• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.296-300
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• 2004

As a building aged, overall performance considering structural safety, equipment safety and fire safety is lowering gradually. Since the building performance and the overall value of the building change as time elapse, exact safety performance of the building should be evaluated not only maintaining the building efficiently and also preventing disputes between buyer and seller of the building. We suggest major elements for assessing building's safety performance through surveying literatures, interviewing experts, reviewing existing assessment models, The assessment elements proposed here ate comprised of structural safety, equipment safety, fire safety, fire protection and fire escape, etc. This study helps to make a safety performance assessment criteria for a building.

• Korean Journal of Construction Engineering and Management
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• v.24 no.1
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• pp.3-11
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• 2023

According to the post evaluation scheme in Korea of a public construction project which is more than 30 Billion KRW, project performance is evaluated by investigating outcomes and effects of the construction after the completion of the project. The current post evaluation results can be used for planning and estimating a construction project in the future. However, it is not easy to utilized for an on-going project because the system does not provide the phase-based performance of a project. Although project planning performance is important for project initiation, few attempt has been made to evaluate planning performance in Korea. The purpose of this study is to provide a conceptual performance evaluation of planning performance using preliminary feasibility study conducted by Korea Development Institute. This study developed a planning performance database using data extracted from preliminary feasibility study reports of the completed 354 road construction projects. This study analyzed the performance of the planning stage of road projects by developing absolute metrics such as standard construction cost and standard construction schedule based on a Lane-Km. Using the standard construction cost and schedule metrics, the planning performance was analyzed by project characteristics. The results of this study can be used for phase-based performance evaluation from planning phase to construction phase.

• Journal of the Korean Geotechnical Society
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• v.23 no.10
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• pp.133-150
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• 2007

This paper presents the results of a research performed to investigate the finite element modeling approach for GESC (Geogrid-Encased Stone Column) method in soft ground within the framework of stress-pore pressure coupled analysis. GESC reinforcement mechanism and construction method was first examined and model verification of stone column on the results of FE analysis was identified. The results indicate that the 3D FE analysis and membrane elements play the most important role in the soft groung using GESC. Based on the results, a modeling method was suggested for stress-pore pressure coupled finite element modelling of GESC in soft ground.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.89-89
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• 2021

부영양화된 호수나 유속이 느린 하천에서 발생하는 녹조의 과도한 발생은 하천 생태계 훼손, 동식물의 건강, 담수의 오염 등 환경 사회 경제적으로 큰 피해를 준다. 현재 수질 측정망은 정해진 지점에서 Chlorophyll-a(Chl-a), Phycocyanin(PC)을 대표농도로 산정하고 조류경보에 활용하고 있으나, 일주일에 한번씩 샘플링을 통해 Chl-a 및 PC를 측정하여 시공간적인 신뢰성의 문제가 제기될 수 있다. 본 연구에서는 기존 점단위 조류 모니터링의 한계점을 개선하기 위해 초분광영상 자료를 머신러닝 기법에 적용하여 Chl-a 및 PC 산정 알고리즘을 개발하였다. 이를 위해 Chl-a와 PC의 최대 흡수, 반사 파장대, 주요 물 흡수 파장대 자료를 조합하여 9개의 파장비를 구축하였으며, 기존 연구에서 활용한 머신러닝 기법인 Partial Least Square, Random Forest, Gradient Boosting, Support Vector Machine, K-Nearest Neighbor, Artificial Neural Network를 검토하여 최적 모델을 선정하였다. 학습된 머신러닝의 성능을 R², NSE, RMSE 목적함수를 이용해 평가하였으며, 그 결과 ANN이 각각 PC 0.801, 0.755, 11.774 mg/m³, Chl-a 0.733, 0.622, 8.736 mg/m³로 가장 우수한 성능을 보였다. 최적화 된 ANN 모델을 백제보 상류 2016-2017년 항공 초분광영상에 적용하여 시공간에 따른 조류 분포변화를 평가하고자 한다.

• Korean Journal of Construction Engineering and Management
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• v.21 no.6
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• pp.84-94
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• 2020

Modular architecture is very important not only in the design phase but also in the construction planning phase because it affects construction methods and module sizes depending on transport equipment. There are economic risks as well as quality, as there may be defects such as internal interiors or elimination of deadlines during transportation, and structural torsion caused by rainfall and shock. However, there is a lack of objective criteria or data to refer to in determining transport equipment that has a material effect on transport. Accordingly, there is no decision model to determine the optimum transportation equipment for each construction site. Therefore, it is necessary to develop a decision support model that can be compared to the review of transport equipment selection factors. The purpose of this study is to propose the transport equipment impact factors and decision support models for systematic review and objective decision making of each construction plan in the construction of small and medium-sized modulators. The decision model proposed in this study can be used as basic data for transport studies, ensuring objectivity and transparency in the equipment selection process.

