• Title/Summary/Keyword: maintenance behavior

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Effect of Strengthening amount and length of CFS on Flexural Behavior of RC Beams (탄소섬유쉬트의 보강량 및 정착길이가 RC보의 휨거동에 미치는 영향)

  • Shin, Sung Woo;Bahn, Byong Youl;Ahn, Jong Mun;Cho, In Chol
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.2 no.2
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    • pp.195-201
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    • 1998
  • The purpose of this study is to evaluate the flexural strengthening effects of RC beams reinforced with carbon fiber sheets (CFS) in variable of strengthening amount and anchorage length of CFS. This study can be summarized as follows ; The CFS shares the tensile stress such as rebar during loading test. Also, as the strengthening amount of CFS is increased, the maximum flexural strength of RC beams reinforced with CFS is increased. Therefore, it is confirmed that the CFS's strengthening method is very effective to improve the flexural strength of RC beams. The maximum flexural strength of RC beams with CFS is determined by bond failure between CFS and concrete surface. So, the evaluation of CFS's strengthening effect can be calculated using the tensile stress of CFS which is peeling. When the anchorage length of CFS is increased, the ductility of RC beams is increased because of delaying the peeling of CFS. But, in case of same anchorage length of CFS, when the strengthening amount of CFS is increased, the ductility is decreased. Therefore, it is considered that the anchorage of CFS in the end zone is necessary.

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An Experimental Study on the Structural Behavior of Reinforced Concrete Columns Rehabilitated with Epoxy-Bonded Steel Plates (강판으로 보강된 철근콘크리트 기둥의 구조적 거동에 관한 실험적 연구)

  • Kim, Jin-Bai;Won, Young-Sul;Cho, Chul-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.3 no.3
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    • pp.269-277
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    • 1999
  • The purpose of this study is to investigate the structural behavior of reinforced concrete columns rehabilitated with epoxy-bonded steel plates subjected to axial load. Eleven specimens were made to evaluate structural capacity of reinforced concrete columns rehabilitated with steel plates. This study considers the change of the internal force and the deformation of reinforced concrete column with reinforcing steel plates, and analyzes the effect of the improvement of strength and ductility. Based on the test results, this study brings the following conclusions. In case of the effect of reinforcement by the ratio of the same volume, the internal force for the test model, which the width of the reinforcing steel plate is small, is effectively higher. The smaller the width and the thickness of reinforcing steel plate, the more effective the effect of reinforcement is. For applying the theorical equation by Uzumeri, the maximum load and the coefficient of effective crossing reinforcement by the width and the thickness of steel plate reflected the properties of reinforcing steel plate.

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Comparison of Statistical Models for Analysis of Fatigue Life of Cable (케이블 피로 수명 해석 통계 모델 비교)

  • Suh, Jeong-In;Yoo, Sung-Won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.4
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    • pp.129-137
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    • 2003
  • The cable in the cable-supported structures is long, therefore it can be reasonable to apply the different models, compared with those used for general steel elements. This paper compares the statistical models with existing cable fatigue data, after deriving the cdf(cumulative distibution function) with modifying the log-normal distribution, the existing extremal distributions so as to include length effect. The paper presents the appropriate model for analyzing and assessing the fatigue behavior of cable which is being used for actual structures.

Ultimate Behavior of Steel Beam Strengthened with External Tendonand Cylindrical Anchorage (원통형 정착구를 사용하고 외부 긴장재로 보강된 강재보의 극한거동)

  • Choe, Dong-Ho;Jeong, Sang-Hwan;Jung, Jae-Dong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.2
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    • pp.102-110
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    • 2006
  • This paper examines experimentally the ultimate behavior of I-type steel beam strengthened with external tendon and cylindrical anchorage and analyzes the strengthening effect on the parameters such as initial tendon force, eccentricity, number of strands, and strand areas. The experiment demonstrated that increasing the number of strands, strand areas and eccentricity is more effective than increasing initial tendon force. The proposed cylindrical anchorage system has advantages in applying these parameters. The results showed that the cylindrical anchorage system is efficient and applicable to strengthen steel beam.

Fracture Characteristics of RC Beams Reinforced with GFSP (유리섬유-강 복합판으로 보강된 RC 보의 파괴 특성)

  • Kim, Chung Ho;Jang, Hee Suk;Ko, Sin Woong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.5
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    • pp.153-159
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    • 2007
  • This paper is experimental investigation for failure characteristics and performance of a RC beams strengthened with GFSP which were developed for improvement of the early debonding problems in the externally bonded FRP systems. To represent damages and load conditions of the existing beam, pre-cracks and repeating loads are adopted for experimental parameters. In this experiment, it is confirmed that strengthening with GFSP is a very effective strengthening method for an increase in strength, a decrease in deflection, a control of the crack. But it shown that the design of the beams to be strengthened with GFSP should be consider a brittle behavior of the grass fiber on the flexural capacity.

Two-Demensional Nonlinear Analysis of Precast Segmental PSC-I Girder with Wet Joint (습식접합부를 갖는 프리캐스트 세그먼트 PSC-I형 거더의 2차원 비선형해석)

  • Kim, Kwang-Soo;Hong, Sung-Nam;Han, Kyoung-Bong;Park, Sun-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.6
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    • pp.103-112
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    • 2007
  • The purpose of this study is to evaluate the characteristics of the structural behavior in precast segmental prestressed concrete girders, which consist of five precast segments. These girders were developed to save labor and cost in construction field reducing a term of work. Therefore, four different types of specimens of 25m in length were built, and they were tested and analyzed for observing flexural behavior. The analysis included the investigation of the flexural behaviors in varying tendon amount and at joints using the relationship between moment and deflection. Moreover, nonlinear finite element analysis was utilized to verify the experimental result.

