• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.213-221
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• 2022

Defects are the risk factors in the construction process of buildings. They cause damage, delaying the construction duration. They especially cause adverse effects on the top-down construction method. This study analyzed the degree of construction delay induced by each work type, focusing on defects in the top-down method. Then, we derived construction delay induction coefficient from different work types in order by using the severity of construction delay per defect and the occurrence probability of defect; this assessment model measures the impact of defects on construction delay for each work type. Furthermore, by comparing each work type based on the defect frequency and the construction delay induction coefficient, we found work types that need to be administered attentively. We identified that plastering work was easy to overlook, requiring caution in defect management. This study provides an efficient defect management system suitable for the buildings that are built using the top-down construction method.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.499-502
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• 2005

Nowadays, the stripping work of form has generated some problems such as increasing total constructing cost result from delayed work schedule by the stripping work of form and environmental issues by wasting the debonded form. According to recent research for form work, it has studied about permanent form to solve economic and environmental problem which is commented above. In this study, high performance permanent form method was developed and tested by adopting COM and TEN specimens adopted on the Compression and Tensile section then the structural behaviour was investigated. In the test result, the specimen adopted the form showed better structural performance than control specimen in the point of ductility, failure mode and ultimate load.

• 한국건설관리학회논문집
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• 제17권3호
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• pp.116-124
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• 2016

건설현장의 주요 작업인 토공사의 경우, 토공 건설장비를 운용하는 개별 작업자에 의해서 작업의 효율성이 좌우되기 때문에 개별 작업자의 숙련도가 전체적인 공사일정에 큰 영향을 미칠 수 있다. 건설현장에는 그 특성상 현장 내 설치된 구조물이나 장비 혹은 움직이는 작업자들이나 장비 등으로 인해 시야가 가려져서 발생하게 되는 비가시 영역이 필연적으로 존재한다. 이와 같은 작업 관련 시각정보의 부재는 작업자가 건설장비를 효율적으로 운용하는데 있어서 결정적인 저해요소가 된다. 증강현실(AR, Augmented Reality)은 현실세계에 가상물체를 중첩시켜 보여주는 컴퓨터 기술이다. 이 기술의 특성을 이용하면 토공사를 수행하는 과정에서의 시각정보 부재 문제를 해결할 수 있고 이를 통한 건설장비의 작업 효율성 향상이 가능하다. 본 연구의 목적은 이러한 토공사에서의 필요 시각정보를 도출하기 위한 작업-시각정보 맵을 제시하고 굴삭기의 작업들 중 AR기술을 적용하기에 적합한 것을 찾아내는 것이다. 연구의 대상이 되는 건설장비는 굴삭기로 한정하였다. 작업-시각정보 맵은 굴삭기 토공작업의 문제점과 그 문제점을 해결하는데 필요한 시각정보를 기반으로 하여 작성되었다. 이 맵으로부터 굴삭기의 작업 효율성을 향상시킬 수 있고, AR기술을 적용하기에도 적합한 4가지 필요 시각정보가 도출되었다. 연구결과를 바탕으로 하여 추후 건설장비 AR 네비게이터 시스템을 더욱 효과적으로 개발할 수 있을 것이라 기대한다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1117-1121
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• 2010

Several isotropic compression-expansion tests and a series of drained conventional traxial tests with various confining pressures for relative density of Beakma river sand 25%, 50%, 80% and 100% selecting Lade's Single Work-Hardening constitutive model. This examination materials use regression analysis as a basis, depending on the relative density of soil parameters change statement attributes. Yield fuction represent the soil parameters h and $\alpha$ is not affected by the changes in the relative density. $\eta_1$ could be replaced by fomula. And Numerical analysis results predicted very good and could confirm that.

• Journal of Construction Engineering and Project Management
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• 제2권4호
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• pp.42-45
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• 2012

In construction industry, the term 'procurement' is considered as a project based job where clients and contractors are always keen to observe performance indicators. These indicators represent financial and non-financial efficiency of project activities. Among these, the monitoring of financial indicators such as cost monitoring is an ongoing process and its importance cannot be undermined during the project life cycle. It can be monitored by using traditional approach of direct reporting of actual cost against budget. However, the comparison of budget versus actual spending does not indicate the worth of the work which is completed at any given time. This approach does not represent the true cost performance of the project. Because of these limitations, this paper discusses the applications of Earned Value Analysis (EVA) for cost monitoring of construction projects in Malaysia. Besides traditional approach, EVA is a three-dimensional approach that compares three cost indicators i.e. the budgeted value of work scheduled with the earned value of physical work completed and the actual cost of work completed. Therefore, cost monitoring by EVA is an objective measure of actual work performed. This paper uses a case study, an example application of EVA as a cost monitoring tool. This case study reaffirms the benefits of using EVA for project cash flow analysis and forecasting.