• Korean Journal of Construction Engineering and Management
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• v.1 no.1 s.1
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• pp.72-79
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• 2000

Design quality in constructed project is a primary consideration to achieve overall project objectives. It is not easy to evaluate the design quality because various factors are involved in the design process. This paper presents a new approach to improve the evaluation process of design quality In the construction project The evaluation model is developed to satisfy the requirement for implementing the ISO 9000 Quality Assurance Standards in the design process. It is assumed that design changes are resulted from the poor management of design quality. The model relates design changes to design quality management items. It assigns weight ratio to each design quality item to evaluate quantitatively Design Quality Index (DQI) is calculated to assess design quality based on the Objectives Matrix. A case study is performed to illustrate the practical implementation of the design quality evaluation.

• The Journal of Engineering Geology
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• v.23 no.3
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• pp.227-234
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• 2013

The vertical shaft of a selective intake structure, which is constructed in a large reservoir, is required to be impermeable and to employ a grouting technology to prevent water inflow from the reservoir or surrounding ground. In this study, groundwater inflow is estimated using a numerical model for two cases (i.e., grouting or non-grouting cases at the exterior of a vertical shaft) and compared with data measured during an excavation at the construction site of a selective intake structure in the Soyang reservoir, Korea. Groundwater inflow is estimated to range from 444 to 754 $m^3/d$ in the case of non-grouting and from 58 to 95 $m^3/d$ in the case of grouting. The groundwater inflow measured in a vertical shaft, which ranges from 30 to 100 $m^3/d$, is similar to the simulated amount. It is recommended that before the excavation of a shaft, water inflow is estimated using a numerical model and a grouting test to ensure excavation stability and improve excavation efficiency.

• Journal of the Korean Geotechnical Society
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• v.32 no.2
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• pp.5-17
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• 2016

Collapse of a tunnel can occur anytime, anywhere due to the special characteristics of tunnel structures and unexpected geological conditions during construction. Tunnel collapse will lead to economic losses and casualties. So various studies are continually being conducted to prevent economic losses, casualties and accidents. In this study, we analyzed data from 56 domestic construction tunnel collapse sites, and input factors to be applied to the artificial neural network were selected by the sensitivity analysis. And for the artificial neural network model design studies were carried out with the selected input factors and optimized ANN model to predict the type of tunnel collapse was determined. By using it, in 12 sites where tunnel collapse occurred applicability evaluation was conducted. Thus, the tunnel collapse type predictability was verified. These results will be able to be used as basic data for preventing and reinforcing collapse in the tunnel construction site.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.6
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• pp.665-674
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• 2015

A TSL (Thin Spray-on Liner) which consists of polymers has a higher initial strength, faster construction time and higher waterproofing performance than the conventional cementitious shotcrete. Main supporting mechanism of TSL is the adhesion and tensile strength which is distinct from the conventional shotcrete. Even though highly in demand due to its outstanding characteristics, TSL is not yet well-known support material. In this study, to evaluate contact behavior of TSL, numerical analysis was performed with comparing result from laboratory tests. From the analysis, cohesive behavior at the contact surface between TSL and rock can be evaluated by using combination of cohesive and the damage model. In addition, results show that the cohesive stiffness controled slope between force and displacement, the fracture energy controled level of force at the contact.

• Journal of Korean Society of Steel Construction
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• v.27 no.5
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• pp.435-445
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• 2015

Concrete filled steel tube(CFT), which has superior ductility and strength, is used for building column, bridge piers of ocean structure. Shear design equations of CFT existing in structural design provisions are excessively conservative. It has an effect on constructability and the economics of CFT. However, to suggest the reasonable shear design equation, experimental studies on the shear capacity of CFT have been rarely conducted. This study is analytical research to suggest improved shear design equations of large-diameter concrete-filled steel tubes. This analytical research was conducted to apply finite element analysis model of CFT based on the prior research. It was verified by comparison with prior test results. The verified model was used for parameter studies to estimate the influence of overhang length, concrete compressive strength and diameter-thickness ratio on shear strength.