• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.339-340
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• 2012

Green frame is combined by structural steel and reinforcements of Green column and beam and unified by cast-in-place concrete. However, when upper reinforcements penetrate structural steel hole, the execution is difficult due to interference of joint and a rib of deformed reinforcements. Therefore, the objective of this study is to propose the reinforcement tools to improve productivity of precast structure connection construction. The reinforcement tools proposed in this study can be helpful to improve constructability, safety, duration, and cost comparing with conventional reinforcement method since unskilled workers can deal with reinforcements easily.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.137-138
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• 2017

Generally, a lot of reinforcements are used in nuclear power plant concrete structures in order to improve the structural safety, but it may cause several potential problems due to the overcrowded reinforcement, such as the degradation of concrete quality, the construction delay and the increase of construction cost. In order to resolve these problems, structural test researches and code change studies on using high-strength reinforcement (Gr.80) in unclear power plant structures are under way, and there is good progress in code change of ASM BPVC.III.2 and ACI 349. This purpose of this study is to review the code change status ASM BPVC.III.2, ACI 349 under way to use the high-strength reinforcement in nuclear power plant structures. Also I will introduce the design optimization of NPP structures with high-strength reinforcements in order to maximize the effect and minimize the problem when using the high-strength reinforcements in NPP structures.

• Advances in concrete construction
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• v.10 no.3
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• pp.185-193
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• 2020

An analytical model is developed in this paper to predict the shear capacity of reinforced concrete (RC) columns with corroded transverse reinforcements. The shear strength model for corroded RC columns is proposed based on modifying the existing strut-and-tie model, which considers the deformational compatibility between truss and arch mechanisms. The contributions to the shear strength from both truss and arch mechanisms are incorporated in the proposed model. The effects of corrosion level of transverse reinforcements are considered in the proposed model through the minimum residual cross-sectional area of transverse reinforcements and the reduction of concrete compressive strength for the cover area. The shear strengths calculated from the developed model are compared with the experimental results from Vu's study (2017), which consisted of RC columns with corroded transverse reinforcements showing shear failure under the cyclic loading. The comparison results indicate satisfactory correlations. Parametric studies are conducted based on the developed shear strength model to explore the effects of column axial loading, aspect ratios, transverse reinforcements and the corrosion levels in transverse reinforcements to the shear strength of RC columns with corroded transverse reinforcements.

• Structural Engineering and Mechanics
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• v.90 no.1
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• pp.71-81
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• 2024

Fiber Reinforced Polymer (FRP) bars have now been widely adopted as an alternative to traditional steel reinforcements in infrastructure and civil industries worldwide due variety of merits. This paper presents a numerical methodology to investigate FRP bar-reinforced beam-column joint behavior under quasi-static loading. The proposed numerical model is validated with test results considering load-deflection behavior, damage pattern at beam-column joint, and strain variation in reinforcements, wherein the results are in agreement. The numerical model is subsequently employed for parametric investigation to enhance the end-span beam-column joint performance using different joint reinforcement systems. To reduce the manufacturing issue of bend in the FRP bar, the headed FRP bar is employed in a beam-column joint, and performance was investigated at different column axial loads. Headed bar-reinforced beam-column joints show better performance as compared to beam-column joints having an L-bar in terms of concrete damage, load-carrying capacity, and joint shear strength. The applicability and efficiency of FRP bars at different story heights have also been investigated with varying column axial loads.

• Composites Research
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• v.34 no.1
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• pp.35-46
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• 2021

This paper aims to reduce weight by replacing the reinforcements of the B-pillar used in vehicles with CFRP(Carbon Fiber Reinforced Plastics) and GFRP(Glass Fiber Reinforced Plastics) from the existing steel materials. For this, it is necessary to secure structural stability that can replace the existing B-pillar while reducing the weight. Existing B-pillar are composed of steel reinforcements of various shapes, including a steel outer. Among these steel reinforcements, two steel reinforcements are to be replaced with composite materials. Each steel reinforcement is manufactured separately and bonded to the B-pillar outer by welding. However, the composite reinforcements presented in this paper are manufactured at once through compression and injection processes using patch-type CFRP and rib-structured GFRP. CFRP is attached to the high-strength part of the B-pillar to resist side loads, and the GFRP ribs are designed to resist torsion and side loads through a topology optimization technique. Through structural analysis, the designed composite B-pillar was compared with the existing B-pillar, and the weight reduction ratio was calculated.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.4
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• pp.231-238
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• 2004