• Earthquakes and Structures
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• 제16권5호
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• pp.547-561
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• 2019

In this work, a new analytical approach using a theory of a high order hyperbolic shear deformation theory (HSDT) has been developed to study the free vibration of plates of functionally graduated material (FGM). This theory takes into account the effect of stretching the thickness. In contrast to other conventional shear deformation theories, the present work includes a new displacement field that introduces indeterminate integral variables. During the manufacturing process of these plates defects can appear as porosity. The latter can question and modify the global behavior of such plates. The materials constituting the plate are assumed to be gradually variable in the direction of height according to a simple power law distribution in terms of the volume fractions of the constituents. The motion equations are derived by the Hamilton principle. Analytical solutions for free vibration analysis are obtained for simply supported plates. The effects of stretching, the porosity parameter, the power law index and the length / thickness ratio on the fundamental frequencies of the FGM plates are studied in detail.

• Geomechanics and Engineering
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• 제13권2호
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• pp.217-235
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• 2017

The stability prediction of shallow buried tunnels is one of the most difficult tasks in civil engineering. The aim of this work is to predict the state of collapse in shallow tunnel in layered soils by employing non-associated flow rule and nonlinear failure criterion within the framework of upper bound theorem. Particular emphasis is first given to consider the effects of dilation on the collapse mechanism of shallow tunnel. Furthermore, the seepage forces and surface settlement are considered to analyze the influence of different dilation coefficients on the collapse shape. Two different curve functions which describe two different soil layers are obtained by virtual work equations under the variational principle. The distinct characteristics of falling blocks up and down the water level are discussed in the present work. According to the numerical results, the potential collapse range decreases with the increase of the dilation coefficient. In layered soils, both of the single layer's dilation coefficient and two layers' dilation coefficients increase, the range of the potential collapse block reduces.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.952-959
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• 2022

Active construction work zones will result in longer travel time and/or longer travel distances for road users because of reduced speed limits and/or detours. This results in increased fuel consumption and increased emissions of harmful gases such as Carbon Monoxide (CO), Nitrogen Oxides (NOx), and Sulfur Oxides (SOx), which causes discomfort to the environment and road users around the work zone. The impact of such emissions should be considered while designing work zones or determining the number of days the roadway will be allowed to be closed partially or fully. This study develops a methodology to compute additional road user costs associated with such work zones. To achieve this goal, a) an extensive literature review is conducted, b) a framework to compute emission cost is developed, c) emission rates are computed for all counties (95) of the state of Tennessee, and d) a case study is conducted to demonstrate the use of the framework to estimate the additional impact of emission because of the work zone. For the case study conducted, the emission cost was computed to be $10,653.60 for the duration of the project. State DOTs can account for such road user costs while selecting contractors using A+B bidding. Accounting for such impact of emission will also indicate the agency's willingness to consider sustainability as a part of the business practices.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.205-209
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• 2015

A significant amount of data including ongoing construction activities, work quantities, resources utilized by contractors, and site conditions is collected in highway construction sites on a daily basis by resident engineers. This data is commonly known as daily work reports (DWRs) in the U.S. Although a lot of time and effort is invested in collecting the DWR data, its utilization has been very limited. This paper discusses current practices of collecting and utilizing DWR data among various Departments of Transportation in the U.S., and discusses the challenges and opportunities for better collection and utilization of the data. An extensive literature review and two nationwide surveys in the U.S. were conducted as a part of this study. Finally, it provides a set of recommendations to effectively address the challenges identified and maximize the benefits of utilizing DWR data such as supporting various decisions for highway project development process. The findings of this study are implementable ideas that can aid DOTs in making data-driven decisions throughout the project development processes in the future.

• 한국건설관리학회논문집
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• 제18권5호
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• pp.32-40
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• 2017

최근 국내 건설산업은 성장의 시기를 지나 침체기로 접어들고 있으며 경쟁력 향상을 위해 건설사업관리 특히 공정관리의 중요성이 더욱 부각되고 있다. 이러한 상황에 토목 건설업계는 생존을 위한 다양한 공사관리 방안의 연구 및 현장 적용에 부단한 노력을 하고 있으며 많은 성과를 이루고 있으나 아직도 체계적이며 효율적이고 현장 활용도가 높은 공정관리 기법의 정착은 이루어지지 못하고 있다. 이에 본 연구에서는 공사관리의 핵심인 공정관리의 활용에 대해 설문조사방식으로 현장기술자들의 인식 및 이해의 정도를 파악하며 현장에서 실제 사용하고 있는 공정표의 작성수준과 활용 현황을 파악을 위해 방문 조사하여 현재 국내 공정관리 현주소 및 문제점을 파악하였다. 아울러, 기존문헌 및 연구논문의 고찰, 현장에의 적용성을 바탕으로 현장 활용성이 높은 WBS 분류에서부터 work pacckage 도출과 Activty도출, 공정표 작성 및 관리방안을 제안하였다.