• Earthquakes and Structures
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• v.8 no.3
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• pp.555-572
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• 2015

This paper presents an experimental study of three two-dimensional (2D/planar) steel reinforced concrete (SRC) T-shaped column-RC beam hybrid joints and six 3D SRC T-shaped column-steel beam hybrid joints under low cyclic reversed loads. Considering different categories of steel configuration types in column cross section and horizontal loading angles for the specimens were selected, and a reliable structural testing system for the spatial loading was employed in the tests. The load-displacement curves, carrying capacity, energy dissipation capacity, ductility and deformation characteristics of the test subassemblies were analyzed. Especially, the seismic performance discrepancies between planar hybrid joints and 3D hybrid joints were intensively compared. The failure modes for planar loading and spatial loading observed in the tests showed that the shear-diagonal compressive failure was the dominating failure mode for all the specimens. In addition, the 3D hybrid joints illustrated plumper hysteretic loops for the columns configured with solid-web steel, but a little more pinched hysteretic loops for the columns configured with T-shaped steel or channel-shaped steel, better energy dissipation capacity & ductility, and larger interlayer deformation capacity than those of the planar hybrid joints. Furthermore, it was revealed that the hysteretic loops for the specimens under $45^{\circ}$ loading angle are generally plumper than those for the specimens under $30^{\circ}$ loading angle. Finally, the effects of steel configuration type and loading angle on the seismic damage for the specimens were analyzed by means of the Park-Ang model.

• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.523-530
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• 2008

In structural design provision, maximum punching shear stress of slabs is prescribed as combined stress in direct shear occurred by gravity load and eccentric shear occurred by unbalanced moment. This means that the effect of unbalanced moment is considered to decide the punching shear stress. However, from the resistance capacity standpoint, the effect of unbalanced moment strength is not considered for deciding punching shear strength. In this paper, a model considering interrelation between unbalanced moment and punching shear was proposed. In the model, the relation between load effect and resistance capacity in unbalanced moment and punching shear was two-dimensionally expressed. Using the interrelation model, a method how unbalanced moment strength should be considered to decide the punching shear strength was proposed. Additionally, effective width enlargement factors for deciding the unbalanced moment strength of flat plates with shear reinforcements were proposed. The interrelation model proposed in this paper is very effective for the prediction of the behavior of slab-column connection because not only punching shear and unbalanced moment strengths but also failure modes of flat plates can be accurately predicted.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1214-1221
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• 2011

It is an well-known fact that dynamic properties should be considered in design and maintenance of civil structures undergoing dynamic force such as rail track. For designing of the rail tack structures, dynamic properties of track bed soil such as shear modulus (G) and damping coefficients(D) obtained in small to medium range of shear strain must be known. In general, small size sample of D=5 cm and H=10cm has been used mostly for test convenience. However, ratio of largest particle diameter of the soil to sample diameter is very important and affects to the values of dynamic soil properties in track bed. In this study, an RC/TS test apparatus was built and was run for testing a medium size soil sample that can handle with compacted soil sample up to 10 cm diameter and 20 cm height.

• Computers and Concrete
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• v.17 no.2
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• pp.157-172
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• 2016

This paper presents a Strut-and-Tie Model for reinforced concrete (RC) columns subject to lateral loading. The proposed model is based on the loading path for the post-yield state, and the geometries of struts and tie are determined by the stress field of post-yield state. The analysis procedure of the Strut-and-Tie Model is that 1) the shear force and displacement at the initial yield state are calculated and 2) the relationship between the additional shear force and the deformation is determined by modifying the geometry of the longitudinal strut until the ultimate limit state. To validate the developed model, the ultimate strength and associated deformation obtained by experimental results are compared with the values predicted by the model. Good agreements between the proposed model and the experimental data are observed.

