• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.673-673
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• 2015

Earthwork is an operation that provides space for structures, and it takes up a large portion of the construction costs in a construction project. In large-scale earthwork, numerous types of construction equipment are used in the operation. The types of equipment should be selected based on the field conditions and the construction methods. These construction vehicles are constantly changing positions during the earthwork operation. Therefore, the equipment operators require effective communication to ensure the efficiency of the earthwork operation. All equipment operators should exchange information with the other equipment operators. Information should be exchanged continuously to support decision making and increase productivity during the earthwork operation at the construction site. This paper investigates the attributes required for an information interface between construction vehicles during an earthwork operation. This paper 1) discusses the importance of an information interface for construction vehicles in order to increase productivity during an earthwork operation, 2) analyses the types of attributes that need to be communicated between construction vehicles, and 3) provides a database that has been built for attribute control. The database built for the information interface between construction vehicles will enhance communication between vehicle operators. Table I shows the typical attributes that should be shared between the excavator operator and the dump truck operator. This information needs to be shared among the operators, as it helps them to plan the earthwork operation in a more efficient manner. A database has been developed to store this information in an entity relation diagram. A user-interface display environment is also developed to provide this information to the operators in the construction vehicles. The proposed interface can help exchange information effectively and facilitate a common understanding during the earthwork operation. For example, the vehicle operators will be aware of the planned volume, excavated volume, transportation time, and transportation numbers. As a part of this study, mobile devices, such as mobile phones and google glasses, will be used as hands-on communication tools.

• 한국농공학회논문집
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• 제52권4호
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• pp.45-52
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• 2010

The purposes of this research are to analyze the internal settlement behavior of Concrete Faced Rockfill Dam (CFRD) typed 'D dam' and to evaluate the stability of the 'D dam' during dam construction using internal settlement measurements and results of numerical analysis. The field measurements were obtained during dam construction period. The numerical analysis was also carried out for the same construction period. The numerical analysis focused mainly on prediction of stress and displacement behavior of 'D dam' during dam construction stage using input parameters obtained from laboratory tests, i.e. large triaxial tests. The behavior of 'D dam' was evaluated to be stable from comparing the results of field measurements and numerical analysis. A simple empirical equation is also presented to predict final settlement at the completion of dam construction, using settlement measurement monitored during dam embankment.

• 한국건축시공학회지
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• 제6권4호
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• pp.77-83
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• 2006

The purpose of this study is to measure the straightness of prefounded columns during underground construction stages. There are several causes of an error of prefounded column: (1) columns connected by welding or bolting, (2) by placement of concrete and aggregates around columns, (3) movement during construction, and (4) load applied during construction. The error of column straightness is different for each column, and the tilting of columns is shown in one or two directions between floors. The additional loads caused by the error of straightness may give damage to buildings. This paper presents the measurement results of column straightness, and thus providing a basis for further analysis.

• 한국구조물진단유지관리공학회 논문집
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• 제5권3호
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• pp.191-201
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• 2001

In spite of the increasing construction of segmental PSC box girder bridges, the techniques associated with real-time monitoring, construction control and safety assessment during construction have been less developed compared with the construction techniques. Thus, the development of an integrated system including real-time measurement and monitoring, control and safety assessment system during construction is necessary fur more safe and precise construction of the bridges. This study presents a prototype integrated monitoring system for preventing abnormal behavior and accidents under construction stages, that consist of behavior control system for precise construction, reliability-based safety assessment system, and structural analysis. Also, a prototype software system is developed on the basis of the proposed model. It is successfully applied to the Sea-Hae Grand Bridge built by FCM. The integrated system model and software system can be utilized for the safe and precise construction of segmental PSC bridges during construction.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.492-499
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• 2022

A large number of employees shifted to Work from home (WFH) due to the COVID-19 pandemic, including the construction workforce. The changes in workload and productivity due to WFH impact the work performance and economic outputs of companies. However, there are mixed results about the impacts of WFH on workload and productivity. In particular, limited studies focused on specific types of work of different occupations in the construction workforce. This study aims to explore the impacts of WFH on workload and productivity considering different types of work for the construction workforce in the U.S. After identifying three main occupations and five types of work, an online survey (N = 69) was distributed. Descriptive analysis showed that participants had less workload (0.82 hours/week) and lower productivity (9.69%) during WFH. Three occupations had varied changes due to the different types of work. Analysis of Variance (ANOVA) indicated that there was no significant difference in workload, while productivity was decreased during WFH. In particular, the productivity of project-related work and communication and documentation decreased significantly. Overall, participants finished 2.85% less workload per week during WFH. The findings provide an insight into WFH in the construction workforce, which improves future remote or hybrid work arrangements in the construction industry.

