• Proceedings of the KSR Conference
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• 2010.06a
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• pp.880-894
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• 2010

The Grout injected precast pile is widely used in rapid-transit railway bridge recently. The existing portland cement of well used filling at injected precast method that with low strength and environmental pollution, unstable in which ground water contamination by cement flow out, ground relaxation by water down, decrease of horizontality resistance and durability and load transfer divide etc. In particular, as in rapid-transit railway bridge need to secure safety from different angle with vibration of high speed train, horizontal force when train stop and earthquake. Works of foundation construction consider to requirements of the times to coal yard green growth. Together, new green foundation method for possible economics and securing of reduce the term of works are material to developments. Therefore, we carried out study that it is using and development new concept environment - friendly filling include durability and earthquake resistance, for secure safety and minimize environment pollution. To achieve this, we carried out difference tests that new green fillings of underwater concrete, high liquidity, high viscosity, early stiffness as compared to existing portland cement fillings. As results, new green filling have outstanding application at precast pile method and micropile construction method with vertical bearing capacity, horizontal bearing capacity and many case. From now on we will be looking forward to development of new environment-friendly foundation method from various further studies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.490-498
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• 2020

In this study, the seismic performance of low-rise piloti buildings with eccentric core (shear wall) positions was analyzed and reviewed. A prototype was selected among constructed low-rise piloti buildings with eccentric cores designed based on KBC2005. The seismic performance of the building showed plastic behavior in the X-direction and elastic behavior in the Y-direction. The inter-story drift is larger than that of a concentric core case and has the maximum allowed drift ratio. The displacement ratio of the first story is much larger than that of upper stories, and the frame structure in the first story is vulnerable to lateral force. Therefore, low-rise piloti buildings with eccentric cores need to have less lateral displacement, as well as reinforcement of the lateral resistance capacity in seismic design and seismic retrofit.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.3
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• pp.1-9
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• 2016

The purpose of this study is to examine the shear strength and structural performance of DH-Beams. The DH-Beam construction method uses thin steel plates as form-works and structural elements. Steel plates and rebars for DH-Beams were prefabricated at factory and then erected before casting concrete at construction sites. In this study, the contribution of steel plates to the shear strength of DH-Beam was evaluated since the plates were expected to work as reinforcements. Five test specimens were made for experimental and analytical studies. They consisted of two DH-Beams for the positive loading test and two DH-Beams for the negative loading test and a RC beam for the comparison purpose. Test results on DH-Beams were compared with design equations and the RC beam test result. It was proven that DH-Beams demonstrated the good shear behavior showing sufficient strengths and deformation capacities. Nonlinear analyses with test specimens were also used to evaluate the contribution of DH plates to strengths. Analytical models included various cases such as beams with lateral plates only or beams without any plates. These analyses also showed that steel plates can contribute to the enhancement of shear strength of DH-Beams. Based on experimental and analytical studies, it was concluded that steel plates of DH-Beams can be used as good shear reinforcements.

• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.83-92
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• 2017

This paper deals with numerical analysis of behavior of curved mechanically stabilized earth(MSE) walls with geosynthetics reinforcement. Unlike typical concrete retaining walls, MSE wall enables securing stability of higher walls without being constrained by backfill height and is currently and widely used to create spaces for industrial and residential complexes. The design of MSE walls is carried out by checking external stability, similarly to the external checks of conventional retaining wall. In addition, internal stability check is mandatory. Typical stability check based on numerical analysis is done assuming 2-dimensional condition (plane strain condition). However, according to the former studies of 3-dimensional MSE wall, the most weakest part of a curved geosynthetic MSE wall is reported as the convex location, which is also identified from the studies of the laboratory model tests and field monitoring. In order to understand the behaviour of the convex location of the MSE wall, 2-dimensional analysis clearly reveals its limitation. Furthermore, laboratory model tests and field monitoring also have restriction in recognizing their behaviour and failure mechanism. In this study, 3-dimensional numerical analysis was performed to figure out the behaviour of the curved part of the geosynthetic reinforced wall, and the results of the straight-line and curved part in the numerical analysis were compared and analysed. In addition, the behaviour characteristics at each condition were compared by considering the overburden load and relative density of backfill.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6A
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• pp.457-464
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• 2011

