• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05b
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• pp.91-96
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• 2011

The flat slab is well-known as a structural system to reduce the story height, so it is broadly used for recent building. However, the normal RC flat slab is not appropriate for the long span, and the quantity of reinforcement bar and concrete is raised. Recently, the post-tensioning system has been introduced and used widely as an alternative method. Nevertheless, in Korea, it is not used broadly due to lack of the understanding and field experience. Especially, the post-tensioning system is hesitated to use due to uncertainty of construction ability and economics. This paper will introduce applicability to site and economics of unbonded post-tensioning system through construction examples.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.226-231
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• 1993

This research is undertaken to the flexural strength, failure mode and ductile capacity of one way concrete slabs, with without splices, reinforcement with Wire-Fabric. Test results are as fallows : (1) Crack of the simple slabs is occured at a position of transerve wire and sntirely crack interval of the fixed slabs is taken place about 20cm, (2)Maximum load of slab with splices has showed almost similar to that of slab without splices, but ductile capacity increased according to rising of splices, (3) Ductile capacity of slab with Deformed Bar is higher 1.44 times than that of slab with Wire-Fabric, and it is higher 3.74 times than that of slab with Loop-wire fabric, but that of specimens of using Wire-Fabric is average 4.6.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.131-132
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• 2010

Seismic design for new built bridges has been considered which is being used now. However, before the revised code for seismic design is issued, the reinforced concrete bridge piers which has been built and being used are pretty weak under the lateral seismic load. experiments of bridge piers are done under iterative lateral load, according to experimental results, the influence of Nikon-Chrome alloy steel barson performance of bridge piers is analyzed, also the shape effect of anti-seismic reinforcement on pier behavior is discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.675-678
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• 2001

In this paper, an investigation was performed on the dynamic interlaminar fracture toughness of CFRP(carbon fiber reinforcement plastics). Specimens used in this experiment are CF/EPOXY laminated plates. In this experiments, Split Hopkinson s Bar test was applied to dynamic and notched flexure test. The mode II fracture toughness of each unidirectional CFRP was estimated by the analyzed deflection of the specimen and J-integral with the measured impulsive load and reactions at the supported points. As an experimental result, the vibration amplitude of 〔$0_{10}F_4/0_{10}$〕laminates appear more than that of 〔0_{10}/F_2/0_{10}$〕laminates for the J-integral and displacement velocity at a measuring point. Also, it is thought that the dynamic fracture toughness of two kind specimen with the increase of displacement velocity becomes great at a measuring point with in range of measurement.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.291-296
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• 2000

The crack of concrete induced by the heat of hydration is s serious problem, particularly in concrete structures such as bridge piers. thick walls, box type walls, mat-slab of nuclear reactor building, dams of foundations of high rise buildings, etc. As a result of the temperature rise and restriction condition of foundation, the thermal stress which way induce the cracks can occur. Therefore the various techniques of the thermal stress control in massive concrete have been widely used. One of them is prediction of the thermal stress, besides low-heat cement which mitigates the temperature rise, design change which consider steel bar reinforcement, operation control and so on. In this study, firstly it introduce the thermal cracks control technique by employing low-heat cement concrete, thermal stress analysis, Secondly it shows the application of the cracks control technique like the bottom of No.15,16 Underground LNG Tank in Inchon.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.513-518
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• 1997

In this study, nine reinforced concrete infilled frames involved bare frames were tested during vertical and cyclic loads simultaneously. This test programs were carried to investigate the horizontal strength and the crack propagation in variance with hoop reinforcement ratio. All specimens were modeling in one-third scale size. In this experimental program structural performance of reinforced concrete shear wall were focus at connection types. Based on the test results, the following conclusions are made. In the boundary column member of reinforced concrete shear wall, increasing the ratio of hoop bar in two or three times, in the fully babel type, the shear and horizontal strength of specimens were increased 1.1-1.2 times than that of fully rigid frame. And infilled shear wall specimen were increased 1.17-1.27 times than that. Fully rigid babel type shear wall specimens were increased 5.7~8.0 times, and infilled shear wall specimens were increased about 4.0~5.6 times than that of infilled shear wall specimens.

• Journal of the Korea Concrete Institute
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• v.12 no.4
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• pp.3-14
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• 2000

Structural performance of the walls subjected to lateral load reversals depends on various parameters such as loading history, sectional shape, reinforcement, lateral confinement, aspect ratio, axial compression, etc. Thus, the performance of the shearwall for wall-type apartment should be evaluated properly considering above parameters. This study investigates the effect of sectional shape on the structural performance of the wall. Sectional shape of the specimen is rectangular, barbell and T. Based on this experimental results, all specimens behaved as ductile fashion and failed by concrete crushing of the compression zone. Deformation index of those specimens evaluated better than 3 of ductility ratio, and 1.5% of deformability specified by seismic provision. Moreover, the performance of the rectangular shaped specimen, whose compression zone was confined with U-bar and cross tie, was as good as the barbell shaped specimen. Therefore, if we considered construction practice such as workmanship and detailing, shearwall with rectangular section may be more economical lateral load resisting system.

• Journal of Korean Association for Spatial Structures
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• v.15 no.4
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• pp.57-64
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• 2015

The construction of vinyl greenhouses are increasing because of economic feasibility, construction period, and construction regulations. However, the vinyl greenhouses are apt to collapse by snow load since they have a small member as a temporary structure. The 3 types of buckling such as global, member and nodal buckling could be occurred to arched structures according to characteristics of cross section. To examine the member buckling, the precision of analysis need to be enhanced. In that case, we can examine the characteristics of the those buckling. The purposes of this study are to verify buckling characteristics of structures using the method of high precision analysis with a center node of member. The results of high precision analysis bring member buckling, and in the analysis method having the center node of member, the value of strength is getting lower than a previous study.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.352-361
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• 1998

The post-processing modules are parts of an integrated system for reinforced concrete structures. This modules are composed of two modules: member design module and calculation report module. The purpose of this paper is to develope modules that increase efficiency and usefulness of an integrated system used reinforced concrete structures design. The development of post-processing modules is necessary for user to design reinforced concrete structures conveniently and quickly. This modules are connected with central database for the benefit of storing amount of input/output data and being used system with little effort. Post-processing modules used Object-Oriented concepts and techniques include identity, classification, polymorphism, and inheritance. Member design module automatically converts no good members into satisfied members by changing section size or reinforcement bar arrangement. This module can be operated both independent member design modules with user input and a part of integrated system with database input. If user operates member design module, calculation report module is created automatically.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1181-1186
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• 2000

The crack of concrete induced by the heat of hydration is a serious problem, particularly in concrete structures such as biers, thick walls, box type walls, mat-slab of nuclear reactor buildings, dams or foundations of high rise buildings, etc.. As a result of the temperature rise and restriction condition of foundation, the thermal stress which may induce the cracks can occur. Therefore the various techniques of the thermal stress control in massive concrete have been widely used. One of them is prediction of the thermal stress, besides low-heat cement which mitigates the temperature rise, design change which considers steel bar reinforcement, operation control and so on. In this study, firstly it introduce the thermal cracks control technique by employing low-heat cement concrete, thermal stress analysis considering season. Secondly it shows the application of the cracks control technique like block placement.