• Korean Journal of Culture and Social Issue
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• v.22 no.4
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• pp.487-522
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• 2016

The main purpose of this research is to investigate Korean adolescents' perception of stress experiences, and related social support. To this end, adolescents were asked about stress events, as well as stress symptoms, in their lives. Also, the adolescents were asked about the people that provided social support and the types of social support provided. The participants were 952 Korean adolescents (Primary 219; Middle 280; High 212; University 241). Among the four measures (stress events, stress symptoms, social supporters, and types of social support), the measure of stress symptoms yielded a reliability of Cronbach α=.88, while the remaining three measures yielded an inter-judger reliability of 89.6%, Kappa=.87. The results were as follows. First, for stress events, the most frequent responses were related to Academic Achievement, followed by Career/Job, Family Relations, Friend Relations, Lack of Capacity, and Financial Difficulties. For high-school students the most frequent responses were related to Academic Achievement, while for university students Career/Job. Second, for stress symptoms there were significant differences among the groups, in that the high-school students showed the highest level of symptoms, while primary school students the lowest. Third, for social supporters, the most frequent responses were related to Friends, followed by Myself, Parents, Teacher, Siblings, and Seniors/Juniors. As the groups aged (from primary to university), support from Friends and Seniors/ Juniors increased, while support from Parents decreased. Fourth, for the types of social support, the most frequent responses were related to Emotional Support, followed by None, Advice, Supporter Directly Solved Problem, and Talked with Me. The highest frequencies of responses were found for Emotional Support among all groups. As the groups aged (from primary to university), Advice increased while Supporter Directly Solved Problem decreased.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.201-209
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• 2010

Generally, PSC girder bridge uses total gross cross section to resist applied loads unlike reinforced concrete member. Also, it is used as short and middle span (less than 30 m) bridges due to advantages such as ease of design and construction, reduction of cost, and convenience of maintenance. But, due to recent increased public interests for environmental friendly and appearance appealing bridges all over the world, the demands for longer span bridges have been continuously increasing. This trend is shown not only in ordinary long span bridge types such as cable supported bridges but also in PSC girder bridges. In order to meet the increasing demands for new type of long span bridges, PSC hollow box girder with H-type steel as compression reinforcements is developed for bridge with a single span of more than 50 m. The developed PSC girder applies compressive prestressing at H-type compression reinforcements using unbonded PS tendon. The purpose of compressive prestressing is to recover plastic displacement of PSC girder after long term service by releasing the prestressing. The static test composed of 4 different stages in 3-point bending test is performed to verify safety of the bridge. First stage loading is applied until tensile cracks form. Then in second stage, the load is removed and the girder is unloaded. In third stage, after removal of loading, recovery of remaining plastic deformation is verified as the compressive prestressing is removed at H-type reinforcements. Then, in fourth stage, loading is continued until the girder fails. The experimental results showed that the first crack occurs at 1,615 kN with a corresponding displacement of 187.0 mm. The introduction of the additional compressive stress in the lower part of the girder from the removal of unbonded compressive prestressing of the H-type steel showed a capacity improvement of about 60% (7.7 mm) recovery of the residual deformation (18.7 mm) that occurred from load increase. By using prestressed H-type steel as compression reinforcements in the upper part of cross section, repair and rehabilitation of PSC girders are relatively easy, and the cost of maintenance is expected to decrease.