• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.4
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• pp.396-403
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• 2016

Objectives: The study is to evaluate biological monitoring and risk assessment for epichlorohydrin-bisphenol A resin exposed from waterproofing or finishing work in the apartment building construction. Methods: Subjected workers were working on spray-painting and waterproofing work for 8 hours per day every 20 days. The urine samples were collected at the end of 20 days working period. For urinary bisphenol A as metabolite from epichlorohydrin-bisphenol A exposure, urine samples were analyzed with liquid chromatography mass-mass spectrometry(HPLC-MS/MS). Results: Geometric means of urinary bisphenol A(BPA) with no hydrolysis and with enzymic hydrolysis(BPA-EH) in the workers were $1.10{\mu}g/L$ and $2.90{\mu}g/L$. BPA-EH was 4 times higher than that of control group. The factors for working period and ages did not affect the variation of BPA and BPA-EH. The levels for BPA and BPA-EH were not higher than 95th percentile for exposure on human-life environment. Conclusions: The BPA and BPA-EH were therefore effective biological markers for epichlorohydrin-bisphenol A exposure workers, but not seem to hazardous exposure level. Waterproofing work in construction workshop is required to measuring work environment and health care management for the workers.

• Nuclear Engineering and Technology
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• v.47 no.3
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• pp.362-379
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• 2015

In this study, Nuclear Power Plant (NPP) construction schedule delay risk assessment methodology is developed and the construction delay risk is assessed for turnkey international NPP projects. Three levels of delay factors were selected through literature review and discussions with nuclear industry experts. A questionnaire survey was conducted on the basis of an analytic hierarchy process (AHP) and Relative Importance Index (RII) methods and the schedule delay risk is assessed qualitatively and quantitatively by severity and frequency of occurrence of delay factors. This study assigns four main delay factors to the first level: main contractor, utility, regulatory authority, and financial and country factor. The second and the third levels are designed with 12 sub-factors and 32 sub-sub-factors, respectively. This study finds the top five most important sub-sub-factors, which are as follows: policy changes, political instability and public intervention; uncompromising regulatory criteria and licensing documents conflicting with existing regulations; robust design document review procedures; redesign due to errors in design and design changes; and worldwide shortage of qualified and experienced nuclear specific equipment manufacturers. The proposed combined AHP-RII methodology is capable of assessing delay risk effectively and efficiently. Decision makers can apply risk informed decision making to avoid unexpected construction delays of NPPs.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.8
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• pp.556-562
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• 2008

The building HVAC systems have very different qualities of performance and durability with the superintendent's ability for management and maintenance. The poor management of these systems finally lead to the shortening of the life expectancy and result in the increase of operating costs and energy consumptions due to low efficiencies. This study presents an example of appropriate use of the LCC(Life Cycle Cost) analysis in a process of maintaining and repairing old HVAC equipments, by demonstrating the difference of optimal economic life, decrease of running cost, and energy consumption according to the management level of the HVAC equipments. But there are no reliable life expectancy and performance history data at present for optimal management of various building service equipments. Therefore, it is necessary to construct long-term database on operation results of them for more accurate and optimized LCC analysis.

• International Journal of High-Rise Buildings
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• v.6 no.1
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• pp.83-89
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• 2017

Due to the time-dependent properties of materials, structures, and loads, accurate time-dependent effects analysis and precise construction controls are very significant for rational analysis and design and saving project cost. Elevation control is an important part of the time-dependent construction control in supertall structures. Since supertall structures have numerous floors, heavy loads, long construction times, demanding processes, and are typically located in the soft coastal soil areas, both the time-dependent features of superstructure and settlement are very obvious. By using the time-dependent coupling effect analysis method, this paper compares Shanghai Tower's vertical deformation calculation and elevation control scheme, considering foundation differential settlement. The results show that the foundation differential settlement cannot be ignored in vertical deformation calculations and elevation control for supertall structures. The impact of foundation differential settlement for elevation compensation and pre-adjustment length can be divided into direct and indirect effects. Meanwhile, in the engineering practice of elevation control for supertall structures, it is recommended to adopt the multi-level elevation control method with relative elevation control and design elevation control, without considering the overall settlement in the construction process.

• Management & Information Systems Review
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• v.19
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• pp.145-170
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• 2006

The purpose of this study is to examine the relationship between core factor of Knowledge Management(KM) and organizational effectiveness. The objects of study are middle manager in hosing construction and civil engineering and construction industry, and the sample size is 228. The core factor of KM and indicator of organizational effectiveness are drawn by literature survey. The core factors are classified into human capital, organizational capital, structural capital, (to put it concretely), job capability, human relation, strategy, information technology, process, sharing culture, leadership, measurement. The indicator of organizational effectiveness are measured by job satisfaction, organization loyalty, competitiveness. The main results of this study can be summarized as the following. 1) The core factor of KM has a positive relationship to organizational effectiveness. Especially, the core factor of sharing culture and leadership are strongly relationship with organizational effectiveness. 2) There was a high positive correlation between job satisfaction and organization loyalty. 3) Human, structural, and structural capital had a different affect on organizational effectiveness. 4) The more job position and educational level high, the more they recognized that KM is necessary for their organization. 5) Among the success factor in KM, the factor of job capability was well perceived to respondent. According to this study, we can analyzed the relationship between success factor and organizational effectiveness, and drawn the most influence success factor on organizational effectiveness. Concurrently, the results of this study will be useful guidelines for shaping the KM operation framework in construction industry.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.75-79
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• 2006

