• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.5
• /
• pp.75-83
• /
• 2019

In order to fulfill the obligation to voluntarily reduce greenhouse gas emissions under the Paris Climate Agreement, the proportion of coal and nuclear power generation is reduced worldwide and national efforts are being made to spread renewable energy including solar power generation. Korea also intends to increase the proportion of renewable energy generation to 30~35% by 2040 by introducing laws and regulations. In addition, while the country is trying to apply solar power generation to sidewalks and roads, there is no research related to it in Korea. Therefore, as a precedent study to develop solar power generation roads, solar power generation concrete blocks applicable to sidewalks and plazas were developed and the applicability was evaluated by constructing them on the site. As a result of indoor experiment, compressive strength was measured by 25.5~35.7MPa and flexural strength was measured by 5.1~10.5MPa, which showed that all domestic standards were satisfied. However, the higher the unit cement amount, the lower the strength was measured according to the mixing of the broken fine aggregate. The absorption rate was 5.7%, which satisfied the domestic standard of 7% or less. As a result of the freeze-thawing test, the reduction rate of the compressive strength after 100 cycles was up to 6.3%. As a result of measuring the settlement amount after construction, the maximum of 2.498mm was measured and irregular settlement occurred in the overall area, which is because the resolution of the sand layer was poor during construction. Maintenance techniques of sidewalk concrete block and solar panel need to be established more efficiently through long-term operation in the further.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.38
• /
• pp.303-325
• /
• 2008

China's "Foreign Trade law" 16.4 revised in 2004 like "Foreign Trade law" 16.2 in 1994 is still stipulated resource restriction to protect domestic resources and it does not satisfy the introduction of article 20 and section (g) of GATT 1994. Through an interpretation of related regulations and China-EU cokes dispute, the paper points out that China's "Foreign Trade law" 16.4 has no validity of the introduction of article 20 and section (g) of GATT 1994. Comparing China's "Foreign Trade law" 16.4 to GATT 1994 20(g), China's "Foreign Trade law" 16.4 does not include important conditions of GATT 1994 20 introduction such as not being arbitrary or unjustifiable discrimination and disguised restriction on international trade. For example, based upon China's "Foreign Trade law" , if she restricts or prohibits important natural resources that Korea mainly relies on China, it will effects not only trade between two countries but also our lives and securities. Hence, it is highly time to analyze China's the Validity of the China's Resource Export-Quota Restrictive Measures under the GATT/WTO. In the process of resolving China-EU cokes dispute in 2004, ministry of Commerce of China shows well its characteristics of dispute settlement and also we can find out EU's logical countermeasures. Therefore, because of the high possibility of disputes between Korea and China in the area of natural resources, Korea needs to pay attention to the China's resource protecting policies, and if it violates GATT 1994 20 introduction and (g), we should consider to sue China to WTO. The paper believes that it will play an important role as an aggressive demand and effect on amendment of China's "Foreign Trade law" in the long term.

• Geotechnical Engineering
• /
• v.10 no.4
• /
• pp.167-180
• /
• 1994

A series of long term consolidation tests were conducted under loading -unloading and loading(pc) -unloading(p.) -reloading(p,) conditions using reconstituted clay in order to investigate the effect of stress history on secondary consolidation characteristics and the applicability of the secondary consolidation model suggested by Bjerrum to overconsolidated clays. According to the test results, the secondary compression settlement affected by the stress history in the first half of experimental period and the coefficient of secondary compression, C‥‥ is dependent on overconsolidation ratio, OCR(p,1 p.), maBium OCR (p./p.), and unloading duration time. Moreover the coefficient of secondary consolidation in the latter half of experimental period Cn is mainly affected by OCR and it gradually reduces with OCR increment. Finally the comparison of the experimental results with the Bjerrum model indicates that the Bjerrum model can be applied beyond certain range of stress history in the overconsolidated clay.

• Journal of Convergence Society for SMB
• /
• v.6 no.4
• /
• pp.123-129
• /
• 2016

This study was conducted to understand influential factors in determining the advance directive attitudes of elderly patients. Structured survey questionnaires were distributed using a convenience sampling method to the residents of long-term-care facilities. As a result, the attitudes toward advance directives were accounted having 2.84 points, the functions of a family with 2.73 points, and the level of self-efficacy with 3.45 points. Participants who have higher family functions were found to have negative attitudes toward self-efficacy, as the relationship between two variables were in the negative correlation (r =-.324, p<.01). However, participants who have higher self-efficacy showed positive attitudes toward advanced directives as the two variables were in the positive correlation (r =.340, p<.01). This study will contribute to the settlement of the AD in Korea.

• Geomechanics and Engineering
• /
• v.8 no.4
• /
• pp.559-594
• /
• 2015

A nonlinear creep function incorporated into the elastic visco-plastic model may describe the long-term soil deformation more accurately. However, by applying the conventional procedure, there are challenges to determine the model parameters due to limitation of suitable data points. This paper presents a numerical solution to obtain several parameters simultaneously for a nonlinear elastic visco-plastic (EVP) model using the available consolidation data. The finite difference scheme using the Crank-Nicolson procedure is applied to solve a set of coupled partial differential equations of the time dependent strain and pore water pressure dissipation. The model parameters are determined by applying the algorithm of trust-region reflective optimisation in conjunction with the finite difference solution. The proposed method utilises all available consolidation data during dissipation of the excess pore water pressure to determine the required model parameters. Moreover, the reference time in the elastic visco-plastic model can readily be adopted as a unit of time; denoting creep is included in the numerical predictions explicitly from the very first time steps. In this paper, the settlement predictions of thick soft clay layers are presented and discussed to evaluate and compare the accuracy and reliability of the proposed method against the graphical procedure to obtain the model parameters. In addition, comparison of the available experimental results to the numerical predictions confirms the accuracy of the numerical procedure.

