• Steel and Composite Structures
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• v.34 no.6
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• pp.891-907
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• 2020

Many studies reveal that during destructive earthquakes, most of the structures enter the inelastic phase. The amount of hysteretic energy in a structure is considered as an important criterion in structure design and an important indicator for the degree of its damage or vulnerability. The hysteretic energy value wasted after the structure yields is the most important component of the energy equation that affects the structures system damage thereof. Controlling this value of energy leads to controlling the structure behavior. Here, for the first time, the hysteretic behavior and energy dissipation capacity are assessed at presence of elliptical braced resisting frames (ELBRFs), through an experimental study and numerical analysis of FEM. The ELBRFs are of lateral load systems, when located in the middle bay of the frame and connected properly to the beams and columns, in addition to improving the structural behavior, do not have the problem of architectural space in the bracing systems. The energy dissipation capacity is assessed in four frames of small single-story single-bay ELBRFs at ½ scale with different accessories, and compared with SMRF and X-bracing systems. The frames are analyzed through a nonlinear FEM and a quasi-static cyclic loading. The performance features here consist of hysteresis behavior, plasticity factor, energy dissipation, resistance and stiffness variation, shear strength and Von-Mises stress distribution. The test results indicate that the good behavior of the elliptical bracing resisting frame improves strength, stiffness, ductility and dissipated energy capacity in a significant manner.

• Journal of Distribution Science
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• v.13 no.9
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• pp.81-93
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• 2015

Purpose - "Showrooming" refers to the phenomenon where a shopper visits a store to see and compare products but makes the purchase online at a lower price. Surveys on showrooming activities at home and abroad indicate that a significant number of consumers pursue showrooming activities. The advent of "showroomers," who engage in buying activities, hovering both on and offline, while selectively choosing sales channels to suit their needs, is powerful enough to erode the borders between channels and bring about seismic changes in the distribution industry. However, surprisingly, there has been no in-depth discussion on showrooming. This study seeks to theoretically investigate what impact personal characteristics have on showrooming preferences and attitudes in a multi-channel environment. Specifically, assumptions have been made that price perception, perceived performance risk, and trust in online shopping not only have a direct impact on showrooming attitudes but also indirectly affect it through the means of contact motivation. Research design, data, and methodology - To test the hypotheses, this study conducted a survey of male and female shoppers, ages 20 through 40s, who live in metropolitan areas, and have actively showroomed fashion items in the last six months. A clothing item usually purchased after a careful decision-making process was chosen as the target product of the study. The survey was conducted between October and November 2014, using a professional survey service provider. A total of 200 surveys were collected, of which 198 were used for analysis. Conceptual model Structural Equation Modeling (SEM) and Amos 18.0 were employed for data analysis and model verification. In addition, following the confirmatory factor analysis and measurement model analysis, the theoretical model that corresponds to the research model was analyzed. Results - Analysis results show that price perception, perceived performance risk, and trust in online shopping have a statistically significant and positive (+) impact on showrooming attitudes. In addition, in terms of the indirect influence of price perception and perceived performance risk on showrooming attitudes through means of contact motivation, price perception had a statistically significant and positive impact on means of contact motivation, whereas perceived performance risk did not have a statistically significant impact on it, with the relevant hypothesis rejected. Conclusions - These analysis results imply that the ultimate goal of consumers is to maximize their shopping benefits by selectively and strategically taking advantage of different channels in a complementary manner. This study presents many implications for distributors to encourage a deep understanding of showrooming consumers who have complicated consumption behaviors and to build channel integration strategies. This study has limitations in theoretical and practical implications. Therefore, subsequent studies need to focus on verifying that showrooming activities are based on reasonable and planned decisions by applying the theory of reasoned or planned behavior. In addition, the scope of the study should expand to include web showrooming, where consumers conduct product research online and purchase offline.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.3 s.43
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• pp.77-85
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• 2005

