• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.21-24
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• 2005

In this paper, field application of mass concrete using setting time difference of super retarding agent is reported to reduce hydration heat of concrete placed at newly constructed apartment house in Daejeon. Horizontal placing lift is applied. According to test results,: slump and air content meets the requirement of target values. For compressive strength, it exceeds the nominal strength ordered by the costumer. For temperature history, maximum temperature of center at top section shows $25.6^{\circ}C$, and at bottom section, $35.4^{\circ}C$. According to naked eye's investigation, no hydration heat crack is observed at the surface of concrete.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.289-289
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• 2000

In this paper, a new text-based method is suggested for the user-system interaction. The use of text-based user interface is mote efficient under situation which don't be introduced the GUI because of the limitation of hardware cost or improvement of system performance. The dialogical method using suggested hierarchical structure is the easier for a convenience of usage and the method in this paper is the more useful as considering knowledgeable background and environment of task for user As a practical example, the method for the proposed text-based user interface construction is applied to Double-Lift Open Shedding Electronic Jacquard.

• Journal of the Korean Professional Engineers Association
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• v.34 no.3
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• pp.64-67
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• 2001

In resent the weight of structure is heavier and bigger than before. Engineers use many heavy equipments to erect buildings and bridges. The heavy equipment is very useful to lift any weight. But most engineers do not know the impact of the weight when the equipment lifts the weight. In this study one researched into the impact of the weight in the crane work which lifts the weight in the construction site. Also along the number of pulley sheave the impact of the weight was researched. From the impact field test the impact coefficient of a single pulley sheave crane was 0.65 and the four pulley sheaves crane was 0.13. The result shows that the impact coefficient of a single pulley crane is more than 5 time of the impact coefficient of the four pulley sheaves crane and that engineers must consider the impact effect of the crane work in the construction site.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.114-115
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• 2019

Gangform is used as exterior wall forms in the most of apartments. Existing system forms developed for high-rise building, RCS and ACS, are too heavy and over-designed to be applied to general apartments, leading to higher costs. A more simplified rail Gangform(R/GF) is also used, but it depends entirely on T/C for the lift like Gangform. The T/C's legal inactivity time for moving Gangform and materials has increased, and the higher allowances have to be paid for overtime work, thus causing to the cost increase and time delay. Therefore, this study aims to develop an automated Gangform climbing system that can be used universally and economically in apartment houses. The use of the development system is expected to improve the safety of Gangform operations and reduce the workload on T/C.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.77-78
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• 2023

As large logistics buildings have high floor heights and long spans, these buildings are designed as PC structures, and large cranes are used to lift PC members. PC erection planning can generally cause errors depending on the field engineer's experience. To solve this problem, a basic analysis method is needed to establish a systematic PC member erection plan. Crane work can be minimized if the trajectory is easily and quickly calculated according to the location of the crane and applied to the site. Therefore, the objective of this study is a basic study of crane trajectory distance calculation for sustainable PC members erection of large logistic building. In this study, a crawler crane commonly used for lifting PC members is limited. The trajectory distance for the PC erection plan was automatically calculated using the algorithm.

• Journal of the Korean Geotechnical Society
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• v.38 no.4
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• pp.21-32
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• 2022

Steel pile foundations are widely used for offshore constructions due to their high bearing capacity and efficiency. Typically, offshore structures that have reached the end of their design life are required to be demolished. However, pile foundations are often left on site due to technical and economic limitations. The pile left on the site not only pollutes the environment, but can also cause obstacles for the construction of new structures. Therefore, research is required to completely eliminate these foundations at the site. In this study, a new type of double-wall pile foundation that can drastically reduce the pull-out load was conceptually proposed, and a series of model tests were performed to validate the performance of the double-wall pile foundation. The installation and extraction of the double-wall pile were simulated in dry sand in the model test, and the measured up-lift load was compared to that of the conventional pile. According to the result, the maximum up-lift load induced by the decommissioning of the double-wall pile was reduced by 45% when compared to the traditional pile in dense sand. This study verified the mechanism for reducing the up-lift load of the double-wall foundation and confirmed the possibility of completely decommissioning a pile that has reached the end of its nominal service life.

• Journal of the Korea Institute of Building Construction
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• v.14 no.6
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• pp.571-581
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• 2014

In the present study, hollow precast concrete wall (PC Double Wall) for staircase construction was developed. Comparing the conventional walls, the PC Double Wall can be reduced the lift weight using hollow core and improves the integrity between the PC members. The cross-section and re-bar details of the PC Double Wall were developed considering precast concrete manufacturing, constructability, and the structural safety. Particularly, a form system was developed to manufacture thin and hollow core PC wall efficiently. A mock-up test for a staircase using the PC Double wall was performed to verify the constructability and integrity of the PC walls. The test result verified that joint deformation and cracking did not occur as showing good constructability.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.593-596
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• 2006

Productivity is the most important factor directly link to success and failure of a work in construction industry. To evaluate this productivity, simulation technique is verified as a fine inspection tool through various experiment reports. On this project, we have proved the part of improvement on productivity using this simulation technique, applied to this field sites. We have used CYCLONE, which is the most appropriate simulation technique on this project. As a result of Simulation analysis, it has been confirmed that the productivity was enhanced due to the advancement of equipment, hence the reduction of air is being effected.

• KIEAE Journal
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• v.7 no.6
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• pp.99-106
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• 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.

• Journal of Drive and Control
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• v.16 no.2
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• pp.8-14
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• 2019

A typical gantry crane is generally used to lift and transport objects in various workplaces. Most of the supporting structures in a gantry crane are fixed on the ground while the moving hoist is running overhead along the girder. There are some disadvantages to its long installation time and high installation cost. Therefore, a hydraulic based gantry crane was studied to solve the issues of typical gantry cranes. The supporting structure of the proposed gantry crane consisted of a hydraulic cylinder and telescopic boom. The dimension of the proposed gantry crane can be decreased due to its simplified structure. The analytical and theoretical methods were used to verify the structural stability of the proposed crane. The most severe load condition was considered for the analysis, and the stress and deflection of the structure are analyzed. The simulation results were as expected from the theoretical analysis. Finally, the structural and dynamic safety of the proposed hydraulic based gantry crane was validated. The obtained results can be used as guidelines in the design process of the hydraulic based gantry crane.