Proceedings of the Korean Institute of Building Construction Conference (한국건축시공학회:학술대회논문집)
The Korean Institute of Building Construction
- Semi Annual
Domain
- Construction/Transportation > Construction Engineering/Materials/Management
2013.05a
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An assessment tool's validity is crucial because its scores are used as basis of decision making. This study assessed the content validity of the indicators for environmental assessment of construction activities. Pool of candidate indicators were constituted from the literature review, and CVR(Content Validity Rate) approach was adopted to investigate the content validity. As a result, 14 indicators are effective and five of them are content valid and retained from the pool.
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Green Frame is a column-beam system formed by composite precast concrete column and beam connected with steel buried in both members. During the installation of Green columns, the columns of Green Frame, covering 3 floors per each piece and beams, the eccentricity can be observed due to the construction error and the weight of beam itself. Such eccentricity may have a little influence on a single frame, yet, it can develop critical issues to the installation of subsequent beams or beams on the upper floors in the context of a building as a whole that has multiple frames. These issues lead to delay in frame installation, decrease of productivity and increase of cost, etc. Therefore, this study presents a steel-joint connection method in order to solve the issues. The steel-joint connection method exists on slope plane and reinforcing plate in steel frame buried in composite PC members. Through this method, the issues can be resolved without requiring additional equipment or manpower.
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Free-form building is increasing because of request that an order to raise the value and request of the local residents and the government trying to own iconic and beautiful buildings. In addition, the installation and production of free-form concrete segment are now available because of development of construction technology, such as the development of materials and equipment. However, the production of free-form concrete segment requires a lot of time and manpower than shaping. In particular, resources of the mold for the production of free-from segment will be invested excessively because mold can not be recycled. Thus, the problems of increased costs, construction periods and loss of productivity occur. To solve these problems, this study proposes a technique of making the mold of for variable within a short time. Technique proposed in this study can be recycled die and will realize fast and accurate free-form concrete segment.
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Green Frame is precast concrete column-beam structure. There are three types on column connection. The coupler type which is one of the three, need to be improved because of unstability caused by pre-installation of column before casting the slab, and quality deterioration caused by lack of workspace. Therefore, in this study, new coupler connection type with thread rebar is suggested. The result of this study shall be used for the efficiency analysis of the new coupler connection.
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A fire outbreak in a reinforcement concrete structure looses the organism by different contraction and expansion of hardened cement pastes and aggregate, and causes cracks by thermal stress, leading to the deterioration of the durability. So, concrete reinforcement structure is damaged partial or whole structure system. Therefore accurate diagnosis of deterioration is needed based on mechanism of fire deterioration in general concrete structures. Fundamental information and data on the properties of concrete exposed to high temperature are necessary for accurate diagnosis of deterioration. In this study, consider case of investigation methods and repair work in fire damaged structure concrete.
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Green Frame is a column-beam system constructed by composite precast column and beam connected by embedded steel of their. From when the precast concrete beam of Green Frame is installed, until the concrete of slab and connection joint is cured, the self load of beam shall be supported by the embedded steel of it. Therefore, the concrete of beam could be separated from the embedded steel if the shear connector of beam of Green Frame is designed by the code on Structural standard. So, this study suggest an equation for the shear connection of composite precast concrete beams of Green Frame. The result of this study will be used as the main equation of the calculation model for shear connectors of composite precast concrete beams.
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Construction industry has become higher, larger and more complicated. Construction projects demand precise planning and management prior and during actual operation. However, it has been analyzed that the process planning in the construction site has been made by the site engineer experience mostly that usually results in unreliable results. Numerous studies in this field have been conducted trying to solve such problems developing methodologies to suggest quantitative results. It has been analyzed that many studies have focused on limited data only and neglected suggesting an appropriate methodology for changing data applications. Therefore, this study suggests a methodology that effectively manages construction productivity by applying bayesian approach focusing on the high-rise curtain wall operations.
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This study aims to investigate cases of using FDS fire investigation performed in a foreign country, use of FDS for the fire investigation to present the plan to clean up the problems and ways to improve future domestic. To be applied to the fire investigation establish the model of fire growth and domestic situation analysis through case studies and examples of this foreign, domestic flammable thermal characteristics data for exterior and interior windows and on the thermal properties of the experimental the purpose is to improve.
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This study investigates the effect of a protective layer on the level of carbonation resistance of concrete. For the protective layer, a PE film, bubble sheets, double layered bubble sheets and styroform were placed in a mold before placing the concrete. In addition, PE film was retrofitted by attaching on the surface of the substrate concrete with a glue. Results showed that the carbonation depths of the control concrete were 4.6 mm and 5.2 mm at one week and two weeks exposure in an accelerated carbonation chamber, whereas the concrete with all types of protective layer except PE flim did not allow the ingress of carbon dioxide during the same period.
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Steel corrosion is the most serious problem in RC structures. Even though patch repair method is normally applied in repair system, the effectiveness is not enough. Cathodic protection in active repair method to deteriorated RC structures. FEM model was developed to simulate the optimized cathodic protection condition. Iro oxidation, hydrogen evolution and oxygen reduction were considered to expect current distribution. Moisture content in concrete which can affect the electrolyte conductivity was used as initial condition.
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ThThe purpose of this study is to investigate the compressive strength properties of fly ash using water eluted from recycled coarse aggregate. When fly ash come into contact with water, they have not a autonomously chemical reaction. But fly ash is a pozzolan reaction when fly ash come into contact with water and calcium hydroxide(Ca(OH)2) in alkaline environment. For that reason, if water eluted from recycled coarse aggregate use mixture water, fly ash is expected to reaction of pozzolan reaction property in early stage. According to the experimentation result, ICP-MS analysis showed water eluted from recycled coarse aggregate has a high alkali-ash value of pH of 12 and over. And mixing ratio 30% fly ash mortar using water eluted from recycled coarse aggregate showed a similar strength of plain mortar due to the pozzolan reaction. Also, poor strength in initial age, disadvantage of mortar using fly ash, can be improved as hydration in early age is expedited due to calcium hydroxide(Ca(OH)2) and unhydrated cement component eluted from recycled aggregate mortar.
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Recently, as the policy of state that it is the low carbon green growth is promoted, the effort for reducing the CO2 gas generation ejected from the construction industry in the cement production is continued. That is, the method using the mineral admixtures including the silica fume and red mud, silica fume and etc. it is the industrial byproduct with the method solving the exhaustion problem of the environmental contamination settlement and natural resources, the great quantity as the cement substitute material is examined. Accordingly, in this research, the strength characteristic of the curing body differentiating the curing method of the ternary system inorganic binder using the blast furnace slag and red mud, silica fume and etc. as the cement substitute material tried to be examined.
