• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2019년도 추계 학술논문 발표대회
• /
• pp.44-45
• /
• 2019

Tower cranes are essential equipments that play a key role in the overall process of large-scale construction projects, as well as high-rise apartments construction projects. Tower cranes hoist various loads near and over people, working in crowded environments, sometimes in overlapping work areas, and often under the constraints of time, budget, and labor. This work system further increases the safety risks of sites with inherently hazardous workplaces. The methodology of this research was based on a comprehensive inquiry of a team of experts, including safety managers and equipment managers of major construction companies and previous literature search. Due to the limited resources available to improve safety and prevent accidents, more attention should be paid to all parties involved in factors that have been evaluated to have a significant impact on site safety due to tower crane operations.

• 해양환경안전학회지
• /
• 제21권1호
• /
• pp.91-96
• /
• 2015

본 연구에서는 크레인 작업시 발생하는 재해발생 사례를 토대로 호이스트의 중량물 이탈 방지에 대한 연구를 수행하였으며, 안전고리의 결합으로 구성된 종래의 체결방식을 벗어나 구조물의 무게에 의한 자동 체결 및 결합 방식의 후크 및 특수목적을 가진 X-jog를 설계 및 제작하여 현장에 적용하고자 하였다. 주요 기구부의 3차원 상세설계와 구조해석을 통해 Safety Hook와 X-jog의 미소변형과 허용응력 이하의 구조안정성을 확인하였으며, 안전율은 일반적인 구조설계시 고려되는 안전율 1.2를 상회하는 평균 1.5를 나타냄을 확인하였다. 따라서, 본 연구에서의 Safety Hook와 X-jog는 구조물이 호이스트와 크레인에 부착되어 운용되어질시 구조적 안정성은 충분할 것으로 판단된다.

• 제어로봇시스템학회논문지
• /
• 제21권4호
• /
• pp.385-390
• /
• 2015

Quay cranes are considered core equipment for container terminal operation. However, unmanned operation systems have not as yet been announced due to the technological difficulties of implementation. In this paper, we developed a wireless controller to control a quay crane simulator remotely and conducted its performance test, a first step toward unmanned operation of quay cranes. The communication delay of a developed wireless controller was about 9.4ms on average while that of existing wired controllers was about 5.6ms. The same functions were implemented and tested on a smart phone where the average communication delay was 7.3ms. In addition, to apply the developed system into a real environment, we proposed a network architecture based on IEEE 802.11ac and carried out its performance evaluation. When the distance between two nodes was 50m apart, the throughputs of the TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) were 57Mbps and 189Mbps, respectively. The communication delay of the control data was 9.1ms through the TCP channel. These results reveal the proper working of remote quay crane operation if we adopt the IEEE 802.11ac network.

• 드라이브 ㆍ 컨트롤
• /
• 제14권2호
• /
• pp.9-15
• /
• 2017

The steering systems of all-terrain cranes have been developed with various control strategies for the stability and drivability. To optimally control the input steering angle, an accurate mathematical model that represents the actual crane dynamics is required. The derivation of an accurate mathematical model to optimally control the steering angle, however, is difficult since the steering-control strategy generally varies with the magnitude of the crane's longitudinal velocity, and the postures of the crane's working parts vary while it is being driven. To address this problem, this paper proposes an automatic steering-control algorithm that is based on the MPC (model predictive control) with a disturbance observer for all-terrain cranes. The designed disturbance observer of this study was used to estimate the error between the base steering model and the actual crane. A model predictive controller was used for the computation of the optimal steering angle, along with the use of the base steering model with an estimated uncertainty. Performance evaluations of the designed control algorithms were conducted based on a curved-path scenario in the Matlab/Simulink environment. The performance-evaluation results show a sound reference-path-tracking performance despite the large uncertainties.

• KIEAE Journal
• /
• 제7권6호
• /
• pp.99-106
• /
• 2007

Tower crane is a large construction equipment which is extremely tall for its section when it is erected, with its high slenderness ratio, and it has a heavy load by itself due to large lifting stuff to handle. In line with the construction projects in these days which increasingly tend to become higher, larger and complex, the stuff and height subject to lifting are also getting larger and higher, which has also increased the risk of disastrous accidents. A stable foundation design thus to deal with the increasing self load becomes more important. When a typhoon Maemi swept the nation in 2003, as many as 43 tower cranes fell down or collapsed, causing a severe damage to the people and the properties. Considering such fatal damages, a technical evaluation of the stability to prevent the safety accident with the tower crane must be very crucial. Tower cranes operation in domestic construction sites, in fact, have been simply dependent on personal experience and intuition of the engineers. Particularly when it comes to the foundation design, it mostly depends on manufacturer's recommendation. The study hence was intended to develop the fundamental measures for granting the objective stability, instead of following the individual's experience only. The simulation model recommended in the study is expected to make a good commitment to achieving an effective lifting work as well as preventing the safety accident.

