• Journal of the Korean Geotechnical Society
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• v.16 no.4
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• pp.51-61
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• 2000

This paper reviews fundamentals of a pseudo-static seismic design/analysis method for soil-reinforced segmental retaining walls. A comparative study on NCMA and FHWA seismic design guidelines, which are one of the most well known design guidelines for mechanically stabilized earth walls, was also performed. The results demonstrate that there exist significant discrepancies in the results of external stability analysis despite the same calculation model used in the two guidelines, due primarily to different seismic coefficient selection criteria. It is also demonstrated that the internal stability calculation model for NCMA guideline tends to yield larger seismic reinforcement force in the shallower reinforcement layers, resulting in an increased number of reinforcement layers at the top of reinforced wall and increased reinforcement lengths to ensure adequate anchorage capacity. The internal stability calculation model adopted by FHWA guideline, however, leads to redistribution of dynamic force to the lower reinforcement layers and thus results n an opposite trend of NCMA guideline. Findings from this study clearly demonstrate a need for more in-depth studies to develop a generally acceptable design/analysis method.

• Journal of Korean Association for Spatial Structures
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• v.6 no.3 s.21
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• pp.111-121
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• 2006

Beam String Structure is a structure system that is composed with beam, strut and string, and the structural capacity of this structure system is enhanced by introducing prestress force in string and controling the stress and deformation of beam. Researching on the established studies and examples, character and composition methods of Beam String Structure was investigated. At the result, It was examined that the design elements of the system are shape and rise of beam, sag of string, plan arrangement and the composition and number of strut, in addition, detailed composition methods of the design elements were represented. Also, it was showed that the method to form the individual mechanism against additional load can be employed in order to reduce stress of Beam String Structure under the heavy additional load.

• Journal of the Korea Concrete Institute
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• v.27 no.1
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• pp.11-20
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• 2015

An unbonded post-tensioned anchor using a 15.2 mm diameter 7-wire strand was developed based on finite element analysis and experimental testing. In order to evaluate its performance, static load tests and load transfer tests were conducted following KCI-PS101. The static load tests and additional strand tensile tests confirmed that the developed anchor had a capacity more than nominal tensile strength of a 7-wire strand without any damage or deterioration. According to the result of load transfer tests for many different reinforcing details, specimens with no additional reinforcing bars sustained at least 1.64 times the nominal tensile strength of the strand.

• Smart Structures and Systems
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• v.6 no.3
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• pp.277-290
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• 2010

Internationally the load carrying capacity of bridges is decreasing due to material deterioration while at the same time increasing live loads mean that they are often exposed to stresses for which they were not designed. However there are limited resources available to ensure that these bridges are fit for purpose, meaning that new approaches to bridge maintenance are required that optimize both their service lives as well as maintenance costs. Wireless sensor networks (WSNs) provide a tool that could support such an optimized maintenance program. In many situations WSNs have advantages over conventional wired monitoring systems in terms of installation time and cost. In order to evaluate the potential of these systems two WSNs were installed starting in July 2007 on the Humber Bridge and on a nearby approach bridge. As part of a corrosion prevention strategy, a relative humidity and temperature monitoring system was installed in the north anchorage chambers of the main suspension bridge where the main cables of the bridge are anchored into the foundation. This system allows the Bridgemaster to check whether the maximum relative humidity threshold, above which corrosion of the steel wires might occur, is not crossed. A second WSN which monitors aspects of deterioration on a reinforced concrete bridge located on the approach to the main suspension bridge was also installed. Though both systems have provided useful data to the owners, there are still challenges that must be overcome in terms of monitoring corrosion of steel, measuring live loading and data management before WSNs can become an effective tool for bridge managers.

• Land and Housing Review
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• v.3 no.1
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• pp.79-82
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• 2012

While there exists a relatively large body of technical information for the engineered design of wood-frame buildings to resist seismic ground motions, the quantitative assessment of seismic resistance of conventional houses built by prescriptive requirements is less well understood. Forintek Canada Corp., in collaboration with other research and industry partners, has embarked on a research project to address this topic. This paper will report on the seismic shake table tests of a full-scale wood-frame building. The two-story specimen, $6m{\times}6m$ in plan, was built on the seismic shake table at Tongji University in Shanghai, China, according to Part 9 of the 1995 National Building Code of Canada and shaken uni-directionally in each of the two principal directions. Three different seismic table motions were applied at increasing peak ground motion amplitudes up to 0.40 and 0.50 g. The specimen was repaired after the above sets of seismic table motions, and successive runs were conducted for increased door openings. Measurements included specimen accelerations, displacements and anchorage forces. Static stiffness of the specimen was measured at low force levels, and natural frequencies were measured after each seismic loading stage by applying low-level random excitation. The results presented consist of the capacity spectra of the shake table tests, changes in specimen stiffness and natural frequencies with increasing seismic loading. These results and those from other recent shake table tests elsewhere will be compared with simplified engineering calculations based on codified values of strength, and on that basis preliminary conclusions will be drawn on the adequacy of the current code provisions and design guides in Canada and the USA for conventional wood-frame construction.

• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.963-974
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• 2005

This paper presented four shear test results from experimental tests of two large prestressed concrete beams cast with high strength concrete. In particular, this experiment investigated the effects of draped strands on shear behavior of these full-scaled beams. This study indicated that the use of draped strands increased the ultimate shear capacity as well as the web-shear cracking load. The test results also showed that draped strands reduced strand slip at ends of beams, which represented that these strands were effective to relieve the anchorage stresses. The test results were compared to predictions by two major codes; ACI 318-02 Building Code and AASHTO LRFD(2002). The shear design provisions in these codes provided conservative results on the shear strengths of all test specimens with reasonable margins of safety, and these provisions were particularly more conservative for test specimens having draped strands.

• The Korean Journal of Physiology and Pharmacology
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• v.28 no.1
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• pp.21-30
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• 2024

The challenging clinical outcomes associated with advanced cervical cancer underscore the need for a novel therapeutic approach. Monensin, a polyether antibiotic, has recently emerged as a promising candidate with anti-cancer properties. In line with these ongoing efforts, our study presents compelling evidence of monensin's potent efficacy in cervical cancer. Monensin exerts a pronounced inhibitory impact on proliferation and anchorage-independent growth. Additionally, monensin significantly inhibited cervical cancer growth in vivo without causing any discernible toxicity in mice. Mechanism studies show that monensin's anti-cervical cancer activity can be attributed to its capacity to inhibit the Wnt/β-catenin pathway, rather than inducing oxidative stress. Monensin effectively reduces both the levels and activity of β-catenin, and we identify Akt, rather than CK1, as the key player involved in monensin-mediated Wnt/β-catenin inhibition. Rescue studies using Wnt activator and β-catenin-overexpressing cells confirmed that β-catenin inhibition is the mechanism of monensin's action. As expected, cervical cancer cells exhibiting heightened Wnt/β-catenin activity display increased sensitivity to monensin treatment. In conclusion, our findings provide pre-clinical evidence that supports further exploration of monensin's potential for repurposing in cervical cancer therapy, particularly for patients exhibiting aberrant Wnt/β-catenin activation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.6
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• pp.205-212
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• 2006

In recent investigations, reinforced concrete beams strengthened with Carbon Fiber Sheets (CFS) subjected to fatigue loading were reported to be failed at the ends of CFS by its debonding. U-shaped CFS were attached to both ends of the CFS when fatigue tests on strengthened beams were conducted to delay and/or prevent fatigue failures of adhesive interface. The experimental parameters of this study were the usage of anchorage at the ends of CFS, the number of CFS layers, and the applied load levels of 60%~90% of the static ultimate load obtained from the static tests. The failure modes and the load cycle-deflection relations were observed and discussed from the experimental results. Those results also showed that the U-shaped anchoring system changes the fatigue failure modes and influences greatly on the fatigue capacity of the strengthened beams.

• The korean journal of orthodontics
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• v.33 no.2 s.97
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• pp.91-102
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• 2003

This study was performed to investigate the effect of immediate orthodontic force on soft md hard tissues surrounding C-Palatal $Plate^{TM}$ in beagle Dog. Immediately after this appliance was implanted on the midpalate of 4 adult beagle Dogs, 400gm continuous orthodontic force was applied. Experimental animals were euthanized at 8weeks, 18weeks, and 22weeks (including post-removal healing time of 4weeks), and a control animal was euthanized at 8weeks after implantation without orthodontic force application. The appliance and the surrounding tissue were studied radiographically, macroscopically, and histologically. The results were as follows: 1. The lateral radiographs taken after euthanasia showed very slight displacement of the vortical plate in the experimental animals, compared with the control animal. Mobility test of all animals confirmed primary stability without any increase of mobility during experimental period. 2. No pathologic changes were found in the healing condition of covering soft tissue and bone-screw interface in experimental animals as well as a control animal. 3. Osseointegration was achieved in the bone-screw interface in 8weeks after implantation and the amount of osseointegration increased in 18weeks. There was little difference of osseointegration between the compression side and the tension side. 4. In the marginal bone area, slight bone apposition and resorption were found regardless of compression and tension side, while there was no change in the control animal. 5. Both 8week-animal and 18week-animal showed the new bone apposition along the surface of screws which were perforated into the nasal cavity, while the control animal showed no change. 6. After 4weeks of plate removal, the covering epithelium was repaired intactly, while the connective tissue showed loose and irregular rearrangement and the connective tissue capsule remained. The C-Palatal $Plate^{TM}$ manifested sufficient anchorage capacity in the context of histological study as well as clinical outcomes, when immediate orthodontic force was applied after implantation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.147-161
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• 2017

Generally, significant amount of reinforcements are used in nuclear power plant structures and it may cause several potential problems during the construction. In particular, it is more difficult to pour concrete into structural member joint area than other areas because of the significant congestion of the joint area due to a lot of hooked bars, embedded materials, and other reinforcements. The purpose of this study is to solve these problems due to the reinforcement congestion by using the high-strength(ASTM A615 Gr.80) headed deformed bars of large-sized diameter(43 mm & 57 mm) in nuclear power plant structures as a alternative of standard hooked bars. In order to use headed deformed bars effectively, It is necessary to find the method how to relax limits on their use while maintaining or improving the anchorage capacity. Therefore, this study will analyze the results of tests planned to evaluate the influence of the restricted variables, such as bar size, yield strength, clear cover thickness.