• Title/Summary/Keyword: Foundations

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A Study on the Education & Wearing Behaviors about Foundation for Middle and High School Girls (여자 중.고등학생의 화운데이션 교육과 착용실태에 관한 연구)

  • Shin, Ji-Young;Oh, Kyung-Wha
    • Journal of the Korean Society of Clothing and Textiles
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    • v.32 no.4
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    • pp.517-529
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    • 2008
  • The education status of the body make-up foundations for teenage girls was evaluated and their purchase & wearing behaviors and the level of satisfaction were studied to analyze the relationship between education level and wearing satisfaction. The research was conducted for 728 middle and high school girls in Seoul and Incheon area, by the questionnaire method. The collected data was analyzed by SPSS. Frequency, percentage, average, standard deviation, $X^2$-test, t-test, and ANOVA were performed. Among various foundation education contents learned in home economics class, most students were aware of the kind of underwear, the fiber content & management methods, laundry methods, and the kind and function of foundations. While more than 80% of all respondents didn't know about the size of foundations. As a results, most of students realized the influence of foundation wearing on the human body, selection methods for brassiere and girdle according to form and age, and matters to be attended to wear brassiere and girdle. The education standard, practical use, and awareness degree on the side effects, and the need for foundation education were positively related each other. Therefore, it is very important to educate teenage girls in the fast growth period the right selection of foundation and its effect on body health, in order to provide normal growth and healthy body.

The UndrainBd Behavir or of Drilled Shaft Foundations Subjected to Static Inclined Loading (정적 경사하중을 받는 현장타설 말뚝기초의 비배수 거동)

  • ;Kulhawy, Fred H.
    • Geotechnical Engineering
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    • v.11 no.3
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    • pp.91-112
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    • 1995
  • Drilled shafts are used increasingly as the foundations for many types of structures. However, very little knowledge of drilled shaft behavior under inclined load is available. In this study, a systematic experimental testing program was conducted to understand the undrained behavior of drilled shaft foundations under inclined loads. A semi-theoretical method of predicting the inclined capacity was developed through a parametric study of the variables such as shaft geometry and load inclination. Test parameters were chosen to be representative of those most frequently used in the electric utility industry. Short, rigid shafts with varying depth/diameter(D/B) ratios were addressed, and loading modes were investigated that includes exial uplift, inclined uplift, and inclined compression loads. Capacities were evaluated using the structural interaction formula and an equation developed from this experimental study. This new equation models the laboratory data well and is applicable for the limites field data.

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A Study on the Improvement of Pile Foundations Based on the Analysis of Field Case Studies (말뚝기초 시공사례 실태분석을 통한 개선방안 연구)

  • Woo, Jae-Gyung;Lee, Su-Gon;Lee, Byok-Kyu;Jang, Seung-Jin
    • Journal of the Society of Disaster Information
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    • v.8 no.1
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    • pp.81-92
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    • 2012
  • In this study, in-depth site investigation related to design and construction of pile foundation was carried out, especially with respect to 103 large-scale bridges located in South Korea. As a result, the depths and location of investigation was unsatisfactory at the foundation investigation process. Moreover, pile load tests were not performed when the capacity of the file is calculated in planning phase, and it was difficult to determine the load capacity limit due to the fact that loading capacity was not specified in pile-loading test. The design criteria related to pile foundation does not reflect the reality of the construction site, and that causes over design, and economic inefficiency in budget. Therefore, the purposes of this study is to review case studies related to the bearing capacity of pile foundations and suggest improvements in the construction specifications.

A Study on the Image of Adult Foundations (남.녀 파운데이션 이미지 연구)

