• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.69-77
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• 2017

By producing pre-engineered modular system in the factory, It is enable to expedite construction and can be distinguished from two types by the method resisting load. One is the open-sided modular system composed of beams and columns. The other is enclosed modular system composed of panels and studs. Of the modular systems, the open-sided modular system buildings the connection between modules are difficult due to closed member sections, and the overall strength is reduced as a result of local buckling. In this study, in order to solve these problems, a modular system with folded steel members filled with concrete are proposed. The capacity spectrum method presented in ATC 40 is used for seismic performance assessment of the proposed model structure and the structure with conventional steel members. The analysis results show that at the performance point of each model the number and rotation of plastic hinge formed in the proposed modular system are smaller than those in the conventional system. Based on this observation it is concluded that the proposed system with composite sections has superior seismic capacity compared with conventional system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.141-147
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• 2017

Recently, lots of researches on concrete with high volume mineral admixtures such as ground granulated blast-furnace slag(GGBS) have been carried out to reduce greenhouse gas. The high volume GGBS concrete has advantages such as low heat, high durability, but it has a limitation in practical field application, especially low strength development in early ages. This study investigated the compressive strength and hydration characteristics of high performanc and volume GGBS cement pastes with low water to binder ratio. The effects of fineness($4,330cm^2/g$, $5,320cm^2/g$, $6,450cm^2/g$, $7650cm^2/g$) and replacement(35%, 50%, 65%, 80%) of GGBS on the compressive strength, setting and heat of hydration were analyzed. Experimental results show that the combination of high volume slag cement paste with low water to binder ratio and high fineness GGBS powder can improve the compressive strength at early ages.

• Journal of The Korea Institute of Healthcare Architecture
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• v.24 no.1
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• pp.33-40
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• 2018

Purpose: The main objective of this paper is, to assess environment, care process, and patient-related factors associated with patient falls. The study also aims at identifying various factors that would affect inpatient falls and, therefore, helping both caregivers and designers contribute to better prevent inpatient falls in their own areas of expertise. Methods: A retrospective analysis of inpatient falls that occurred in the unit of General Medicine in the United States has been conducted and environment, care process, patient-related factors associated with those falls have been analyzed at the same time. Results: The study identified several factors associated with inpatient falls. They range from environmental factors to care process- and patient-related factors. Patient visibility and patient accessibility can matter to patient falls and where those falls occur, along with patient days per room, the percentage of patient days with high fall risk patients per room, the percentage of high fall risk patients per room. Implications: The findings of the study can provide design implications that can be incorporated into design process and design decisions to promote fall prevention in inpatient care units. Inpatient falls can be effectively reduced when caregivers and designers work together to understand the complex nature of inpatient falls and the importance of multidisplinary efforts among various experts in the areas of healthcare.

• Journal of Korean Society of Steel Construction
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• v.30 no.1
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• pp.13-23
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• 2018

The use of a built-up H-beam (BH) that can easily manufacture a section is increasing. This is a basic study on standardization of BH. It confirmed the material properties of SM490 and SM520 steel such as yield strength, tensile strength, elongation, charpy absorbed energy, and else. The six BH specimens were manufactured with single-SAW or tandem-SAW. The welding performance was confirmed by collecting the macroscopic specimen and T-bar tensile specimen form the BH. As a result of the material property test, the properties of SM490 and SM520 which are made in Korea both satisfied the KS. As a result of the welding performance experiment, it is determined that the weld zone of BH has sufficient welding performance. Therefore, they are determined that the SM490 and SM520 steel are a proper material of BH, and the single-SAW and the tandem-SAW show a sufficient welding performance.

• Transactions of the Korean hydrogen and new energy society
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• v.10 no.1
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• pp.19-26
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• 1999

The effectiveness of a double-tube heat exchanger has been investigated experimentally. This problem is of particular interest in the design of the heat exchanger in a hydrogen liquefaction system. Temperature, pressure, and mass flow rate for hydrogen were measured both in inner tube and in annulus of a double-tube heat exchanger. The effectiveness could be evaluated from the measured temperature and mass flow rate. It is found that the effectiveness increases with an increase in the heat transfer area of a double-tube heat exchanger and with a decrease of the heat capacity ratio. But the increase rate of the effectiveness decreased with a decrease of the heat capacity ratio. Therefore, it is presented that a criterion for selecting the heat exchanger length and heat capacity ratio to obtain the effectiveness required in a hydrogen liquefaction system.