Behavior of Coupling Shear Wall with New Openings (개구부 신설에 따른 병렬 전단벽의 거동특성)

  • Choi, Hyun-Ki;Choi, Youn-Cheul;Choi, Chang-Sik
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.5
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    • pp.152-160
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    • 2008
  • Since wall system apartment used the shear wall as main lateral resistance member, installation of openings which causing section loss of walls may cause significant problem to structure. Also, there are few studies for inducing coupling beam or slabs which are occurred by installing openings. Therefore, this study planned isolated 2-story shear walls which are reduced three half-scale specimen to find out walls behavior characteristic. The test results showed that strength reduction caused by loss of effective section of walls and different result of stiffness and energy dissipation regarding to the coupling beam and coupling slabs.

Evaluation of Behavior and Ductility of Reinforced Concrete Beams Strengthened With AFRP (AFRP로 보강된 철근콘크리트 보의 휨 거동과 연성도 평가)

  • Kim, Jun-Won;Kim, Tae-Wan;Hong, Sung-Nam;Park, Sun-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.2 s.54
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    • pp.206-214
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    • 2009
  • Due to its outstanding feature, FRP is used widely for the material of strengthening in USA and Japan recently, and there have been active researches in korea as well. This study evaluates the behavior and ductility of each structure experiment using EBR and NSMR strengthening method with different AFRP types and strengthening area. There was the biggest increase in the load when the strengthening area is expanded showing a brittle aspect, and eventually the immature failure occurred. With regard to the methods, it is found that the NSMR method is more effective to strengthen the structure, and the uneven surface causes ductile failure.

Analysis of Failure Behavior of the Box Culvert with 3-Axes Loading System (3축 가력시스템에 의한 박스형 암거의 파괴거동 분석)

  • Woo, Sang-Kyun;Kwon, Yong-Gil;Cho, Jun-Hyong;Han, Sang-Hoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.5 s.57
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    • pp.142-148
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    • 2009
  • This paper is to investigate the fracture behavior characteristics of box culvert and incremental crack width of upper slab for the incremental loading by the 3-axis loading system. In the 3-axes loading system, loading directions are upper side, left and right side which simulate earth pressure and static traffic load. With the incremental load, crack patterns is investigated on the upper slab, left and right wall. Especially, on the upper slab, crack width is measured by crack gage. Based on the experimental results, structural internal force indices of box culvert are estimated quantitatively.

A Study on Value Orientation of Health of Rural Health Center Milieu (농촌지역 보건소 환경에 있어서의 건강가치관에 관한 일 조사연구)

  • 김순자
    • Journal of Korean Academy of Nursing
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    • v.5 no.1
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    • pp.17-30
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    • 1975
  • The concept and definition of nursing and her role have been changing in accordance with the socio-cultural factors of the initial society. At present, nursing is conceptualized as a health care profession assisting man to restore, maintain and promote health by providing knowledge, wilt strength and resources through various processes of interaction. Man′s behavior, of individual and group activities for health inclusive, is driven by the initial man′s value orientation. The purpose of this study is to investigate the value orientation regarding health of rural health center milieu in order to give data for; 1. the planning for the delivery of community nursing service, 2. the health education plan at all level of nursing care activities, and 3. the planning of curriculum for nursing education. A hundred opinion leaders among the labor population residing in rural areas (P-group), hundred and six professional nurses at rural health centers (N-group) were indirectly interviewed through questionaries. And ninety five of N-group were interviewed likewise of their perceptions of P-group (NP-group) from July 15, to October 15, 1974. The result is as follows: 1. Maintenance of health is revealed to be the most valued component for man′s happiness in all the three groups. (P-group: 7.30 S. D.=1.31), (N-group :7.84 S. D. =49), and (NP-group : 5.93 S. D. =2.28) 2. The average value score of the maintenance of health revealed significant difference by P〈.001 level between each of the three groups. (Between N-group and P-group : T= -4.07 P and NP ; T=-6.93, N and NP: T=-9.35) 3. Basic health maintenance activities necessary for maintenance and promotion of personal health were moderately valued by all the three groups, P-group ; 3.74 (S. D. =.43) , N-group: 3.52 (S. D. =.34), NP-group: 3.07 (S. D. :.55) Among the 8 categories of basic health maintenance activities, "food intake" was highly valued by P-group (mean value score; 4.00 S. D=.51) , "exercise and rest" and "personal cleanliness" was highly valued by both P-group (4.02, 4.08) and N-group (4.08, 4.22). 4. The mean value score of basic health maintenance activities revealed significant difference by P〈.001 level between each of the three groups (between P-group and N-group: T=-4, 07, N-and NP: T=-6.93, P and NP T=-9.35) 5. Among the 30 questionaries, dynamic activities for health maintenance were more valued in comparison to passive activities in an tile three groups. 6. In N-group, correlation between the value of basic health maintenance activities and the personal health status personal revealed moderate significance. Correlation between the value of basic health maintenance activities and the age revealed low significance. 7. In group, correlation between the value of basic health maintenance activities and; perception of personal health status revealed non significance, between the age and sex revealed low sign affiance, and between the educational status revealed moderate significance. Recommendations are as follows ; 1. The efforts towards alteration of value orientation concerning health in general in community nursing practice de focussed be that of family Planning. 2. In order to prepare professional nurses competent in understanding individual and group, social science and behavioral science be strength ended in planning nursing curriculum. 3. Milieu of nursing experience during nursing education be Planned to begin at simple nursing problem and move towards complex, f. e. home care towards health crisis situation in order to achieve dynamic role mastery.

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