• Structural Engineering and Mechanics
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• v.68 no.3
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• pp.277-287
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• 2018

This paper presents the experimental study of nine pieces of reinforced concrete (RC) short columns. RC short columns were tested with cyclic loading with displacement control under the influence of constant axial load with load index of 0.2. Three columns within the tested nine columns are reference columns which have the details of the reinforcement given in the modern regulations and six of them are 150 mm and 100 mm externally collared columns. In addition to the parameter of the collar spacing, aspect ratio (as=2-1.5-1) is also considered as a parameter. The data obtained from experimental results have shown that externally collar contributes significantly to increasing the shear resistance of RC short columns and limiting the shear dominant behavior. It has been observed that the effectiveness of the externally collar increases with the decrease of the aspect ratio.

• Journal of the Korea Concrete Institute
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• v.12 no.3
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• pp.57-66
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• 2000

The ductility is an important consideration in the design of reinforced concrete structures. In the seismic design of reinforced concrete columns, it is necessary to allow for relatively large ductilities that the seismic energy be absorbed without shear failure of significant strength degradation after the reinforcement yielding in columns. Therefore, prediction of the ductility should be as accurate as possible. This research investigate the ductile behavior of rectangular reinforced high-strength concrete columns like as bridge piers with confinement steel. The effects on the ductility of axial load, lateral reinforcement ratio, longitudinal reinforcement ratio, shear span ratio, and compressive strength of concrete were investigated analytically using layered section analysis. as the results, it was proposed the proper relationship between ductility and variables and formulated into equations.

• Magazine of the Korea Concrete Institute
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• v.9 no.4
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• pp.145-153
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• 1997

전단벽제 양단의 보강기둥은 비선형 휨거동에 주요 영향을 미치는 구조 요소이다. 본 연구에서는 전단 벽체에 일반적으로 사용되는 모델인 TVLEM에서, 수직 스프링 요소로 표현되는 보강기둥의 반복이력 모델을 제안하고 기존의 모델과 비교 검토하였다. 제안된 단순모델은 Vulcano의 모델 중 철근의 거동을 이중직선으로 가정하여 유도되었으며, 제안된 모델을 검증하기 위하여 Vulcano와 Kabeyasawa의 모델 사용시의 수치해석 값과 비교하였다. 비선형 해석은 자체 개발된 프로그램을 사용하였으며, Vallenas와 Bertero가 실험(1979)한 SP6의 모델에 대하여 수치해석을 수행하여 반복이력특성과 변위이력 및 발산에너지량을 비교하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.75-76
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• 2010

Two-way slabs reinforced with high-performance steels were constructed and tested. The influences of the yield strength of flexural reinforcements, the flexural reinforcement ratio, and concentrating the reinforcement in the immediate column region on the punching shear resistance, post-cracking stiffness, strain distribution, and crack control were investigated.

• Computers and Concrete
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• v.19 no.5
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• pp.589-597
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• 2017

Strut-and-tie modeling method, which evolved on truss-model approach, has generally been preferred for the design of complex reinforced concrete structures and structural elements that have critical shear behavior. Some structural members having disturbed regions require exceptional detailing for all support and loading conditions, such as the beam-column connections, deep beams, short columns or corbels. Considering the general expectation of exhibiting brittle behavior, corbels are somewhat dissimilar to other shear critical structures. In this study, reinforcement layout of a corbel model was determined by the participation of structural optimization and strut-and-tie modeling methods, and an experimental comparison was performed against a conventionally designed model.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.169-176
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• 2005

Many RC building structures of multiple uses constructed in Korea have the irregularities of torsion and soft story at bottom stories. A typical irregular building was selected as prototype and shaking table tests were performed to investigate the seismic performance of this building. The objective of this study is to evaluate the correlation between the experimental and analytical responses of this irregular building structure subjected to the earthquake excitation by using OpenSees(Open System for Earthquake Engineering Simulation). The results of analyses simulate well the effect of axial forces on the shear force of column and axial deformation. However, some discrepancy between analytical and experimental results in the distribution of shear forces and overturning deformation were observed.