• Title/Summary/Keyword: Foundations

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A Study on the Thermal Crack Control of Foundation for Large Turbine (대형 터빈 기초 구조물의 온도균열 제어에 관한 연구)

  • Ha, Ju-Hyung;Cho, Yun-Gu;Lee, Kewn-Chu;Lim, Chang-Keun
    • Journal of the Korea Concrete Institute
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    • v.26 no.3
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    • pp.287-297
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    • 2014
  • Heat of hydration of mass concrete is one of the most important factors that significantly affect structural quality and construction period. Therefore, appropriate methods to control heat of hydration are essential technologies for mass concrete construction. In this study, probability of thermal cracking was checked by thermal analysis prior to the construction of a turbine foundation in a domestic power plant. Subsequently, changes of concrete mix proportion and an effective curing method were proposed to control heat of hydration of mass concrete structures. Concrete manufactured by slag cement was proposed instead of concrete produced by ordinary Portland cement, and an automated curing method was proposed to improve the curing method using typical moist curing with blanket. The automated curing method maintains the temperature difference between center and surface of concrete below a setting value by temperature monitoring. Concrete with slag cement was used for actual construction. One of two identical turbine foundations was cured by an insulated curing method, and the other was cured by the automated curing method to compare the curing methods. And then, the effects of control of heat of hydration were evaluated based on temperature/strain monitoring and crack investigations.

A Study on the Role and Transition of the Tapgu in Stone Pagoda (석탑 탑구(塔區)의 역할 및 변천에 관한 연구)

  • Chung, Hae-Doo;Jang, Suk-Ha
    • Journal of architectural history
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    • v.19 no.1
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    • pp.91-104
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    • 2010
  • Korea's stone buildings are varied in their types such as stone pagodas, stone lanterns, stone bridges, stoneworks, etc. These account for more than 30% over the entire cultural properties, but research achievements are lacking compared to wooden buildings. Accordingly, this study aims to identify the shape, role and transition of Tapgu, which had been used to set up boundary at a stone pagoda, one of the stone buildings. The 20th stone pagodas, which have relative accuracy in its forming year, have been studied around national treasure or treasure between 7th century and 9th century. There are a lot of different opinions about the role and meaning of Tapgu, and at this writer's option, Tapgu is defined as follows: First, each structure plays a different role. A structure to pass the load in the upper part to the ground can be seen as a stair or a pedestal, but a structure to form double foundations can be considered as Tapgu. Second, Tapgu can be used to divide areas with stones or stepping stones. As a result, the shape, role and transition of Tapgu is as follows: Firstly, when it comes to its shape, Tapgu includes flagstone type, belt type, double foundation type, compound type. Flagstone type had been used to set up boundary at stone pagodas by using foundation stone, belt type by keeping apart from stone pagodas, and double foundation stone by installing dual foundation stones. Secondly, Tapgu is considered to set up boundary in the case of flagstone and plate stone, and acts like a structure which can prevent surrounding area of stone pagoda from coming up while being stuck around stone pagodas. Belt type was installed only for the purpose of forming boundary. At the bottom, double foundation stone had been used to pass the load in the upper part to the ground in the same way as the foundation stone in the upper part, and the boundaries were set varying the size. Thirdly, when it comes to the transition of Tapgu, flagstone type of boundary stone had been installed in the 7th century, and belt type of boundary stone had been mainly installed in the 8th century. And double foundation stone had been installed in the 9th century. Comprehensively, flagstone type and belt type had been made around the 7th and 8th century when Tapgu was regarded important and stone pagoda started to be built. At the turn to the 9th century, the role of Tapgu had been increasingly losing in the construction of stone pagoda, and foundation stone started to appear.