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Electric arc furnace oxidizing slag from massively produced steel slag has been used in road bases and subbases, hot mix asphalt, and landfill. Electric arc furnace oxidizing slag contains iron (15%~30%) and has a high density of 3.0~3.7 ton/m3. Depending on the type and amount of concrete aggregates, the radiation-shielding characteristics can vary. Therefore, aggregates of electric arc furnace oxidizing slag can be considered for the production of radiation-shielding concrete. The experimental design of this study is experiments on Compressive strength experiments, X-ray irradiation experiments, and experiments related to the unit volume weight were carried out on hardened concrete. This experiment compared the performance evaluation of radiation shielding of concrete using electric arc furnace oxidizing slag.
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The fine powder obtained from the manufacturing process of recycled coarse aggregate contains unhydareted cement particles on their surface. It is believed that the alkalinity of the powder (11.0-12.5) is enough to active the slag-based composites. In this paper, the obtained powder was sieved and divided into two sizes, i.e., 0.08 mm and 0.3 mm, and added to the slag-based mortar. Results showed that the fine powder had an effect on the slump and the compressive strength of slag-based composites. With the different pH values of the powder, it could be seen that the distance between the two level powders. And found the peak 28 days compressive strength as the replacement ratio of the recycled aggregate powder changed. The findings from this study provide an indication that with achieved compressive strength, the fine powder can be used in a light weight concrete.
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The purpose of this study is to obtain basic data for making performance criteria about the structural safety of lightweight dry wall later by examining types and characteristics of horizontal load acting on the wall. The subjects applying horizontal load to the wall are human and objects. The types of horizontal load are classified as static load and dynamic load depending on the difference of acting time. The magnitude of horizontal load "0.25kN/㎡" defined by KBC 2009 has no significant meaning since it is the unsubstantial nominal load. The result of examining types and characteristics of horizontal load is as follows. (1) Static load by human needs to have more systematic investigation including differences in wall hardness and human weight. (2) Dynamic load by human needs to raise the significance of study result by increasing the number of subjects. (3) Dynamic load by objects needs to accumulate the load specific data for various load subjects considering real situations.
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This study investigates the effect of a grading of aggregate on the properties of concrete. It is a common sense in Korea that the production of coarse aggregate in ready mixed concrete industry excludes particular aggregate size ranged from 5 mm to 13 mm for saving the production cost. This causes a gap grading of the aggregate for concrete, which can lead to the increase of unit water, the development of drying shrinkage-induced crack and the reduction of compressive strength. In this study, conventional aggregate obtained from a ready mixed concrete factory and the aggregate with a modified grading produced in lab. condition were prepared. Results showed that a good grading of aggregate (i.e., the ratio of 5~13 mm and 13~25 mm is 6 to 4) produced in the lab. condition significantly improved the slump and the compressive strength of the concrete.
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In this study, Car fire for test using ISO 9705 10MW Large Scale Calorimeter. Especially, study on the underground parking for the fire resistance performance. The underground parking lot of the fire resistance regulations in according to with the standard heating curve in Korea. Because of this burning car through experiments to the propose a new heating curve.
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Generally, Adiabatic temperature rise and temperature rise rate are reported to increases when placement temperature, W/B and the unit water content is fixed. In this study, properties of adiabatic temperature rise on placement temperature consider the hot weather environments from of W/B 0.29, 0.34, 0.40 was reviewed, the amount of cement on mixing condition of the same W/B and unit water content evaluated on the impact of the adiabatic temperature rise. As a results, the adiabatic temperature rise of concrete is proportionate to binder as well as the cement content under the same unit water content.
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Nitrite-Type hydrocalumite (calumite) is a material that can provied a self-corrosion inhibition function to the reinforce concrete. In this study, bisphnol A·F type epoxy-midified mortars without hardner contaning calumite is prepared with various polimer-binder ratios, calumite contents and tow types of curing condition, and tested for flexural and compressive strength tensile strength and corrosion-inhibition. As a result, in the case of wet/dry curing condition, strengths of bisphnol A·F type epoxy-modified mortars without hardener contaning calumite is inclined to decrease with increasing of polymer-binder ratio and calumite content. However, dry cured specimens are slightly improved by using bisphnol A·F type epoxy resin. Finally, regardless of polymer-binder ratios and calumite contents, corrosion-inhibition of bisphnol A·F type epoxy-modified mortars without hardener containing calumite is superior than that of unmodified mortar.
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In order to develop concrete generating compressive strength of 15MPa~30MPa aging for 6~12 hours in the room temperature curing, Hardening accelerator containing Ca2+ mixed with rapid hardening portland cement containing C3S in quantity. The result was that the more addictive contents of Hardening accelerator is, the more greatly early compressive strength was improved. That s because the composition of Ca(OH)2 was mass-produced at early-ages.
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The purpose of this study was to present the necessary data concerning the selection and development of floor-coverings in view of slipperiness by comparing the relationship between CSR measured with O-Y·PSM and RCOF calculated from the result of gait analysis. CSR was calculated from maximum tensile load(Pmax) divided by perpendicular load(785N) when pulled 18 degrees upward the moment the bottom of the slip piece contacted the surface of the test piece. RCOF was calculated based on Fy/Fz from when horizontal load reached the maximum point within the sections from the moment the front of outsole touched the test piece to when pulled off the test piece. The results from the research were as follows: (1) Range of CSR was 0.15-1.02, which meant the differences of slipperiness of the test pieces definitely showed up. (2) RCOF are inadequate to express the characteristic about the slipperiness of the floors, since there were no differences between the test pieces.
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As a result of executing Cone Calorimeter experiment on 12 samples among combustibles of domestic residential facilities, flooring materials showed higher HRR and THR than wall papers, and in case of toxicity and SPR, wall papers having adhesive components in one side by considering use conveniences were measured high.
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In this paper, the compressive strength of an insulating gang form member, which was developed to improve the cold weather concreting quality, and a general gang form member was measured by age to examine the compressive strength characteristics of the two members compared with the standard curing test piece.
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This is an foundational study to adequacy the non-destruction testing for the estimation of compressive strength of high strength concrete The results are as follows, In high strength concrete, H type is NR type rebound number rather than higher. The relation between rebound number and compressive strength of high strength concrete have lower coefficient. when compressive strength estimation of high strength concrete, it consider that rebound hardness test is not applied and should be consider to combined method or addition method.
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This study investigates the effect of the diameters of reinforcement bars located in an euro-form before placing concrete in a cold weather condition. The diameters of reinforcement bars with 13 mm, 19 mm, 25 mm and 32 mm were prepared for the experimental tests. Results showed that the larger the size of the diameter of the bars, the higher were the temperature drop. However, this study found that its effect on the temperature drop of the bars was insignificant.
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In this study, we examined the properties of the concrete for the adsorption of carbon dioxide by adding in photosynthetic bacteria. As for the experimental plan, we measured slump, carbon dioxide concentration and compressive strength. The findings revealed the non-plastic cement added with photosynthetic bacteria had the greatest flexibility and showed carbon dioxide absorption and condensation delay due to the sugar constituents of photosynthetic bacteria. Giver the progress in the studies on the strength development, it is estimated to be used as CO2 reduction concrete.
