• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.347-358
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• 2009

Recently, it is getting into a good situation for the flat-plate slab system to be applied. The flat-plate slab without beam, however, is often too weak to control deflection properly compared to other typical slab-beam structures, for which the post-tension method is generally regarded as one of best solutions. The post-tension (PT) method can effectively control deflection without increase of slab thickness. Despite this good advantage, however, the application of PT method has been very limited due to cost increase, technical problems, and lack of experiences. Therefore, in order to reduce difficulties on applying full PT method under the current domestic circumstances and to enhance constructability of PT system, this research proposed the partial PT method with top jacking anchorage applied in a part of span as need. For the top jacking anchorage system, the efficiency of deflection control shall be considered in detail because it can vary widely depending on the location of anchorage that can be placed anywhere as need, and tensile stresses induced at back of the anchorage zone also shall be examined. Therefore, in this study, analysis were performed on the efficiency of deflection control depending on the location of anchorage and on tensile stresses or forces using finite element method and strut and tie model in the proposed top jacking anchorage system. The proposed jacking system were also applied to the floor slabs at a construction site to investigate its applicability and the analysis results of slab behavior were compared to the measured values obtained from the PT slab constructed by the partial PT method. The result of this study indicates that the partial PT method can be very efficiently applied with little cost increase to control deflection and tensile stresses in the region as a need basis where problem exists.

• Korean Journal of Construction Engineering and Management
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• v.16 no.1
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• pp.52-63
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• 2015

Business facilities among domestic architectures have rapidly been constructed along with domestic economic development. It is an important facility taking the second largest proportion next to apartment buildings among current 31 building types of fire department classification of 2012 year for urban architectures. The expected service life of business facilities is 15 years, but 70% of those in urban areas have surpassed the 15 year service life as of the present 2014. Thus, the demand for urgent rehabilitation of such facilities is constantly increasing due to the aging and performance deterioration of the facilities'main finishing materials. Especially, the business facilities are being used for the lease of company office or private office, and such problems as aging and performance deterioration of the facilities could cause less competitive edge for leasing and real estate value depreciation for the O&M (Operation & Management) agent and the owner, respectively. Therefore, an effective planned rehabilitation as a preventive measure according to the standardized repair rate by the number of years after the construction is in need in order to prevent the aging and performance deterioration of the facilities(La et al. 2001). Nonetheless, domestic repair/rehabilitation standards based on the repair rate are mainly limited to apartment buildings and pubic institutions, resulting in impractical application of such standards to business facilities. It has been investigated and analyzed that annual repair rate data for each finishing material are required for examination of the applicability of the repair rate standard for the purpose of establishment of a repair plan. Hence, this study aimed at developing a repair rate computation model for finishing materials of the facilities and verifying the appropriateness of the annual repair rate for each finishing material through a case study after collecting and analyzing the repair history data of six business facilities. The results of this study are expected to contribute to the planning and implementation of more efficient repair/rehabilitation budget by preventing the waste of unpredicted repair cost and opportunity cost for the sake of the business facilities' owners and O&M agents.

• Advances in Computational Design
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• v.3 no.1
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• pp.17-34
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• 2018

Tall buildings are categorized as important structures because of the large number of occupants and high construction costs. The choice of competent lateral load resisting systems in tall buildings is of crucial importance. Bracing systems have long been an economic and effective method for resisting lateral loads in steel structures. However, there are some potential adverse aspects to bracing systems such as the limitations they inflict on architectural plans, uplift forces and poor performances in compression. in order to eliminate the mentioned problems and for cost optimization, in this paper, six 20-story steel buildings and frames with different types of bracing, i.e., conventional, mega-scale and buckling-restrained bracing (BRB) were analyzed. Linear and modal push-over analyses were carried out. The results pointed out that Mega-Scale Bracing (MSB) system has significant superiority over the conventional bracing type. The MSB system is 25% more economic. Some other advantages of MSB include: up to 63% less drift ratio, up to 38% better performance in lateral displacement, up to 100% stiffer stories, and about 50% smaller uplift forces. Moreover, MSB equipped with BRB attests even a better seismic behavior in the aforementioned parameters.

• Korean Institute of Interior Design Journal
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• v.20 no.5
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• pp.3-12
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• 2011

The purpose of this study is to analyze the sustainable characteristics of London city hall designed by Norman Foster. The most important part of sustainable architecture might be the energy reduction including minimizing CO$_2$ emission but social and economical aspects of sustainability should not be neglected. London City Hall as a successful example of sustainable architecture depends its success on the harmony of social, environmental and economical aspects of sustainability. Social sustainability in London City Hall appears on appropriateness and public good in the facility. London City Hall act as a symbol of redevelopment and civic community. Environmental sustainability of London City Hall summarized as using unique building form, double skin and underground water cooling system for the purpose of energy saving. Computer modeling technology was introduced to save construction cost for economic aspect of sustainability. Rational configuration of mechanical system strengthen the durability of facility. In case of London City Hall, the function of building, site condition and architectural concept fulfill the every aspects of sustainability in architecture. Besides these conditions, Foster applied sustainability to London City Hall as active and concrete design concept to complete its design goals.

