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Parametric analysis of hybrid outrigger system under wind and seismic loads

  • Neethu Elizabeth Johna;Kiran Kamath
    • Structural Engineering and Mechanics
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    • v.86 no.4
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    • pp.503-518
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    • 2023
  • In tall constructions, the outriggers are regarded as a structural part capable of effectively resisting lateral loads. This study analyses the efficacy of hybrid outrigger system in high rise RCC building for various structural parameters identified. For variations in α, which is defined as the ratio of the relative flexural stiffness of the core to the axial rigidity of the column, static and dynamic analyses of hybrid outrigger system having a virtual and a conventional outrigger at two distinct levels were conducted in the present study. An investigation on the optimal outrigger position was performed by taking the results from absolute maximum inter storey drift ratio (ISDmax), roof acceleration (accroof), roof displacement (disproof), and base bending moment under both wind and seismic loads on analytical models having 40, 60 and 80 storeys. An ideal performance index parameter was introduced and was utilized to obtain the optimal position of the hybrid outrigger system considering the combined response of ISDmax, accroof, disproof and, criteria required for the structure under wind and seismic loads. According to the behavioural study, increasing the column area and outrigger arm length will maximise the performance of the hybrid outrigger system. The analysis results are summarized in a flowchart which provides the optimal positions obtained for each dependent parameter and based on ideal performance index which can be used to make initial suggestions for installing a hybrid outrigger system.

Inelastic Behavior of Post-tensioned Wide Beam System with different Reinforcement ratios within Column core (포스트텐션을 도입한 넓은 보에서 기둥 폭 내부에 배근된 보강재의 정착비에 따른 비탄성 거동 평가)

  • Choi Yun-Cheul;Lim Jae-Hyung;Moon Jeong-Ho;Lee Li-Hyung;Kwon Ki-Hyuk
    • Journal of the Korea Concrete Institute
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    • v.17 no.1 s.85
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    • pp.85-94
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    • 2005
  • Post-tensioned Precast concrete System(PPS) consists of U-shaped precast wide beams and concrete column. The continuity of beam-column joint is provided with floor concrete cast on the PC shell beam and post-tensioning. The purpose of this paper is to evaluate the response of PPS interior beam-column joint subjected to cyclic lateral loading. To this end, an experimental investigation was performed with three half-scale specimens of interior connection. The design parameters are the amount of beam reinforcement placed inside the joint core. The test results showed that cracks were distributed well without my significant degradation of strength and ductility. Also, it was found that the prestressing may affect to alter the torsional crack angle. And the specimens sufficiently resist up to limiting drift ratio of 0.035 in accordance with the provisional by ACl of acceptance criteria for concrete special moment frames.

A New Refined Truss Modeling for Shear-Critical RC Members (Part I) - lts derivation of Basic Concept - (전단이 지배하는 RC부재의 새로운 트러스 모델링 기법 연구 (전편) - 기본 개념 유도를 중심으로 -)

  • Kim Woo;Jeong Jae-Pyong;Kim Dae-Joong
    • Journal of the Korea Concrete Institute
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    • v.16 no.6 s.84
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    • pp.785-794
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    • 2004
  • This paper describes a new refined truss modeling technique derived based on the well-known relationship of V=dM/dx=zdT/dx+Tdz/dx in a reinforced concrete beam subjected to combined shear and moment loads. The core of the model is that a new perspective on the shear behavior can be gained by considering the variation of the internal arm length along the span, so that the shear resistance mechanism can be expressed by the sum of two base components; arch action and beam action. The sharing ratio of these two actions is determined by accounting for the compatibility of deformation associated to the two actions. Modified Compression Field Theory and the tension-stiffening effect formula in CEB/FIP MC-90 are employed in calculating the deformations. Then the base equation of V=dM/dx has been numerically duplicated to form a new refined truss model.

Community Health Education (지역사회 보건교육)