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In this study, the characteristics of temperature history was evaluated for three hot wires with different capacity installed in slab concrete which are relatively thin. Results can be summarized as follows. First, for the case of material using 5W hot wire, all decreased to below zero at or around 24 hours. Similarly, the material using 20W hot wire decreased to 2℃ below zero at or around 80 hours but satisfied the accumulative temperature of 45° D·D at 7 days of material age. On the other hand, the case of 30W hot wire, the biggest capacity, showed the high temperature history of 5℃ in average at all areas except the corners. Thus, the target accumulative temperature was secured at or around the 3 days of material age. Considering the above, the initial damage by freezing can be prevented only if 20W or higher hot wires are used for the slabs at -10℃ of extremely low temperature environment.
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As a part of study to maximize the amount used of the ground granulated blast-furnace slag, the study deals with setting properties of paste that is mixed the ground granulated blast-furnace slag with CaO-Al2O3 based inorganic blinder. The results of the experiment show that the setting time is most fast in the mix of 25% rate of CaO-Al2O3 based inorganic blinder. It is generally needed 2 hours for work time in precast concrete products. In this study, this requirement is achieved when using the retarder of 0.5%.
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Weakness of fine powder of blast furnace slags includes the decrease of initial intensity and delay of setting time. To solve this problem, there has been research on the alkali activation to induce hardening using alkaline chemical. However, the use of chemicals is dangerous and not cost effective, which can be solved by using recycled aggregates, one of construction wastes. The role of alkali activator can be substituted by alkali of non-hydrated cement included in recycled aggregates. In this study, the alkaline value of recycled aggregates will be evaluated through the comparison of molarity of sodium hydroxide (NaOH).
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Korea rapidly arranged urbanization and overpopulation with high growth of economy and all kinds of decrepit facilities are scattered all over the downtown. If there is a strong wind in fire, fire is rapidly increased by various fire spread factors. And Korea cannot build prediction model of urban fire combustion phenomena because there is no studies that physically explains the suitable flame phenomena for its real state. In this study, based on the Japanese Urban fire simulation to target the wooden building congested Area and suitability of fire risk assessment were reviewed.
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This study is to predict the compressive strength for the concrete of ground granulated blast-furnace slag, and use Plowman's, Gompertz's model. The results are as follows; The prediction compressive strength were simiar using Rastrup's equivalent age model. but The prediction compressive strength using Freiesleben's equivalent age model weren't simiar in bfs replacement Ratio of 50%, because it is analyzed as the activation energy.
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Yoon, Min-Ho;Kim, Gyu-Yong;Shin, Kyoung-Su;Choe, Gyoeng-Choel;Lee, Bo-Kyeong;Miyauchi, Hiroyuki 91
The strength of ultra-high-strength concrete can be reduced even if the spalling is prevented at a high temperature. Therefore, in this study, we measured internal temperature history and residual compressive strength using a 300×300×450mm short column specimens which use the fiber(NY 0.15+PP 0.10+SF 0.30vol·%) and respectively silica sand, washed sand, the slag sand. As a result, the temperature history and residual compressive strength are almost similar regardless of the fine aggregate types. -
Recently, with the increase in the construction of ultra-high buildings and long-span structures, there is great demand for high-strength concrete which can reduce the structural weight and thickness of member sections. While developing high-strength concrete to meet performance requirements, certain issues at the design stage must also be considered. The issues include diseconomy from a great amount of per-unit cement, spalling failure by fire at ultra-high building, autogenous shrinkage caused by increased hydration activity of binder from use of a superplasticizer. Therefore, the purpose of this study is examined the strain characteristics of Fiber-reinforced-high-strength concrete(FRHSC), which differ from those of general concrete owing to autogenous shrinkage. Based on the experimental data, we proposed an autogenous shrinkage prediction model.
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Research and analysis on thermal insulation status of existing buildings are needed to make data for repair and rehabilitation caused by deterioration in insulating material performance. To do this, we have researched and analyzed the insulation status of existing buildings according to the balcony with measuring instruments in pre-set investigation conditions.
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The amount of surface chlorides of architectural structure in incoming salt environment depends on the characteristics of distribution of incoming salt in atmosphere. Therefore, many researches are being conducted on deducting the correlation between incoming salt amount attached to the surface of real structure and that of atmosphere after quantitative measurement. However, in real environment, these studies are somewhat far fetched. That is because incoming salt in atmosphere are changed by various climatic conditions and in the case of the structures surface, attached incoming salt may be carried away due to the rainfall. Therefore, this study aims to draw an improved proportional relation between the amount of sodium chloride in atmosphere and that attached to the surface of architectural structures by measuring the amount attached to each architectural material using artificial incoming salt generator that can control various climatic variables that can be caused in real environment.
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As a result of experimenting 6 loading combustibles in domestic residential facilities by using Furniture Calorimeter, values of 2,391.26kW were appeared from sofas, 1,891.80kW from drawers, 1,778.95kW from mattress, 1,104kW from chairs, 291kW from tables, and 135.09kW from TV. Also, if applying α value of fire growing rate by classifying fire- growing speeds at NFPA 72 (National Fire Alarm Code 2007, Annex B), mattress can be defined as Ultra-Fast, sofa and drawers Fast, TV Slow, tables Slow, and chairs Medium.
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The construction of modern society, the use of high-strength concrete structures is becoming frequent. Admixture has been reported as a factor causing the explosion occurred. This study was experimental research on high strength concrete according to the kinds of admixture. Admixture of four different mix. fire resistance test results are outstanding when using blast furnace slag aggregate. When using silica fume spalling phenomena were most violent.
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In this study, combustibles investigation and fire growth rate experiment were performed for predicting initial fire behavior in buildings. Combustibles investigation was performed for residential buildings, which is most frequently affected by fire in Korea. Spatial characteristics and combustibles properties were separately investigated, and occupied area and layout characteristics of combustibles were identified to produce general layout models. Of the layout models, room was selected for fire test of a single compartment. From this test, fire propagation for each combustible was identified, which was delayed compared to the summed heat release rate of a single combustible.
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The purpose of this study was to investigate pozzolanic activity according to the firing temperature of the rice straw ash. In order to measure amount of SiO2 of rice straw ash, XRF(X-ray fluorescence) analysis was tested. Also to evaluate properties of mortars using rice straw ash, mortar flow, cement setting time, compressive strength was tested. As a results, as the mortar with a mixture ratio of rice straw ash up to 15% was found to have a compressive strength superior to that of plain mortar.
