• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.29-34
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• 2001

An experimental study was conducted to investigate the effectiveness of transverse reinforcement in reinforced concrete tied columns subjected to monotonically increasing axial compression. Eighteen large-scale columns(260$\times$260$\times$120mm) were fabricated to simulate similarly an actual structural members size. Effects of main variables such as the concrete compressive strength, the tie configuration, the transverse reinforcement ratio, the tie spacing, and the spatting of the concrete cover were studied in this research program.

• Structural Engineering and Mechanics
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• v.73 no.2
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• pp.143-152
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• 2020

Deep coupling beams are more prone to suffer brittle shear failure. The addition of steel fibers to seismic members such as coupling beams can improve their shear performance and ductility. Based on the test results of steel fiber reinforced concrete(SFRC) coupling beams with span-to-depth ratio between 1.5 and 2.5 under lateral reverse cyclic load, the shear mechanism were analyzed by using strut-and-tie model theory, and the effects of the span-to-depth ratio, compressive strength and volume fraction of steel fiber on shear strengths were also discussed. A simplified calculation method to predict the shear capacity of SFRC deep coupling beams was proposed. The results show that the shear force is mainly transmitted by a strut-and-tie mechanism composed of three types of inclined concrete struts, vertical reinforcement ties and nodes. The influence of span-to-depth ratio on shear capacity is mainly due to the change of inclination angle of main inclined struts. The increasing of concrete compressive strength or volume fraction of steel fiber can improve the shear capacity of SFRC deep coupling beams mainly by enhancing the bearing capacity of compressive struts or tensile strength of the vertical tie. The proposed calculation method is verified using experimental data, and comparative results show that the prediction values agree well with the test ones.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5A
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• pp.443-462
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• 2010

The strut-tie model approach has proven to be effective in the ultimate analysis and design of structural concrete with disturbed regions. For the reliable analysis and design by the approach, however, the effective strength of concrete struts must be determined accurately. In this study, the validity of the effective strength of concrete struts, presented by the several design codes and many researchers including the author, was examined through the ultimate strength analysis of 24 reinforced concrete panels, 275 reinforced concrete deep beams, and 218 reinforced concrete corbels by using the conventional linear strut-tie model approach of current codes. The present study shows that the author's approach, resulting in an accurate and consistent evaluation of the ultimate strength of the panels, deep beams, and corbels, may reflect rationally the effects of primary variables including the types of strut-tie model and structural concrete, the conditions of load and geometry, and the strength of concrete in the strut-tie model analysis and design of structural concrete.

• Journal of Digital Convergence
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• v.12 no.5
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• pp.69-78
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• 2014

This study deals with the digital policy proposal through the path modeling study on the effect of the strength of weak ties & emotional perception leading to the user's satisfaction, WOM between game users, and the verification on the effect of the emotional real name SNS on the social network game's diffusion. Researcher confirmed that the effect of the strength of weak ties & emotional perception led to the user's satisfaction, WOM of SNG. Even though weak tie, researchers estimate that the users emotionally interact with the real name relation effect of SNS. And effective factors for WOM are not a tie relationship or emotional interactivity of weak tie antecedently but user's satisfaction. As a result, though antecedent factors (weak tie & interactivity) had a positive effect as real name SNS, eventually powerful factor of making buzz was the SNG user's satisfaction. Thus researchers expect the practical policy proposition for government & corporation, which means SNG service providers more carefully manage the service satisfaction for WOM with SNG user's experience.

• Information Systems Review
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• v.15 no.3
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• pp.89-110
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• 2013

Affiliate marketing is classified as a type of online advertising, where merchants share a percentage of sales revenue generated by each customer, who visited the company's website via a content provider. Content provider, referred to as an affiliate, usually places an online advertisement at its website. For the past few years, there have been a lot of companies or individuals who participate in affiliate marketing. Generally speaking, most of them have websites and post the merchant's ads on their own websites. However, building and maintaining websites have some technology requirements. The widespread use of Social Network Service (SNS), especially microblog-based SNS such as Twitter and Sina Weibo, provides opportunities for individuals who want to be content providers of affiliate marketing. Since information spreads quickly on microblog-based SNS and the easy in targeting customers, it is both an effective and an efficient tool to do affiliate marketing. The relationship between a content provider and the potential customer, which is referred as "tie strength", is quite an important issue in such situation. This paper proved that service characteristics of the microblog-based SNS (security, community drivenness and navigability) and content quality all had positive influence on click-through intention, while tie strength played a moderating role. For the group with strong tie, tie strength is crucial in influencing click-through intention. While for the weak tie group, content quality was very important. Finally, we proposed some implications for both academics and practitioners.

