• Title/Summary/Keyword: Construction Stage Analysis

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Study on mechanical behaviors of large diameter shield tunnel during assembling

  • Feng, Kun;Peng, Zuzhao;Wang, Chuang;He, Chuan;Wang, Qianshen;Wang, Wei;Cao, Songyu;Wang, Shimin;Zhang, Haihua
    • Smart Structures and Systems
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    • v.21 no.5
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    • pp.623-635
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    • 2018
  • In order to study the mechanical behavior of shield tunnel segments during assembly stage, the in-situ tests and FDM numerical simulation were conducted based on the Foguan Shiziyang Tunnel with large cross-section. Analysis for the load state of the assembling segments in different assembly steps as well as the investigation for the changing of inner forces and longitudinal stress of segments with assembling steps were carried out in this paper. By comparing the tested results with the simulated results, the conclusions and suggestions could be drawn as follows: (1) It is the most significant for the effects on axial force and bending moment caused by the assembly of adjacent segment, followed by the insertion of key segment while the effects in the other assembly steps are relative smaller. With the increasing value of axial force, the negative bending moment turns into positive and remains increasing in most monitored sections, while the bending moment of segment B1and B6 are negative and keeping increasing; (2) The closer the monitored section to the adjacent segments or the key segment, the more significant the internal forces response, and the monitored effects of key segment insertion are more obvious than that of calculation; (3) The axial forces are all in compression during assembling and the monitored values are about 1.5~1.75 times larger than the calculated values, and the monitored values of bending moment are about 2 times the numerical calculation. The bending moment is more sensitive to the segments assembly process compared with axial force, and it will result in the large bending moment of segments during assembling when the construction parameters are not suitable or the assembly error is too large. However, the internal forces in assembly stage are less than those in normal service stage; (4) The distribution of longitudinal stress has strong influence on the changing of the internal forces. The segment side surface and intrados in the middle of two adjacent jacks are the crack-sensitive positions in the early assembly stage, and subsequently segment corners far away from the jacks become the crack-sensitive parts either.

A case study on Korea Creative Leadership - Focusing on the contribution of social benefiting (한국의 창안(創案)리더십 사례연구 - 사회편익(社會便益)의 공헌(貢獻)을 중심으로 -)

  • Lee, Kyung Nam
    • The Journal of Korean Philosophical History
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    • no.23
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    • pp.129-154
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    • 2008
  • This essay is a landscape of core values and relevant evidences about Creative Leadership in order to make sketches of Korean-style leadership framework. Glancing through this work, you can smell the distinctions of Korea creative leaders, particularly, in the aspects of procommunity pragmatism and ordinary innovation. Most Korea creative leaders were social mentors and masters who had enlarged their influences from the individual domain to social area in all the dimensions of human life. At the individual stage, the Creative Leadership suggests 'Jungki(正己)' as a core value of themselves, which is materialized as such competencies as self-assertiveness, observation and experimentation, and strong inquiry. Because most of them were technical masters dealing with new methodology and new knowledge including alchemy, medicine and weapons, the creative leaders show us very unique core values and competencies in the life sequences of the individuation, relationship, organization and community unlike other Korean-style leaderships and global practices. You can taste and compare these things: 'Kihyulsangtong(氣血相通)' as a core value and respect- for- others, style analysis, persuasion as core competencies in the stage of relationship, nextly, 'Suhshi(授時) & Jungeum(正音)' as a core value and coordination and adjustment, teamwork as core competencies in the stage of organization, finally, 'Hunmin(訓民) & Hwalin(活人)' as a core value and vision-building, social benefiting, ordinary innovation as core competencies in the stage of community. The value of this study is focused on the construction of Korean-style leadership framework based on the Creative Leadership through vivid stories about great leaders in our history.

An analysis of the processes of conceptual change through the successive refinement and articulation of student's conceptual framework - Focused on the university students' responses - (학생 개념의 연속적 세련화와 정교화를 통한 변화 과정 - 대학생 반응 분석 -)

  • Park, Jong-Won
    • Journal of The Korean Association For Science Education
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    • v.23 no.3
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    • pp.276-285
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    • 2003
  • In the earlier study, Park (2002) described the process of student' conceptual change as a successive refinement and articulation of their conceptual framework. In this study, the process of conceptual change for three university students were analyzed more in depth. As results, six types of conceptual change through successive refinement and articulation were observed: (1) original conception was elaborated in detail, (2) conception was differentiated according to the context, (3) some conceptions were re-explained theoretically after construction it based on experimental data, (4) non-coherent conceptions in the early stage get to have coherency in the later stage, (5) model of explanation gets to be complicated by excluding ideal conditions, (6) qualitative explanations were changed into quantitative ones.