  • Lee, Ju-Yul;Park, Chun-Man;Suh, Mee-Kyung;Choi, Eun-Jin
    • Korean Journal of Health Education and Promotion
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    • v.24 no.4
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    • pp.241-249
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    • 2007
  • Health education aims at behavior change rather than just delivering health knowledge to people. In Korea health education activities in public sector began in 1960 and they were included in the primary prevention program in communities. This article reviewed current health education programs in healthy living practice programs provided by local public health centers in Korea and drew implications for the future role of health education in community setting. Health education has been a core function of the National Health Promotion programs in the nation since the enactment of the National Health Promotion Law in 1995. The National Health Promotion programs are funded by the National Health Promotion Fund which are drawn from tobacco tax. The National Health Promotion programs include healthy living practice programs (smoking prevention and cessation programs, moderate alcohol use programs, physical activity promotion programs, and nutrition programs), chronic disease prevention programs, oral health programs and public hygiene programs. Methods of the National Health Promotion programs include health education, health counseling, health class, health information management, survey and research. Smoking prevention and cessation programs include smoking cessation clinic, smoking cessation education, non-smoking environment program, and non-smoking campaign. Moderate alcohol use programs include alcohol use education, moderate alcohol use campaign, alcohol use counseling, and alcohol free environment programs. Physical activity promotion programs include obesity control, targeted exercise program, and exercise civic group programs. Nutrition programs include nutrition management, obesity management, nutrition education, breakfast eating program, and nutrition counseling and treatment programs. The health education programs in community are not efficient today because there are many overlapping contents and short term goals. Community health education programs needs to be more comprehensive. Workforce development is another big issue at the moment because the National credential program will begin in 2009. Variety of community health education programs should be developed and funded by the national health promotion fund.

Study on the Performance of Infrared Thermal Imaging Light Source for Detection of Impact Defects in CFRP Composite Sandwich Panels

  • Park, Hee-Sang;Choi, Man-Yong;Kwon, Koo-Ahn;Park, Jeong-Hak;Choi, Won-Jae;Jung, Hyun-Chul
    • Journal of the Korean Society for Nondestructive Testing
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    • v.37 no.2
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    • pp.91-98
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    • 2017
  • Recently, composite materials have been mainly used in the main wings, ailerons, and fuselages of aircraft and rotor blades of helicopters. Composite materials used in rapid moving structures are subject to impact by hail, lightning, and bird strike. Such an impact can destroy fiber tissues in the composite materials as well as deform the composite materials, resulting in various problems such as weakened rigidity of the composite structure and penetration of water into tiny cracks. In this study, experiments were conducted using a 2 kW halogen lamp which is most frequently used as a light source, a 2 kW near-infrared lamp, which is used for heating to a high temperature, and a 6 kW xenon flash lamp which emits a large amount of energy for a moment. CFRP composite sandwich panels using Nomex honeycomb core were used as the specimens. Experiments were carried out under impact damages of 1, 4 and 8 J. It was found that the detection of defects was fast when the xenon flash lamp was used. The detection of damaged regions was excellent when the halogen lamp was used. Furthermore, the near-infrared lamp is an effective technology for showing the surface of a test object.

Inquisition of Meaning in Life for Logotherapy Application in Hospice Nursing (호스피스 간호에서 의미요법 적용을 위한 생의 의미 고찰)

  • Choi, Soon-Ock;Kim, Sook-Nam
    • The Journal of Korean Academic Society of Nursing Education
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    • v.9 no.2
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    • pp.329-339
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    • 2003
  • The purpose of this study is to consider of meaning in life based on Frankl's theory and to propose of hospice nursing according to conceptual framework of meaning in life. The conceptual framework of meaning in life is composed of 4 phases. According to the first phase, acceptance & awareness of self and life, hospice nurse should helps dying patient to accept limitedness of human existence and death. and according to the second phase, actualization of creative value, hospice nurse can helps dying patient to discover meaning in life through doing a deed for last time before his death. According to the third phase, actualization of experiential value, hospice nurse can helps them to discovery of meaning by experiencing of love through meetings with other people, nature, and god. According to the forth phase, actualization of attitudinal value, hospice nurse can helps them to discovery of meaning by realizing meaning in suffering and death through exercising of the inner freedom to choose bravery and acceptance in the face of death and misfortune. As mentioned above, the Frankl's theory accords with the core of hospice nursing that helps people to accomplish human essence in suffering and death. therefore we accepted Frankl's point of view, asserted that one of the most important roles of a hospice nurse as a supporter and sustainer for dying patients is to help patients to find meaning in life even in the course of death. To achieve the goal, hospice nurses should try to have a firm faith through philosophical introspection about life, death, human existence and meaning in life what the most important goal of life is to discover meaning in life and human have the duty and responsibility of recognizing and pursuing meaning up to the last moment of life.

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A Study on the Reform Plan of Computer Education Curriculum(I) - Characteristics & Learning Objectives - (컴퓨터교과 교육과정 개정 방안 연구(I) - 성격 및 목표를 중심으로 -)

  • Kim, Tae-Gyun;Kang, Shin-Cheon
    • The Journal of Korean Association of Computer Education
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    • v.10 no.2
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    • pp.1-8
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    • 2007
  • Although the core of national competitiveness in the knowledge information society lies in IT, school education at the moment is failing to execute systematic and organized computer education. Recently, the 7th on-demand partial amendment of educational curriculum at national level is being executed in full-scale. Educational curriculum for elementary and middle class at national level is the systematic and organized program for cultivation of competent persons in order to foster the desired image of human kind for the future society pursued by the nation. For such reason, stabilization of program for cultivation of competent persons for establishment of true IT superpower is not irrelevant with the 7th amendment of the educational curriculum. Therefore, this thesis shall look into the 7th national level education curriculum at level of general outline as well as their particulars, and present means of amendment of computer subject educational curriculum through the means connecting the issues raised in general outline and their particulars regarding the direction of the amendment of the national level educational curriculum for establishment of true IT superpower.