• 건축역사연구
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• 제15권5호
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• pp.19-39
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• 2006

This study deals with construction contract bid-rigging by Japanese contractors who monopolized the construction market of the Korean Peninsula during the Japanese colonial rule, and investigates the abuses of the contract bid-rigging. First of all, construction contract bid-rigging in Korea was triggered by Japanese construction contractors and contract brokers, who had savored the benefits of bidrigging in Japan and had repeated the bid-rigging in Korea since 1903. Second, the agency played a significant role to mediate construction contractors, and existed throughout the Japanese colonial rule on the Korean Peninsula with changing their names. Most of them were engaged in major contract bid-rigging scandals. Among them was Construction Association of Korea, which existed for over 13 years. The agencies had took part in governmental services since the mid-1930s when Japan exploited Korean people during wartime, and focused on sweating human resources for the constructions. Third, one of the biggest construction bid-rigging scandals during the Japanese colonial rule was "the 1st and 2nd scandal on Daegu construction contract bid-rigging." Indeed, the second scandal paved the way for the serial scandals: "Kyeongseong construction contract bid-rigging scandal", "Busan construction contract bid-rigging scandal", and other cases throughout the nation. Fourth, along with the contract bid-rigging cases related to the Japanese Government-General of Korea and local authorities, bid-riggings firmly took rooted in local governments' farmland reclamation projects in the 1920s and the poor relief services in the 1930s. The "bid-rigging charges" forced contractors to compensate their losses with exploiting material costs and labor costs, generating serious problems. The construction contract bid-rigging enabled Japan to monopolize the construction industry and to sweat farmers on the Korean Peninsula. Against this backdrop, contract bid-rigging by Japanese construction contractors during the its colonization made Korean contractors ruled out, and helped Japanese monopolize the industry. A large amount of bid-rigging charges drove Japanese contractors to do fraudulent work with cheap materials and to exploit Korean labor force.

• Environmental Engineering Research
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• 제16권3호
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• pp.131-136
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• 2011

The degradation of 30 pharmaceuticals and personal care products (PPCPs) subjected to $O_3$, $O_3$/UV, and $O_3/H_2O_2$ treatments were investigated using semi-batch tests and evaluated by their pseudo-first-order rate constants. The additional application of UV or $H_2O_2$ during $O_3$ treatment significantly improved the degradation rate of most of the PPCPs. At the same $O_3$ feed rate, $O_3$/UV treatment exhibited much higher PPCP degradation efficiency than that of $O_3$ treatment. This was probably due to degradation of the PPCPs by $O_3$, direct UV photodegradation, and OH radicals that formed from the photodegradation of $O_3$ during $O_3$/UV treatment. PPCP degradation by $O_3$ was also promoted by adding $H_2O_2$ during the $O_3$ treatment. However, when the initial $H_2O_2$ concentration was high during $O_3$ treatment, OH radicals were likely to be scavenged by excess $H_2O_2$, leading to low PPCP degradation. Therefore, it is important to determine the appropriate $H_2O_2$ dosage during $O_3$ treatment to improve PPCP degradation when adding $H_2O_2$ during $O_3$ treatment.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.622-624
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• 2015

As uncertain factors are latent in a construction project by nature, a change order occurs frequently. The occurrence of change orders in construction projects conducted during construction phase is known to cause unexpected negative impacts such as cost overrun, schedule delay, quality problem, and claims in the post-process. Thus, an efficient management method is necessary to prevent and minimize change orders during construction phase when they occur frequently. This paper analyzed the causes of change orders and the impact factors that occur during the construction phase of a construction project and suggested a direction for change order database building.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.46-51
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• 2011

High-rise buildings are widely being constructed in the Middle-East, South-East, and East Asia. These buildings are usually willing to stand for the landmark of the region and, therefore, exhibit some extraordinary features such as super-tall height, elevation set-backs, overhangs, or free-form exterior surface, all of which makes the construction difficult, complex, and even unsafe at some construction stages. In addition to the elaborately planned construction sequence, prediction and monitoring of building's movement during construction and after completion are required for precise and safe construction. This is often called the Building Movement Control during construction. This study describes Building Movement Control of the KLCC Tower, a 58-story office building currently being built right next to the famous PETRONAS Twin Towers. The main items of the Building Movement Control for the KLCC Tower are axial shortening and verticality. Preliminary prediction of these items are already carried out by the structural design team but more accurate prediction based on construction stage analysis and combined with time-dependent material testing, field monitoring, and site survey is done by the main contractor. As of September 2010, the Tower is under construction at level 30, where the plan abruptly changes from rectangle to triangle. Findings and troubleshooting until the current construction stage are explained in detail and implementations are suggested for future applications.

• 한국조경학회지
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• 제25권2호
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• pp.43-53
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• 1997

The purpose of this study is to investigate the administrative system of landscape construction during Chosun-Dynasty. This study is based on the analysis of historic documents including the Codes and the Chronicles published during Chosun-Dynasty. The landscape construction controlled by government during Chosun-Dynasty was mainly undertaken by the government office titled "Seon-Gong-Gam" undr the Ministry of Industry. There were two functions of the "Seon-Gong-Gam" : one was construction including building and landscape, the other was the supply of materials and technicians to the field of constructino work. The construction function was carried out through government office titled "Cha-Mun-Gam" was in charge of the construction works of inside Chang-Dog Palace, while "Five Units" classified by work were responsible for the works of outside Chand-Dog palace in Han-Yang. In view point of the activities and responsibilities of the above two divisions, : "Cha-Mun-Gam" and "Five Units", it is concluded that one of the functions of "Seon-Gong-Gam" was to construct and manage the royal gardens.