Merits and Demerits of Analytical Marxism Searching for Solutions to the Political Economy of Media/Communication Industry (분석적 마르크시즘의 공과(功過) ‘마르크스주의 경제학’과 ‘신고전파 경제학’의 방법론 논쟁을 통한 미디어/커뮤니케이션 정치경제학의 방향 찾기)

  • Lee, Sang-Khee
    • Korean journal of communication and information
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    • v.45
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    • pp.7-48
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    • 2009
  • The recent crises of Marxism do not mean Marx’s crisis. Marx said that he was not a Marxist. The purposes of this essay explore (1) the modern identity of the political economy; (2) the possibilities of mutual understanding between neoclassical economics and Marxist economics; (3) problems of the political economy in media and communication industry. I have begged for analytical Marxists, because of their good fruits. They accepted the methods of modern social science and they constituted a tremendous advance in the application of the scientific methods to the study of society. In insisting on micro-foundations(methodological individualism), analytical Marxism distinguished itself from structuralism and functionalism. I appreciate that analytical Marxism has reduced a theory to practice. But the works didn’t listen to everyone(from Marxists to un-Marxists), and explain everything. Making theory with production/consumption, macro/micro, and structure/behavior is a road to the political economy in the long run. It also applies to media and communication industry. The realm of media/communication is broad, which in philosophy, humanities, politics, economics, sociology, and engineering. And media policy is more complicated by politicians who look at the same situation from different angles. By the aid of interdisciplinary research, the political economy of media/communication shall explain at full length.

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A Study on the Behavior Characteristics of Soft Clay Ground by C.G.S Method (C.G.S공법을 적용한 연약점토지반에서의 거동특성에 관한 연구)

  • 천병식;여유현
    • Journal of the Korean Geotechnical Society
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    • v.19 no.6
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    • pp.307-323
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    • 2003
  • In this study the pilot test of C.G.S (Compaction Grouting System) as injection method by low slump mortar was performed and the results were analyzed in order to find out the application of this method to the soft ground and the effect of settlement restraint. The site for pilot test is adjacent to apartments supported by pile foundations. Sand drain method was performed previously as countermeasures against settlement, but settlement occurs continuously because this ground is very soft. Site investigations such as SPT, CPT and vane shear test were performed to determine the characteristics of ground improvement after the installation of C.G.S. Field measurements were performed on purpose to find out the displacement of ground during the installation of C.G.S. From the results of this study, C.G.S method can be optimized by the control of radius, space, depth, injection material and injection pressure. C.G.S improves soft ground with radial consolidation of adjacent soft ground. Considering that increase of N value to about 3, C.G.S can be considered as an effective method to increase the bearing capacity as well as constrain the settlement of soft ground. It is also expected to be economic and effective in the improvement of ground when it is used in applicable sites.

Reduction Factor of the Site Coefficient due to the Foundation Embedment in the Soft Soil Layer for the Seismic Analysis of a Building (건축물의 지진해석을 위한 연약지반에 묻힌 기초로 인한 지반증폭계수에 대한 저감계수)

  • Kim, Yong-Seok
    • Journal of the Earthquake Engineering Society of Korea
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    • v.14 no.4
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    • pp.1-15
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    • 2010
  • In this study, the reduction factor of the code-defined site coefficient due to the embedment of a foundation was estimated for the seismic analysis of a building built on a soft soil site. This was done by utilizing the in-house finite element software P3DASS, which has the capability of pseudo 3D seismic analysis with nonlinear soil layers. A 30m thick soft soil site laid on the rock was assumed to be homogeneous, elastic, viscous and isotropic, and equivalent circular rigid foundations with radii of 10-70m were considered to be embedded at 0, 10, 20 and 30m in the soil layer. Seismic analyses were performed with 7 bedrock earthquake records deconvoluted from the outcrop records of which the effective ground acceleration was scaled to 0.1g. The study results showed that the site coefficients are gradually reduced except in the case of a small foundation embedded deeply in the weak soil layer, and it was estimated that the deviation of the site coefficients due to the foundation size was not significant. The standard reduction factor due to the foundation embedment were calculated adding the standard deviation to the average of 5 reduction factors calculated for 5 different foundation radii. Standard reduction factors for the site amplification factor were proposed for the practical amplification and the codes of KBC, etc., in accordance with the average shear wave velocity of the site, and the site class.

