• Title/Summary/Keyword: Strength of Concrete

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Study of the Reactivation for Art & Culture Content Space Centering to Local Area, Yeongwol (영월지역의 문화예술 콘텐츠 공간 활성화 방안)

  • Park, Ki-Bok
    • Cartoon and Animation Studies
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    • s.17
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    • pp.163-173
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    • 2009
  • The reactivation for Art & Culture Content Space in Gangwon province need new turning point according to new approach with internal and external change. That should be established in sustainable possibility model with preexisted natural advantage instead of economical depression and global warming of in these days. That is not a choice to get a successful construction of art & culture content space in Gangwon province. Throughout of reactivation of art & culture content space in Gangwon province, this proposal should go on with diversity of culture and concrete art & culture educational program absolutely to get a goal in regional economical success and social good influence. Already Yeongwol region had lots of art & cultural spaces and developmental strategy compared with other regions in decade. In these points, I choose this region and would like to research Yeongwol region in limit. Thus I would examine and study about art & culture content space in Yeongwol region. And I will concretely suggest that this proposal is composed with economical creating employment and incoming. The reactivation for Art &Culture Content Space in Yeongwol will build up social and cultural influences to this region to get a new modern cultural images and improvement of common life of regional people by and large. In the way of the process to globalization, this reactivation project for Art &Culture Content Space in Yeongwol should go on the base of regional culture background as a mean of glocalization paradigm strategically. Ahead of developing model for globalization in macroscopic view point, we have to research the demend of reginal situation of cultural content and build up its own strength points. Because Art & Culture Content Space in Yeongwol is the place of people in Yeongwol directly as itself. And managing plans of reactivation of art & culture content space in Yeongwol should build up with diversity of culture and environmental circumstances.

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Theoretical Analysis for Strengthening Effects of RC Beam with Reinforced FRP Sheet (FRP 시트로 보강된 RC 보의 보강 효과에 대한 이론적 분석)

  • Ha, Sang-Su
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.4
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    • pp.100-107
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    • 2018
  • The objective of this study is to assess the strengthening effects of fiber reinforced polymer(FRP) sheets such as Carbon fiber, Glass fiber, and PET(polyethylene terephthalate) on reinforced concrete flexural members. Variables of theoretical analysis are types of strengthening materials, material properties and amount of strengthening materials. A virtual flexural member without FRP sheets was created as a control specimen to understand the structural behavior of the non-strengthened specimen in terms of elastic and ultimate cross section. In total, 11 specimens including one non-strengthened and ten strengthened specimens were investigated. Various variables such as types of strengthening, strengthening properties, and amount of strengthening were studied to compare the behavior of the control specimen with those of strengthened specimens with regard to moment-curvature relationship. Results of theoretical analysis showed that the moment capacity of strengthened specimens was superior to that of the control specimen. However, the control specimen indicated the best ductility among all the specimens. As the amount of strengthening increased, flexural performance was improved. Furthermore, the results indicated that the ductile effect of members was affected by the ultimate strain of FRP sheets. The strengthening effect on the damaged member was similar to that on the non-damaged one since there was less than 10% difference in terms of flexural strength and ductility. Therefore, even if a damaged member is treated as non-damaged for analysis there is probably no noticeable difference.

Probabilistic Risk Assessment of a Cable-Stayed Bridge Based on the Prediction Method for the Combination of Failure Modes (붕괴모드 조합 예측법에 의한 PSC사장교의 위험도평가)

  • Park, Mi-Yun;Cho, Hyo-Nam;Cho, Taejun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.4A
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    • pp.647-657
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    • 2006
  • Probabilistic Risk Assessment considering statistically random variables is performed for the preliminary design of a Cable Stayed Bridge, which is Prestressed Concrete Bridge consisted of cable and plate girders, based on the method of Working Stress Design and Strength Design. Component reliabilities of cables and girders have been evaluated using the response surface of the design variables at the selected critical sections based on the maximum shear, positive and negative moment locations. Response Surface Method (RSM) is successfully applied for reliability analyses for this relatively small probability of failure of the complex structure, which is hard to obtain through Monte-Carlo Simulations. or through First Order Second Moment Method that can not easily calculate the derivative terms of implicit limit state functions. For the analysis of system reliability, parallel resistance system consisting of cables and plate girder is changed into series connection system and the result of system reliability of total structure is presented. As a system reliability, the upper and lower probabilities of failure for the structural system have been evaluated and compared with the suggested prediction method for the combination of failure modes. The suggested prediction method for the combination of failure modes reveals the unexpected combinations of element failures in significantly reduced time and efforts compared with the previous permutation method or system reliability analysis method, which calculates upper and lower bound failure probabilities.