Construction of Large Library of Protein Fragments Using Inter Alpha-carbon Distance and Binet-Cauchy Distance (내부 알파탄소간 거리와 비네-코시 거리를 사용한 대규모 단백질 조각 라이브러리 구성)

  • Chi, Sang-mun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.12
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    • pp.3011-3016
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    • 2015
  • Representing protein three-dimensional structure by concatenating a sequence of protein fragments gives an efficient application in analysis, modeling, search, and prediction of protein structures. This paper investigated the effective combination of distance measures, which can exploit large protein structure database, in order to construct a protein fragment library representing native protein structures accurately. Clustering method was used to construct a protein fragment library. Initial clustering stage used inter alpha-carbon distance having low time complexity, and cluster extension stage used the combination of inter alpha-carbon distance, Binet-Cauchy distance, and root mean square deviation. Protein fragment library was constructed by leveraging large protein structure database using the proposed combination of distance measures. This library gives low root mean square deviation in the experiments representing protein structures with protein fragments.

A Study on the Characteristic of Furniture Design of John Pawson (존 파우슨(John Pawson)의 가구 디자인 특성 연구)

  • Kim, Na-Eun;Park, Chong-Ku;Lee, Jung-Wook
    • Korean Institute of Interior Design Journal
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    • v.23 no.3
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    • pp.56-63
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    • 2014
  • Furniture has been developed in pursuit of human convenience and comfort, but nowadays it does not consider human users and gradually loses the essence of furniture. Especially furniture design that disregards the relation with space loses both the meaning and purpose of furniture. In this regards, it is necessary to understand the essence of furniture design and establish a design direction for future progress. Based on the relation between furniture and space, this paper intended to study on John Pawson's works that pursued the essence of design focusing on users, and propose a direction in a sense of real meaning for modern furniture design after exploring the characteristic of the furniture design of John Pawson. The study method of this paper was to investigate the design language of John Pawson and analyze his furniture in the morphological structural, functional, and material aspects. Based on such analysis, this study investigated the characteristics of the furniture design and found out what the core of the design that he pursued was. The scope of the study included the Independent Furniture that was restricted furniture collections of Driade and Spatial Furniture designed and installed at the stage of space construction. The study result showed that the design of John Pawson considered 'the suitability to a specific place' as important factor and furniture was planned at the stage of planning space. Each independent furniture defines all spaces in the morphological, lay-out and functional aspects of furniture and emphasizes their own property. As Spatial Furniture shares the function of spatial composition element, Pawson's furniture can be all called Spatial Furniture.

Energy Analysis in CO2 Membrane Separation Process via Heat Integration (열통합 기법을 통한 이산화탄소 막 분리공정 에너지 해석)

  • Kim, Seong Hun;Kim, Tae Yong;Kim, Beom Seok;Cho, Hyun-Jun;Yeo, Yeong Koo
    • Plant Journal
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    • v.12 no.2
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    • pp.24-30
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    • 2016
  • The membrane separation processes have received attention due to advantages such as compactness, modularity, ease of installation, flexibility of operation, lower capital cost and lower energy consumption. In this study, we evaluated accuracy of cross-flow, co-current and counter-current models. With the most accurate model, we identified the operating conditions of the two-stage membrane separation and examined the effects of permeance and selectivity of the membrane by simulation. Futhermore, power requirements and operating cost savings due to the introduction of the heat exchanger were investigated by applying heat exchanger network synthesis technique in the two-stage membrane separation using vapor sweep.

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Creep and shrinkage properties using concrete test results and prediction models for high strength and high performance concrete (실험결과와 예측식을 통한 고강도 고성능 콘크리트의 크리프 및 건조수축 특성파악)

  • Cha, Han-Il;Moon, Hyung-Jae;Seok, Won-Kyun;Park, Soon-Jeon;Lee, Joo-Ho
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.709-712
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    • 2008
  • RC super tall buildings are planned and constructed recently in domestic area. Concrete is characterized by time dependant material such as creep and shrinkage. For this properties of concrete, differential shortening is one of the main issues on super tall buildings construction. This study includes material research, which is performing as a pre design stage to solve differential shortening on Lotte Super Tower Jamsil core structure(50, 60, & 70 MPa). The major part of this study is composed with comparison and analysis between experimental data and predicted data on total shrinkage and total compliance which were used on design stage. Four models, ACI209R Model, Ba${\check{z}}$ant-Baweja B3 Model, CEB MC99 Model, & GL2000 Model, were employed to predict them. It also tries to seek a proper model for high strength and high performance concrete in the case of no concrete test.

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Development of a Practical Surface Image Velocimeter using Spatio-Temporal Images (시공간영상을 이용한 실용적인 표면영상유속계 개발)

  • Yunho Lee;Kwonkyu Yu
    • Ecology and Resilient Infrastructure
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    • v.10 no.4
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    • pp.208-216
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    • 2023
  • The purpose of this study is to present the most appropriate hardware and software configurations to produce a practical SIV (surface image velocimeter). To make a practical SIV, we constructed the system with a CCTV, a water stage gauge, and an analysis software installed on an Android board. The camera captures continuously images for 30 seconds with 2 minute intervals. And the 11-parameter projection method was used in the software that analyzes the captured images to reconstruct the exact measurement points according to the changing water stage. In addition, a spatio-temporal image construction method was developed so that the directions of the images could be arranged in the main flow direction at each measurement point. The surface image velocimeter composed of the proposed method was produced and installed at the Insu Stream, Seoul for a test site. And a result of measurement during a heavy rainfall event showed that the proposed system can measure flow discharge in proper, rapid and continuous manner.