• Journal of Korean Society of Steel Construction
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• v.21 no.5
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• pp.537-544
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• 2009

The design standards, such as AISC-LRFD (2005) and KBC-2005, specify the maximum width-to-thickness ratio that can be used for computing the strength of the concrete-filled tube (CFT), and do not include any formula for computing the strength when the width-to-thickness ratio is over the limit. This paper proposes a strength equation for CFTs with a large width-to-thickness ratio by acknowledging the fact that the stiffened slender steel platehas substantial postbuckling strength, and that it therefore can be more economical to use it. The equation adopts the concept of effective width,which is very useful for plate analysis. By comparing the strengths of AISC2005, KBC2005, and the proposed method with the results of the experiment, where the width-to-thickness ratio was regarded as the main parameter, the applicability of the proposed method was verified.

• Journal of Korean Society of Steel Construction
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• v.19 no.6
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• pp.575-585
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• 2007

In this study, a new design equation was presented for square CFTs with high-strength concrete subjected to axial compression and bending. In a previous study, a design equation for square CFTs with normal strength concrete was proposed. A parametric study by fiber analysis was performed taking the width-to-thickness ratio (b/t) and the relative concrete strength to the yield strength of the steel tube (fck/Fy) as the main parameters of this study to determine the maximum moment and the axial load at the maximum moment. A new constitutive model for concrete was adopted for fiber analysis in order to take into account the effect of high-strength concrete. The results of the parametric study were embedded into the method which was presented in the previous study to formulate a new design equation that can be easily used for estimating the strength of square CFTs with high-strength concrete.

• Journal of Korean Society of Steel Construction
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• v.28 no.5
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• pp.313-323
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• 2016

Seven types of tests were conducted to experimentally evaluate the material properties of ultral-thick (or 120mm-thick) SM490TMC plate. The investigation of through-thickness properties was among the most significant considerations. All chemical and mechanical test results showed the through-thickness homogeneity as required and conformed to the KS(Korean industrial Standards), although the thickness was 1.5 times thicker than the thickness limit (80mm) imposed by Steel Structure Design Code. No reduction in the yield strength of 120mm-thick SM490TMC plate is recommended for design.

• Journal of The Korea Institute of Healthcare Architecture
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• v.21 no.3
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• pp.37-45
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• 2015

Purpose: The main objective of this paper is, to evaluate the unit design for patient-centered care and to draw lessons-learned for further improvement. Methods: This study conducted a case study of the intensive care unit, designed to fulfill patient-centered care in the US. It evaluated the effectiveness of the unit by incorporating several study methods such as plan analyses, direct observations through nursing tracking and behavior mapping, and focus group interviews. Results: The major design decision made in this patient-centered unit was the use of patient rooms with designated family areas and distributed nursing stations. Both design features appeared to be a success on a variety of research metrics and outcomes. The study identified that the patient rooms ultimately help family members to spent more time with their loved ones, which leads to increased satisfaction of family members and nurses also report that they generally enjoy the distributed nurses' stations, which provide a comfortable environment to complete their regular lines of work such as charting, monitoring patients, and collaborating with their colleagues. Implications: Certain design features in intensive care units such as patient rooms with designated family areas and distributed nursing stations could appropriately support hospitals to fulfill patient-centered care.

• Journal of Korean Society of Steel Construction
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• v.24 no.6
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• pp.743-751
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• 2012

This paper investigates an experimental behavior of circular columns and beam-columns made of HSB600 high strength steel as a fundamental study to enhance the applicability of HSB steel. The applicability of the current Standard such as KBC and Eurocode 3 is also evaluated. A total of six specimens are fabricated and tested. The main parameters are slenderness ratio(KLe/r = 12, 14, 40, 65), diameter-to-thickness ratio(D/t = 25, 40), and eccentricity ratio(e/D = 0, 0.5). It is drawn from the experiment that both the KBC and Eurocode 3 can be used to predict the strength of circular columns and beam-columns made of HSB600 high strength steel.