Womenswear Collections based on Italian Fashion Market Trends-utilizing 1990's demographics data- (이태리 패션시장 트렌드 분석을 통한 여성복 컬렉션 기획-1990년대 통계자료를 중심으로-)

  • 김유경
    • Journal of the Korean Society of Costume
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    • v.38
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    • pp.193-211
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    • 1998
  • Without a solid marketing system in placed, the fashion industry cannot flourish on out-standing design or technology alone. Even though the significance of collecting and analyzing information, merchandising, and retail distribution is recognized, these functions are not firmly rooted or prevalent in our industry. In contrast, Italy which possesses similar demographic traits such as the lack of natural resources and other physical factors has succeed-ed in globalizing its fashion market by responding swiftly and exercising flexiblity to its constantly changing consumer demand. This in turn has earned Italy the competitive edge in the global fashion arena. Italy's unique management skills and operation know-how, along with successful market strategies come into play in bringing competitiveness to Italy's fashion market. Firstly, smaller companies with ability to adopt swiftly to the ever changing market. Secondly, fashion friendly social environment. Thirdly, niche marketing through highly specialized system and differentiation. Fourthly, timeless innovation through intense corporate competition. Lastly, establishment of foundations to support the industry through diverse networking. The alone building blocks have formed a basis for erecting an unparalleled market with a reputation for excellence in design and quality in the global fashion world. This study has examined how Italy's fashion industry has evolved from an underdeveloped textile business into a cutting edge fashion in-dustry. Italy's unique business processes and practices were studied to come up with a collection and merchandising ideas in a niche market. By selecting this venue we are able to continuously grow and develop in a market with diverse consumer needs. To analyze the Italian fashion market, data from 3 institutions were utilized, namely, CIT-ER which has provided consumer trends and sales analysis, SITA,a data service provided statistics from the textile and apparel businesses, and NBI has also furnished valuable data. Italian consumer preference, buying behavior, consumer profile, retail channels and other related data from the above institutions has formed a backbone for market segmentation and target markets, and as a result, we were able to zero in on the type of consumer, produce, pricing and retail channels for our womenswear. Going forward the direction is to elevate product image and pretige, and create syn-ergy between related industries, and at the same note, in order to develop internationally recognized brands such as Max Mara and Benetton. Certain elements such as the specialization of the fashion industry, alon-g with fashion-related data base and systems support, and most importantly experts with acute fashion sense and capacity to analyze pertinent data are in need. I firmly believe that we can achieve Italy's level in the fashion market with support from the government and unrelenting effort within the industry itself, and hope that this report can prove to be useful.

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Improved Method Evaluating the Stiffness Matrices of Thin-walled Beam on Elastic Foundations (탄성지반위에 놓인 박벽보의 강성행렬산정을 위한 개선된 해석기법)

  • Kim, Nam-Il;Jung, Sung-Yeop;Lee, Jun-Seok;Kim, Moon-Young
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.2
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    • pp.113-125
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    • 2007
  • Improved numerical method to obtain the exact stiffness matrices is newly proposed to perform the spatially coupled elastic and stability analyses of non-symmetric and open/closed thin-walled beam on elastic foundation. This method overcomes drawbacks of the previous method to evaluate the exact stiffness matrix for the spatially coupled stability analysis of thin-walled beam-column This numerical technique is accomplished via a generalized eigenproblem associated with 14 displacement parameters by transforming equilibrium equations to a set of first order simultaneous ordinary differential equations. Next polynomial expressions as trial solutions are assumed for displacement parameters corresponding to zero eigenvalues and the eigenmodes containing undetermined parameters equal to the number of zero eigenvalues are determined by invoking the identity condition. And then the exact displacement functions are constructed by combining eigensolutions and polynomial solutions corresponding to non-zero and zero eigenvalues, respectively. Consequently an exact stiffness matrix is evaluated by applying the member force-deformation relationships to these displacement functions. In order to illustrate the accuracy and the practical usefulness of this study, the numerical solutions are compared with results obtained from the thin-walled beam and shell elements.