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Architecture has a large influence in the environment and human health. Therefore eco-friendly concept and sustainable development are important in Architectural field. This study aims to analyze impact of green building rating system on an apartment housing CO2 emission using multiple regression analysis. But in this result, green building rating system has no effect on CO2 emission. So, future study is required to analyze factors of green building rating system on the CO2 emission.
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This study is to investigate the effect of the diameter of reinforcement bars located in an aluminum-form on the temperature histories of the re-bars before placing concrete during a cold weather condition. The diameters of reinforcement bars with 13 mm, 19 mm, 25 mm and 32 mm were prepared for the experimental tests. Results showed that the larger the size of the diameter of the bars, the higher were the temperature drop. However, this study found that its effect on the temperature drop of the bars was insignificant.
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Property of the compressive strength of high strength concrete was investigated in adiabatic temperature history considering hot-weather conditions. As a result, compressive strength of specimens subjected to high temperature history showed more than 120% at 3days of age compare to standard cured specimens. But, at 91days of age showed the incidence of strength less than 100%.
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Research on the "Modernized Korean traditional housing" (Hanok) has been actively studied in succeeding to Korean traditional housing and providing the public with housing that required for modernized life style. The purpose of this study is to classify work sections for Hanok specifications. This paper analyzed the concepts and characteristics of existing specifications. It was found that the absence of standard classifications is one of the causes of missing work items and mixed scopes. Also, the contents of carpentry works have low level of details. Therefore, Hanok specifications, in this study, are required to have upper level standards and to encompass traditional and new construction methods. Further research will develop standard classifications, standard codes, and automated systems of Hanok specifications for improving quality and effectiveness.
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The purpose of this research is to propose an approximate estimation system for Modernized Hanok. Mock-up (Jisinjae) site data has been collected and analysed to characterize the modernized Hanok and to examine the range of cost fluctuation rate with each work items. As a result, number of floor, area (㎥), shape, methods and materials were considered as key factors for price change on the total construction cost. Furthermore, wood structure (34%) and roof (17%) account for major cost percentage. The cost fluctuation rate of two factors were -3.3%~+5.6% (wood structure) and -4.1%~+4.2% (roof). For further research, existing method will be analysed in order to developing the Hanok estimation system. And the cost fluctuation rate of every work items will be continually evaluated.
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The government has implemented the policy that encourages Hanok to preserve and widely spread. In fact, the interest and demand of its construction have generally increased but the systematically educated labor force in this field has tended to be lacked. This paper proposes to train experts of Hanok domestic construction-related the University and Hanok professional education institutions on the basis of the curriculum for students majoring in Architecture and Architectural Engineering at the University of Hanok education.
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Recent increased interest for long-life housing so research and policy transition is underway. Is the trend these days in the long-life housing to promote resident lifestyle as the most important element of the design elements that reflect. Through the purpose of this study has the paradigm of future construction industry with sustainable architecture In front of paradigm has come, through this study, long-life housing to consider when designing a the residents perspective of critical design elements for to draw.
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The purpose of this study is to select the sustainability evaluation criteria of detached house and assess it's importance. The theoretical study is performed to select the evaluation criteria. Expert's survey and AHP(Analytic Hierarchy Process) technique are conducted to assess the importance of each factors. In a result, the four sustainability evaluation criteria was energy, economy, environment, and quality of life. Also, the energy was the most important sustainability evaluation criteria factor, while the weight of four factors showed similar weights.
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The most difficult process in the construction of free-form buildings is to manufacture and construct exterior panels designed in a complex way. The façade of the free-form buildings include flat-panels, one-way curvature-panels, and bi-directional curvature panels. To construct these forms, it is necessary to go through the process of optimizing. But as for the optimizing technologies, BIM-specializing companies exclusively protect those technologies, so small construction companies have difficulty in rough estimates. Therefore, this study was aimed to provide the basic data in making the rough estimates of free-form buildings by carrying out the optimizing process for the façade of Dongdaemun Design Plaza and conducting the rough estimates according to the stage of production methods and optimization.
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Construction industry has been participated in the effort for the reduction of environmental pollution such as introduction of green building certification, enactment of environment related regulation. However these efforts are focused on the design and maintenance phases of entire life cycle, construction phase that can occur intensive environmental impact in a short period is insufficient. Therefore this study aim to derive environmental management factors in construction phase and assess them using reliability analysis and factor analysis. As a results, the 20 factors was classified into 4 superordinate such as 'plan and supervision', 'environmental factor management', 'licensing management', 'surrounding environment management'.Based on result of this study, further study should be developed the checklist for effective environmental management in construction phase.
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Green building certifications and environmental assessments are extensively implemented and studied to decrease the environmental impact during the life cycle of buildings. However, most of them are not appropriate to assess the environmental performance during the construction phase due to the difference of environmental factors. To develop an environmental index of construction projects, normalization should be conducted to compare the relative impact of each factor. As a first step, this study deduced normalization references of 4 environmental factors : noise, waste, greenhouse gas, and dust.
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With the increasing public concerns on sustainability in construction industry around the world, a variety of standards for sustainable construction have been developed and implemented. However, most of the them focuses operation and maintenance phases and do not have been approached integrally in terms of all construction phases. Especially, considering the quantities of environmental loads occurred intensively at the construction phases, it should not be overlooked. Therefore, the purpose of this study is to deduct primary management works for reduction of the potential environmental loads at the construction phases. In order to assess them quantitatively, we conduct a survey from professionals who are in the relevant fields and analyze these data using Fuzzy-AHP.
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Recently Construction industry is try to minimize effects on the Environment. So, Korea government is provided the Environmental law, but environmental managers who works in construction phase are not easy to understand the Environmental law because the laws are scattered in the several legislations and hardly to find the clauses for the environmental law. Therefore this study intends to deduct the improvement directions of Environmental laws. The basis data is selected through survey targeting environmental managers and analyzed by AHP.
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Energy systems in increasing energy efficiency are actively performed at home and abroad. But Generally systems in the country are limited in a new building or sort of some buildings like a public and office building. So, this research suggest a new direction of energy system for existing buildings. It need to set a new bound for containing the green remodeling. For a direction, we analysis domestic energy system in perform and compared their bounds, standard and methods of energy evaluation. This study is necessary for an additional research for proposing detailed evaluation items and for a feasibility study research. And it contribute to develope internal energy systems and set a new system bound.
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Ground source heat pump(GSHP) systems have been attracted as high-efficient energy-saving technology, but the building clients and designers have hesitated to use GSHP systems which is a expensive initial installation and a uncertain economic feasibility. Therefore In order to reduce the initial cost, many researchers have focused on the energy-pile system using the structure of the building as a heat exchanger. Even though many of experimental studies for energy pile system have been conducted, there was not enough data of a quantitative evaluation with the economic analysis and comprehensive analysis for energy-pile. In this study, the feasibility study for the energy pile system with a barrette pile was conducted by the performance analysis and LCC assessment.
