• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1523-1528
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• 2013

It is necessary to develop the simple and efficient technique that ease entry of man and equipment and take the role of foundations of temporary or small structures on the soft ground. This study intends to verify the effects on the increase of bearing capacity of base projecting walls under shallow foundations and to investigate the variance of the bearing capacity of the foundations according to the interval and length of the walls. For this, model soft ground in the chamber equipped with loading apparatus is made and the loading tests on the model foundations with base projecting walls of various intervals and lengths using the apparatus are performed with measuring the loads and settlements. The results show that the base projecting walls under shallow foundations on soft ground are effective on the increase of bearing capacity and the more the number and length of the walls the larger the effects. And, when the ratio of interval to length of the walls is 1, i.e. the shape forming the base of the foundation and the walls is square, the bearing capacity is increased by 25% and the effect is optimum.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.60-68
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• 2017

This study was made to examine the motion characteristics according to the reinforcement of the reinforcement length and stiffener reinforcement for shear reinforcement to the foundation structure reinforced with shear reinforcement steel plate. Experimental study was made after specimen was installed on the ground as the same as in the practical site. Reinforcement lengths of the steel for shear reinforcement are divided into 1,000 mm, 1,200 mm and 1,400 mm in the specimen and as for reinforcement method of the stiffener, 4 stiffeners with interval of 100mm reinforced with the same materials as the shear reinforcement were manufactured for the experiment. Considering result of the experiment, it is expressed that no effect of the stiffener reinforcement was found and regarding the reinforcement length of shear reinforcement material the crossed point of the two converted lines of the value that the shear force is expressed in the bearing power in the expanded dangerous section and the value that the shear capacity receivable by the reinforcement materials in the dangerous section is proposed as effective reinforcement length.

• Fire Science and Engineering
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• v.28 no.3
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• pp.49-54
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• 2014

Beams play an important role to transfer an applied load on the floor into columns. However, if the beams affected by a fire the length will be changed longer or shorter and the structural stability decreased gradually and resulted in structural failure. Therefore, the fire regulation requires that structural beam has to satisfied with a constant fire resistance. The fire resistance conducted by a constant size and boundary condition in an horizontal furnace. But this is not enough to adopt a beam made of high structural steels having various lengths. In this study, in order to suggest structural behaviors of beams made of high structural steels at high temperature, mechanical properties at high temperature and heat stress analysis were used and the surface temperature, expansion, displacement and variance of maximum load according to lengths of the beam were compared with those of SM 400.

• Fire Science and Engineering
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• v.27 no.6
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• pp.21-25
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• 2013

Fire resistance steel, grading 490 MPa, had developed by using Thermo-mechanical control process (TMCP) and it has better performance at welding, seismic resistance than those of the ordinary structural steel, But the fire resistance performance is required to verify against the ordinary fire resistance, FR 490. Therefore this study was done to make database of mechanical properties at high temperature and to evaluate the structural stability at high temperature in terms of materials and structural member such as H-section from that of FR 490. The result of this study was that the structural stability of TMCP was lower than that of ordinary FR 490 at the range up about $700^{\circ}C$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5290-5298
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• 2013

In order to apply a mechanical deck joint to the prefabricated steel grid composite decks, shear resistance of a joint composed of concrete shear key and high-tension bolt is experimentally evaluated by the push-out test. Shear resistance evaluated by the test is compared with resistance estimated by empirical and design equations based on the shear friction theory. Test results show that joint specimens bonded by epoxy have about 10% more shear resistance than specimens with strengthened shear key by steel plates, but in the case of specimens with strengthened shear key there is smaller resistance deviation than specimens bonded by epoxy. In comparison with resistances estimated by empirical and design equations, the deck joint can be safely designed. But because the existed shear resistance of deck joint is underestimated by the ACI-318, application of the LRFD design equation could be more reasonable.

• Fire Science and Engineering
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• v.31 no.6
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• pp.60-66
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• 2017

Steel framed building can be destroyed due to deteriation of structural stabilities in a fire. This leads a TMC Fire Resistant Steels and this study analyzed the structural stabilities such as a deflection and a reduction of maximum load capacity for the structural beams built with a TMC Fire Resistant Steel. In this study the structural stabilities were evaluated using a mechanical properties in high temperatures not only a heat transfer theory but a heat stress anlaysis with a statistically determinated beam and a statistially indeternated one. The results showed that a TMC Fire Resistant Steels demonstrated a little lower those of Fire Resistant Steels.

• Fire Science and Engineering
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• v.25 no.4
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• pp.22-27
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• 2011

Fire resistance ceiling system is the structure of which the ceiling installed under the slave of the structure has the fire resistance performance. Because of having the fire resistance performance, fire resistive coatings on steel beams can be reduced and large span structures can be constructed. So, it have advantages of convenience for construction, shorten for construction time and cost reducing. In foreign country, it is general that one system consisting of slave and ceiling is constructed as a fire resistance system. But in Korea, there are no fire resistance ceiling systems thus economical efficiency due to being high-rise and light-weight of structures is not secured. Therefore research and development of nominal fire resistance ceiling systems is necessary. On this study, fire resistances of standard non-loadbearing ceiling systems were assessed and basic informations for developing the fire resistance non-loadbearing ceiling systems were presented.

• Fire Science and Engineering
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• v.28 no.5
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• pp.52-57
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• 2014

When structural elements of steel framed structures are exposed to fire situations, the structural stability begins to decrease due to dislocation of substantial. The increase of the beam length causes an additional stress and deflection. These can be serious factors to cause a severe failure of structures. To improve the fire resistance of beams, prevention of the heat from a fire by coating with fire protection material is essential for beams. The FR 490 was developed to enhance fire resistance compared with SM 490 steel. However, the fire resistance of FR 490 H-beams has not been evaluated by analysis method since it was developed. In this paper, materials properties in high temperature and a heat transfer and thermal stress theory were used in the evaluation of the fire resistance of FR490 H-beams. The fire resistance of FR490 steel beams was compared with that of SM490 beams. The comparison verified that the structural stability of FR490 beams at high temperature was superior to that of SM490 beams.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1179-1185
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• 2007

The study of girder-to-column joints under experiment and numerical analysis was carried out to evaluate change of the flexural capacity of the joints with the 2-layer upper reinforcement of girder within rectangular section and the single-layered upper reinforcement at the girder flange. According to the analysis results using the flange width, the flange thickness and the location of reinforcements in the upper flange as variables, in the models with a same effective width, the increasing rate of capacity has nothing to do with the flange width with a same effective width. However, the capacity of the models with the upper reinforcements arranged close to the rectangular beam section is larger than that of the models with the upper reinforcements arranged remotely from the rectangular section. If the range of arrangement fur reinforcement exceeds the effective width, despite of increasing the flange thickness, the capacity is not increased.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.2
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• pp.161-167
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• 1992

Centrifuge model tests were performed to find the capacity and the failure mechanism of reinforced earth retaining wall subjected to the failure due to breakage of reinforcements. Parametric model tests were carried out to figure out effects of factors on the capacity of wall by changing materials of reinforcing strip, strip length, strip arrangement. Tests were analyzed and were compared with the various design methods currently in use to verify feasibility of them. As a result of it, a proper design method was recommended.