• 드라이브 ㆍ 컨트롤
• /
• 제19권4호
• /
• pp.62-69
• /
• 2022

Construction machinery is exposed to accidents such as collisions, narrowness, and overturns during operation. In particular, mobile crane is operated only with the driver's vision and limited information of the assistant worker. Thus, there is a high risk of an accident. Recently, some collision avoidance device using sensors such as cameras and LiDAR have been applied. However, they are still insufficient to prevent collisions in the omnidirectional 3D space. In this study, a rotating LiDAR device was developed and applied to a 250-ton crane to obtain a full-space point cloud. An algorithm that could provide distance information and safety status to the driver was developed. Also, deep-learning segmentation algorithm was used to classify human-worker. The developed device could recognize obstacles within 100m of a 360-degree range. In the experiment, a safety distance was calculated with an error of 10.3cm at 30m to give the operator an accurate distance and collision alarm.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제10권1호
• /
• pp.95-102
• /
• 2018

This paper proposes a dual lifting and its cooperative control system with two different kinds of floating cranes. The Mega-erection and Giga-erection in the ship building are used to handle heavier and wider blocks and modules as ships and off-shore platforms are enlarged. However, there is no equipment to handle such Tera-blocks. In order to overcome the limit on performance of existing floating cranes, the dual lifting is proposed in this research. In the dual lifting, two floating cranes are well-coordinated to add up the lift capabilities of both cranes without any loss such that virtually a single crane is lifting, maneuvering and unloading. Two main constraints for the dual lifting are as follows: First, two barges of floating cranes should be constrained as a rigid body not to cause a relative motion between two barges and main hooks of the two cranes should be controlled as main hooks of a single crane. In order words, it is necessary to develop the cooperative control of two floating cranes in order to sustain a center of gravity of the module and minimize the tilting angle during the lifting and unloading by the two floating cranes. Two floating cranes are handled as a master-slave system. The master crane is able to gather information about all working conditions and make a decision to control the individual hook speed, which communicates the slave crane by TCP/IP. The developed control system has been embedded in the real floating crane systems and the dual lifting has been demonstrated five times at SHI shipyard in 2015. The moving angles of the lifting module are analyzed and verified to be suitable for hoisting control. It is verified that the dual lifting can be applied for many heavier and wider blocks and modules to shorten the construction time of ships and off-shore platforms.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2005년도 추계학술대회 논문집
• /
• pp.241-246
• /
• 2005

본 연구는 컨테이너 크레인이 강풍에 대비하여 크레인을 고정하는 계류 시에 75m/s의 풍하중이 50ton급 컨테이너 크레인에 작용될 때, 풍향변화와 기계실의 위치 변화가 50ton급 컨테이너 크레인의 구조적 안정성에 미치는 영향을 분석하였다.. 본 연구에 적용된 설계 풍하중은 "건축물 하중 기준"에 의거하여 산출하였으며. 풍향은 $0^{\circ}\~180^{\circ}$를 $15^{\circ}$ 간격으로 적용하여 각 지지점에서의 반력을 분석하였다. 그리고 전체 자중의 $15\%$를 차지하는 기계실의 위치 변화가 컨테이너 크레인의 구조 안정성에 미치는 영향을 분석하였다. 그리고 이 결과들을 바탕으로 컨테이너 크레인의 전도방지장치인 타이다운(Tie-down)의 설계기준을 제시하였다.

• 한국안전학회지
• /
• 제36권5호
• /
• pp.18-26
• /
• 2021

The effect of heavy construction equipment on the excavated slope is investigated by slope stability analysis. A mobile crane with 500 kN capacity is applied as a working load to the background surface of the excavated slope, in both sandy soil and clay, designed to guarantee the safety of slope stability. Major parameters such as the distance between the edge of the slope and the mobile crane, groundwater level, and ground plate size of the mobile crane are considered. Only 23.8% and 14.3% of the analysis models with sandy soil and clay excavated slope, respectively, satisfied the slope stability. By changing the slope of the sandy soil from 1:1.0 to 1:1.2, the number of analysis models securing slope stability increased from 23.8% to 40.5%. For the clay excavated slope, the analysis models securing slope stability increased from 14.3% to 42.9% by changing slope inclination from 1:0.8 to 1:1.2. In addition, it is found that the increase in the size of the ground plate of the mobile crane increases the analysis models that secure slope stability. Therefore, it is an effective way to relax the excavated slope's inclination angle and simultaneously increase the ground plate size to guarantee stability.

• 한국대기환경학회지
• /
• 제19권6호
• /
• pp.805-810
• /
• 2003

The annual air pollution emissions from construction and agricultural equipments were estimated from 1987 through 2000. The annual numbers and operation hours of 5 major construction equipments (Excavator, Bulldozer, Loader, Fork lift, Crane) and 3 major agricultural equipments (Power Tiller, Agricultural Tractor, Combine) were investigated for emission estimation. And monthly variation factors of operation hours of construction equipment were investigated too. The NO$_{x}$ emission from construction equipment have been gradually increased since 1987 to 1997, but sharply decreased as -45％ in 1998 due to economic crisis in Korea. The NO$_{x}$ emission was estimated as 64,300 ton/year from construction equipment, and as 23,300 ton/year from agricultural equipment in 2000.000.