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Kim, Kyong-Gon;Jeong, Mingu;Jeong, Gyeong-Hwan;Han, Byeong-Min;Shin, Yoonseok;Kim, Gwang-Hee 158
The purpose of this research is to propose a method that measures facilities condition around the construction sites in real time. In a result, using the Ubiquitous Sensor Network (USN) technology, it was possible to monitor and share the data of facilities condition in real time. The proposed method can contribute to prevent and deal with danger promptly. -
Progress measurement is one of key tasks for cost and schedule management in construction management. However, there has been shortage of effort to implement for automated progress measurement. This paper proposes to use a face recognition (FR) technology for automated progress measurement and management in construction sites. The FR technology can acquire detailed progress data that includes the in and out information of labors by location. The expected effectiveness of the proposed system is to provide accurate labor information for progress measurement by utilizing automated data acquisition technology (DAT) with high-speed reading face. In addition, it could be applied to real-time safety and quality management by using the camera images.
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A temporary work are lifting equipment that tower crane or lift, and temporary architectures that office building and storage in construction site. And it is main construction work that built and used temporarily like to a scaffolding, a walk plate, and a formwork. This study is to adjust breakdown structure of temporary work to introduce technical tendency. With a site manager, it is collected a detailed statement and compared. As a result to break down a tendency that temporary equipment, additional function, and direct work of temporary technique, first, existing detail technical indexes that group I, group J, group K, and group L are classified. Second, due to set up and manage to main agents in case of existing detail technical indexes that B1, B2, it is not wrong to classify. But, it is somewhat different, and therefore adjust it to same level. Finally, as a technical tendency that temporary equipment, additional function, and direct work of temporary technique, it is adjusted the others.
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Currently, the process of selecting products such as construction materials and equipment in the design phase proceeds based on the reuse of products used in the previous projects or samples from design companies as well as information on the limited products provided from the website of several manufactures. In particular, it is urgently required to formulate a standard product information management system that can be utilized in the BIM-based design environment these days. In Korea, domestic construction information classification system was developed, but its utilization has been underestimated since continuous studies on the practical usability are still lacking. Therefore, this paper derived problem of domestic construction materials information system by comparing with abroad material information system. Issues and implication is derived in terms of (1) Input information (2) Provide information, and (3) Utilize Information.
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There has been a defect dispute of apartment building in Korea. The defect dispute is complicated by main issues and details of dispute. It is yet to be solved. Meanwhile, a judge does not a inspection and analysis, but, related field expert who contracted professional engineer does. As a result, defect consulting report that an important judgment is used in a defect dispute. Therefore, this study does research on structure of defect consulting report. A defect consulting report has same items, irrespective of a defect consultant as a result that check 7 indexes about 10 cases. It has different structure's details depending on each defect consultants. And, it inserts new detail or deletes existing detail, does not show clear distinction.
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An operation planning of lift car is crucial in tall building construction especially it's arrangement plans, because it is related with transportation distance of finishing materials affecting construction productivity. Since tall building construction, composed of complicating and huge plane have complex traffic lines of finishing materials, to determine the position of lift car empirically or intuitively has limits. Therefore this paper suggest an optimum layout model of lift car minimizing the transportation distance both at site-level and floor-level using Graph theory and Dijkstra algorithm.
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In tall building construction, the equipment operation plans have an effect on productivity. Equipment, used in tall building construction, has operating plans of each it and restrictively operate owing to the first placed equipment operation. Therefore the interference of equipment was occur frequently. As it, the productivity is less effective and the construction delay occurs. This research was analysis the interference elements between the equipment for constructing the efficient equipment associated operational processes. The interference elements between the equipment derive through expert advice and analysis using IPA. Through the IPA, this research deducted the interference elements located 'Concentrate Here' which is the highest importance and the lowest performance.
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The composite PC rahmen structure, called Green Frame, allows the main structural members such as PC column and beam to be produced on the site, resulting in a reduction of PC member transportation cost and the margin of PC plant (operation cost and profit), making it more economic than the bearing wall structure. To apply the Green Frame to practice, not only installation but also insitu-production process should be considered. Therefore, this study analyse the influence factors on insitu-production and installation schedule of composite precast concrete members. The results shall be used as basic criteria on the planning of insitu-production and installation of Green Frame.
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After the introduction of the design VE system in 1990s, based on the legal system has made a rapid growth. Also It is evaluated as qualitative growth. Despite this growth, VE effort can cause the occurrence of the risk. In this paper carried out to hindrance factor that decrease the productivity in VE phase for strategy to improve the utilization of basic data.
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In order to draw indirect cost rates, theories of indirect cost were investigated, and recent field data were collected from steel factories. As a result, it was found that the ratio of indirect labor productivity compared to the direct labor ratio was approximately 17% and the ratio of indirect cost compared to direct cost was approximately 93%. Furthermore, 'The economy of construction industry' and 'size of steel factory' were found to be influence factors of the indirect cost ratio.
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A Study on the Analysis of Factors Influencing Labor-Productivity using Structural Equation ModelingMeanwhile, the importance of managing factors affecting labor productivity has been recognized and emphasized. However, in the previous study, qualitative evaluation only took place for these factors. In this study, therefore, identified and quantified the priority of factors decreasing labor productivity, and established basic data.
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Analysis of cable net facade by examing the literature and technical manual for it's characteristics, types, elements of construction management. And it will be performed research on the construction quality management such as development of guidelines and specification, analysis of the structural behavior.
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In recent years, risks associated with mixed used development in urban regeneration projects which have actively been implemented have been on the rise due to uncertainties and complexities of those projects. Thus, risk management is needed to effectively manage those risks that may occur during the process of a project. Many studies have contributed to deal with risk management of those projects. These studies, however, have focused main on identification stage and deriving the main risk factors and have limitations on presenting the relationship among those risk factors. Since many risks are interdependent and have multiple effects, the purpose of this study is to present a way(ISM method) to provide a hierarchical structural framework of risks in Urban Regeneration. The structural of risks can helps decision makers to trace the actual source of these risks.
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Recently, It is a fact that the percentage of female field managers has increased in the construction industry. Therefore, this study investigated the percentage of female construction site managers by conducting a survey of current male and female construction site managers and then analyzed the workload, work difficulty, work importance and performance level of female employees in charge of public affairs, which is the most common tasks.
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As I mentioned, education cause accounts for a great part of accident cause. Therefore safety education is the important safety measure to be efficiently used for accident prevention. Domestic construction sites focusing big companies make an effort for safety education, but it is short of reducing construction accident with education applying educational contents to actual work. This study analyzed the education contents in domestic construction companies to provide basic contents for improving efficient education method, and drew a limitation of education contents used in construction cites.
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In a construction project in which cooperation among project members gets its importance, trust among construction site members should be foundation to enhance team spirit and achievement. This study analyzes the trust network among staff by using social network analysis (SNA) theory for organizations in apartment complex construction sites in Korea. The analysis illustrates higher level of trust for those positioning in the higher positions in hierarchy and having greater experiences. It might be attributable to own features of construction works where skills are acquired by site experience.