Effect of stud corrosion on stiffness in negative bending moment region of steel-concrete composite beams

  • Yulin Zhan;Wenfeng Huang;Shuoshuo Zhao;Junhu Shao;Dong Shen;Guoqiang Jin
    • Steel and Composite Structures
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    • v.48 no.1
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    • pp.59-71
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    • 2023
  • Corrosion of the headed studs shear connectors is an important factor in the reduction of the durability and mechanical properties of the steel-concrete composite structure. In order to study the effect of stud corrosion on the mechanical properties in the negative moment region of steel-concrete composite beams, the corrosion of stud was carried out by accelerating corrosion method with constant current. Static monotonic loading was adopted to evaluate the cracking load, interface slip, mid-span deflection, and ultimate bearing capacity of four composite beams with varying corrosion rates of headed studs. The effect of stud corrosion on the stiffness of the composite beam's hogging moment zone during normal service stage was thoroughly examined. The results indicate that the cracking load decreased by 50% as the corrosion rate of headed studs increase to 10%. Meanwhile, due to the increase of interface slip and mid-span deflection, the bending stiffness dropped significantly with the same load. In comparison to uncorroded specimens, the secant stiffness of specimens with 0.5 times ultimate load was reduced by 25.9%. However, corrosion of shear studs had no obvious effect on ultimate bending capacity. Based on the experimental results and the theory of steel-concrete interface slip, a method was developed to calculate the bending stiffness in the negative bending moment region of composite beams during normal service stage while taking corrosion of headed studs into account. The validity of the calculation method was demonstrated by data analysis.

Upper Boundary Line Analysis of Rice Yield Response to Meteorological Condition for Yield Prediction I. Boundary Line Analysis and Construction of Yield Prediction Model (최대경계선을 이용한 벼 수량의 기상반응분석과 수량 예측 I. 최대경계선 분석과 수량예측모형 구축)

  • 김창국;이변우;한원식
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.46 no.3
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    • pp.241-247
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    • 2001
  • Boundary line method was adopted to analyze the relationships between rice yield and meteorological conditions during rice growing period. Boundary lines of yield responses to mean temperature($T_a$) and sunshine hour( $S_{h}$) and diurnal temperature range($T_r$) were well-fitted to hyperbolic functions of f($T_a$) =$$\beta$_{0t}$(1-EXP(-$$\beta$_{1t}$ $\times$ ($T_a$) ) and f( $S_{h}$)=$$\beta$_{0t}$((1-EXP($$\beta$_{1t}$$\times$ $S_{h}$)), to quadratic function of f($T_r$) =$\beta$$_{0r}$(1-($T_r$ 1r)$^2$), respectively. to take into account to, the sterility caused by low temperature during reproductive stage, cooling degree days [$T_c$ =$\Sigma$(20-$T_a$] for 30 days before heading were calculated. Boundary lines of yield responses to $T_c$ were fitted well to exponential function of f($T_c$) )=$\beta$$_{0c}$exp(-$$\beta$_{1c}$$\times$$T_c$ ). Excluding the constants of $\beta$$_{0s}$ from the boundary line functions, formed are the relative function values in the range of 0 to 1. And these were used as yield indices of the meteorological elements which indicate the degree of influence on rice yield. Assuming that the meteorological elements act multiplicatively and independently from each other, meteorological yield index (MIY) was calculated by the geometric mean of indices for each meteorological elements. MIY in each growth period showed good linear relationship with rice yield. The MIY's during 31 to 45 days after transplanting(DAT) in vegetative stage, during 30 to 16 days before heading (DBH) in reproductive stage and during 20 days after heading (DAH) in ripening stage showed greater explainablity for yield variation in each growth stage. MIY for the whole growth period was calculated by the following three methods of geometric mean of the indices for vegetative stage (MIVG), reproductive stage (HIRG) and ripening stage (HIRS). MI $Y_{I}$ was calculated by the geometric mean of meteorological indices showing the highest determination coefficient n each growth stage of rice. That is, (equation omitted) was calculated by the geometric mean of all the MIY's for all the growth periods devided into 15 to 20 days intervals from transplanting to 40 DAH. MI $Y_{III}$ was calculated by the geometric mean of MIY's for 45 days of vegetative stage (MIV $G_{0-45}$ ), 30 days of reproductive stage (MIR $G_{30-0}$) and 40 days of ripening stage (MIR $S_{0-40}$). MI $Y_{I}$, MI $Y_{II}$ and MI $Y_{III}$ showed good linear relationships with grain yield, the coefficients of determination being 0.651, 0.670 and 0.613, respectively.and 0.613, respectively.

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