• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.487-490
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• 1999

Nowadays, the pushover analysis technique is becoming a very useful tool for the prediction of inelastic behavior of structures in the seismic evaluation of existing buildings in the world. However, the reliability of this analysis method has not been fully checked by the test results. The objective of this study is to verify the correlation between the analytical and experimental response of a high-rise masonry infilled reinforced concrete frame using DRAIN-2DX program and the test results performed previously. This study concludes that the strength and stiffness of members can be predicted with quite high reliability while the ductility capacity of members can not be described reasonably.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.692-695
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• 2004

Seismic performance of reinforced concrete(RC) column bent piers to bidirectional seismic loadings was investigated experimentally. RC column bent piers represent one of the most popular forms of piers used in highway bridges. Further to series of previous experimental researches for the performance of single bridge columns subjected to seismic loadings, four column bent piers were constructed in 400 mm diameter and 2,000 mm height. Each pier has two circular supporting columns. These piers were tested under lateral load reversals with axial load of $0.1f_{ck}A_g$. Bidirectional lateral loadings were applied. The test parameters included: different transverse reinforcement contents and lap-spliced longitudinal reinforcing steels. Test results indicate that lap-splices of longitudinal reinforcing steels have significantly influence on hysteretic response of column bent piers. Column capacity changed with the level of transverse confinement, and bidirectional repeated loadings induced more strength and stiffness degradation than unidirectional repeated loading.

• 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.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.169-170
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• 2009

CFT structure has many advantages compared with the ordinary structural member made of steel or reinforced concrete. Because of increases in ductility, stiffness and load carrying capacity of overall structure owing to confinement effect of steel box and concrete, CFT structure is widely used to columns. Recently, the utilization of CFT member has been expanded to bridge structure as a girder member. The purpose of this study is to develop the analytical model and propose design method for CFTA girder bridge consisting of CFT structure, arch shape and tendons.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.631-638
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• 2006

This paper considers the nonlinear direct spectrum method to estimate seismic performance of mixed building structures without iterative computations, given dynamic property $T_1$ from stiffness skeleton curve and nonlinear pseudo acceleration $A_{1y}$ and/or ductility ratio $\mu$ from response spectrum. Nonlinear response history analysis has been performed and analysed with various earthquakes for evaluation of correctness and confidence of nonlinear direct spectrum method.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.319-326
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• 2000

The purpose of this study is to evaluate seismic performance of reinforced concrete pier columns in Seohae Ground Bridge. Since the bridge was designed before preparing the seismic design specification the bridge columns of hollow hexagonal section were designed and constructed with insufficient seismic reinforcement details such as longitudinal and transverse reinforcement lap-splices. In order to take the necessary measures to improve its seismic performance experimental study was performed by small-scale test for the bridge columns, From the quasi-static test for small-scale column specimens the lap-splices were not critical for overall behavior of the column if sufficient lap-splice-length was provided. The test results of failure mode effective stiffness ductility and equivalent viscous damping ratio are presented.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.323-328
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• 2002

The 1995 devastating Hyogoken-Nambu earthquake sent mental shock waves that awakened the public concern about the seismic performance of infrastructures in Korea. Seismic safety of reinforced concrete bridge piers could be secured through sufficient strength and stiffness of longitudinal steels and confined core concrete, and through ductile behaviour of bridge piers in the inelastic range. This study has been performed to verify the effect of lap spliced longitudinal steel for the seismic behavior of reinforced concrete bridge piers. Quasi-static test has been done to investigate the physical seismic performance of RC bridge piers, such as displacement ductility, energy absorption etc.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.415-418
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• 1999

This paper presents a study in the ductility of reinforced concrete beam-column-slab joints Three assemblies were designed 2/3 scale (f'c=240kg/$\textrm{cm}^2$, f'c=700kg/$\textrm{cm}^2$) and tested to investigate seismic behavior. From the test results, 1) flexural cracks emerge to inside of beam deeply for high strength concrete member, 2) the high-strength specimens degraded in stiffness and strength, and unstable hysteretic behaviors were observed, owing to the brittleness of high-strength concrete beyond its range. 3) The confinement provided by the additional hoops to the column bar is probably the main reason for this improvement in behavior.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.337-342
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• 1994

This experimental study is aiming to investigate the hysteritic behavior of high-strength R/C columns subjected to axial load and lateral load reversals. The five 1/4 scaled specimens were made of high-strength concrete with the design strength load(n=0.2f'cAg, n=0.4f'cAg) and type of transverse reinforcement. From the test results, strength and stiffness degradation of columns under higher axial load is much more serious than that under lower axial load. ductility of columns is enhansed with increasing amount of transverse reinforcement, shear strength is depended on the level of axial load.

• Earthquakes and Structures
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• v.6 no.1
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• pp.45-69
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• 2014

The 2009 L'Aquila, Italy earthquake shook a high density area causing a wide spectrum of damage to reinforced concrete with infill buildings, one of the most common building types used in Italy. The earthquake has proven to be a "full-scale" laboratory to further understand building performance. This paper presents the first results of a joint research effort between the University of Bologna and Degenkolb Engineers, aimed at investigating the seismic behavior of an infilled frame building that collapsed during the earthquake. State-of-the-practice techniques were implemented as a way to determine the reliability of these modeling techniques in anticipating the observed building performance. The main results indicate that: (i) the state-of-the-practice techniques are able to predict the observed behavior of the buildings; (ii) the masonry infills have a great influence on the behavior of the building in terms of stiffness, strength and global ductility.