• 제목/요약/키워드: change construction design

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Thrice Repair Works and Three Space Conceptions in Seokguram - focusing on Seokguram Architecture and Virtual Space Division of Inside and Outside - (석굴암, 세 번의 수리 공사와 세 개의 공간 개념 - 석굴암 건축과 안팎의 공간 구분을 중심으로 -)

  • Yoon, Chae-Shin
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.35 no.8
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    • pp.89-100
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    • 2019
  • The purpose of this study is to critically review the repair works of Seokguram architecture and to search for its original form and space. Seokguram's architectural form has been transformed throughout three repair works. The first transformation occurred during the repair work of the Colonial Government in 1913-1915, and the second occurred during the repair work of the Colonial Government in 1920-1923. The repair work done by the Korean Government in 1961-1964 also caused a severe change in the architectural form and space of Seokguram architecture. The more the repair work was added to Seokguram, the more its original form flew away like a mirage. Through the three repair works, the spatial composition of Seokguram changed in the following directions: from ((front chamber + passageway) + main chamber) to (front chamber + (passageway + main chamber)) through the second repair work, from (front chamber + (passageway + main chamber)) to (front chamber + passageway + main chamber) through the last repair work. Although the compositional space hierarchy of Seokguram was maintained during the first repair work, the architectural form based on the dry method was changed to the form based on the wet method. The Korean government's repair work was a tragedy for the 'Seokguram conservation project' that the people who led the conservation process misunderstood the architectural nature of Seokguram.

Prediction model for electric power consumption of seawater desalination based on machine learning by seawater quality change in future (장래 해수수질 변화에 따른 머신러닝 기반 해수담수 전력비 예측 모형 개발)

  • Shim, Kyudae;Ko, Young-Hee
    • Journal of Korea Water Resources Association
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    • v.54 no.spc1
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    • pp.1023-1035
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    • 2021
  • The electricity cost of a desalination facility was also predicted and reviewed, which allowed the proposed model to be incorporated into the future design of such facilities. Input data from 2003 to 2014 of the Korea Hydrographic and Oceanographic Agency (KHOA) were used, and the structure of the model was determined using the trial and error method to analyze as well as hyperparameters such as salinity and seawater temperature. The future seawater quality was estimated by optimizing the prediction model based on machine learning. Results indicated that the seawater temperature would be similar to the existing pattern, and salinity showed a gradual decrease in the maximum value from the past measurement data. Therefore, it was reviewed that the electricity cost for seawater desalination decreased by approximately 0.80% and a process configuration was determined to be necessary. This study aimed at establishing a machine-learning-based prediction model to predict future water quality changes, reviewed the impact on the scale of seawater desalination facilities, and suggested alternatives.

Interaction Analysis between Waves and Caissons by Damping Zone Effect for Installing New Caisson on Old Caisson Breakwater (기존 케이슨방파제에 신규 케이슨 추가설치 시 댐핑존 영향에 따른 유체와 케이슨들간의 상호작용 평가)

  • Park, Min Su;Kim, Young Taek;Park, Sangki;Min, Jiyoung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.34 no.5
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    • pp.156-168
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    • 2022
  • The design and construction are carried out to improve the structural stability of caisson breakwaters by installing new caissons on the front or rear of old caissons. The wave forces acting on caisson are excessively calculated by the resonance of fluid existing between the old caisson and the new caisson in the numerical analysis using potential flow. In this study, we used the damping zone option in ANSYS AQWA program to analyze the wave forces acting on individual caissons according to the interaction effects between the incident wave and the caisson. By applying the damping zone option to the fluid in which resonance occurs, the wave forces acting on individual caissons were calculated by the change of damping factor. In addition, the wave force characteristics acting on individual caissons were analyzed for the different distances between caissons in the frequency domain analysis.

