• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.2
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• pp.49-57
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• 2012

Recently, in field of bridge construction, modular technology has been studied to reduce construction period. However, main stream of the study is limited to the pier, girder and deck of bridge, which are huge or main members. Studies on incidental facilities like concrete barrier is out of sight. Thus, in this study, connection system of concrete barrier was developed to apply to modular bridges and static experiment was performed in order to verify structural capability of proposed system. Variables of experiment are composed of bolt direction such as vertical and horizontal. The experimentation due to the designed variables was conducted by comparison with a standard concrete barrier, which is a traditional barrier. As a result, vertical joint way of the bolt showed nearly identical structural performance and healthy to standard specimen's. it can be applied to modular bridges.

• Journal of Korean Society of Steel Construction
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• v.27 no.4
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• pp.377-386
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• 2015

In this study, inelastic buckling strength of HSA800 steel columns were tested to investigate the applicability of current column curve (KBC2009, 2010 AISC-LRFD) to HSA800 steel. Key test variables included width-thickness ratio, plate-edge restraints, and column slenderness ratio. Specimens made of ordinary steel (SM490) were also tested for comparison purposes. All the concentrically loaded HSA800 specimens exhibited sufficient buckling strength compared to the current column curve, but some of SM490 specimens showed understrength. This difference can be explained by the lower residual stress present in HSA800 specimens.

• Journal of Korean Society of Steel Construction
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• v.24 no.1
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• pp.23-34
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• 2012

In this study, stub columns subjected to concentrical and eccentrical loads were tested to check the applicability of the current local stability criteria (KBC2009, AISC2005) to 800MPa high-strength steel (HSA800). The key test variables in the concentrically loaded tests included the plate-edge restraints and the width-to-thickness ratio normalized by the yield strength of steel. Specimens made of ordinary steel (SM490) were also tested for comparative purposes. Eccentrically loaded stub column tests were conducted for a range of the P-M combinations by controlling the loading eccentricity. All the concentrically loaded specimens with non-compact and slender sections developed sufficient strengths according to the current local stability criteria. All the eccentrically loaded specimens with non-compact H sections also exhibited a sufficient P-M interaction strength that was even higher than that of compact H- section counterparts. Residual stresses were also measured by using the non-destructive indentation method to demonstrate their dependency or independency on the steel material's yield strength. The measured results of this study also indicated that the magnitude of residual stresses bears no strong relation to the yield strength of the steel material.

• Fire Science and Engineering
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• v.23 no.6
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• pp.66-74
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• 2009

When a fire occurs, the concrete structure's strength decreases by the increasing temperature under the fire in certain condition of constant load. And, the ratio of the axial force is changed by such decreased strength so that the structure is deformed. In this research, considering such case, we have conducted an actual fire test for the concrete lining with constant loading condition and various fire conditions. The specimen adopts the shape condition for small practical specimen defined by the EFNARC and we used 24MPa, 40MPa and 50MPa to analyze the thermal properties by the strength. The ratio of loading is imposed by a certain loading condition based on 20% and 40% of the sectional stress in concrete and MHC Fire is selected to realize the thermal impact of the concrete by rapid increasing temperature. As the result of the experiment, in the same ratio of loading, the 50MPa specimen shows more cracks and spalling as time goes on. The area damaged by the fire, according to the functional criteria of the concrete lining under the fire in ITA, does not satisfy with the standard in lack of 50mm depth from the heating surface at total 200mm lining.

• Journal of Korean Society of Steel Construction
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• v.23 no.2
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• pp.229-236
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• 2011

This study was conducted to understand the characteristics of the compression behavior of steel plate-concrete(SC) structures with a width-to-thickness ratio under axial loading. SC structures are structural systems where concrete is poured into steel plates to which headed stud bolts had been attached inside. The specimens were classified according to the two width-to-thickness (W/T) ratios of 1.60 and 3.56. Through these experiments, the following conclusions could be arrived at. The fracture pattern of the specimens showed that steel plate buckling occurred between the stud lines, and that a crack occurred at the concrete spalling from the sides of the concrete before the system reached the maximum compressive strength. The maximum compressive strength of the specimens was larger than that of the existing equations (AISC 2005, ACI 318-05, and KBC 2005). With the increased W/T ratio of the specimens, the strength of the concrete core was decreased to account for the confinement effects from the steel plates.