Study on Affecting Factors for the Segmental Joint Behavior of Spliced Girder Bridges (분절교량 접합부 거동의 영향인자에 대한 연구)

  • Nam, Jin-Won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.3
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    • pp.9-16
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    • 2019
  • Recently, precast PSC girder bridges have been widely applied for short and middle span bridges. The construction of the spliced girder bridges has been increasing to overcome the length limit of girder and transportation restrictions. In case of the spliced girder, the integrity of the segmental joints is very important to secure the structural soundness of bridge because the discontinuity on the segmental joints between adjacent segments could be vulnerable point. The study of segmental joint behavior with different influence factors of joint type, shear key installation, confining force is very important. In this research, finite element analysis and scaled model test with different shear key shapes and confining forces were carried out and the comparative study was performed to evaluate the segmental joint behavior of precast spliced PSC girder bridge. It was confirmed that the installation of shear key with height and depth ratio of 1/2~1/3 and applying of confining force of 1/2 of the concrete strength at the joint was effective in improving the integrity of segmental joint. In addition, the field loading test for existed precast spliced PSC girder bridge was performed and the measurement of the difference of deflection between adjacent segments at segmental joint was proposed as the assessment solution of the integrity of segmental joint.

Damage Analysis of Manganese Crossings for Turnout System of Sleeper Floating Tracks on Urban Transit (도시철도 침목플로팅궤도 분기기 망간크로싱의 손상해석)

  • Choi, Jung-Youl;Yoon, Young-Sun;Ahn, Dae-Hee;Han, Jae-Min;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.5
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    • pp.515-524
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    • 2022
  • The turnout system of the sleeper floating tracks (STEDEF) on urban transit is a Anti-vibration track composed of a wooden sleeper embedded in a concrete bed and a sleeper resilience pad under the sleeper. Therefore, deterioration and changes in spring stiffness of the sleeper resilience pad could be cause changes in sleeper support conditions. The damage amount of manganese crossings that occurred during the current service period of about 21 years was investigated to be about 17% of the total amount of crossings, and it was analyzed that the damage amount increased after 15 years of use (accumulated passing tonnage of about 550 million tons). In this study, parameter analysis (wheel position, sleeper support condition, and dynamic wheel load) was performed using a three-dimensional numerical model that simulated real manganese crossing and wheel profile, to analyze the damage type and cause of manganese crossing that occurred in the actual field. As a result of this study, when the voided sleeper occurred in the sleeper around the nose, the stress generated in the crossing nose exceeded the yield strength according to the dynamic wheel load considering the design track impact factor. In addition, the analysis results were evaluated to be in good agreement with the location of damage that occurred in the actual field. Therefore, in order to minimize the damage of the manganese crossing, it is necessary to keep the sleeper support condition around the nose part constant. In addition, by considering the uniformity of the boundary conditions under the sleepers, it was analyzed that it would be advantageous to to replace the sleeper resilience pad together when replacing the damaged manganese crossing.

Evaluation of Serviceability and Flexural Performance for RC Hollow Slab by Hollow Ratio and Damping Ratio (중공율과 감쇠율을 이용한 RC 중공 슬래브의 사용성 및 휨성능 평가)

  • Jong Hoon Kim;Dong Baek Kim;Yong Gon Kim;Jae Won Lee;Jeong Ho Choi
    • Journal of the Society of Disaster Information
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    • v.18 no.4
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    • pp.930-935
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    • 2022
  • Purpose: The purpose of this study is to evaluate the stiffness reduction and damping ratio of reinforced concrete hollow slabs and to analyze their performance, and to study the effect of the damping effect of hollow bodies and the stiffness reduction on the serviceability of slabs. Method: Test specimen was made in a size of 0.6m*0.21m*3.6m to evaluate the vibration effect of the slab, and the hollow ratio was set in six steps from 0.0% to 30% to measure the change in rigidity and damping according to the change in the hollow ratio. Result: As the hollow ratio increases, rigidity decreases and the natural frequency decreases, but as the mass decreases, the natural frequency increases gradually. Since energy is hardly dissipated up to the hollow ratio of 20%, the hollow ratio should be reduced by 30%. Conclusion: It was found that the bending strength degradation of the slab with a hollow ratio of about 30% is minimized, but an appropriate natural frequency can be maintained, and a certain damping effect can be obtained.

