• Journal of the Korea Institute of Building Construction
• /
• v.10 no.3
• /
• pp.65-70
• /
• 2010

Steel frame construction in high places entails many risk factors. In order to improve the safety and productivity of steel frame construction, a project to develop a robotic tower-crane has been undertaken. As the first step, a real-time lifting-path tracking system is being developed. In a previous study, a laser-based tracking system was proposed. While a laser-based tracking system requires at least three laser sensors to detect the x, y, z coordinates of a lifted steel member, a GPS-based system has an advantage over the laser-based system, in that the x, y, z coordinates of a lifted steel member can be detected by a single GPS sensor. To improve the accuracy, arelative positioning method using two GPS sensors was proposed in a previous study. This paper reports an improved GPS-based lifting-path tracking system of a tower crane based on an integrated RF modem and GPS system. The results showedthat the RF modem could successfully send the identifier information to a server a maximum distance of 1 km away from the lifted steel beam, and the lifting path information of each beam captured by the GPS-based tracking system was successfully saved together. Also, byusing an improved algorithm for the GPS relative positioning method, the deviation was reduced to 0.61 m on average.

• Journal of the Korean Society of Safety
• /
• v.36 no.1
• /
• pp.9-17
• /
• 2021

This study analyses the load imbalance of the tower crane used in telescoping work for structural safety, owing to the difference in wind speed and balance weight position. This is because wind speed and position of the balance weight have a significant impact on the structural stresses of a tower crane during telescoping work. Therefore, structural analysis was performed on the 290HC model, which is often used at construction sites and has only one cylinder installed. Moreover, two models were classified to determine the load acting on the connecting part of the telescopic cage to slewing platform and the cylinder. Five types of balance weight positions were applied at regular intervals from jibs; moreover, four types of wind load criteria were differently applied. Hence, the telescopic cage columns were destroyed at all balance weight positions at a wind speed of 30 m/s and only at certain locations at a wind speed of 20 m/s. Furthermore, failures occurred for cylinders, torsional, and bending at wind speeds of 30 m/s and 20 m/s, load imbalances above the allowable thresholds considering the safety factor. In addition, the load imbalance in the telescoping work also varied depending on the position of the balance weights. The results of these studies have validated that the current standards of adjusting the appropriate position of the balance weights on the jib are completely valid, with the telescoping work to be executed only at wind speeds of less than equal to 10 m/s.

• Journal of the Korea Institute of Building Construction
• /
• v.7 no.3
• /
• pp.115-122
• /
• 2007

As buildings become higher, larger, and more complex, safety issues for construction workers working at such environments become more important. We analyzed 83 critical accident cases reported to the KOSHA(Korea Occupational Safety & Health Agency) for construction cranes by types of cranes and by patterns of accidents and causes. There are more number of accidents related to mobile cranes than that related to tower cranes, but the numbers of dead were similar in both cases. The most dominant cause of crane accidents was "fall of materials". We also analyzed the cases of crane accidents using the FMEA(Failure Mode and Effect Analysis) in order to set up a priority for safety management and also to prioritize research and development items relating tower cranes. In the process, we tried to eliminate subjective indexes such as an expert group survey and use objective and quantitative indexes. As a result, it was found that critical crane accidents occurs most during the "lifting and translating" activity.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2011.11a
• /
• pp.145-146
• /
• 2011

Lifting plan in conjunction with the overall construction plan will be established. It is being created by executive director of the Corporation and other such as an experienced site manager. But, written lifting plan based on the limited information and experience is causing some problems such as decreasing productivity, workability loss, delay. The reasons for the problems are lack of prediction of construction execution, inappropriate materials on the past performance, individual experience, limits of knowledge, lack of technical materials, shortage of advisor. Therefore, to solve the problems, we have to overcome the situation in which we depends on lifting planner's experience and intuition, limited information by accumulating objective and reliable materials. Because unorganized lifting plan will lower efficiency of lifting equipment and make reducing construction period difficult. In this study, influence factors on lifting plans will be derived through reviewing literatures and lifting plan cases. Derived influence factors will be classified as components and classes, classified influence factors are assessed suitability. Also, Decision making items are derived from the factors. Finally, tower crane lifting plan process will be suggested from the result.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2004.11a
• /
• pp.472-475
• /
• 2004