An experimental study was performed to evaluate the possibility of using stiff type PolyUrea(PU) on RC slab as a strengthening material. Stiff type PU(STPU) was sprayed on the bottom surface of the slab specimens, which were then attached with CFRP or GFRP sheets. Also the evaluation of the bond capacity, the single most influential parameter on strengthening of RC structures, was carried out the flexural capacity evaluation test results showed that the load carrying capacity of the PU specimen was greater and less than the unstrengthened and FRP sheet attached specimens, respectively. The STPU specimens showed a ductile flexural behavior in the plastic displacement range. With respect to bond capacity, the bond strength of all of the specimen exceeded the code required bond strength of 1.5 MPa. Also, the STPU sprayed specimen without using epoxy resin did not peel off when the tensile grip was applied for testing. The stability of the PU bond failure indicate a good bond strength of PU when applied to concrete.

• Korean Journal of Social Welfare
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• v.56 no.1
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• pp.253-282
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• 2004

The study is to examine the actual conditions and problems of educational welfare which is a part of social welfare and to offer its future directions and things to do. First of all, education has been considered to be part of social welfare in developed countries for a long time and it has been used the same as school educational welfare. These days Korea is confronted with increasing needs of educational welfare caused by emphasis of manpower, appearance of new poor class after IMF, handing down poverty to their children, absence of public education and educational fever, stress of life long learning and extending needs of students' social welfare service. In advanced countries compared to Korea, people perceive education as an equal opportunity. To reach this thesis, various efforts have been making in terms of manpower development such as reform of related laws, financial and official support, offering of parental skills and protecting children for the disadvantaged, dispatching school social workers and overall life improvement. The subjects and age of educational welfare are also diverse ranging from poor families and pre school children to general public and adults. On the other hand, Korea lacks related laws and financial support that are supposed to enforce educational welfare systematically. Also integrated and professional services are not often available due to the lack of cooperation between related agencies. Therefore, government's role and responsibility should be defined clearly in the future directions of educational welfare in Korea. For this, it is needed to establish related laws and build a concrete financial and executive interrelationship. Also every person should be a target of educational welfare putting priorities on the disadvantaged. A lot of efforts should be made to achieve things mentioned above. Multi-dimensional approach intertwined with education, welfare and labour, establishment of cooperation system between related agencies, reinforcement of life long learning, extension of free education including infants and toddlers, and offering financial support to the poor are a few among these efforts. Finally, institutionalization of school social welfare and improvement school facilities are strongly recommended to get to the right track of educational welfare.

• Journal of the Korean Geosynthetics Society
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• v.6 no.1
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• pp.9-16
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• 2007

Geotextile is one of the most useful and effective polymer material in civil construction works and the main function of geotextile is separation, reinforcement, filtering and drainage. Recently, because of the shortage of natural rock, traditional forms of river and coastal structures have become very expensive to build and maintain. Therefore, the materials used in hydraulic and coastal structures are changing from the traditional rubble and concrete systems to the cheaper materials and systems. One of these alternatives employs geotextile tube technology in the construction of coastal and shore protection structures, such as embankment, see dyke, groins, jetties, detached breakwaters and so on. Geotextile tube technology has changed from being an alternative construction technique and, in fact, has advanced to become the most effective solution of choice. This paper presents case history of sea dyke filter construction using geotextile tube mattress and also, various issues related to the tube mattress design and construction technology.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.6
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• pp.195-200
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• 2011

