• Journal of Korean Society of Steel Construction
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• v.13 no.4
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• pp.419-431
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• 2001

This study was to investigate structural behavior of composite structure beams composed of end-RC. center-Steel according to respective reinforcing method for connection zone composed of different materials (SRC) while attaching main bars on steel-flange by welding. The main reinforcing methods are as follows ; non-reinforcing, vertical shear reinforcing (type-stirrup), inclined reinforcing(type-x), horizontal reinforcing(type-web, 0.3L), double horizontal reinforcing (type-web, 0.3L), vertical reinforcing (type-flange, 0.3L). Consequently, It showed little difference in structural properties like ductility and strength according to the attaching method of main bars. For Maximizing the structural properties of composite beam, the most effective methods were vertical reinforcing one and double horizontal reinforcing one.

• Journal of the Korea Concrete Institute
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• v.29 no.2
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• pp.201-208
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• 2017

In exterior beam-column joints, hooked bars are used for anchorage, but usage of high-strength and large-diameter bars increases, headed bar is preferred for solving steel congestion and difficulty in construction. To investigate the structural performance of headed bars, Six exterior beam-column joints were tested under cyclic loading. Tests parameter were the anchorage methods and concrete strength. The test results indicate that behavior of headed bar specimens shows similar performance with hooked bar specimens. All specimens failed by flexural failure of the beam. Headed bar specimens shows better performance in anchorage and joint shear. All specimens were satisfied the criteria of ACI374.1-05. Test results indicate that use of headed bar in exterior beam column joint is available.

• The Journal of the Korea Contents Association
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• v.12 no.2
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• pp.310-321
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• 2012

This study was conducted to establish collaborative governance for North Korean Refugees' settlement support service. Three major actors were identified. At the central government level, there is no control center to coordinate various functions. This study suggested three roles for central government in collborative governance, which are policy planning based on public value, allocating financial resources to implementing organizations, and program evaluation for securing public accountability. The rloes of local government are establishing communication channels between implementing participants, maintenancing good relations, and coordination. Finally, the role of private actors is developing high quality service programs, connecting local resources for settlement service.

• Journal of the Korea Concrete Institute
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• v.15 no.6
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• pp.894-901
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• 2003

The objective of this study is to clarify the seismic capacity and the characteristics in the hysteretic behavior of RC structures with non-seismic detailing. Interior and exterior beam-column subassemblages were selected from a ten-story RC building and six 1/3-scale specimens were constructed with three variables; (1) with and without slab, (2) with and without hoop bars in the joint region, (3) upward and downward direction of anchorage for the bottom bar in beams of exterior beam-column subassemblage. The test results have shown; (1) in case of interior beam-column subassemblage, there is no almost difference between nonseismic and seismic details in the strength and ductility capacity; (2) the Korean practice of anchorage (downward and 25 $d_{b}$ anchorage length) in the exterior joint caused the 10%∼20% reduction of strength and 27% reduction of ductility in comparison with the case of seismic details; and the existence of hoop bars in the joint region shows no effect in shear strain.

• Journal of Korean Society of Steel Construction
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• v.22 no.6
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• pp.511-521
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• 2010

This paper presents a simplified analysis method of determining the initial shape of suspension bridges, including the horizontal tension force of the main cable and the locations of each hanging point, considering the force equilibrium condition of each hanging point. This method is effective because it requires less effort than the methods used in other studies, for which complicated non-linear analysis was used, to comparatively determine the exact initial shape. The accuracy and validity of the present method are demonstrated by comparing the results of this study with those of previous researchers' numerical examples, including 2D and 3D models.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.369-376
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• 2003

One of the most complex reinforcement location in the precast building frame is the beam-column joint in a prefabricated construction. It is generally resulted from the vortical bars of column, anchorage bars of beam, and bars of hoop. Particularly the hooked anchorage bars of beam are confronted with hoop and main column bars. The headed reinforcement is considered to place them easily and to reduce the anchorage length in a precast construction. Reversed cyclic loading tests are performed on four beam-column specimens to evaluate the strength and behavior of beam to column and column to column connections. The result of test shows that the headed reinforcement has a similar performance than that of hooked reinforcement in a precast specimen with strong column and weak beam joints. The splice column joints which are used frequently in the domestic fields also show reliable behaviors in those tests with strong column and weak beam joints.