Digital Twin Model Design And Implementation Using UBS Process Data (UBS공정 데이터를 활용한 디지털트윈 모델 설계 및 구현)

  • Park, Seon-Hui;Bae, Jong-Hwan;Ko, Ho-Jeong
    • Journal of Internet of Things and Convergence
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    • v.8 no.3
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    • pp.63-68
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    • 2022
  • Due to COVID-19, many paradigm shifts in existing manufacturing facilities and the expansion of non-face-to-face services are accelerating worldwide. A representative technology is digital twin technology. Such digital twin technology, which existed only conceptually in the past, has recently become feasible with the construction of a 5G-based network. Accordingly, this paper designed and implemented a part of the USB process to enable digital twins based on OPC UA communication, which is a standard interlocking structure, between real object objects and virtual reality-based USB process in accordance with this paradigm change. By reflecting the physical characteristics of real objects together, it is possible to simulate real-time synchronization of these with real objects. In the future, this can be applied to various industrial fields, and it is expected that it will be possible to reduce costs for decision-making and prevent dangerous accidents.

Numerical Analysis on Drained and Undrained Pullout Capacity in Reinforced Soil (보강토에서의 배수 및 비배수 인발력에 대한 수치해석)

  • Lee, Hong-Sung;Son, Moo-Rak
    • Journal of the Korean Geotechnical Society
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    • v.23 no.4
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    • pp.113-123
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    • 2007
  • In order to ensure the stability of reinforced structures backfilled with low permeability soil, it is very important to determine the change in undrained pullout capacity compared to drained pullout capacity prior to design. In this research, a series of numerical analyses on laboratory pullout tests have been performed on different materials (clean sand, 5, 10, and 15% silty sand), different overburden pressures (30, 100 and 200 kPa), and different drainage conditions (drained and undrained) in order to compare drained pullout capacity with undrained pullout capacity. The results of numerical analysis also have been compared with the results of the laboratory pullout tests. The analysis results show that both drained and undrained pullout capacity are influenced by silt contents and increase with increase of friction angle of the soil and overburden pressure. In undrained condition, the effective stresses acting on the reinforcement decrease as excessive pore pressures are generated, resulting in decrease in pullout capacity; 57% for 30 kPa, and 70% for 100 and 200 kPa. These results show a good agreement with the results of the laboratory pullout tests performed under the same condition.

The effect of in-situ stress parameters and metamorphism on the geomechanical and mineralogical behavior of tunnel rocks

  • Kadir Karaman
    • Geomechanics and Engineering
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    • v.37 no.3
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    • pp.213-222
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    • 2024
  • Determination of jointed rock mass properties plays a significant role in the design and construction of underground structures such as tunneling and mining. Rock mass classification systems such as Rock Mass Rating (RMR), Rock Mass Index (RMi), Rock Mass Quality (Q), and deformation modulus (Em) are determined from the jointed rock masses. However, parameters of jointed rock masses can be affected by the tunnel depth below the surface due to the effect of the in situ stresses. In addition, the geomechanical properties of rocks change due to the effect of metamorphism. Therefore, the main objective of this study is to apply correlation analysis to investigate the relationships between rock mass properties and some parameters related to the depth of the tunnel studied. For this purpose, the field work consisted of determining rock mass parameters in a tunnel alignment (~7.1 km) at varying depths from 21 m to 431 m below ground surface. At the same excavation depths, thirty-seven rock types were also sampled and tested in the laboratory. Correlations were made between vertical stress and depth, horizontal/vertical stress ratio (k) and depth, k and Em, k and RMi, k and point load index (PLI), k and Brazilian tensile strength (BTS), Em and uniaxial compressive strength (UCS), UCS and PLI, UCS and BTS. Relationships were significant (significance level=0.000) at the confidence interval of 95% (r = 0.77-0.88) between the data pairs for the rocks taken from depths greater than 166 m where the ratio of horizontal to vertical stress is between 0.6 and 1.2. The in-situ stress parameters affected rock mass properties as well as metamorphism which affected the geomechanical properties of rock materials by affecting the behavior of minerals and textures within rocks. This study revealed that in-situ stress parameters and metamorphism should be reviewed when tunnel studies are carried out.

