameters. The maximum load and ultimate displacement values through the developed model
showed the difference with the experimental results within 6% of mean error. It was verified that the
proposed analytical model reasonably reflects the behavior of actual columns.
Keywords: confined concrete; polygonal cross-section; ICH RC; concrete column
1. Introduction
Recently, the trend of enlargement of structures, such as skyscrapers, pier for long-span
bridges, and wind turbine towers, has been growing. According to Gabel [
1
], the number
of skyscrapers over 200 meters high has been increasing (Figure 1). The increase in building
height is accompanied by an increase in building weight and moment due to lateral force.
The performance of a building’s structural system is determined by resistance to lateral
force, which increases with the building height. Various studies have been conducted on
the column structure for improving the building performance. Tailor et al. [
2
] proposed a
concrete-filled steel tube (CFST) and evaluated its seismic performance by comparing the
static and dynamic behavior with a steel column. The growth of the lateral force with an
increase in building height is closely related to the outline of the building. Elshaer et al. [
3
]
conducted a study related to wind load at the building edge according to the shape of the
buildings. Bai et al. [
4
] conducted a study about thin-walled CFST columns to enhance
seismic collapse performance of high-rise steel frames.
In the case of bridges, both the span and height have been increased, and several
studies have been conducted on piers and girder-supported bridges [
5
,
6
]. In the case of
a wind tower, the installation height of the turbine has been increased to obtain high-
quality wind, which increases the power generation efficiency; hence, the slenderness ratio
increases due to an increase in the tower height to support the wind turbine [
7
]. This
increase in slenderness can cause problems due to the reduced safety of the wind tower.
According to Ma et al., 48 tower accidents collapsed by various causes during the 16 years
since 2000 [8]. A wind turbine tower also broke by the buckling failure in 2019 [9,10].
Appl. Sci. 2021, 11, 4302. https://doi.org/10.3390/app11094302 https://www.mdpi.com/journal/applsci
