Article
Safety Assessment for Upper Part of Floating Crane
Considering Minimum Luffing Angle
Min-Woo Lee
1
, Ji-Hyun Lee
2
, Yeon-Seung Lee
3
, Hyun-Jin Park
4
and Tak-Kee Lee
5,
*
Citation: Lee, M.-W.; Lee, J.-H.; Lee,
Y.-S.; Park, H.-J.; Lee, T.-K. Safety
Assessment for Upper Part of
Floating Crane Considering
Minimum Luffing Angle. Appl. Sci.
2021, 11, 5104. https://doi.org/
10.3390/app11115104
Academic Editor: João Carlos de
Oliveira Matias
Received: 7 April 2021
Accepted: 27 May 2021
Published: 31 May 2021
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4.0/).
1
Dong-Ah Geological Engineering Inc., Busan 46235, Korea; clicklee7@naver.com
2
Samwon Millennia Inc., Yongin 17095, Korea; jhlee@cae.co.kr
3
Department of Naval Architecture & Ocean Engineering, Hongik University, Sejong 30016, Korea;
yslee132@hongik.ac.kr
4
Department of Ocean System Engineering, Graduate School, Gyeongsang National University,
Tongyeong 53064, Korea; hyunjinpark@gnu.ac.kr
5
Department of Naval Architecture & Ocean Engineering, Gyeongsang National University,
Tongyeong 53064, Korea
* Correspondence: tklee@gnu.ac.kr; Tel.: +82-55-772-9193
Abstract:
Floating cranes are used for the construction and installation work of harbors, various
heavy industries, and offshore structures. In the case of floating cranes that need to move around the
work site, their navigation can be constrained due to marine bridges. In some cases, the clearance
under the bridge between the water surface and the bottom of the marine bridge may be too low,
and floating cranes cannot pass under the marine bridge. In this study, the height of the marine
bridges and the boom height of the floating cranes considering the minimum luffing angle were
investigated. Through minimizing the boom luffing angle of the floating crane by the height of back
tower, a floating crane with improved mobility through marine bridges was developed. A structural
analysis model was produced to check whether the developed crane design satisfies the design criteria
obeying the KR, DNVGL, and ABS rules, including luffing condition as a special consideration. As a
result of the structural analyses, structural safety was validated for the service, stowage, and luffing
conditions in terms of combined stresses, displacements, and buckling.
Keywords: floating crane; safety assessment; safe working load; luffing condition
1. Introduction
“Crane” is a machine that applies repeated motion within a constant work space for
the purpose of hoisting and transportation by using hook or other attachments [
1
]. These
cranes lift and move relatively heavy objects, so it can be exposed to a number of accidents
during operation. Shepherd et al. [
2
] investigated more than 500 crane-related accidents
in the United States from 1985 to 1995; then, they grouped related data and analyzed the
patterns. King et al. [
3
] also investigated 75 crane accidents in North America from 2004 to
2010 and used the survey results to strengthen crane safety programs and improve industry
standards. Recently, Milazzo et al. [
4
] analyzed hundreds of worldwide crane accident data
records in different industrial fields. According to their investigation and analysis, most
of the accidents are due to impacts between the load and the crane or objects, which are
often caused by a limited or poor visibility of the surrounding workspace from the crane
operator point of view. So, they said that the crane navigation system has a great potential
for safety improvement.
Studies were also conducted to quantify the degree of risk according to the type of risk,
such as the case of a crane falling or a falling object hitting the crane. This quantified risk
assessment was used for the purpose of prioritizing risk reduction measures [5]. Ancione
et al. [
6
] had been proposed for the integration of dynamic features into the risk assessment
procedure by taking into account the interaction between the plant activity and crane
Appl. Sci. 2021, 11, 5104. https://doi.org/10.3390/app11115104 https://www.mdpi.com/journal/applsci
