• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.42-45
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• 2006

This study investigated headed bar anchorage of exterior beam column joints in nuclear power plants. In nuclear power plant structures, anchorage of headed bar is recommended to satisfy ACI 349-01 App. B that are based on the Concrete Capacity Design (CCD) method. However, CCD method may lead to very conservative results for beam column joints where head is anchored within the diagonal strut and concrete is confined by transverse rebar. Compared with results of 5 joint specimens, the anchorage capacities calculated by ACI 349-01 are underestimated by 70-90%. Therefore, it is necessary to amend ACI 349-01 for the mechanical anchorage in beam column joints.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.552-557
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• 1997

In this study, a quantitative analysis technique for the damage process of reinforced concrete beams under repeated shear loading is proposed, which can express the progressively increasing strain and stiffness reduction. The analysis technique is mainly based on the modified compression field theory and scalar damage concept. which describe the strain and stress configuration in the shear zone by considering the 2-dimensional effect, and express the degradation of principal compressive strut by cyclic strain increment, secant modulus decrement, and modifying the parabolic stress strain relationship. The analysis of the response of RC beams under repeated shear-flexure loading has been carried out and compared with the experimental results. The present theory may efficiently be used to evaluate the deflection and strain accumulation under repeated loadings.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.95-98
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• 2005

The objective of this experimental study was to understand the structural behavior of reinforced concrete continuous deep beams with welded deformed wire fabric(WWF) as shear reinforcement. The structural behavior of deep beams reinforced with WWF was compared with that of deep beams reinforced with orthogonal shear reinforcement which had standard anchorage corresponding to ACI 318-02. Test results showed that the load transferring capacity and the control of splitting cracks in the strut of WWF were almost as effective as those of orthogonal shear reinforcement with standard anchorage.

• Structural Engineering and Mechanics
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• v.16 no.3
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• pp.275-294
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• 2003

In this study, 24 high-strength concrete dapped-end beams were tested to study the effects of the amount of main dapped-end reinforcement, the nominal shear span-to-depth ratio, and the concrete strength on the shear strength of dapped-end beams. Test results indicate that the shear strength of dapped ends increases with the increase in the amount of main dapped-end reinforcement and the concrete strength. The shear strength of dapped-end beam increases with the decrease of nominal shear span-to-depth ratio. A simplified method for determining the shear strength of reinforced concrete dapped ends is also proposed in this paper. The shear strengths predicted by the proposed method and the approach of PCI Design Handbook are compared with test results. The comparison shows that the proposed method can more accurately predict the shear strength of reinforced concrete dapped-end beams than the approach of PCI Design Handbook.

• Structural Engineering and Mechanics
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• v.14 no.3
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• pp.307-330
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• 2002

This study aims at postulating a simple methodology for predicting the failure modes of monotonically loaded reinforced concrete beam-column joints. All the factors that affect the failure modes of joints are discussed in detail using an experimental database of monotonically loaded exterior beam-column joints. The relative contributions of the strut and truss mechanisms to joint shear strength are determined based on the test results. A simple design equation for the beam longitudinal reinforcement ratio for joints with low, medium and high amount of stirrups is developed. The factors influencing the failure modes of monotonically loaded exterior beam-column joints are investigated in detail. Design charts that predict the failure modes of exterior beam-column connections both with and without stirrups are developed. Experimental data are compared with the design charts. The results show that the simple methodology gives very accurate predictions of the failure modes.

• Computers and Concrete
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• v.12 no.3
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• pp.243-259
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• 2013

Recent developments in Artificial Intelligence (AI) and computational intelligence have made it viable in the construction industry and structural analysis. This study usesthe Adaptive Network-based Fuzzy Inference System (ANFIS) as a modelling tool to predict the strain in tie section for High Strength Self Compacting Concrete (HSSCC) deep beams. 3773 experimental data were collected. The input data andits corresponding strains in tie section as output data were recorded at all loading stages. Results from ANFIS are compared with the classical linear regression (LR). The comparison shows that the ANFIS's results are highly accurate, precise and satisfactory.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.102-105
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• 2006

Nowadays, increase of demands on efficient utilization of resources while construction process stimulates structural engineers to select remodeling to improve old buildings. To analyze the effects of openings that may be installed in the course of remodeling old buildings, an experimental research was carried out using four approximately half scale of specimens subjected to constant axial forces, and cyclic loading to simulate seismic conditions. Consequently, the existence of opening was verified to induce different observed damages, which caused by reduction of compression strut support formed on the surface of wall. Especially, the maximum force was revealed to decrease approximately 35% as openings were existed. As this tendency was appeared with stiffness and energy dissipation capacity.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.253-257
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• 1996

A basic assumption in the current design and analysis of reinforced concrete(RC) box structures, which are constructed by the open cut and fill method, is that the displacements and forces are uniform in the longitudinal direction of the structure. The solution may be therefore obtatined from the analysis of a unit wide strip along longitudinal axis. This strip is said to be in a plane strain condition, meaning that the out of plane deformations are vanished. The current design of box structure is carried out by the result of planar frame model for the sake of simplicity. The purpose of this study is to show more rational design method of box culverts considering a rigid zone of corner joints. The current analysis of box structures will be compared with the plane strain analysis as well as 3-d shell model. Reinforcement quantity is also determined to resist the tensile force in corner joints of box structures using strut-tie model which has been developed through the elastic analysis.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.383-386
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• 2005

철근콘크리트 부재가 하중을 받을 때, 응력교란구역에서의 힘의 흐름은 스트럿-타이 모델을 이용하여 효과적으로 표현할 수 있다. 그러나 스트럿-타이 모델을 이용하여 철근콘크리트 부재의 해석과 설계를 하기 위해서는 큰크리트 압축스트럿이 가지는 유효강도를 정확히 산정하여야 한다. 본 연구는 철근콘크리트 부재에 휨과 전단력이 동시에 작용할 때 발생하는 대각선 균열이 콘크리트 압축스트럿에 미치는 영향에 대해 설명하고 있다. 대각선 균열의 발생 메커니즘과 이로 인한 콘크리트 압축스트럿의 강도 저하를 이론적으로 설명하였으며, 그 결과를 철근콘크리트 보의 강도 산정에 적용하였다. 최종적으로 철근콘크리트 보의 강도 예측값을 기존 연구자들의 실험결과와 비교하여 제안된 이론의 합리성을 검증하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.71-74
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• 2005

The increasement in the floor hight may be one of the most significant problem in the use of precast concrete double slab in the multi-story buildings. The modified double-tees including duct space at the ends of slab were considered in this study. The length and thickness of nib of modified double tee was increased to receive the uniform reaction from rectangular beam, while the original PCI dapped one to receive the point load from inverted tee beam to the leg of double tee. Shear tests were performed on the ends of the modified double tees which were designed by strut-tie model. The modified double tees generally show more ductile flexural failure in the long thickened nib. It is concluded that they show superior failure patterns than that of original dapped one with shear failure.