• Korean Journal of Computational Design and Engineering
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• v.21 no.3
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• pp.281-295
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• 2016

Lately, the management of domestic BIM performance is quite lacking, as the evaluation and management data from successful cases of BIM implementation both on projects and in companies, and related effects (time, cost and other physical gains) are not well kept for future use in BIM development. In order to overcome the above obstacles, a systematic approach to evaluating BIM adoption with focus on particular elements like BIM implementation environment and processes, and the physical factors yielded by BIM, is necessary. In this study, objective and detailed assessment indicators and weights that are appropriate for the domestic situation were derived through research for purposes of developing a web-based BIM maturity measurement program that is tailor-made for the Korean construction atmosphere. Through a company's self-maturity measurement, excellent quality of BIM deliverables and output can be achieved and managed. Furthermore, the domestic BIM capacity can gradually increase since design firms' BIM capability can be judged during procurement basing on measurement indicators.

• Journal of the Korean Institute of Educational Facilities
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• v.24 no.6
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• pp.27-36
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• 2017

Educational facilities have an affect to make a decently learning environment. After constructed, it needs a maintenance plan to keep the performance or function which provide the repair time, repair scope and ratio. But the fundamental data are so insufficient that the field worker can't provide the maintenance plan and has no choice use the other data which concerned with apartment or office building. Above all, the service life is indispensible to make a repair plan because the repair time and scope would be provided within the service life. This study aimed at providing the method to make a service life of component in educational facilities and applying the method into the roof proof and floor finishing. Results are shown that first, it is important to set the $1^{st}$ repair time after constructed. when it proposes the three ways with the probability approach, choice probability model and cumulative cost function. Second, the service life of roof proof is provided with about 35 years. In addition, the service life of the floor finishing is about 40 years. These result would be utilized to conduct the repair plan under the service life.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.11
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• pp.776-781
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• 2007

Optimized capacity of equipments are essential for energy saving and low cost construction and operation. So we must use proper design data for HVAC system design. We investigated for architectural data, equipment capacity, cooling and heating load design criteria of 52 office buildings. Following research results were obtained by carrying out each task. Office building effective area rate is 63%. The average building cooling load of South Korea is $140W/m^2$ and average heating loads in Seoul and Pusan area are $120{\sim}130W/m^2$ and $70{\sim}80W/m^2$. We also analysised HVAC design criteria. Person ratio in effective building area is $0.2person/m^2$, sensitive and latent heat loads of a person are 60W and 65W, light and equipment loads of office buildings are $25W/m^2$ and $20W/m^2$.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.1
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• pp.64-71
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• 2015

Silica fume is generally adopted as admixture for Ultra High Strength Concrete (UHSC) owing to its remarkable contribution to the strength and durability but increases significantly the fabrication cost of UHSC. Accordingly, this study investigates the replacement of silica fume by blast furnace slag (BS) and fly ash (FA) in order to lower the fabrication cost of 80MPa-UHSC. To that goal, experiment is conducted on the mix proportions of mortar in terms of its binder combination, water-to-binder ratio (W/B) and unit binder content. Based on the experimental data, a mix design of concrete is derived and its properties are verified. The results reveal that a W/B of 21% and unit binder content of $720kg/m^3$ are appropriate to achieve 80MPa-UHSC using a binder composed of 60% of OPC, 30% of BS and 10% of FA. The properties of the corresponding UHSC are seen to be satisfactory with a slump flow of 715mm and compressive strength of 97MPa at 28days. The application of the binder combination derived in this study is analyzed to reduce the cost by 50% of binder compared to the mix using silica fume while realizing equivalent performance.

• Korean Journal of Construction Engineering and Management
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• v.13 no.6
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• pp.3-12
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• 2012

The slowdown of private building industry resulted in growth of remodeling market as a way to improve energy performance. Remodeling is considered more cost-effective and eco-friendly approach for energy efficient building than new construction. Since 2008, Seoul has promoted Building Retrofit Project (BRP) preponderantly to attract energy-saving renovation by supporting building owners to switch building system into energy-saving system when they remodel their old buildings. According to 2012 press release, 254 Private sectors participated in this green building project and annually reduced 41000ton of greenhouse gas emission, 14000TOE, which also result in 7.5 billion won energy cost savings per year. The paper focuses on the building envelope remodeling as a way to improve energy efficiency. Different components of the building envelope such as wall insulation, window, and shading, were applied to the baseline model and the comparison was analyzed to come up with the ideal solution. This study only assesses the building envelope as to suggest the way to redesign the better energy performing building. Offering solution focusing on the architectural feature is essential because it will provide basic information and standard when remodeling a building for energy efficiency, especially, for the nonresidential buildings used as rental offices.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.175-180
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• 2009

According to an increasing demand of political support and development on renewable energy as a solution for the energy problem in Korea, the government has established a goal to raise renewable energy supply from 2.27% to 5% until 2011. Especially in the case of public building in which energy use is in great demand, it would bring a great advantage to develop and utilize the Photovoltaic System as an electric energy and Geothermal Heat Pump System as a thermal energy. On the occasion of Photovoltaic System, Photovoltaic module can be used as an architectural material so that it can reduce construction cost and when we use solar energy, it is possible to make building's own power supply. As for Geothermal Heat Pump System, It can be used infinitely as long as the solar energy exist and operation cost is cheap and yearly efficiency is stable. However, we need to make a plan to reduce early investment expanses for these two renewable energy systems and to expand a diffusion rate as we develop a competitive domestic technology level. So in this study, we are going to perform evaluation of economical efficiency according to the introduction of Photovoltaic System and Geothermal Heat Pump System in public buildings which will be built up inside of Daegu Sin-seo innovation city. As a first step, we will investigate present installation condition of these two renewable energy systems and based upon that, will seek efficient introduction program of renewal energy systems that can be applied in public buildings.