The objective of this study is to develope reasonably accurate prediction models to assess hoisting times of tower cranes in the high-rise building construction. The efficient use of the tower crane is critical to achieving the Planned floor cycle time. This research describes the derivation of mathematical models to predict the hoisting times in using a tower crane. 28 factors such as nature of load, characteristics of tower cranes, hoisting movements, operation of cranes, weather conditions and so on is considered to influence hoisting times. In order to develop the predicting hoisting times Correctly, it is divided hoisting upward and downward. Then multiple regression models for predicting supply and return hoisting times have been built up separately.

• Journal of the Korea Institute of Building Construction
• /
• v.9 no.6
• /
• pp.131-139
• /
• 2009

It is critical to select the appropriate type of tower cranes for the construction of super tall buildings. However the selection is often made based on subjective personal experiences due to the lack of historical and analytical data. As a result, planning mistakes and efficiency errors sometimes occur. This research is to develop a system of hoisting analysis for appropriate tower crane selection and to provide a flexible statistical model based on the Burj Dubai project. In addition, this system hassupporting functions that can estimate the target construction period per floor, and a decision-making construction period computation method which is based on the characteristic of the selected tower cranes.

• Journal of the Korea Institute of Building Construction
• /
• v.5 no.4 s.18
• /
• pp.121-130
• /
• 2005

A systematic hoisting planning for tower crane is the most important elements in highrise building construction. However without sufficient data, systematic approach, it is not with ease to produce an appropriate planning at the rite. Therefore, this research aims at developing a systematic hoisting planning system in visual graphic with systematic procedure. The result of this research is that developed system on hoisting load calculation, numbers and specification of tower cranes are graphically visualized easily at the site. The study of applying this system to real project proves that it presents a sufficient capability as a useful tool in the hoisting planning of highrise building projects.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2004.05a
• /
• pp.42-47
• /
• 2004

This paper describes basic structural design for the large floating crane barge of fixed undulation type. Structural analysis is performed to divide two parts because crane barge is composed two parts, crane part of jib boom back stay and back tower and barge part to support crane part. The structural strength for jib boom structure members are in compliance with JIS B 8821 and scantling of all barge structural members are in compliance with the requirement of KR (Korean Register of Shipping) Steel Barges and Rules for Classification of Steel Ships. For the structural analysis of large floating crane, MSC/NASTRAN & MSC/PATRAN software is used.

• Journal of Ocean Engineering and Technology
• /
• v.19 no.1 s.62
• /
• pp.71-76
• /
• 2005

This paper describes basic structural design for the large floating crane barge of fixed undulation type. Structural analysis was performed separately after dividing the floating crane into two parts, The crane part was composed of jib boom, back stay and back tower and the barge part supported the crane part. The structural strength for jib boom structural members are in compliance with JIS B 8821 and scantling of all barge structural members are in compliance with the requirement of KR (Korean Register of Shipping) Steel Barges and Rules for Classification of Steel Ships. For the structural analysis of large floating crane, MSC/NASTRAN and MSC/PATRAN software were used.

• Korean Journal of Construction Engineering and Management
• /
• v.13 no.4
• /
• pp.48-59
• /
• 2012

Gangform, compared to the traditional forms, is a systemized form which can reduce construction duration and cost by the advantage of using it repeatedly. However, transportation and climbing process of the Gangform is highly dependant on the performance of tower crane. Gangform climbing process takes one day out of six to seven days of a structural work cycle. Tower cranes can not be used in other lifting works when they lift the Gangform during the structural work cycle, causing the delay in the construction project. Numerous efforts and researches have been done in domestic and international industry to solve such limitations of Gangform climbing process. Especially, "A Study on the Development of Automatic Gangform Climbing System for Apartment Housing Construction"has suggested a conceptual model which can climb the Gangform system without a tower crane. In this paper, the technical and economical feasibilities of previously proposed Automatic Gangform climbing system are examined by evaluating its structural stability and lifting load reduction effect.