KS F 2782 (for shotcrete accelerators) standard cross-section of tunnel construction or repair is a reinforcement used in the field of shotcrete accelerators as a criterion in assessing shotcrete performance. Thus, KS F 2782 by standard accelerator will determine the nature of the product of concrete accelerators that will be used to record variations in the product roles, through determination of the quality of the experimental method to identify only the quality of the many variables that exist. This evaluation standard has so far distinguished accelerator products in indoor experiments that do not meet quality standards but were mostly for an on-site accelerator mixed with the shotcrete after being quite satisfied with the level of quality in a certain number of products. This observation is derived from the results of an indoor experiment considered to verify whether the site is suitable for indoor experiments, and whether its actual location in the city is relevant to the accelerator quality, to find a way to test if it fits. This study centers on the material conditions of the shotcrete accelerator and a variety of experimental results, and used the Gilmore needle to compare the compressive strength and KS F 2782 specification of the accelerator as a means to ensure product quality conformity analysis and for further research experiments. In conclusion, a portion of KS F 2782 standard that fixes the problems that can be resolved from the ground up as a whole is not a review for the domestic reality. As an indoor experiment to ensure uniformity in the field when applied in a sufficient correlation, complement must be in place.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.4
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• pp.144-152
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• 2016

This paper focuses on the experimental study for investigating the performance for lap splice of hooked or headed reinforcement in beam with different depths. In the experiment, seven specimens, with its variables as the lap length of headed or hooked bar, the existence of stirrups, etc., was manufactured. Bending test was conducted. Lap strengths by test were compared with the theoretical model based on KCI2012. The result showed that the cracks at failure mode occurred along the axial direction to a headed bar. The initial stiffness and the stiffness after initial crack were similar for all specimens. For HS series specimens without stirrups, a 25% increase in lap length was increased 11.8~18.1% maximum strengths. For HH series specimens without stirrups, a increase in lap length did not affect the maximum strengths because of the pryout failure of headed bar. For HS series specimens, the theoretical lap strengths based on KCI2012 considering the B grade lap and the reduction factor for stirrup were evaluated. They are smaller than the test strengths and can ensure the safety in terms of strength capacity. For HH series specimens, the stirrups in the lap zone are needed to prevent the pryout behaviour of headed bar.

• The Journal of Korean Society for School & Community Health Education
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• v.6
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• pp.89-107
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• 2005

The purposes of this study were to investigate the recognition and the needs and problems of in-service education for school nurse, and to suggest the desirable guidelines, for supples the basic data of in-service education for school nurse to upgraded the quality as school nurse's professional specialist. The subjects of this study were 376 school nurses who were working in Jollanamdo. The research instruments used in this study was 'Needs of In-service Education questionnaire'. 305 collected Data were analyzed with the frequency analysis, $x^2$-test. The conclusions were as follows; First of all, the most important motives for the school nurses to participate in-service education are the enhancement of their specialties on teaching profession, self-realizations as educators, and improvement of health teaching skill. However, the motives to obtain the skill for school management or to obtain a high rank qualification and promotion are quite low. School nurses are generally satisfied with duration, time, place of in-service education, But they are not satisfied with contents of in-service education, professional specialist and understanding of real educational situation of the instructors. On the urgent problem of school nurses, promotion of health teaching skill was highest in the rank, and establishment of firm educational philosophy and a sense of teaching profession, proceed to university and graduate school ranked next, respectively. Second, the need of a school nurses on in-service education direction ranked the application of teachers' character and need, practicable and concrete educational programs, planning of school health development, reinforcement of health education, expansion of practical knowledge and on reflection thought, respectively. The need of a school nurses on in-service education contents(major part) ranked health education, health promoting program of student, knowledge and practice of practical medicine and oriental medicine, consultation process, health education of advanced country, respectively. The need of in-service education supervisory organization, the need for a cities provinces educational office was highest in the rank. The need of in-service education type, duty training ranked high, and abroad training, qualification training, general training ranked next. the need for specialist for lecturer of in-serve education ranked among the highest, along with school nurses and university professor. The need of school nurses on education method(duplication answer), need for conference and discussion teaching was highest in the rank. The need on evaluation method, evaluation through a examination ranked the highest. On the needs of in-service education times, need for vacation during the winter and summer was the highest. As for the duration, 31 to 60 hours in duration of in-service education was need most, and most school nurses need cities and provinces in-service training institute as the location of in-service education. On the organization size, need for 21 to 30 people was the highest, where as need for 41 people was relatively low. Lastly, on the problem of in-service education for school nurses, lack of opportunity of in-service education for school nurses was highest in the rank, and improperness of in-service education contents and method, lack of incentive ranked next, respectively.