This paper presents the tensile behavior of the stud connection between reinforced concrete(RC) and steel members. Hanger reinforcements are placed around the studs to transfer the tensile and flexural loads to the opposite side of the concrete member. Eight specimens for the tensile tests are tested with variables, which are the arrangement details of hanger reinforcements, the reinforcing bars, and the embedment length of stud. The results of the tensile tests show that hanger reinforcements are effective to increase tensile strength for stud connections. Hangers and reinforcing bars near stud bolts contributed to the reduction of brittle failure. From the evaluation on the tensile strength by previous design guidelines, it was shown that CCD (Concrete Capacity Design) method was more suitable for estimation of test strength.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.3
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• pp.545-555
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• 2002

This paper presents a matrix analysis to get the torsional behavior of core structures with torsional reinforcements. Based on simplified assumptions, formulae for the forces and displacements of cote structures subjected to three typical load cases, i.e. uniformly distributed torque, triangularly distributed torque and a concentrated torque at the top of the structure, are derived analytically. The behavior of the cote according to the variation of reinforcement locations is investigated to estimate the optimum locations of reinforcements to minimize the core rotations and bimoments. The results by the program MIDAS-GEN have shown that this analysis can give quite satisfactory results for structural models with torsional reinforcements. Although three dimensional analysis by computer has come within reach as a normal structural design procedure, its use as an optimization tool may not be desirable in view of the expense and time required. Formulae that we presented here can be used to estimate the torsional rotations and forces of practical cote structures at the preliminary design stages.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.519-524
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• 1998

The shear behavior and reinforcement effects of simply supported reinforced concrete deep beams with web opening subject to concentrated loads have been scrutinized experimentally to verify the effects of structural parameters such as size, location and reinforcements of web opening. A total of 14 specimens were tested at the laboratory under two-point top loading. The shear span ratio was taken constantly 0.8, and various types of reinforcements based on truss models were adopted. In the tests, the effects of loction, reinforcements of web openings on the shear behavior, and crack initiation and propagation have been carefully checked and analyzed.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.665-670
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• 1999

The shear behavior and strength of simply supported reinforced concrete deep beams with web opening subject to concentrated loads have been investigated experimentally on the effects of structural parameters such as location of web opening and reinforcements. A total of 12 specimens were tested at the laboratory under two-point top loading. The shear span-to-depth ratio was taken constantly 0.8, and various types of reinforcements based on truss models were adopted. In the tests, the effects of location, reinforcements of web openings on the shear behavior, and crack initiation and propagation have been carefully checked and analyzed. The test results have been compared with the formulas proposed currently being used and analyzed by nonlinear finite element method. Shear strengths obtained from the tests showed good matches with Kong and Ray's equation, and also with the results calculated by nonlinear finite element method.

• Journal of Construction Engineering and Project Management
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• v.7 no.4
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• pp.13-19
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• 2017

This study is based on the use and performance of bamboo reinforcements in construction of low-cost structures. This study investigated the physical and mechanical properties of bamboo reinforcements. Bamboo reinforced concrete beam specimens were tested with different reinforcement ratios and observed the load capacity, deflection and failure patterns. It was observed that, flexural strength of bamboo reinforced column is sufficient higher than plain cement concrete and comparable to steel reinforced concrete beams. Bamboo reinforced concrete columns with different reinforcement ratio also tested and observed the ultimate compressive strength and failure pattern. It found, all columns failed in a similar pattern due to crushing of concrete. According to cost analysis, bamboo reinforced beams and columns with moderate reinforcement ratio showed the best strength-cost ratio among plain cement concrete and steel reinforced concrete.