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In a situation that building energy consumption is increasing worldwide, the research utilizing BIM technology to analyze building energy has been actively conducted. On the other hand, data input method of the building energy analysis has been still manually entered. This paper proposed a improved input method of required information for building energy analysis using the ECO2-OD program. As a result, although some required information of BIM based design software could be almost entered when it comes to general information and architectural sector, it has a problem to be handled in HVAC sector. Therefore, in the both of general and architectural sectors, the BIM information from the BIM-based design software could be directly used to automatically and systematically input the information. Future research should be studied the algorism and method in connection with data exchange to utilize input method of ECO2-OD from BIM data.
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Recently, there is a growing interest in BIM and modular method because of changing in users attitudes about quality of building and construction environment. however, In domestic, study on Modular method still have addressed primarily basic contents. This study check efficiency about this process through comparative analysis of Modular method and RC method used 5D BIM tool for real project and suggest a fitting schedule management method for modular method.
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The construction cost estimates during the design phase becomes the standard to judge profitability and validity, and is very important in various decision-makings by project owner. However, since approximate costs are quoted when many parts are undecided in the early stage of project, differences are bound to occur between the construction cost calculated through approximate quotation and that put into construction actually. Also, since in existing quotation works, quantity calculations have been dependent on the staff's manual work, involving error potential, and thus differences are likely in quantity calculation depending on the quotation staff's method of calculation. In this study, the process of creating space model to deduce 3D geometry information for approximate quotation in association with knowledge information and the expression for calculation of finishing area were proposed.
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Recently, modular construction has been begun to introduce actively for improvment of productivity in the construction industry. By the way, the construction technology is being IT through BIM. This is why modular construction needs BIM technology. In this study, we analyze the problems in the current modular construction at factory production stage. The way to extract 3D shop drawings using BIM is suggested to solve this problem.
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The maintenance management in buildings has got more important by the increasing complexity of building sizes and use. Nowadays an expectation and a possibility of BIM technology become accepted as a new construction management method, therefore many studies and legal systems of it are being suggested actively. Although orders for BIM projects are supposed to be increasing, at present the BIM information accumulated from planning and design still doesn't have its continuity at the maintenance step after completion of construction in terms of LCC. It can't use the possibility that BIM originally has, and also causes some confusion in communication. This study analyzes and classifies required information in terms of BIM in the range of estimating repair costs of apartment buildings, as an example of a way to use BIM information at the maintenance step.
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Existing polyurethane membrane waterproofing has been raised defects such as heaving. Therefore, We will be utilizing as the basic experimental data by the water vapor permeability test to the air cell structure of ultra rapid harding membrane waterproofing using the static mixing system in this study.
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Recently, it is certain that the increase of heating and cooling energy consumption by radical change in climate condition has caused serious problems related to environmental and energy concerns associated with increase of fossil fuel usage and carbon dioxide production as well as global warming. So, various actions to reduce greenhouse gas exhaustion and energy consumption have been prepared by world developed countries. The energy consumption by buildings approximately reaches 25% of total korea energy consumption. The greatest part in the buildings of the energy consumption is building facade. but a few research projects on concrete comprising more than 70% of outsider of buildings has been tried. This research structural insulation concrete what improved insulation performance using insulation performance improve material.
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In this study, the qualitative characteristics of the permeability concrete by the changes in the grading of the recycled aggregates were analyzed and its results are as follows. First, the compressive strength represented the low range of strengths comparing with the typical concrete, and the high compressive strengths were represented as the aggregates with small grading of 2.5mm were used. The bending strengths did not satisfy the targeted range, and the permeability coefficient represented to be good when the aggregates with single grading greater than 5.0mm and the mixed aggregates of 5.0mm with 10.0mm.
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The unit-water content in fresh concrete determines consistency, and play an important role in condensing the structure of concrete and enhancing the durability of concrete. The capacitance measurement method measure quickly unit-water content and is the best way to apply to construction site. In this study, the unit-water content of capacitance measurement method is estimated according to types and replacemment ratio of admixture. and the field application of capacitance measurement method is reviewed.
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In order to evaluate the properties of reduced heat of hydrationof concrete mixed with slag, in the present study, we have evaluated by experimental and analytical characteristics of heat of hydration of concrete using the latent heat material and slag.
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In recent years, the use of glass applied to curtain wall as a building facade material has increased in our nation. However, the non-tempered curved double glass is very easy to broke because it is difficult to guarantee the quality in process of making it into double glazing. So, it is more vulnerable to thermal breakage than tempered double glass. In this paper, surface temperature difference on curved double glazing was compared to that of heat strengthened glass and flat glass by conducting thermal breakage experiments. As a result, flat single glass was broken at temperature difference of 100~140 degrees but curved double glazing was broken at that of 40~60 degrees. Therefore, it was concluded that curved double glazing is more vulnerable than flat double glazing to thermal breakage, and it should be considered the possibility of thermal breakage when curtain wall glazing is applied as a building facade material.
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A system to efficiently utilize construction information has been in demand as a result of the changing society where information and knowledge leads to added value. Consequently, the government established a comprehensive information network system for construction industries to manage and utilize construction information which is the currently in use. However, this system is oriented toward management and business performance estimation for engineering and does not integrate a management system for design, construction technology, and construction engineering services. Therefore, this study proposes to develop object technology and management system of construction services and its evaluation to provide such information in real time.
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The construction of green building has distinct charicteristics by work classification by applying green technologies. Thus if the new technologies are applied to construction, unskiiled worker can experience construction time delay, reconstruction occurrence and quality decrease because of mistakes during the construction and work progress. For this background, we establish the work progress manual to secure quality and performance during the construction phase of green building and provide method to be used in the construction sight operation.
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The waterproof construction for walls and floor in the underground parking lot in the construction of the apartment buildings have been excluded to the introduction of the waterproof design until now, because of the shorten construction period and the reduced construction costs. The concrete structures are existed to the joints in the vertical or horizontal parts commonly. In case of cracks, there are generated due to behavior by subsidence and external changing temperature environment. The cracks are generated by the frequent water leaks. So, the repair methods of the water leaks are proposed as the quick micro-cement and the polyacrylic resin in this study.
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The government has applied the Construction New Excellent Technology Endorsement System to enhance national competitiveness and advance domestic construction technology since 1989. Nevertheless, It's application hasn't been expanded to overall construction industry, due to insufficient verification of the cost effectiveness. So, the government has established the standardized cost estimation guideline to verify the cost effectiveness in 2011. This research classified the technology group based on 27 cases of the cost estimation reports to increase understanding of the cost effectiveness of the new excellent technology. It is expected to contribute establishing reasonable and feasible cost estimation standards.
