• Title/Summary/Keyword: structural analysis and design

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The design of coffer dam utilized P.R.D. method (P.R.D. 공법을 활용한 가물막이 설계)

  • Park, Chal-Sook;Lee, Kyu-Tak;Yum, Kyung-Taek;Kim, Yoon-Ku;Kang, Bong-Gwon;Lee, Jae-Weon;Lim, Seok-San;Jeong, Ji-Yearl
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.869-887
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    • 2008
  • Coffer dam for tunnel type spillway in inflow section of Dae-am dam was originally planned as 2 lines sheet piles with Water Zet method. But, the result of pilot test was caused of some problems that vibration during installation of pile could pollute water and water leakage could the lower part. So, sheet piles was not satisfactory for faculty of coffer dam. Structural instability of sheet pile system need to reinforcement. Characteristic of Dae-am dam was small reservoir capacity but wide drainage area, of which it was judgment that security of leakage and stability was difficult during excavation of inlet part. So, we consider that water curtain method utilized with in site pouring concrete pile method was designed at weir part of spillway. We were known about basement rock that geological boring was carried out in weir part. After taking a deep consideration, PRD method was accepted as a new method. Concrete pile by PRD was installed to below country rock. CJM method was carried out with PRD. After making concrete wall using Top-down method, earth anchors were installed for supporting it. According to the result of numerical analysis, as water level rises, wall is stable.

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A Study on the Fracture Behavior of a Crack in 9% Ni Steel Considering Constraint Effect (구속효과를 고려한 9% Ni강 균열의 파괴거동 해석에 관한 연구)

  • Kim, Young Kyun;Yoon, Ihn soo;Kim, Jae Hoon
    • Journal of the Korean Institute of Gas
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    • v.25 no.6
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    • pp.14-21
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    • 2021
  • Inner shell material of LNG storage tanks that store ultra-low temperature LNG at -162℃ requires structural integrity assessment of a crack-like defect. From the viewpoint of conventional fracture mechanics, the assessment has mainly performed by single parameter using stress intensity factor K, J-integral and CTOD. However, the stresses in a material of crack tip are not unique caused by constraint loss due to size and geometry of the structure. Various attempts have been made to complement a single parameter fracture mechanics, typically with Q-stress. In this paper, we have performed a two-parameter approach by deriving the Q-stress coupling with J-integral suitable for the evaluation of the crack tip stress field in the non-linear elastic region. A quantitative evaluation of the constraint effect has performed by using the J-Q approach. It was evaluated that the SENB type specimen had a crack ratio of 0.1 to 0.7 and the wide type specimen had a crack ratio of 0.2 to 0.6.

The Relationship of Country Image, Product-Country Image, and Purchase Intention of Korean Products: Focusing on Differences among Ethnic Groups in South Africa

  • Lee, You-Kyung;Robb, Charles Arthur
    • Journal of Korea Trade
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    • v.23 no.6
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    • pp.33-51
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    • 2019
  • Purpose - The purpose of this study is to provide practical implications for Korean companies searching for new market opportunities. From the experimental analysis, the impact of country image on product-country image and purchase intention of Korean products are measured. In addition, this study disaggregates the impacts of country image and product-country image and purchase intention among ethnic groups in South Africa for searching further useful implications. Design/methodology - To examine South African consumers' country image and product-country image towards Korean products, data were collected between June and July 2019 through an online questionnaire, and 335 questionnaires were used for analysis. Firstly, the multivariate analysis was conducted to examine the general tendency of South African consumers' perceptions of country image to Korea, product-country image, and purchase intention among three ethnic group consumers. Then in order to verify the country image model and hypotheses of the study, we analyzed the structural models for each of the three ethnic groups and compared the sizes of the path coefficients for each groups. To compare the difference of path coefficients across ethnic groups, configural invariance, metric invariance, and scalar invariance tests were conducted sequentially. Findings - In the black and white ethnic groups, the country image had a statistically significant impact on product-country image, but it did not affect the purchase intention to Korean products. The product-country image showed a statistically significant impact on the purchase intention to Korean products in both ethnic group. However, in the coloured ethnic group consumer, the country image had a significant effect on the product-country image, but it did not affect the purchase intention of Korean products. In addition, the product-country image did not have a significant influence on the purchase intention of coloured ethnic group consumers unlike black and white ethnic group consumers. The results of this study suggest that even though differences in terms of the impact of CoI on PCI and PI were investigated for the sample of white, coloured, and black respondents, the groups seemed to respond in a reasonably comparable manner. Originality/value - South Africa occupies more than 20% of Africa's total GDP in sub-Saharan Africa and is a hub for Southern African logistics as a hub for Korean companies to enter Africa. However, it is rare to find a study focused on the determinants of consumer behavior in South Africa. In particular, this study disaggregates the impacts of country image and product-country image on consumer behavior across ethnic groups in South Africa. Therefore, this study could provide practical implications for Korean firms which desire to diversify their export markets and pioneer future markets.