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Forces and Displacements of Highrise Braced Frames with Facade Riggers (여러개의 파사드리거를 갖는 고층구조물의 응력과 변위)

  • Yuk, Min-Hye;Jung, Dong-Jo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.18 no.2
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    • pp.181-190
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    • 2005
  • In the conventional outrigger system, the outriggers are located in the planes of the core walls and this system has disadvantage of obstructing flexibility in the interior layout. But thc facade riggers in the structure uc located In the exterior frames in the direction of the lateral loading. The interaction between the traced frames and facade riggers is through the floor diaphragms adjacent to the chords of the riggers. This paper presents an approximate analysis technique lot preliminary analysis of multiple facade rigger stiffened braced frames in tall buildings subjected to uniformly and triangularly distributed loads as well as a lateral point load at the top of the structure. Comparisons with the results by the program MIDAS for the structural models have shown that this analysis can give reasonably accurate results for highrise braced frames with multiple facade riggers. The method allows a simple procedure for obtaining the optimum level of the facade riggers in addition to a rapid assessment of the influence of the facade riggers on the performance of the highrise structure such as the reduction in lateral deflection at the top and the overturning moment at the base of the braced frame.

Evaluation of a Drill Bit Button Arrangement for Enhanced Drilling Efficiency (천공 효율 향상을 위한 드릴비트 버튼배열 성능평가 방법)

  • Kang, Hoon;Cho, Jung Woo;Jeong, Myeong Sik;Cho, Yong Jae;Lee, Sang Kon;Lee, Jae Wook
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.6
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    • pp.575-581
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    • 2015
  • The drill bit, which directly transmits percussive forces and torque to the rock, is the core part of a rock drilling machine. For effective drilling, the button arrangement of a drill bit should be optimized because it is the most important design factor in determining drilling efficiency. Furthermore, a quantitative method is necessary to evaluate the button arrangement for the optimization of the drill bit button. Therefore, we propose a new method for the evaluation of the drill bit button arrangement using new evaluation indices, which include the overlapped impact area, blank area, and moment. Moreover, we verify the suitability of the proposed evaluation method by applying it to the conventional button arrangement.

The Changes in Range of Motion after a Lumbar Spinal Arthroplasty with Charite$^{TM}$ in the Human Cadaveric Spine under Physiologic Compressive Follower Preload: A Comparative Study between Load Control Protocol and Hybrid Protocol

  • Kim, Se-Hoon;Chang, Ung-Kyu;Chang, Jae-Chil;Chun, Kwon-Soo;Lim, T. Jesse;Kim, Daniel H.
    • Journal of Korean Neurosurgical Society
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    • v.46 no.2
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    • pp.144-151
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    • 2009
  • Objective: To compare two testing protocols for evaluating range of motion (ROM) changes in the preloaded cadaveric spines implanted with a mobile core type Charite$^{TM}$ lumbar artificial disc. Methods: Using five human cadaveric lumbosacral spines (L2-S2), baseline ROMs were measured with a bending moment of 8 Nm for all motion modes (flexion/extension, lateral bending, and axial rotation) in intact spine. The ROM was tracked using a video-based motion-capturing system. After the Charite$^{TM}$ disc was implanted at the L4-L5 level, the measurement was repeated using two different methods: 1) loading up to 8 Nm with the compressive follower preload as in testing the intact spine (Load control protocol), 2) loading in displacement control until the total ROM of L2-S2 matches that when the intact spine was loaded under load control (Hybrid protocol). The comparison between the data of each protocol was performed. Results: The ROMs of the L4-L5 arthroplasty level were increased in all test modalities (p < 0.05 in bending and rotation) under both load and hybrid protocols. At the adjacent segments, the ROMs were increased in all modes except flexion under load control protocol. Under hybrid protocol, the adjacent segments demonstrated decreased ROMs in all modalities except extension at the inferior segment. Statistical significance between load and hybrid protocols was observed during bending and rotation at the operative and adjacent levels (p< 0.05). Conclusion: In hybrid protocol, the Charite$^{TM}$ disc provided a relatively better restoration of ROM, than in the load control protocol, reproducing clinical observations in terms of motion following surgery.