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In this paper, we introduce the insulation of aluminum truss dry installation method for construction for the development of the Angle. Features of the development of anchor bolts have been identified as no risk of fire, and ease of construction, which has the advantage of being the adiabatic efficiency is increased. In future research, to study the angle of the field on the Application of the development for the construction.
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New Seoul city hall completed in 1926 is a registered historical building. The remodeling plan has been developed for the expansion after the review by the governmental agency. Based on the plan, a new city hall should be constructed behind the current city hall while the facade, the main lobby and the dorm structure of the existing building, A new construction method, FUSEM, has been developed for this mission for the safety of the historical structure.
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Roof and exterior wall of general formal buildings are designed and constructed through design focused exterior wall system and drainage and waterproof roof system. However, there are no classification of exterior wall and roof in freeform buildings and they are integrated as a surface of freeform buildings. Therefore it is necessary to develop the dry roof construction method using double skin roof system satisfying the design and function of the envelope. In this study, we have an effort to develop construction method of double-skin roof system using metal panel and PV.
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Recently, architectural design has been changing from formal design to freeform design due to the digitalization of construction industry. Especially, the formal design has been accepted as a design trend recently and applied many times as a design concept in the architectural design competitions such as turn-key. However, various deflects such as water leak and cracks have been occurred because the traditional construction methods had been applied without any revision or adaptation of the formal construction method for the freeform building construction. Therefore this research proposes location point control method for freeform metal panel installation which is focused on the application of LH JinJu new office.
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Recently, It is being reduction to market of the domestic construction industry for the instability of the domestic market structure. So it is necessary to plan response measures for to ensure the competitiveness of the construction market of overseas. The purpose of the study is suggest of improvement of the project delivery system for the efficiency of the construction of the unit modular housing of considering the reducing cost and technological competitiveness of the domestic construction industry.
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The construction project can be defined as a network combined between elements which are engineering, procurement, construction, start-up, and has a plenty of subjects and partners. For the successful project management in construction industry, it is necessary to adopt various management methods, such as lean production, information network system, SCM(Supply Chain Management), which can increase the efficiency of project management. During recent years, even though various management techniques have been applied, the SCM system has not formulated in construction industry. Especially, the Nuclear Power Plant Construction which requires high regulations of the safety and security has not applied SCM. Therefore, this study aimed to propose technology area of SCM in Korean Nuclear Power Plant Construction.
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The Korean nuclear industry acquired technology for each construction stage including engineering, procurement, construction and commissioning from advanced nuclear countries. While the levels of technology and quality have greatly improved, the same cannot be said for the level of project management. In particular, the level of project performance measurement and forecasting project risk still remain at the single project management level. Thus, this paper reviewed the concept of the EVMS method and requirement for the system. The adoption of the EVMS, an advanced project management method, can enable efficient management of project risks and promote an adequate environment for project implementation.
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If the mechanical development is applied to the Nuclear Power Plant Structures instead of the standard hook development, the problem of overcrowding re-bars in the anchorage zone can be solved and the construction quality of the concrete work will be improved. But there are some problems in applying it to the NPP structures because of the restriction on the yield strength and diameter of the re-bar. After the performance evaluation test for the mechanical development, we can develop the new design equation of the mechanical development length in order to solve the limitation and apply it to NPP structures.
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Complex facilities and major equipment in nuclear power plants check to use analog measuring device. Operating and maintenance using 3D data for geometric information management method, which is a virtual reality technology development is urgently needed. Therefore, this paper defines the information requirements for the implementation of a virtual reality-based technology in nuclear power plant. Furthermore developing owner requirements for applying the virtual reality-based technology is purpose.
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To minimize construction quantity of nuclear facility, it is required to reduce reinforcing bar amount and solve reinforcing bar concentration and for this, it is necessary to develop application design technology and modular of high strength reinforcing bar. Hence, KHNP reduces excessive reinforcing bar amount which can cause possibility of poor construction of concrete through design standard development and modular of nuclear facility structure using high strength reinforcing bar to raise economics and has its purpose to maintain high-level safety and durability as they are.
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In this paper, standing water level control system and a comparison of existing methods (anchor, PDD, DM) and economic analysis was conducted. 1) Cost PDD method (6%), DM system (4%), and the SAL standing water level control system (4%), except for the anchor system is similar to the construction of three methods based on the portion of the anchor system was analyzed that. 2) construction and maintenance costs compared with the sum of the partial was, anchor system (100%), PDD method (39%), DM system (37%), the SAL standing water level control system (21%), the SAL standing water level control system was identified as the lowest cost method of.
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This study evaluated basic material properties of finishing mortar in ondol floor using NSB(Non-sinetering binder), and the binder for the purpose of the developing of high performance mortar and reducing crack problem without shrinkage-reduction agent.
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When the number of skyscrapers are increased in the domestic, it has increased the need of the outer wall cleaning robot. However, it does not exist the construction specification of the outer wall cleaning robot in the domestic. it is difficult to apply in the domestic that the outer wall cleaning robot. For this reason, it raised the need of the construction specification. And it is urgent that the construction specification of the outer wall cleaning robot is needed to develop in the domestic. Therefore, this study aims to propose the construction specification framework of the outer wall cleaning robot. In the future, this study will be based on the development of the construction specification on the outer wall cleaning robot.
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Reinforcing bar coupling method has a variety of ways including lap-splice method. However, there are problems that need to be improved in terms of constructability, economics analysis. We should be improved about the problems of the existing methods. Accordingly, this study were developed a new type of staggered grip type reinforcing bar coupling. The proposed method show the following effects than existing methods. First, this method can be reduce time through improved workability. Second, increasing safety through the slip removal. Third, improving economic efficiency by reduce the manufacturing costs.
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Depending on the very large and complicated of the LNG plant project, for the successful execution of the project, the operating system that is seamlessly integrated in EPC phase is needed. Therefore, we surveyed and analyzed the PMIS development and application status in domestic and international plant construction. Based on the results of the research, we proposed the development direction for PMIS in LNG plant construction.
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Green building can contribute to reduce the energy usage dramatically and can be applied to new building projects. This paper explored the efficient construction process for sustainable and green building. Construction process will be performed on the new green building projects and performance evaluation will be carred out as well. For this background, a pilot project of POSCO Green Building provides how to invigorate the low-energy green building which ensure quality and performance by establishing process concept of construction phase to realize the sustainable green building.
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The field application through the quality control of self adhesive rubberized asphalt waterproofing sheet was regulated by KS F 4934 of Korea Standard in 2003. However, the regulations that the different material properties of self-Adhesive waterproofing sheets are difficult to quality control on the standard. Therefore, this research was performed for of quality control all affiliations of self-adhesive waterproofing sheet through basic properties test and proposed quality standard revised bill in KS F 4934.