Effects of Restaurants' e-Wom Characteristics on Attitude and Visit Intention: Focused on Visit Intention Over Time (레스토랑의 e-Wom 특성이 시간 경과에 따른 방문의도를 중심으로 한 태도 및 방문의도에 미치는 영향)

  • KIM, Sung-Hwan;JEON, Young-Mi;LEE, Ji-Ah
    • The Korean Journal of Franchise Management
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    • v.13 no.2
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    • pp.17-31
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    • 2022
  • Purpose: With the development of the Internet, consumers can quickly access the electronic word-of-mouth. Consumers seek to reduce uncertainty by referring to the opinions of other consumers about products and services when making purchase decisions. In the food service industry, evaluating a restaurant before an actual visitation is difficult. Therefore, electronic word-of-mouth is important to interact with the customer in restaurants. as it can be used as an exchange of information in which consumers participate and interact with other customers. This study was conducted to verify how online word-of-mouth characteristics (Consensus, Vividness, Neutrality) on attitudes and visit intention from the perspective of social exchange theory. And it was performed to verify the structural relationship between short-term visit intention, mid-term visit and long-term visit intention. Research design, data, and methodology: A survey was conducted on customers who have visited restaurants. Of a total of 312 responses, 306 responses were used, excluding insincere responses and missing values for factors analysis. SPSS 25.0 and AMOS 25.0 were used for statistical analysis, and hypothesis testing was conducted after verifying the validity and reliability of the questionnaire items. Result: The result of the analysis showed that, consensus and neutrality have a positive effect on attitude but not much on vividness. In addition, consensus, vividness, and neutrality have no effect on the short-term visit intention. Finally, the short-term visit intention has a positive effect on mid-term visit intention, and mid-term visit intention has a positive effect on long-term visit intention. Conclusions: Based on the results, this study suggested that it is necessary to have practical implications for marketing and monitoring restaurant reviews in consideration of the characteristics of electronic word-of-mouth. When managing electronic-word-of-mouth, it is necessary to manage the consensus and neutrality is essential to provide sufficient information about the restaurant. The focus should not only be on vividness, such as photos and videos. In addition, restaurants should also provide a good experience for first-time visitors as the short-term visit intention positively affects mid-term and long-term visit intention.

Development of Self-centering Viscous Damper System for Seismic Retrofit of Ordinary Concentrically Braced Frame (보통중심가새골조의 내진보강을 위한 자가복원형 점성감쇠기 시스템 개발)

  • Do Yeon Kim;Hyuck Soon Choi;Joohyung Kang;Yongsun Lee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.6
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    • pp.70-78
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    • 2023
  • The ordinary concentrically braced frame has an advantage of having simple design procedure. For this reason, it has been widely used for the small-sized frame structures subject to moderate or lower magnitude earthquake, even though its seismic performance against the earthquake load is not much effective compared to that of other frame systems. To enhance seismic performance of the ordinary concentrically braced frame where the bracing has a weakness for compressive behavior under lateral earthquake, seismic retrofitting by viscous damper has been commonly introduced. However, the viscous damper, itself, generally does not have stiffness for restoring the structure to the original position. This may cause residual displacement to the structure. In this paper, a self-centering viscous damper system in which upper and lower beams having flexural rigidity play a role as a nonlinear-elastic spring, restoring the spring-damper system subject to external displacement history to its original location, is developed. The numerical analysis for a simplified frame structure shows how including the developed self-centering viscous damper system leads to an enhanced seismic performance of the frame structure through energy dissipation during earthquake excitation.

Transient Structural Analysis of Piston and Connecting Rods of Reciprocating Air Compressor Using FEM (FEM을 이용한 왕복동 공기압축기의 피스톤 및 커넥팅로드의 구조해석)