• Journal of the Korean Geosynthetics Society
• /
• v.13 no.1
• /
• pp.85-92
• /
• 2014

Structures that have constructed in soft clay might suffer from many issues related to consolidation settlement or lateral movement of soft-clay during long-term period. Therefore, it is important to establish proper design and construction processes related to site investigation, soil improvement, construction management, and so on. This case study focused on the construction of the rahmen structure supported by pile foundations. Especially, the structure in this case had been constructed without improving underlying soft clay and before constructing backfill embankment due to the limited construction time and the traffic connection of the old road crossing new highway. Therefore, in order to satisfy the structural stability, the construction processes and countermeasure methods were carefully planned based on the results of preliminary numerical analyses and monitoring of ground behaviors. Through the trial and error precess during the construction, the structures had been successfully constructed.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.519-526
• /
• 2010

The construction site for $\bigcirc\bigcirc$ transformer substation was located at a mountain valley. In order to prepare the site, the valley was first filled with crushed rock debris up to 63m. Since the main concern of this project is to minimize differential settlement of the foundation of transformer facilities, dynamic compaction was performed every 7m followed by reinforcement with EMP(Ez-Mud Piling). The EMP is one of bored piling methods, in which a hole is bored by means of air percussion and maintain by injecting Ez-Mud. Then a PHC pile (Pretensioned spun High strength Concrete pile) is embedded and finalized with a hammer. In this study, bearing capacities and long term behavior of a pile installed by EMP were investigated. To achieve these objectives, a series of tests such as static and dynamic load tests were conducted. In addition, a construction quality control standard was proposed based on the test results.

• Journal of the Korean Society for Railway
• /
• v.13 no.5
• /
• pp.521-527
• /
• 2010

The Paved Track is applied to reduce maintenance cost of conventional line. The Paved Track could be used in all types of lines including earthwork, bridge, tunnel and turnout sections. In case of earthwork section, the construction joint is the most critical factor to track durability. The construction joint does not affect to the track structure directly, but the gap due to discontinuity of slabs may affect to the long-term serviceability. To evaluate this problem, the accelerated track test has been performed on the construction joint and the middle part to of the real scale Paved Track. The purpose of this test is that evaluate the vulnerability of construction joint section comparing the trends of settlement and earth pressure under repeated loads of construction joint with those of the middle slab part.

• Korean Institute of Interior Design Journal
• /
• v.20 no.5
• /
• pp.197-207
• /
• 2011

In general, collections in museum are kept in storage according to a preservation and administration program in long or short term, after conservators' conservation treatment. Museum activities related to conservation science are common to do before and after exhibitions. That is, the museum collections include a flow mechanism, which circulate a space in where conservation science related activity is carried on centering around its storage. The purpose of this study is to suggest the design guidelines of a conservation area in a museum. The results of this study as follows. First, to program space planning, conservation area of museum is divided into 4 kinds of zone. Second, space for relics unloading in basically includes 'unloading room', 'control room', 'worker room', 'unpacking room', and 'unloading tools storage' and considers to install 'outdoor arrangement space', etc. In case of space for making relics collections, 'arrangement room' and 'temporary storage' are separately planned in order to arrange and temporarily store relics taken in. Conservation analysis space should be divided into 2 kinds of zone, 'conservation analysis lab' for analysis of collection characters and 'restoration lab' for conservation treatment in the bigger museum. In case of large-scale museum, conservation treatment space is basically classified with characters of museum collections. And it considers installing 'waterlogged wood lab', 'painting clothes treatment lab', 'storage of treated relics' etc. Third, for 'the spaces for analysis treatment', must consider activity contents and sizes of the department for scientific conservation every museum, can classify in detail required space, and must review the space for relics settlement in construction.

• International Journal of Highway Engineering
• /
• v.14 no.2
• /
• pp.45-53
• /
• 2012

Hollows are easily made and bearing capacity is lowered near underground structures of concrete pavement because of poor compaction and long term settlement of the ground. Distresses occur and lifespan is shortened because of larger stress induced by external loadings expected than that in the design. In this paper, the distresses of the concrete pavement slab over box culverts were investigated at the Korea Expressway Corporation(KEC) test road. The transverse cracking of the slabs over the culverts was compared between up and down lines with different soil cover depth. The box culvert without soil cover and concrete pavement were modeled and analyzed by the finite element method(FEM) to verify the transverse cracking at the test road. Wheel loading was applied after self weight of the pavement and temperature gradient of the concrete slab at Yeojoo, Gyeonggi where the test road is located were considered. Positions of maximum tensile stress and corresponding positions of the wheel loading were found for each loading combination. Joint position minimizing the maximum tensile stress was found and optimal slab length over the culverts with diverse size were suggested.