Recently, more highly effective construction materials are needed for the reasonable and economical structure system is required as the construction structures become more multi storied, large-sized and diversified. That is to say, the highly qualified concrete is positively promoted as a part of plan to establish the effective space according to the dead load of structures and diminish of segment profile and to build up the economic structures. However, the high strength concrete has the problems such high brittleness and low ductility. Specially, for the high strength concrete, it has different strength from normal concrete as the internal temperature goes up steadily due to high heat of hydration by the quantities of highly level of cement, so the concrete which is mixed with various miscible materials is used. As the development and study for high strength concrete (more than $100N/mm^2$) is under way actively and the strength of high strength concrete increases, the strength different from the existing high strength concrete of ten than $100N/mm^2$, but the study for this is not adequate and indefinite. In addition, the study and report to apply the strength expression and analysis results of internal structure. Therefore, this study is an experiment about using the miscible materials affects what happens to the longitudinal physical property.

• International Journal of High-Rise Buildings
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• v.4 no.3
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• pp.191-198
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• 2015

It is important to accurately predict structural responses to external excitations such as typhoons and earthquakes when designing structures for serviceability. One of the key procedures to predict reliable vibration responses is to evaluate accurate structural dynamic properties using finite element (FE) models, which properly represent the realistic behavior of buildings. In the case of historic masonry buildings, structural damage could also be caused by ambient vibrations or impacts. Therefore, the preservation plans of historic buildings for low-level vibrations or impacts should be provided by analyzing structural damages within serviceability levels. For this purpose, it is required to provide FE model construction and response analysis methods verified with field measurement data. In this research, long-term field measurement was performed for a cathedral and its dynamic properties were evaluated using measured data. Then, the model was calibrated based on the measured dynamic properties and an overall construction method for the masonry cathedral was proposed. Using the measured accelerations, the vibrations of the belfry were analyzed using the calibrated FE model and finally, the FE model for the cathedral was verified by comparing the measured accelerations with the modeled results.

• Structural Engineering and Mechanics
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• v.43 no.1
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• pp.31-51
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• 2012

This paper presents a computational study that explores the design of rigid steel frames by considering construction related costs. More specifically, two different aspects are investigated in this study focusing on the effects of (a) reducing the number of labor intensive rigid connections within a frame of given geometric layout, and (b) reducing the number of different member section types used in the frame. A genetic algorithm based optimization framework searches design space for these objectives. Unlike some studies that express connection cost as a factor of the entire frame weight, here connections and their associated cost factors are explicitly represented at the member level to evaluate the cost of connections associated with each beam. In addition, because variety in member section types can drive up construction related costs, its effects are evaluated implicitly by generating curves that show the trade off between cost and different numbers of section types used within the frame. Our results show that designs in which all connections are considered to be rigid can be excessively conservative: rigid connections can often be eliminated without any appreciable increase in frame weight, resulting in a reduction in overall cost. Eliminating additional rigid connections leads to further reductions in cost, even as frame weight increases, up to a certain point. These complex relationships between overall cost, rigid connections, and member section types are presented for a representative five-story steel frame.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.179-182
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• 2013

Many kinds of fire-stop sealants have been used for joint sealing, cable penetration part sealing and fireproof structure finishing etc in building sectors which need water-proofing and fire-stop properties. But, fire-stop sealant itself has no specific industry standards in Korea even though there are so many required properties for the application. So, in this study, for the evaluation, we adopted and applied UL standard 94(UL 94) which is commonly used for the fire retardant testing in inflammable materials like plastics and rubbers in electronics industry. In this study, we demonstrated fire resistance properties of each fire-stop sealants which varied with different formulation, thickness and origins available in Korea. Overall, fire stop sealant had better fire resistance performance than normal construction sealant. And the thicker the material, the better the fire resistance performance was. Because there is no national or industry guideline for fire stop sealant itself, each sealant products showed different level of performances under UL94 desigation. Even certain product had very poor fire proof propeties although it claims it can be used for the application.

• Korean Journal of Construction Engineering and Management
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• v.5 no.2 s.18
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• pp.144-152
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• 2004

Defining value as a measure of how well the project value objectives are met, Value Management Process (VMP) is considered to be any management effort or process that can proactively pursue one or more project objectives (i.e., security/safety, cost effectiveness, schedule optimization, and risk containment). The collection of 44 VMPs has been established based on a rigorous effort conducted by Construction Industry Institute (CII). Because varying circumstances on each project determine the level of suitability, it is crucial to identify which VMP should be implemented on a particular project. The current VMP selection process is primarily based on human intuition. The main objective of this paper is to provide a systematic method to facilitate the usage of VMPs on a particular project. This paper identified and quantified the selection principles (i.e., targeted value objectives, timing of initiation, project characteristics, and relative impact). The data collected from industry practitioners and VMP experts characterized each VMP in terms of the magnitude of benefit. An automated selection tool by Visual Basic Application (VBA) on MS Excel TM, was developed and proved its validity. As a pioneering study, this paper provides a comprehensive and structured knowledge on the subject of VMPs. From the industry's perspective, the automated selection tool, the premier of this study, contributes the facilitation of the VMP implementations in the construction industry thereby maximizing the potential benefits to a particular project.