• Journal of the Korean Wood Science and Technology
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• v.29 no.1
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• pp.52-59
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• 2001

The fixation characteristics of CCA and CCFZ in Japanese red pine, Japanese larch, and ezo spruce sapwood were compared at various temperatures and fixation conditions (drying and nondrying fixation). Fixation was monitored by the rates of reduction of hexavalent chromium to trivalent one, and optimal fixation time was estimated based on the results. The rate of fixation was highly temperature dependent, and the fixation rate of treated wood conditioned under nondrying conditions was much more faster than that under drying conditions, especially when the moisture content of treated wood was below fiber saturation point. Preservative types affected fixation; CCA-Type B had the highest fixation rate, followed by CCA-Type C and then CCFZ. The differences in fixation rates of preservative components were also observed among wood species; Japanese red pine fixed the fastest, followed by Japanese larch and then ezo spruce. Time required to complete fixation according to the fixation temperature could be predicted successfully using the regression equations between the temperatures and fixation time, regardless of conditioning methods, preservative types, and wood species.

• The Journal of Engineering Geology
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• v.17 no.1 s.50
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• pp.65-73
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• 2007

Recently, large-scale underground cavern such as underground hydraulic-power plant tend to be constructed very largely, so long-length rock bolt are generally used to support the huge plastic zone. However, problems fur bend-ing shape of the long-length steel bar and the bonding effects of anchoring systems are caused during the construction of the long-length rock bolt. In this study, field pull-out test for long-length rock bolt are carried out to estimate the most efficient anchoring system among the saw-toothed shape, grooved shape and smoothed shape with each 6 shells for 5.0m, 7.5m, 10.0m, 15.0m length. The axial load and axial displacement are measured with each load stage and than test results are analyzed to evaluate the behavior characteristics for each anchoring systems of long-length rock bolt. Also, the improvements of anchoring systems are proposed and discussed in this paper.

• Journal of Korean Society of Steel Construction
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• v.26 no.1
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• pp.1-10
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• 2014

In this study, out-of-plane flexural test was performed to analyze behavior properties for a beam specimen which imitated a structure with connection member between reinforced concrete and steel plate concrete part. Tie bars between a upper and a lower steel plate, and tie wide flange shapes between upper and lower ribs were designed to prevent the steel plate or the ribs from breakaway in the connection of the specimen. As a result of the test, ductile failure behavior of the specimen and the functionality of the tie members were conformed as originally intended. Also, tension tests were performed to evaluate the design appropriateness of two specimens produced to anchor and connect mechanically #14 bars. The two test results showed that the anchorage connection system behaves in elastic limit during the main bars yielded, and the integrity of the designed system was verified.

• Journal of the Korea Concrete Institute
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• v.13 no.6
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• pp.593-601
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• 2001

In RC structure, sufficient anchorage of reinforcement is necessary for the member to produce the full strength. Generally, conventional standard hook is used for the reinforcement's anchorage. However, the use of standard hook results in steel congestion, making fabrication and construction difficult. Mechanical anchor offers a potential solution to these problems and may also ease fabrication, construction and concrete placement. In this paper, the required characteristics and the design considerations of mechanical anchor were studied. Also, the mechanical anchor was designed according to the requirements. To investigate the pull-out behavior and properness of mechanical anchorage, pull-out tests were performed. The parameters of tests were embedment length, diameter of reinforcement, concrete compressive strength, and spacing of reinforcements. The strengths of mechanical anchor were consistent with the predictions by CCD method. The slip between mechanical anchor and concrete could be controlled under 0.2mm. Therefore, the mechanical anchor with adequate embedment could be used for reinforcement's anchorage. However, it was observed that the strength of mechanical anchors with short spacing of reinforcements was greatly reduced. To apply the mechanical anchor in practice (e.g. anchorage of the beams reinforcements in beam-column joint), other effects that affect the mechanical anchor mechanism, such as confinement effect of adjacent member from frame action or effects of shear reinforcement, should be considered.