• Journal of the Korea Concrete Institute
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• v.23 no.1
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• pp.13-22
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• 2011

In this study, ultimate strengths of 51 continuous reinforced concrete deep beams were evaluated by the ACI 318M-08's strut-tie model approach implemented with the presented indeterminate strut-tie model and load distribution ratio of the companion paper. The ultimate strengths of the continuous deep beams were also estimated by the shear equations derived based on experimental results, conventional design codes based on experimental and theoretical shear strength models, and current strut-tie model design codes. The validity of the presented strut-tie model and load distribution ratio was examined through the comparison of the strength analysis results classified according to the primary design variables of shear span-to-effective depth ratio, flexural reinforcement ratio, and concrete compressive strength. The present study results of ultimate strengths obtained using the indeterminate strut-tie model and load distribution ratio of the continuous deep beams agree fairly well with those obtained using other approaches. In addition, the present approach reflected the effect of the primary design variables on the ultimate strengths of the continuous deep beams consistently and accurately. Therefore, the present study will help structural designers to conduct rational and practical strut-tie model designs of continuous deep beams.

• Knowledge Management Research
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• v.10 no.4
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• pp.163-183
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• 2009

Numerous studies in the field of buyer-supplier relationship research have focused on the buyer's performance. In contrast, supplier's performance has been paid relatively little attention by researchers, especially the research about the supplier's innovation in the relationship is still in its early stage. In this paper, we examine the relation between the attribute of buyer-supplier relationship and the attribute of supplier's innovation through case research. We define the attribute of buyer-supplier relationship as 'tie strength' (Granovetter, 1973), and the attribute of supplier's innovation as 'exploitation or exploration' (March, 1991). We selected the semiconductor equipment industry of U.S.A, Japan and Korea and firm (JUSUNG Engineering) as cases that examine the relation. We found that a strong tie relationship is positively associated with supplier's exploitation based innovation, and a weak tie relationship is positively related to it's exploration based innovation in this research also. In addition, we could verify reduction of strong tie relationship cause supplier's organizational change.

• Computers and Concrete
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• v.10 no.3
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• pp.259-276
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• 2012

A total of nine reinforced concrete corbels were tested, in this study. Six were externally strengthened with carbon fiber reinforced plastics (CFRP), in the horizontal direction. The cross-sectional area of CFRP and the shear span-to-effective depth ratios are the parameters considered, in this study. Test results indicate that the higher the cross-sectional area of CFRP, the higher is the shear strength of the corbels, and the lower the shear span-to-effective depth ratios, the higher is the shear strength of corbels. The shear strength predicted by the design provisions in section 11.8 of the ACI Code, the strut-and-tie model in Appendix A of the ACI Code, and the softened strut-and-tie (SST) model were compared with the test results. The comparisons show that both the strut-and-tie model in Appendix A of the ACI Code, and the SST model can accurately predict the shear strength of reinforced concrete corbels, strengthened with CFRP.

• Journal of Korean Association for Spatial Structures
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• v.18 no.2
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• pp.69-78
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• 2018

In current research, it was attempted a preliminary design and evaluation of non-uniform ultra high-strength concrete (UHSC) truss members. UHSC used here has the compressive strength of 180 MPa, the tensile strength of 8 to 20 MPa, and the tensile strain after cracks up to 2%. By the three-dimensional finite element stress analysis as well as strut-tie approach on concrete solid beams, the non-uniform truss shape of UHSC truss was designed with the architectural esthetic concept. In a series of examples, to compare with conventional concrete members, the proposed UHSC truss members have advantages in capabilities of the slender design with minimum weight with high performances under transverse loadings as well as the aesthetically non-uniform design for spatial structures.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.179-182
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• 2005

Recently, many design codes including ACI 318-02 recommend the use of a strut-tie model approach for design of structural concrete with D-region(s). However, there are several unclear problems and shortcomings in the codes' strut-tie model approach. A grid strut-tie model approach was proposed to resolve these problems. In this study, the ultimate strengths of 17 deep beams, the most familiar type of D-regions, were evaluated for the validity check of the grid strut-tie model approach. The analytical results obtained by the approach are compared with those by the strut-tie model approach presented by CEB-FIP, AASHTO LRFD, and ACI 318-02.