  • Lee, Hyo-Jin;Yang, A-Rang
    • The Research Journal of the Costume Culture
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    • v.19 no.2
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    • pp.255-268
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    • 2011
  • This study carefully explored today's preferable beauty images, analyzed Korean adult purchasing trends of functional underwear and market analysis of the most popular items and their designs. Information and methods are based largely on reference book material as well as analysis of real domestic data. The paper's research timeline simply spans the last three years, as in accordance with project parameters. Helping improve body shape, foundation literally means 'substructur' and 'base'. The formativeness in these adult foundations typically has three main category classifications. First, natural modern image. This is where we find natural beauty including that which embodies a cool modern sense. Here, you can often see such patterns as either stripes and dots, or simply no patterns at all. Colors are green, red-brown, incarnadine, or khaki from a natural or basic human body color. Its products are marketed as both solid and durable eco-friendly materials, and lace-seethrough. Fashion's natural modern image is undoubtedly the most popular style purchase choice among both genders. Second, sweet romantic image. This mainly consists of two concepts : a sweet and romantic theme, and visual appeal. Patterns include flowers, lips, heart, stars, candies and various other appealing characters. Its main colors are pink, yellow, red, purple, and violet. Products are decorated with laces, frills and ribbons. Since only men's semi-girdles carry such designs, this fashion foundation is largely a women's world. While men show an obvious interest in foundation, they still mostly prefer the choice of natural modern images. Third, mystic sexy image. This is defined as all feminine images of mysterious and classic sexual beauty. Patterns are variously expressed as paisley, flowers, and geometric. Colors are largely purple, blue-green, royal-blue, cobalt, and black. Products are commonly decorated with beading, spangles, hot-fixes and so on. While this image can be found in all kinds of women's foundations, it typically appears only in men's corsets and girdles.

Jacking Penetration Resistance of Bucket Foundations in Silty Sand Using Centrifuge Modelling (실트질모래 지반에서 버켓기초의 압입저항력에 대한 원심모형실험 연구)

  • Kim, Dong-Joon;Youn, Jun-Ung;Lee, Kyu-Yeol;Jee, Sung-Hyun;Choo, Yun Wook
    • Journal of the Korean Geotechnical Society
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    • v.31 no.1
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    • pp.25-35
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    • 2015
  • Penetration resistance of bucket foundations with skirt wall in the silty sand of the western coast of Korea was analyzed by centrifuge modelling. The penetration resistance is induced when the bucket foundations are jacked into the soil without suction, and is directly related to the self-weight penetration depth. The procedure by Houlsby and Byrne (2005), which takes into account the effect of stress increase by frictional resistance of skirt wall, was utilized to generate the penetration resistance similar to the experimental results. This paper describes the methods by which major parameters such as lateral earth pressure coefficient and friction angle between the skirt wall and the soil are evaluated. The effect of changes in these parameters on the predictions is analyzed. Also, observed soil behaviour during jacking penetration is investigated.

Static impedance functions for monopiles supporting offshore wind turbines in nonhomogeneous soils-emphasis on soil/monopile interface characteristics

  • Abed, Younes;Bouzid, Djillali Amar;Bhattacharya, Subhamoy;Aissa, Mohammed H.
    • Earthquakes and Structures
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    • v.10 no.5
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    • pp.1143-1179
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    • 2016
  • Offshore wind turbines are considered as a fundamental part to develop substantial, alternative energy sources. In this highly flexible structures, monopiles are usually used as support foundations. Since the monopiles are large diameter (3.5 to 7 m) deep foundations, they result in extremely stiff short monopiles where the slenderness (length to diameter) may range between 5 and 10. Consequently, their elastic deformation patterns under lateral loading differ from those of small diameter monopiles usually employed for supporting structures in offshore oil and gas industry. For this reason, design recommendations (API and DNV) are not appropriate for designing foundations for offshore wind turbine structures as they have been established on the basis of full-scale load tests on long, slender and flexible piles. Furthermore, as these facilities are very sensitive to rotations and dynamic changes in the soil-pile system, the accurate prediction of monopile head displacement and rotation constitutes a design criterion of paramount importance. In this paper, the Fourier Series Aided Finite Element Method (FSAFEM) is employed for the determination of static impedance functions of monopiles for OWT subjected to horizontal force and/or to an overturning moment, where a non-homogeneous soil profile has been considered. On the basis of an extensive parametric study, and in order to address the problem of head stiffness of short monopiles, approximate analytical formulae are obtained for lateral stiffness $K_L$, rotational stiffness $K_R$ and cross coupling stiffness $K_{LR}$ for both rough and smooth interfaces. Theses expressions which depend only on the values of the monopile slenderness $L/D_p$ rather than the relative soil/monopile rigidity $E_p/E_s$ usually found in the offshore platforms designing codes (DNV code for example) have been incorporated in the expressions of the OWT natural frequency of four wind farm sites. Excellent agreement has been found between the computed and the measured natural frequencies.

