• Structural Engineering and Mechanics
• /
• v.48 no.6
• /
• pp.809-822
• /
• 2013

Base isolation is widely used in seismic resisting buildings due to its low construction cost, high reliability, mature theory and convenient usage. However, it is difficult to design the isolation layer in high-rise buildings using the available bearings because high-rise buildings are characterized with long period, low horizontal stiffness, and complex re-distribution of the internal forces under earthquake loads etc. In this paper, a simple and innovative isolation bearing, named Teflon-based lead rubber isolation bearing, is developed to address the mentioned problems. The Teflon-based lead rubber isolation bearing consists of friction material and lead rubber isolation bearing. Hence, it integrates advantages of friction bearings and lead rubber isolation bearings so that improves the stability of base isolation system. An experimental study was conducted to validate the effectiveness of this new bearing. The effects of vertical loading, displacement amplitude and loading frequency on the force-displacement relationship and energy dissipation capacity of the Teflon-based lead rubber isolation bearing were studied. An analytical model was also proposed to predict the force-displacement relationship of the new bearing. Comparison of analytical and experimental results showed that the analytical model can accurately predict the force-displacement relationship and elastic shear deflection of the Teflon-based lead rubber isolation bearings.

• Structural Engineering and Mechanics
• /
• v.73 no.3
• /
• pp.303-317
• /
• 2020

In this study an innovative rocking zipper braced frame (RZBF) is proposed to overcome the deficiencies of common concentrically braced frames. RZBF is an improved rocking concentrically braced frame which is based on combination of rocking behavior and zipper columns. The base rocking joints and post-tensioned bars provide rocking response and restoring force, respectively. Also, zipper columns distribute the unbalance force over the frame height and reduce the damage concentration. To evaluate seismic performance of RZBF, a comparison study is carried out considering concentrically braced frame, zipper braced frame, rocking concentrically braced frame and RZBF. Thereby, a suite of non-linear time history analyses had been performed on four different types of archetypes with four, six, eight, ten and twelve stories. Frames were designed and non-linear time history analyses were conducted in OpenSees. To compare the seismic behavior of the archetypes, roof drifts, residual roof drifts, story drifts, the forces of first and top story braces, PT bars forces, column uplift and base shears were taken in to consideration. Results illustrate that using RZBF, can reduce the damage due to reduced residual drifts. Zipper columns enhance the seismic performance of rocking systems. As the number of stories increase in the RZBF systems, larger top story braces were needed. So the RZBF system is applicable on low and midrise buildings.

• Steel and Composite Structures
• /
• v.37 no.3
• /
• pp.341-351
• /
• 2020

Steel plate shear wall with self-centering energy dissipation braces (SPSW-SCEDB) is a lateral force-resisting system that exhibits flag-shaped hysteretic responses, which consists of two pre-pressed spring self-centering energy dissipation (PS-SCED) braces and a wall plate connected to horizontal boundary elements only. The present study conducted a series of cyclic tests to study the hysteretic performances of braces in SPSW-SCEDB and the effects of braces on the overall hysteretic characteristics of this system. The SPSW-SCEDB with PS-SCED braces only exhibits excellent self-centering capability and the energy loss caused by the large inclination angle of PS-SCED braces can be compensated by appropriately increasing the friction force. Under the combined effect of the two components, the SPSW-SCEDB exhibits a flag-shaped hysteretic response with large lateral resistance, good energy dissipation and self-centering capabilities. In addition, the wall plate is the primary energy dissipation component and the PS-SCED braces provide supplementary energy dissipation for system. The PS-SCED braces can provide up to 90% self-centering capability for the SPSW-SCEDB system. The compressive bearing capacity of the wall plate should be smaller than the horizontal remaining restoring force of the braces to achieve better self-centering effect of the system.

• International Commerce and Information Review
• /
• v.11 no.3
• /
• pp.239-262
• /
• 2009

This study shed light on the status of Korean Kimchi industry in overseas markets and presented methods for promoting Kimchi industry of Gwangju Jeonnam metropolitan city and stimulating the export of Kimchi produced in Gwangju Jeonnam, a city that has come to the fore as the center of Kimchi industry, which aimed to explore the ways of ratcheting up competitiveness of Kimchi industry in the global market as Kimchi has become more likely to be globalized amid the recent "Korea Trend" boom and the growing consumption of fermented food. Therefore, methods for promoting Kimchi industry and stimulating the export of Kimchi should be explored to ensure the promotion of Kimchi industry and the stimulation of the export of Kimchi, ultimately restoring the status of Korea as the home of Kimchi, in consideration of the great spillover effect on the regional economy, through a series of measures such as the clusterization of Kimchi industry, expansion of cultural experience projects related to Kimchi for the globalization and the increased consumption of Kimchi, government support to increase Kimchi companies in size and achieve the modernization of Kimchi companies, introduction of Kimchi KS audit system and quality certification system, development of new product targeting global market and making Kimchi a high-end product, expansion of export, support of export market diversification, assurance of safety and price competitiveness of Kimchi, differentiated production and marketing strategy by means of technological research, and others.