After the collapse of the World Trade Center in september 11, 2001 and due to the frequent fire-caused damages of buildings during earthquake attacks, social concerns have been increased for the fire proof of the structural members of buildings. Recently, researches have been conducted to improve the fire resistance for building members not by the traditional ways but by utilizing the fire-resisting characteristics of reinforced concrete and structural characteristics of H-steel. In this paper, laboratory tests were conducted in room temperature to investigate the structural performance of the composite beams, which were developed to improve the fire resistance, comprising with concrete incasement between upper and lower flanges of H steel. From the experimental results, the displacement ductility factors of $6\~8$ were obtained. The difference of flexural behavior ol H steel-partial concrete incased composite beams with various composite details seems to be minor. The amount of longitudinal rebars is the most influential factor for the flexural strength of the composite beams. Therefore, if this type of composite beams are selected for designing a building located in moderate seismic lone, identical beam size could be used in several stories of the building.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.3
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• pp.1-10
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• 2002

A series of unreinforced masonry(URM) walls were analytically investigated by FEM for a limited version of seismic in-plane performance. For this, URM walls were assumed to be continum and modeled as isotropic plane stress elements, within which the nature of cracking was propogated. Accordingly, behavioral mode of cracking in URM was modeled by smeared-crack approach. Total of 70 cases were considered for various parameters such as axial load ratio, aspect ratio and effective section area ratio due to the existence of opening, etc. The analysis results indicate that these parameters significantly and interactively influence over the ultimate strength of URM walls. Finally, it is suggested that the response modification factor for URM adopted in the current Korean Standard should be validated considering various forms of brittleness and probable failure modes in URM.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.6
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• pp.53-61
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• 2007

This study investigates the effect of site class, post-yield stiffness ratio, damping ratio, yield-strength reduction factor, and natural period on inelastic displacement ratio of bilinear SDF systems located at the sites classified as NEHRP site class B,C,D. The previous studies developed inelastic displacement ratio using equal displacement rule in the intermediate and long period range. But, this approximation overestimates the inelastic displacement ratio. Furthermore, inelastic displacement ratio has not been developed for the systems having a damping ratio less than 5%. This study conducts nonlinear regression analysis for proposing equations for calculating median and deviation of the inelastic displacement ratio of the bilinear SDOF system having damping ratios ranging from 0 to 20%. Using median and deviation of the inelastic displacement ratio, probabilistic inelastic displacement ratio is estimated, which can be used for performance-based seismic evaluation.

• Earthquakes and Structures
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• v.23 no.1
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• pp.23-34
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• 2022

This paper presents experimental studies on reinforced concrete moment resisting frames that have engineered cementitious composite (ECC) in plastic hinge length (PHL) of beam/column members and beam-column joints. A two-story frame structure reduced by a 1:3 scale was further tested through a shake-table (seismic simulator) using multiple levels of simulated earthquake motions. One model conformed to all the ACI-318 requirements for IMRF, whereas the second model used lower-strength concrete in the beam/column members outside PHL. The acceleration time history of the 1994 Northridge earthquake was selected and scaled to multiple levels for shake-table testing. This study reports the observed damage mechanism, lateral strength-displacement capacity curve, and the computed response parameters for each model. The tests verified that nonlinearity remained confined to beam/column ends, i.e., member joint interface. Calculated response modification factors were 11.6 and 9.6 for the code-conforming and concrete strength deficient models. Results show that the RC-ECC frame's performance in design-based and maximum considered earthquakes; without exceeding maximum permissible drift under design-base earthquake motions and not triggering any unstable mode of damage/failure under maximum considered earthquakes. This research also indicates that the introduction of ECC in PHL of the beam/column members' detailing may be relaxed for the IMRF structures.

• Journal of the Korean Geotechnical Society
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• v.30 no.5
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• pp.47-54
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• 2014

Although shear wave velocity ($V_s$) is an important design factor in seismic design, the measurement is not usually made in typical field investigation due to time and economic limitations. In the present study, an investigation was made to predict sand $V_s$ based on the standard penetration test (SPT) results by using artificial neural network (ANN) model. A total of 650 dataset composed of SPT-N value ($N_{60}$), water content, fine content, specific gravity for input data and $V_s$ for output data was used to build and train the ANN model. The sensitivity analysis was then performed for the trained ANN to examine the effect of the input variables on the $V_s$. Also, the ANN model was compared with seven existing empirical models on the performance. The sensitivity analysis results revealed that the effect of the SPT-N value on $V_s$ is significantly greater compared to other input variables. Also, when compared with the empirical models using Nash-Sutcliffe Model Efficiency Coefficient (NSE) and Root Mean Square Error (RMSE), the ANN model was found to exhibit the highest prediction capability.