A Study on the Factors Affecting Relationship Retention in Medical Service - Focus on Customers' Self-Determination - (의료서비스 고객의 관계지속에 영향을 미치는 요인에 대한 연구 - 고객관점의 자기결정성을 중심으로 -)

  • Suh, Munshik
    • Management & Information Systems Review
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    • v.33 no.3
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    • pp.35-57
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    • 2014
  • Relationship marketing has been dealt with as an effective strategy for customer loyalty in prior research. It seems to be essential that organizations should make efforts to develop successful relationship between the organizations and the customers. However, a customers' voluntary efforts are also needed to strengthen the relationship meaningfully. Relationships are built on the foundations of mutuality. In other words, customers' efforts are necessary for relationship development, as well as an organization's efforts. Hereby, the role of customers for the development of a relationship with an organization has been overlooked in previous research so far. This study applied the Self-Determination Theory (SDT) to explain the role of customer motivation in developing customer relationship. Thus, the author chose customers who have experienced medical service recently as survey participants. Then, this paper verified the path relationships between self-determination factors (autonomy, perceived competence, relatedness) and relational factors(shared responsibility, commitment, relationship retention). It suggested that role of customers is inevitable in developing the relationship. In conclusion, this research has several implications on relationship marketing. For service providers, they should understand that the customer's perceived self-determination can improve tangible and intangible performance in relationship development.

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Basic study of new concept environment-friendly pile foundations with earthquake resistant foundation and lateral reinforcement on rapid-transit railway bridge (고속철도교 기초 내진 및 수평저항성능 보강형 신개념 친환경말뚝 신공법의 실용화 기초연구)

  • SaGong, Myung;Paik, Kyu-Ho;Lim, Hae-Sik;Cho, Kook-Hwan;Na, Kyung
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.880-894
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    • 2010
  • The Grout injected precast pile is widely used in rapid-transit railway bridge recently. The existing portland cement of well used filling at injected precast method that with low strength and environmental pollution, unstable in which ground water contamination by cement flow out, ground relaxation by water down, decrease of horizontality resistance and durability and load transfer divide etc. In particular, as in rapid-transit railway bridge need to secure safety from different angle with vibration of high speed train, horizontal force when train stop and earthquake. Works of foundation construction consider to requirements of the times to coal yard green growth. Together, new green foundation method for possible economics and securing of reduce the term of works are material to developments. Therefore, we carried out study that it is using and development new concept environment - friendly filling include durability and earthquake resistance, for secure safety and minimize environment pollution. To achieve this, we carried out difference tests that new green fillings of underwater concrete, high liquidity, high viscosity, early stiffness as compared to existing portland cement fillings. As results, new green filling have outstanding application at precast pile method and micropile construction method with vertical bearing capacity, horizontal bearing capacity and many case. From now on we will be looking forward to development of new environment-friendly foundation method from various further studies.

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불국사 석탑의 지반 특성에 대한 지구물리탐사

  • Seo, Man-Cheol;O, Jin-Yong;Choe, Hui-Su
    • Journal of the Korean Geophysical Society
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    • v.5 no.2
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    • pp.143-151
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    • 2002
  • Bulku temple in the city of Kyungju, Korea, built in 791 and reconstructed in the 20th century, is the home of seven national treasures including two three-story stone pagodas, Dabotap (height 10.4m, width 7.4m, weight 123.2ton) and Seokgatap (height 10.8m, width 4.4m, weight 82.3 ton). An earlier archaeological investigation shows that stone pagodas have experienced severe weathering process which will threaten their stability. At the base part of Dabotap, an offset of the stone alignment is also observed. For the purpose of the structural safety diagnosis of two pagodas, we introduce the nondestructive geophysical methods. Site characteristics around the pagodas are determined by the measurement of multiple properties such as seismic velocity, resistivity, image of GPR(ground-penetrating radar). Near the pagodas, the occurrence of high resistivity (up to 2200 Ωm) is obvious whereas their outskirts have as low as 200 Ωm. For the velocity of the P wave, the site of Dabotap has the range of 500~800 m/s which is higher than counterpart of Seokgatap with the velocity of 300~500m/s, indicating the solider stability of Dabotap site. Consequently, in addition to GPR images, the foundation boundaries beneath each stone pagodas are revealed. The Dabotap site is in the form of an octagon having 6-m-long side with the depth of ~4m, whereas the Seokgatap site the 9m × 10m rectangle with the depth of 3m. These subsurface structures appear to reflect the original foundations constructed against the stone load of ~8 ton/㎡. At the subsurface beneath the northeast of each pagoda, low seismic velocity as well as low resistivity is prominent. It is interpreted to represent the weak underground condition.

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