Numerical Analysis on the Structure Behavior of the Connected Long-span Beam during Excavation in Narrow Streets (도로 폭이 좁은 굴착공사에서 연결부가 적용되는 장지간 주형의 수치해석적 거동 평가)

  • Choi, Kwang-Sou;Ha, Sang-Bong;Lee, Hwan-Woo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.33 no.4
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    • pp.263-270
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    • 2020
  • This study evaluates the structural behavior of connected long-span beams applied for excavation in urban areas with a narrow street. Generally, the reliability of the connection is reduced owing to the defect of the upper flange in the connection. An improved connection part was developed to complement the defects in the connected long-span beam. A finite element analysis based on a commercial program, ABAQUS, was employed to evaluate the behavior of the improved connection part. A numerical analysis model was proposed to analyze the high-strength bolt connection and the composite behavior of steel and concrete applied to the improved connection. The suitability of the proposed numerical analysis was verified by comparing the experimental and numerical analysis results of the references. Using the proposed numerical analysis method, the improved and general connections were analyzed and compared with each other. The stress distribution and elastic-plastic behavior of the long-span beam were analyzed numerically. The analysis confirmed that 25% of the compressive stress was improved, resulting in the improvement of structural safety and performance.

Experimental Study on Evaluation of Rotational Resistance of Multi-Span Greenhouse Foundations (연동비닐하우스 기초의 회전저항성능 평가에 관한 실험적 연구)

  • Lee, Hyunjee;Shin, Jiuk;Kim, Minsun;Choi, Kisun
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.9
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    • pp.5-12
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    • 2018
  • The foundation of the multi-span greenhouse structures is designed with small shallow concrete foundation considering mainly the vertical load. However, recently, due to an abnormal climate such as strong wind, horizontal load and up-lift load over design strength are applied to the foundation, causing safety problems of the greenhouse foundation. In order to reasonably evaluate the safety of greenhouse foundations, rotational and pullout stiffness expressed by the ground-foundation interaction should be evaluated, which also affects the safety of the upper structural members. In this study, three representative basic foundation types were selected by classifying greenhouse standards in Korea according to the shape, and the horizontal loading tests and theoretical calculation were performed for each foundation type. As a result of the comparison and analysis of the test and calculation, it was found that rotational resistance of the foundation is different according to the ratio of the contact area between the foundation and ground when the conditions of the foundation - ground contact surface and the mechanical properties of the ground are the same.

An Analytical Study on the Strength Behavior of Column-Foundation Connection with High Tension Bolts (고장력 볼트 기둥-기초 연결부의 강도특성에 관한 해석적 연구)

  • Hwang, Dong A;Hwang, Won Sup;Ham, Jun Su;Jeong, Jin Il
    • Journal of Korean Society of Steel Construction
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    • v.28 no.2
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    • pp.121-128
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    • 2016
  • In order to suggest a reasonable design for the circular concrete filled tube steel column-foundation connection applying high-tension bolts, Overall structural behavior and characteristics according to various variables of column-foundation connection are numerically analyzed using a commercial FE analysis program, ABAQUS. To that goal, finite element analysis is conducted on the basis of the previous study replacing anchor bolts to high-tension bolts, and the analytical results are validated by comparison with experimental results. Also, the various variables(embedded depth and grade of anchor, and height and thickness of rib) involved in behavior of the column-foundation connection are selected through analyzing the current design criteria, and the characteristics of the column-foundation connection are compared and analyzed according to the various variables. In case of the anchor bolts, Applying the high-tension bolts is more advantage and securing the embedded depth beyond 0.5D is recommendable. In case of the rib, a minimum of 0.5D for rib's height and $0.4t_b$ for rib's thickness should be secured to develop the structural performance.

Study on the Testing Method for Setting Time of Set Accelerating Agent Using Shotcrete by Gilmour Needles (길모어침에 의한 숏크리트용 급결제의 품질시험방법에 대한 고찰)

  • Kim, Chun Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.6
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    • pp.195-200
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    • 2011
  • KS F 2782 (for shotcrete accelerators) standard cross-section of tunnel construction or repair is a reinforcement used in the field of shotcrete accelerators as a criterion in assessing shotcrete performance. Thus, KS F 2782 by standard accelerator will determine the nature of the product of concrete accelerators that will be used to record variations in the product roles, through determination of the quality of the experimental method to identify only the quality of the many variables that exist. This evaluation standard has so far distinguished accelerator products in indoor experiments that do not meet quality standards but were mostly for an on-site accelerator mixed with the shotcrete after being quite satisfied with the level of quality in a certain number of products. This observation is derived from the results of an indoor experiment considered to verify whether the site is suitable for indoor experiments, and whether its actual location in the city is relevant to the accelerator quality, to find a way to test if it fits. This study centers on the material conditions of the shotcrete accelerator and a variety of experimental results, and used the Gilmore needle to compare the compressive strength and KS F 2782 specification of the accelerator as a means to ensure product quality conformity analysis and for further research experiments. In conclusion, a portion of KS F 2782 standard that fixes the problems that can be resolved from the ground up as a whole is not a review for the domestic reality. As an indoor experiment to ensure uniformity in the field when applied in a sufficient correlation, complement must be in place.