• Journal of architectural history
• /
• v.20 no.6
• /
• pp.21-39
• /
• 2011

This research is to analyze the modern warehouses in Gunsan during the Japanese Colonial Period. They were the spatial and urban symbol of City of Rice, Gunsan. The main purpose of this study is to survey the modern warehouses in the original center of city, to find their architectural characteristics and to set up a possibility of reuse. 7 existing warehouse buildings are located at Jangmi-Dong and Jooksung-Dong, and they have been built between 1935 and 1940. The warehouse buildings have a module of 6m and they are generally 12m wide, 24~48m long and 8m high. Their structure is composed of reinforced concrete and wooden truss. All warehouse buildings have a rectangular form. Now the diverse commercial programs occupy the original space. Modern warehouse in Gunsan has the spatial and symbolic value as industrial heritage. Therefore, it is necessary to respect the original value of modern warehouse and to create a reusing space for the current generation. It is also essential to verify restoring possibility of three symbolic warehouse buildings in the harbour that were demolished.

• Restorative Dentistry and Endodontics
• /
• v.41 no.3
• /
• pp.225-230
• /
• 2016

Enamel microabrasion has become accepted as a conservative, nonrestorative method of removing intrinsic and superficial dysmineralization defects from dental fluorosis, restoring esthetics with minimal loss of enamel. However, it can be difficult to determine if restoration is necessary in dental fluorosis, because the lesion depth is often not easily recognized. This case report presents a method for analysis of enamel hypoplasia that uses quantitative light-induced fluorescence (QLF) followed by a combination of enamel microabrasion with carbamide peroxide home bleaching. We describe the utility of QLF when selecting a conservative treatment plan and confirming treatment efficacy. In this case, the treatment plan was based on QLF analysis, and the selected combination treatment of microabrasion and bleaching had good results.

• Journal of Conservation Science
• /
• v.9 no.1
• /
• pp.33-39
• /
• 2000

A well-bucket excavated from Seobu-dong, Kyungju was characterized and conserved. The bucket was heavily degraded by a diverse set of microorganisms during its long-term storage in the burial site. The distribution of maximum saturated moisture content was in the range of 614-1050%. The identification of species using optical microscope showed that the species was Pinus densiflora. The dimensional stability of the bucket was examined using sucrose as a dimension-stabilizing agent. The concentration of sucrose was started at 10% level and raised to 30, 50, 70% for 8 weeks. The changes of weight increase were varied with concentration. When the concentration of sucrose reached to 30%, 50%, the bucket showed the significant increase of weight, especially. Epoxy adhesives was used for the joining and restoring. Dimensional change and crack were not observed afterward.

• International Journal of High-Rise Buildings
• /
• v.4 no.1
• /
• pp.57-64
• /
• 2015

Recently, new keywords such as "Resilience" and "Repairability" have been discussed from the perspective of the sustainability of damaged structures after a severe disaster. To evaluate the repairability and recovery of structures, it is necessary to establish an analytical method that can simulate the behavior of repaired structures. Furthermore, it is desirable to establish an evaluation method for the structural performance of repaired structures. This study investigates the repairability and recovery of steel members that are damaged by local buckling or cracks. This paper suggests a simple analytical model for repaired steel members, in order to simulate the inelastic behavior and evaluate the recoverability of the structural performance. There is good agreement between the analytical results and the test results. The proposed analytical method and model can effectively evaluate the recoverability.

• The Journal of Korean Academy of Prosthodontics
• /
• v.36 no.1
• /
• pp.104-119
• /
• 1998

The purpose of this study was pertinent design of the framework of the fixed bone anchored bridge using implants in the edentulous mandible through analysis of stress distribution by the three dimensional finite element analysis method. The results were as follows: 1. The L-shaped framework was favorable in restoring the edentulous mandible by implants and fixed bone anchored bridge. 2. The structure of the framework should be designed to endure the occlusal load because of stress concentration at the most distal abutment of the framework. 3. The stress at the distal implant where cantilever starts was twice as much as that of other portions. 4. Compressive stress was generated on the framework of the mesial side of the distal implant and extrusive force was induced to the mesially positioned implants. 5. The height of vertical plate was high as possible as can be to distribute stresses concentrating bucco-lingually and labio-lingually in the framework between abutments, 6. Reinforcement of the horizontal plate thickness was needed because stress was loaded more on the horizontal plate than on the vertical plate of the framework. 7. Lengthening of the vertical plate can compensate for any limitations in horizontal plate width.

• Journal of Ocean Engineering and Technology
• /
• v.15 no.3
• /
• pp.134-141
• /
• 2001

An experimental method to investigate the dynamic characteristics of buoys in extreme environmental condition is established. Because the buoy model requires a resonable size for accurate experiment, the test condition in model basin that satisfies the similarity law is hardly compatible with capability of test facilities. It is suggested that the linear wave component that is unable to satisfy similarity is separated with others. The model experiment is carried out with mitigated condition for the linear wave components while others including wave drift, current and wind are keeping the similarities. Then, the result can be extrapolated to give the dynamic behavior of buoys n extreme condition because linear wave component is solely responsibly to oscillatory buoy motion and other environmental components are applied as a initial tension. The similarity for current and wind conditions is viewed as equivalence of restoring forces. The validity of proposed method is examined with different types of standard ocean buoys and it indicates that the linearity of measured characteristics is assured with a limitation of resonable distance between test and estimated wave conditions.