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In this paper, we test and evaluate in terms of workability the epoxy resin mortar and the EVA powder resin mortar used on the concrete structures. The initial viscosity of the epoxy resin mortar is lower than the EVA powder mortar, but after 20 minutes work can not be rapidly increased to 40 minutes. In the other hand, the EVA powder resin mortar is able to measure of viscosity for the past 40 minutes. In the flow test for evaluate workability, the flow of the epoxy resin mortar is rapidly decreased from 230 to 100 in the 90 minutes, but the flow of the EVA powder resin mortar is reduced to 198 to 175 that there is no significant change. In the coverage test of the pinhole on the concrete surface, the EVA powder mortar appears coverage in the all pinhole size but the epoxy resin mortar is not concealed from 2mm pinhole size.
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The study carried out the experiment with presenting as the fundamental data for developing non-cement by using red mud generated in blast furnace slag and bauxite generated in the process of manufacturing the pig iron process of manufacturing Al(OH)3/Al2O from as the binding material using the accelerator of NaOH. After fixing the thing and the NaOH adding the blast furnace slag and NaOH 10, 20, 30 (%) with 10, 20, 30 (%) substituted the red mud in the blast furnace slag and the experimental method carried out the experiment. And it measured the flexural strength and compressive strength and took a photograph EDS analysis and SEM. Consequently, the compressive strength was improved as the addition rate of the NaOH was high and the compressive strength according to the replacement ratio of the red mud was degraded. This is determined that film of the blast furnace slag is destroyed and it makes the hydration reaction condition and the intensity is revealed.
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To analyze vertical fire spreadability of aluminum composite panel, real scale test of aluminum composite panel and fire retardant aluminum composite panel was conducted as well as analysis of domestic code, test and domestic reaserch resulted in following conclusion. Fire spread risk assessment of aluminum Composite Panel is impossible with the current regulations (Cone Calorimeter Test). It need to changes of regulatory and combustion expanded risk assessment and regulatory changes in the test methods need to be judged. Also, there is quite a big different between the general aluminum Composite Panel and semi-non combustible of aluminum Composite Panel. However it is also deemed to be danger when present in the sidewall to the top consisting of fire spread. From now on, it is needed the study about interpretation of fire spread and sidewall of vertical fire spread analysis not only experiments for aluminum Composite Panel.
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The spherical bead manufactured by rapidly cooling process shows high density of 3.64g/㎤, high unit volume weight of 2.6kg/l, and high solid volume of 71%. When it applies to the grouter, it is possible to obtain even high fluidity with only a small amount. This study, focusing the grouter using a rapidly-cooled electric arc furnace oxidizing slag(RC-EAFS), deals with the properties of flow and setting time in fresh state, compressive strength and length variation at 1, 3, 7 and 28 curing day in hardened state. As the results, even though the grouter with RC-EAFS shows comparative low strength, it will be possible to development the competitive product due to the properties of increasing flow and low cost.
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Recently, the exhaustion of resource and environmental damage is serious due to the global warming because of the CO2 exhaust and each type the natural aggregate picking described below. meanwhile, The rest is the actual condition gone to the dumping ground that there is nearly no use which the waste glass can recycle and it is recycled. This research applied the waste glass as the cement substitute material the inorganic binder and coares aggregate substitute material. It utilizes the substitute material of the cement according to it and natural aggregate and tries to develop the environment-friendly artificial stone. The inorganic binder used the blast furnace slag, red mud, and fly ash. The straight type steel fiber, PVA fiber, PA fiber, and cellulosic fiber were used with a kind of fiber. As to the experimental item according to it, the compressive strength is the flexural strength and compressive strength.
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This study on the proposes a spalling mechanism based on the results of a fire resistance test of HSC(High Strength Concrete) considering important factors of spalling occurrence. The factors considered in this two-sided are fire resistance test to ISO 834 fire curve. In this study, explosive spalling phenomena in the specimens were investigation.
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This study compares the periods of cold weather concrete determined by the codes regulated by KCI (Korean Concrete Institute) and AIJ (Architectural Institute of Japan). For the calculation of the periods of cold weather concrete, the climate data for last 5 years obtained from Korean weather forecast station is used. Calculated data indicated that the period of cold weather concrete by AIJ code is longer than that by KCI code. Although global warming causes the decrease of the period of winter season, the temperature differences are large in Korea. Therefore, it is required that the current KCI code should be accordingly upgraded to reflect the weather variation in Korea over time.
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The salt damage resistance of waterproofing membrane was evaluated on the cracked mortar substrate. The types of specimens are urethane, acrylic waterproofing membrane, and no coating mortar substrate. After these specimens were cured by water curing for 4 weeks, they were cured by atmospheric curing at 20±2Co for 8 weeks. The salt water immersion test was carried out by following KS F 2737, and the penetration depth of chloride ion into substrate was measured in 1, 4, 8, and 13 weeks. As a result, in the case of non coating specimen, the chloride ion penetrated within one week. In the coated specimens, a regardless of the membrane type, the chloride ion did not penetrate during 13 weeks-tests on condition that the cracked width of substrate is less than 0.3mm. Also, the penetration speeds of the coated specimens were lower than that of non coating specimen. Therefore, our results reached a conclusion that waterproofing membrane has high salt damage resistance.
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This research utilizes the modified sulfur having the low melting point which 65℃ is tries to study the strength property of the mortar according to the cure method of the modified sulfur mortar. And we try to use as basic data for investigating the curing condition of the light panel optimum utilizing the modified sulfur. We experimented by five kinds; 20℃ water curing method and 20, 40, 60, 80(℃) air dry curing method. In 3 day curing, the compressive strength was improved caused by high curing temperature. But the compressive strength was degraded caused by enhanced temperature in 7day curing and 28day curing. Therefore, the curing temperature of the modified sulfur mortar is determined that it comes 20 time case curing and the water curing is the most recommendable.
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In this study, the temperature history was evaluated for the improved bubble sheets combining hot wires and PE films, which were developed under the extreme environmental condition of -10℃ and applied on the top surface of slab to prevent initial damage by freezing. Results can be summarized as follows. If improved bubble sheets combining hot wires with different capacity on double and quadruple bubble sheets are used, the temperature history for all materials decreased to 2~3℃ below zero but all test materials except Type 1 secured the accumulative temperature of 45° D·D at 7 days of material age, required for the prevention of initial freezing damage. This indicates the bubble sheets can prevent the initial damage by freezing.
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Recent research is needed for the reduction of the pH of the recycled aggregates, recycled aggregates for alkali social problems have emerged. This was confirmed through preliminary experiments using a self-made reactor with dry ice, the possibility of reducing the pH of the recycled aggregates. The pH reduction of coarse recycled aggregates plant was made to apply the field to the middle of construction waste treatment process to reduce the pH of the plant room, and measured the pH change with time. The measurement results showed that dry ice after the reaction, the pH of the aggregate 5% reduction than untreated recycled aggregates.