Economic Feasibility of Bucket Foundation for Offshore Wind Farm (해상풍력발전 버켓기초공법의 경제성 평가)

  • Oh, Myoung-Hak;Kwon, O-Soon;Kim, Keun-Soo;Jang, In-Sung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.4
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    • pp.1908-1914
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    • 2012
  • As the turbine capacity and the water depth of wind farms are increasing, the construction cost of substructures and foundations for offshore wind turbines is expected to increase. Since the installation of suction bucket foundation is achieved by both self-weight and applied suction, the construction generally does not require heavy equipment for penetration. This study provides an economic analysis on the tripod which have the bucket foundations and compares that the jacket foundation at 50m water depth on sand layer or soft layer. As the strength of the soil and the number of the foundation is increasing, the construction cost of the tripod with the bucket foundations is more economically feasible than the jacket foundation.

Study on the Dynamic Characteristics of Foundation-Soil System for the Seismic Analysis of Structures (구조물 내진설계를 위한 기초지반체계 동특성에 관한 연구)

  • 김용석
    • Journal of the Earthquake Engineering Society of Korea
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    • v.1 no.3
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    • pp.1-10
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    • 1997
  • It is recognized that the dynamic of a structure is affected by the characteristics of the soil layer and foundation. However the design codes for the seismic design of structures are partially reflecting the caharcteristics of the soil layers due to the inherent complexity of them and the lack of systematic study results for the foundation-soil system, and leading to unconservative or too conservative results. In this study, the kinematic interaction effects of foundation-soil system was investigated for the seismic analyses of structures estimating the effects of the shear wave velocity, the depth of the soil layer, the embedment of a foundation and pile foundation, and the modified classification criteria of soil layers are proposed for the reasonable seismic analyses of structures considering the characteristics of soil layers and foundations. For the embedded medium or large foundations (including pile foundations), at least 60m soil layer below the foundation should be considered for the seismic analyses of structures to tate into account the kinematic interaction effects of the foundation-soil system, and also the rocking motion of foundation-soil system with or without piles should be included in the seismic analyses of structures.

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Accumulated Rotations of Suction Bucket Foundations under Long-term Cyclic Loads in Dry Sandy Ground (건조 사질토 지반에 설치된 석션 버켓기초의 장기 반복하중에 의한 누적회전각 산정)

  • Lee, Si-Hoon;Choi, Changho;Kim, Sung-Ryul
    • Journal of the Korean Geotechnical Society
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    • v.32 no.12
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    • pp.69-78
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    • 2016
  • A suction bucket foundation has been considered to be a potential foundation type for offshore wind turbines. A suction bucket foundation is usually installed in soft soil, so the accumulated displacement of the foundation may occur under long-term cyclic loads. In this study, a series of 1-g model tests were performed to analyze the accumulated rotation of suction bucket foundations under long-term cyclic horizontal loads. The dry model ground was prepared to have two different soil densities by air-pluviation method. The model tests were performed varying the embedment depth of the suction bucket, the soil density, and the amplitude of cyclic load. A one-way horizontal cyclic load was applied over $10^4$ cycles. Test results showed that the accumulated rotation of the suction bucket foundation increased with the increase in the number of cycles and load magnitudes. Based on the model test results, a new equation was proposed to evaluate the accumulated rotation of the suction bucket foundations in dry sandy ground under long-term cyclic horizontal loads.

The Behavior and Resistance of Connected-pile Foundations for Transmission Tower from In-situ Lateral Load Tests (송전용 철탑기초의 현장수평재하시험을 통한 연결형 말뚝기초의 거동 및 지지력특성)

  • Kyung, Doo-Hyun;Lee, Jun-Hwan;Paik, Kyu-Ho;Kim, Dae-Hong;Kim, Dae-Hak
    • Journal of the Korean Geotechnical Society
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    • v.28 no.2
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    • pp.57-70
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    • 2012
  • For soft ground, a pile foundation is typically used as a substructure of transmission tower. However, differential settlement between the foundations can cause structural damage of transmission tower. The connected-pile foundation is a type of group foundation consisting of four foundations connected with beams, and it was suggested in USA and Japan. In this study, a series of 1/8 scale model pile tests were performed to investigate the effect of load direction and stiffness of connecting beam on the responses of connected-pile foundation. As a result, the load capacities of the connected-pile foundation were larger than those of the conventional group pile foundation. For example, under the given test conditions in this paper, the resistibility against differential settlement was improved significantly for connected-pile foundation and its efficiency was maximized when the stiffness of connecting beams is about 25% of the mat foundation.