  • Pham, Minh-Ngoc;Yang, Chang-Jo;Kim, Jun-Ho;Kim, Bu-Gi
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.23 no.4
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    • pp.393-399
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    • 2017
  • In a reciprocating compressor, the piston and connecting rod are important parts. Excess mechanical stress on these parts may cause damage, and broken parts are expensive and difficult to replace. Therefore, it is necessary to analyze the mechanical stress affecting durability and longevity. The main purpose of this study was to identify locations of maximum stress on pistons and connecting rods. Based on dynamic calculation of the working process of a specific air compressor, an analysis of piston and connecting rod performance has been completed. A three-dimensional model for the air compressor's pistons and connecting rods was built separately, and FEM analysis of these components was carried out using a numerical method. The pistons were loaded by pressure which was changed according to crankshaft angle without thermal boundary conditions. The simulation results were used to predict and estimate stress concentration as well as the value of this stress on pistons and connecting rods. The maximum equivalent stress calculated are over 190 MPa on pistons and 123 MPa on connecting rods at crank angle $135^{\circ}$ and $225^{\circ}$ but these are under tensile yield strength. Besides, the calculated safety factors of connecting rods and pistons is higher than 1. Moreover, the results obtained can be used to provide manufacturers with references to optimize the design of pistons and connecting rods for reciprocating compressors.

Application of ultrasonic energy to enhance capability of soil improving material (지반보강용 주입재의 성능향상을 위한 초음파 에너지의 활용)

  • Moon, Jun-ho;Xin, Zhenhua;Jeong, Ghang-bok;Kim, Young-uk
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.4
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    • pp.567-576
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    • 2017
  • In a performance-based design, the structural safety is estimated from pre- defined damage states and corresponding damage indices. Both damage states and damage indices are well defined for above-ground structures, but very limited studies have been performed on underground structures. In this study, we define the damage states and damage indices of a cut-and-cover box tunnel which is one of typical structures used in metro systems, under a seismic excitation from a series of inelastic frame analyses. Three damage states are defined in terms of the number of plastic hinges that develop within the structure. The damage index is defined as the ratio of the elastic moment to the yield moment. Through use of the proposed index, the inelastic behavior and failure mechanism of box tunnels can be simulated and predicted through elastic analysis. In addition, the damage indices are linked to free-field shear strains. Because the free-field shear strain can be easily calculated from a 1D site response analysis, the proposed method can be readily used in practice. Further studies are needed to determine the range of shear strains and associated uncertainties for various types of tunnels and site profiles. However, the inter-linked platform of damage state - damage index - shear wave velocity - shear strain provides a novel approach for estimating the inelastic response of tunnels, and can be widely used in practice for seismic designs.

The Roles of Economic Benefits and Identity Salience: Inducing Factors in the Behavioral Intent to Use Outlet Shopping Centers (아울렛 쇼핑센터의 이용의도에서 아이덴티티 현저성의 요인과 경제성의 역할)

  • Choi, Nak-Hwan;Lim, Ah-Young;An, Lina
    • Journal of Distribution Science
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    • v.11 no.6
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    • pp.41-50
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    • 2013
  • Purpose - Inducing consumers' behavioral intent to use an outlet shopping center is a critical issue for managers since it can be used as a guide for developing marketing strategies. Low prices could lead to a growth in retail purchases, but there might also be a positive relationship between prices and customer perceptions of product quality. The extent to which consumers use price as a predictor of quality may differ according to the availability of important alternative cues such as brand, store name, and identity salience triggered by the store. Consumers can obtain non-economic benefits from marketing exchanges that go beyond basic economic achievement. We argue that identity salience can play a crucial mediating role when consumers, acting as exchange partners, seek to obtain social benefits. This study shows that identity salience could mediate the relationship between identity salience-inducing factors such as multi-finality, prestige and role performance, and consumers' behavioral intent to use an outlet shopping center. Research design, data and methodology - The survey was conducted on college students enrolled in marketing classes. A total of 200 questionnaires were distributed, of which only 194 were returned. After five incomplete questionnaires were excluded, a final sample of 189 was used for empirical analysis. Using a covariance structural analysis in Amos17, we confirmed the fit of the research model and estimated its parameters by using the maximum likelihood method. Results - The results of the hypotheses testing are as follows. First, both identity salience and economic benefits have positive effects on the behavioral intent to use an outlet shopping center. Second, role performance, prestige, and multi-finality have positive effects on identity salience. Finally, the additive analysis of the direct effects of identity salience-inducing factors shows that the role performance, prestige, and multi-finality factors have no direct effects on the behavioral intent to use an outlet shopping center, suggesting that identity salience plays a positive mediating role. Conclusions - This study informs marketers that not only price but shoppers' identity salience directly affects their intent to visit an outlet shopping center. To strengthen shoppers' identity salience, marketers should find ways to help shoppers fulfill their multiple social roles, realize their multiple goals, and achieve prestige. In other words, outlet shopping centers must improve their personal service environment in order to enhance their employees' service quality and assist the execution of multi-finality by minimizing the perceived costs (e.g., travel time, effort) associated with shopping trips, thus making it easier for consumers to combine visits to multiple stores in outlet shopping centers and buy the items required for their consumption goals. Outlet shopping centers must also offer assortments with both breadth and depth in order to help consumers play the social roles their social networks have given them.

