• Journal of the Korea Concrete Institute
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• v.24 no.5
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• pp.517-524
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• 2012

In this study, the effects of the inelastic shear behavior of beam-column joint and the vertical distribution of lateral load are evaluated considering higher modes on the response of RC OMRF using the pushover analysis. A structure used for the analysis was a 5-story structure located at site class SB and seismic design category C, which was designed in accordance with KBC2009. Bending moment-curvature relationship for beam and column was identified using fiber model. Also, bending moment-rotation relationship for beam-column joint was calculated using simple and unified joint shear behavior model and moment equilibrium relationship for the joint. The results of pushover analysis showed that, although the rigid beam-column joint overestimated the stiffness and strength of the structure, the inelastic shear behavior of beam-column joint could be neglected in the process of structural design since the average response modification factor satisfied the criteria of KBC2009 for RC OMRF independent to inelastic behavior of joint.

• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.535-542
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• 2005

Two series of experiments on the performance of beam-column joints in High-Strength Reinforced concrete frames were carried out. Main experimental parameters were : concrete strength, column axial load and amount of joint hoop reinforcement. Test result showed that the ultimate shear strength of exterior joints increased of column axial compressive force and the amount of the joint hoop reinforcements. Through the regression analysis on the 24data, the following equation is obtained $jv_u=(2.935{\times}10-3\;{\rho}jw{\cdot}fy\;+\;0.365){\sqrt{f_{ck}}}$

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.73-74
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• 2010

The objective of this research is to improve the flexural capacity of RC Beams. To delay prematured tension failure of concrete specimen and to improve flexural capacity of RC beam by increasing the contribution of FRP strengthening plates, a method for inserting a laminate to the interface between concrete and FRP materials. This method makes it possible to increase overall flexural performance of RC beam by FRP plate compared to normal RC beams and RC beam strengthened by bonded FRP plates. The new bonding technique is applicable to all types of reinforcement available FRP laminate, and in principle is also applicable to materials other than FRP.

• Journal of the Korea Concrete Institute
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• v.23 no.5
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• pp.617-626
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• 2011

Seven post-tensioned lightweight concrete (LWC) beam specimens were tested under a symmetrical two-point top loading system. The parameters investigated were the amounts of mild longitudinal reinforcement and effective prestressing. The design compressive strength and dry density of the LWC tested were 30 MPa and 1,770 $kg/m^3$, respectively. Similar to post-tensioned normal weight concrete (NWC) beams, the crack propagation and stress increase of the unbonded tendons were significantly affected by the amounts of mild longitudinal reinforcement and effective prestressing. With the increase in the amounts of mild longitudinal reinforcement and effective prestressing, the serviceability and flexural capacity of the beams were enhanced whereas the stress increase in the unbonded tendons decreased. To control the crack width in post-tensioned LWC beams, a minimum amount of mild longitudinal reinforcement specified in ACI 318-08 provision is required. The flexural behavior of post-tensioned LWC beams and stress increase of the unbonded tendons could be rationally predicted by the proposed non-linear two-dimensional analysis. On the other hand, ACI 318-08 flexure provision was too conservative about the post-tensioned LWC beams.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.57-58
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• 2009

This paper reports experimental data on the structural performance of reinforced concrete beams with recycled aggregates. Reinforced concrete beams with recycled coarse aggregate and recycled sands were tested to evaluate their failure modes, flexural behavior and compared with a standard.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.4
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• pp.83-94
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• 1999

High-strength concrete has demonstrated characteristics of both increased strength and enhanced durability; hence its use has become more and more widespread. But, due to the lack of experimental evidance on the seismic performance of frame members constructed with high-strength concrete, the current codes of their design provisions are based on normal concrete test. The purpose of this study is to compare the response of the high-strength concrete beam-column-slab subassemblies with the response of a normal-strength concrete specimens. Four assemblies $(f_c'=240kg/\textrm{cm}^2, f_c'=700kg/\textrm{cm}^2)$ with 2/3 scale were designed and tested to investigate seismic behavior.

• Journal of Korean Society of Steel Construction
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• v.12 no.4 s.47
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• pp.429-436
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• 2000

The composite system, which is consisted of the steel girder and reinforced concrete column has some advantages in the structural efficiency and the construction productivity by complementing the shortcomings between the two materials. This research is aimed at the development of the composite beam-column connection system by which the steel beam can be connected to the R/C column with smooth stress transfer. And, to ensure safety of this system, the tests of moment and shear resisting performance have been carried out for actual size specimen. From the test, the connection system has been preyed to take good resistance and stress transfer between steel girder and reinforced concrete column.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.6
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• pp.201-211
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• 2011

Many reinforced concrete structures have been constructed at the offshore in Korea and those are exposed in environments for long period. Due to that, the reinforcement of the structure faces possibility of corrosion by the salt damage. Such corrosions are effects on the bond performance between concrete and reinforcing bar as well as the performance of the structure. In this study, the performance of RC structure has been investigated when the reinforcing bars are totally bonded and unbonded in the structure. Through the experimental tests and finite element analyses of beam-column joint with bond and unbonded reinforcing bar, the energy dissipation capacity, strength, and crack distribution are compared and discussed.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.823-829
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• 2002

The composite frame system with reinforced concrete column and steel beam has some advantages in the structural efficiency by complementing the shortcomings between the two systems. The system, however has also a lot of problems in practical design and construction process due to the material dissimilarities. Considering these circumstances, this research is aimed at the development of the composite structural system which enables the steel beams to be connected to the R/C columns with higher structural safety and economy. Basically the proposed connection system is composed of four split tees, structural angles reinforced by stiffener, high strength steel rods, connecting plates and shear plates. The structural tests have been carried out to verify the moment transfer mechanism from beam flange to steel rods or connecting plates through the angle reinforced by siffener. The four prototype specimens have been tested until the flange of beam reached the plastic states. From the tests, no distinct material dissimilarities between concrete and steel have been detected and the stress transfer through wide flange beam - structural angle - high strength steel rod or connecting plate is very favorable.

• Magazine of the Korea Concrete Institute
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• v.1 no.2
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• pp.93-100
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• 1989

철근콘크리트부재의 강도는 여러 가지 요인으로 인하여 변이를 보이고 있다. 주요 요인들은 콘크리트나 철근의 강도 및 역학적 특성의 변이, 시공오차등이다. 이들중 콘크리트의 강도는 상대적으로 높은 불확실성을 가지며, 다양한 요인(배합, 운반, 타설, 양생등)에 의해 변화정도가 영향을 받는다. 본 연구에서는 국내 철근콘크리트 구조물이 가지는 신뢰도의 수준을 분석하기 위한 기초자료 조사로서, 현장에서 타설되는 콘크리트를 설계강도별로 직접채취하여 습윤양생과 현장조건양생을 통하여 콘크리트의 28일 압축강도의 확률적 특성을 분석하였다. 분석된 결과를 이용하여 현장타설 부재내에서의 콘크리트의 압축강도를 추정하였다.