Effects of hygro-thermal environment on dynamic responses of variable thickness functionally graded porous microplates

  • Quoc-Hoa Pham;Phu-Cuong Nguyen;Van-Ke Tran
    • Steel and Composite Structures
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    • v.50 no.5
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    • pp.563-581
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    • 2024
  • This paper presents a novel finite element model for the free vibration analysis of variable-thickness functionally graded porous (FGP) microplates resting on Pasternak's medium in the hygro-thermal environment. The governing equations are established according to refined higher-order shear deformation plate theory (RPT) in construction with the modified couple stress theory. For the first time, three-node triangular elements with twelve degrees of freedom for each node are developed based on Hermitian interpolation functions to describe the in-plane displacements and transverse displacements of microplates. Two laws of variable thickness of FGP microplates, including the linear law and the nonlinear law in the x-direction are investigated. Effects of thermal and moisture changes on microplates are assumed to vary continuously from the bottom surface to the top surface and only cause tension loads in the plane, which does not change the material's mechanical properties. The numerical results of this work are compared with those of published data to verify the accuracy and reliability of the proposed method. In addition, the parameter study is conducted to explore the effects of geometrical and material properties such as the changing law of the thickness, length-scale parameter, and the parameters of the porosity, temperature, and humidity on the free vibration response of variable thickness FGP microplates. These results can be applied to design of microelectromechanical structures in practice.

Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014 (설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.7
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

A Experimental Study on the Structural Performance of Column Spliceswith Metal Touch Subjected to Axial Force and Bending Moment (압축력과 휨모멘트를 받는 메탈 터치된 기둥 이음부의 구조성능에 대한 실험적 연구)

  • Hong, Kap Pyo;Kim, Seok Koo;Lee, Joong Won
    • Journal of Korean Society of Steel Construction
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    • v.20 no.5
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    • pp.633-644
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    • 2008
  • The structural framework design uses high-strength bolts and welding in column splices. However, for the column under high compression, the number of the required high-strength bolts can be excessive and the increase of welding results in difficulty of quality inspection, the transformation of the structural steels, and the increase of erection time. According to the AISC criteria, when columns have bearing plates, or they are finished to bear at splices, there shall be sufficient connections to hold all parts securely in place. The Korean standard sets the maximum 25% of the load as criteria. Using direct contact makes it possible to transfer all compressive force through it. The objective of this study is to examine the generally applied stress path mechanism of welded or bolted columns and to verify the bending moment and compression transfer mechanism of the column splice according to metal touch precision. For this study,22 specimens of various geometric shapes were constructed according to the change in the variables for each column splice type, which includes the splice method, gap width, gap axis, presence or absence of splice material, and connector type. The results show that the application of each splice can be improved through the examination of the stress path mechanism upon metal contact. Moreover, the revision of the relative local code on direct contact needs to be reviewed properly for the economics and efficiency of the splices.

An Experimental Study on a Performance Evaluation of Internal Insulation of Buildings Over 20 Years Old (20년 이상 경과된 노후건축물의 단열재 성능평가에 관한 실험적 연구)

  • Kim, Hyun-Jin;Choi, Se-Jin
    • Journal of the Korea Institute of Building Construction
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    • v.19 no.6
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    • pp.539-547
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    • 2019
  • Recently, the international community signed a climate change agreement to prevent global warming. Yet currently, the fossil fuels have been widely used in to supply building energy for cooling and heating. The Green Building certification (G-SEED), an energy efficiency rating for new or existing buildings requires that buildings meet certain conditions. Insulation is used as a building material to reduce the energy supply to buildings and to improve the thermal insulation, and it accounts for more than 90% of the total heat resistance provided by the building surface components that meet the energy-saving design standards of new buildings. In this investigation, a performance evaluation study was conducted through an experimental study by directly extracting the foam polystyrene insulation on-site during the remodeling of a building that was in the range of 22~38 years old. Through tests, it was found that the thermal conductivity of the extrusion method insulation (XPS) was reduced by 48% and the compressive strength of XPS decreased by 36% compared to KS M 3808, which is the initial quality standard. For bead method insulation (EPS) with a thickness of 50mm, the thermal conductivity, the compressive strength, and flexural failure load were similar to the initial quality standard. Therefore, in the calculation of the primary energy requirement per unit area per year, the performance of bead method insulation can be estimated simply by considering the thickness of the insulation, while a correction factor that considers its performance deterioration should be applied when extrusion method insulation is used.