Motivations of Selecting Restaurants for Eating-out: Focus on Fashion Premium Outlets (외식 소비동기가 레스토랑 선택속성 중요도에 미치는 영향: 패션 프리미엄 아울렛을 중심으로)

  • Lyu, Moon-Sang
    • The Journal of Industrial Distribution & Business
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    • v.9 no.2
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    • pp.57-63
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    • 2018
  • Purpose - This research examined the effect of hedonic and utilitarian eating-out motivations on the evaluation of restaurant selection attributes in a fashion premium outlet. Additionally, the influence of experimental and functional attributes on customers' preference for hedonic eating-out motives and utilitarian eating-out motives, and variation of moderating effects through the gender was examined. Research design, data, and methodology - A survey was conducted to verify the established research hypothesis. The questionnaire items for the research were modified to fit the situation of the present study. In order to elaborate the questionnaire, the literature of the previous researchers was reviewed and supplemented. The survey conducted 207 online questionnaires for consumers who have visited domestic fashion premium outlets from July 4, 2017 to July 27, 2017. A total of 207 questionnaires were collected, and a total of 206 questionnaires were used for the empirical analysis after excluding one inappropriate response. In order to verify the reliability and validity of the measured variables, exploratory factor analysis and reliability analysis were performed using SPSS 20.0. Next, the structural equation model (SEM) statistical method was used to test the hypotheses of the study. Results - Hedonic motivation had more influence on experimental attribute importance than the functional attribute importance of the restaurant. However, this result was different depending on the gender. The effects of hedonic motives on empirical attributes were more influenced by female groups, and when influencing functional attributes, male groups were more influenced. However, it was statistically significant (p <0.05) in the female group only when the hedonic eating out motives influenced empirical attributes. Conclusions - This study analyzed the effect of eating-out motivation on the restaurant preference attributes and suggested practical implications. First, customers with hedonic eating-out motivations were evaluating experiential attributes to be more important than functional attributes. Second, for customers who are motivated to use practical eating-out habits, companies should provide services that meet practical and economic needs. In particular, female customers visiting restaurants need differentiated marketing strategies that make them feel new experiences rather than practical ones. In addition, it is necessary to study more complex and integrated studies which will influence restaurant selection attributes of premium outlets customers by adding various eating out motives and selection attributes.

Hysteretic behaviors and calculation model of steel reinforced recycled concrete filled circular steel tube columns

  • Ma, Hui;Zhang, Guoheng;Xin, A.;Bai, Hengyu
    • Structural Engineering and Mechanics
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    • v.83 no.3
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    • pp.305-326
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    • 2022
  • To realize the recycling utilization of waste concrete and alleviate the shortage of resources, 11 specimens of steel reinforced recycled concrete (SRRC) filled circular steel tube columns were designed and manufactured in this study, and the cyclic loading tests on the specimens of columns were also carried out respectively. The hysteretic curves, skeleton curves and performance indicators of columns were obtained and analysed in detail. Besides, the finite element model of columns was established through OpenSees software, which considered the adverse effect of recycled coarse aggregate (RA) replacement rates and the constraint effect of circular steel tube on internal RAC. The numerical calculation curves of columns are in good agreement with the experimental curves, which shows that the numerical model is relatively reasonable. On this basis, a series of nonlinear parameters analysis on the hysteretic behaviors of columns were also investigated. The results are as follows: When the replacement rates of RA increases from 0 to 100%, the peak loads of columns decreases by 7.78% and the ductility decreases slightly. With the increase of axial compression ratio, the bearing capacity of columns increases first and then decreases, but the ductility of columns decreases rapidly. Increasing the wall thickness of circular steel tube is very profitable to improve the bearing capacity and ductility of columns. When the section steel ratio increases from 5.54% to 9.99%, although the bearing capacity of columns is improved, it has no obvious contribution to improve the ductility of columns. With the decrease of shear span ratio, the bearing capacity of columns increases obviously, but the ductility decreases, and the failure mode of columns develops into brittle shear failure. Therefore, in the engineering design of columns, the situation of small shear span ratio (i.e., short columns) should be avoided as far as possible. Based on this, the calculation model on the skeleton curves of columns was established by the theoretical analysis and fitting method, so as to determine the main characteristic points in the model. The effectiveness of skeleton curve model is verified by comparing with the test skeleton curves.