• Journal of the Korea Concrete Institute
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• v.23 no.1
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• pp.109-120
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• 2011

This paper presents an experimental study results on the crack control of flexure-dominant reinforced concrete beams repaired with strain-hardening cement composite (SHCC). Five RC beams were fabricated and tested until failure. One unrepaired RC beam was a control specimen (CBN) and remaining four speciemens were repaired with SHCC materials. The test parameters included two types of SHCC matrix ductility and two types of repair method (patching and layering). Test results demonstrated that RC beams repaired with SHCC showed no concrete crushing or spalling until final failure, but numerous hair cracks were observed. The control specimen CBN failed due to crushing. It is important to note that SHCC matrix can improve crack-damage mitigation and flexural behavior of RC beams such as flexural strength, post peak ductility, and energy dissipation capacity. In the perspective of crack width, crack widths in RC beams repaired with SHCC had far smaller crack width than the control specimen CBN under the same deflection. Especially, the specimens repaired with SHCC of PVA0.75%+PE0.75% showed a high durability and ductility. The crack width indicates the residual capacity of the beam since SHCC matrix can delay residual capacity degradation of the RC beams.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.37-38
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• 2009

In this paper, the load transfer test of Korean PS anchorage system was conducted for 1860MPa PS strand and 2200MPa PS strand. The test is in compliance with ETAG013. All the anchorage system tested satisfied the allowance criteria of the test for 1860MPa PS strand but only one of the anchorage systems for 2200MPa PS strand. In order to generally use 2200MPa PS strand to prestressed concrete structures, new anchorage systems shall be developed.

• Journal of Korean Society of Steel Construction
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• v.14 no.6
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• pp.823-834
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• 2002

Maximum-strength concrete-filled steel square tubular columns were tested under concentric and biaxial eccentric load. Buckling length-section depth ratio $L_k/D$, magnitude of eccentricity e, and angle of eccentric load ${\theta}$ were selected as experimental parameters. Strength and behavior were also examined. Test results showed that the maximum strength of columns under biaxial eccentric load could be predicted using the previously proposed strength formula of columns undr uniaxia eccentric load. Likewise, the behavior and maximum strength of columns could be predicted using the analysis.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.17-20
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• 2010

기존의 무량판 구조와 동일한 이방향 슬래브구조인 TVS(two-way void slab)공법은 구조적 하중지지 성능이 불필요한 슬래브 단면상의 중앙부 콘크리트를 제거하여 슬래브의 자중을 줄이고 무량판 구조의 단점을 보완하여 장점을 극대화시킨 구조형식이다. 그러나 이러한 장점을 보유한 공법을 현장적용하기 위해서는 내화성능평가를 통해 화재안전성을 확보하여야 하므로, 이에 대한 화재 실증실험을 수행하여 현장적용을 위한 최소 요구내화 시간에 따른 내화성능 확보방안의 도출이 제시되어야 한다. 이에 본 연구에서는 TVS공법의 실제 스팬길이로 슬래브 피복두께에 따른 화재거동 영향성 분석을 위하여 화재실험을 수행하였다. 하중조건은 고정하중과 적재하중을 고려하여 실험체에 등분포 조건으로 사전재하하였으며, 표준화재조건으로 재하가열 실험을 수행하였다. 슬래브의 화재가열 노출면으로부터의 깊이별 온도변화와 처짐변형 특성을 측정하였으며, KS F 2257-1 평가기준에 의거하여 슬래브의 내화성능을 평가하였다. 실험결과 피복두께 50 mm를 확보할 경우, EPS중공체로 제작한 실험체의 경우 약 2시간정도의 내화성능을 확보할 수 있는 것으로 나타났다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.6
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• pp.46-55
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• 2016

Three small scale hollow circular reinforced concrete columns(4.5 aspect ratio) were tested under cyclic lateral load with constant axial load. Diameter of section is 400 mm, hollow diameter is 200 mm. The selected test variable are transverse steel ratio. Volumetric ratio of spirals of all the columns is 0.302~0.604% in the plastic hinge region. It corresponds to 45.9~91.8% of the minimum requirement of confining steel by Korean Bridge Design Specifications, which represent existing columns not designed by the current seismic design specifications or designed by seismic concept. The final objectives of this study are to provide quantitative reference data and tendency for performance or damage assessment based on the performance levels such as cracking, yielding, steel fracture, etc. In this paper, describes mainly failure behavior, strength degradation behaviour, displacement ductility of circular reinforced concrete bridge columns with respect to test variables.