• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.4
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• pp.87-97
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• 2008

The purpose of this study is to analyse and compare experimentally flexural behavior of RC beams strengthened with CFRP plates by different methods, and finally develop the nonlinear analysis model with the aim of predicting the improving effects of structural capacity and the structural behaviors of RC beams. From this study, the characteristics of bond and flexural behavior of the prestressed CFRP plates were analyzed and examined. In deed, the beams were tested with experimental parameters of strengthening methods and prestressing level, and the developed analysis model was evaluated with the testing results. From this study, it is concluded that the developed analysis model have a good reliability and can be applied to the strengthening design of beams using CFRP plates.

• Journal of Korean Society of Steel Construction
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• v.24 no.2
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• pp.233-243
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• 2012

This study verifies the structural capacity of the composite PHC pile (Pretensioned spun high-strength concrete) consisting of a PHC pile and two CT structural steels. Four full-scale specimens are fabricated and the experimental tests were performed to investigate the flexural behaviors of the composite PHC piles. The composite PHC pile can enhance both the structural capacity and functional convenience, since the web of CT structural steel with holes in the web acts as a shear connector (referred to as the perfobond rib), which can connect concrete and steel. All specimens exhibited flexural failure and the ultimate strengths were larger than the anticipated design strength according to the design standard. Thus, the composite PHC pile can be applicable to wall structures with sufficient strength. In addition, it seems that the web of the CT structural steel with holes performs its role as shear connectors.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.290-297
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• 2000

A new form of construction utilizing structural steel as the boundary elements in ductile flexural concrete walls is proposed to solve the bar congestion problems associated with such a heavily reinforced region. Two wall specimens containing rectangular hollow structural sections(HSS) and channels at their ends respectively were constructed rectangular hollow structural sections(HSS) and channels ar their ends respectively were constructed and tested under reversed cyclic loading to evaluate the construction process as well as the structural performance. One companion standard reinforced concrete wall specimen was also tested for the comparison purpose At an Initial stage all three specimens were carefully detailed to have the approximately same flexural capacity. Analysis and comparison of test results indicated that the reversed cyclic responses of the three walls showed similar hysteretic properties but in those with steel boundaries local bucking of the corresponding steel elements following significant yielding of structural steel was prominent. Design procedures considering local instability of the structural steel elements and the interaction between steel chord and concrete web members in such composite walls are presented.

• Journal of Korean Society of Steel Construction
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• v.24 no.4
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• pp.411-422
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• 2012

The purpose of this study is to evaluate the flexural and shear capacity of steel wire-integrated void deck plate slabs. In order to evaluate flexural and shear capacity, we make five 150mmspecimens and three 200mmspecimens by slab depth as main variable. Each series of specimen is comprised of an existing steel wire-integrated deck-plate slab and two specimens using topping depth as variable. From the series of experiments, steel wire-integrated void deck plate slabs has any decline in flexural and shear performance. Therefore, a void-deck-plate slab which inserts Omega-steel plate showed reducing a using concrete-volume and had flexural and shear capacity following existing steel wire-integrated deck-plate.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.3
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• pp.143-150
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• 2007

Six full scale column specimens have been tested under the constant axial and cyclic lateral load. An equivalent stress block parameter was used to estimate flexural capacity of columns confined by carbon sheet tube. Through the non-linear regression analysis, behaviors of CFCST(Concrete Filled Carbon Sheet Tube) columns under the cyclic lateral load were estimated and compared with test results.

• Steel and Composite Structures
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• v.35 no.3
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• pp.371-384
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• 2020

The steel-concrete double composite girder in the negative flexural region combines an additional concrete slab to the steel bottom flange to prevent the local steel buckling, however, the additional concrete slab may lower down the neutral axis of the composite section, which is a sensitive factor to the tensile stress restraint on the concrete deck. This is actually of great importance to the structural rationality and durability, but has not been investigated in detail yet. In this case, a series of 5.5 m-long composite girder specimens were tested by negative bending, among which the bottom slab configuration and the longitudinal reinforcement ratio in the concrete deck were the parameters. Furthermore, an analytical study concerning about the influence of bottom concrete slab thickness on the cracking and sectional bending-carrying capacity were carried out. The test results showed that the additional concrete at the bottom improved the composite sectional bending stiffness and bending-carrying capacity, whereas its effect on the concrete crack distribution was not obvious. According to the analytical study, the additional concrete slab at the bottom with an equivalent thickness to the concrete deck slab may provide the best contributions to the improvements of crack initiation bending moment and the sectional bending-carrying capacity. This can be applied for the design practice.

• Composites Research
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• v.29 no.6
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• pp.328-335
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• 2016

The purpose of this study is to develop fiber reinforced cement matrix composite (ECC) produced with limestone powder in order to achieve high ductility of the composite, and to evaluate flexural performance of structural members made with ECC. Four kinds of mixture proportions were determined on the basis of the micromechanics and a steady state cracking theory considering the matrix fracture toughness and fiber-matrix interfacial characteristics. The mechanical properties of ECC, represented by strain-hardening behavior in uniaxial tension, were investigated. Also, strength property of the composite was experimentally evaluated. Two structural members made with ECC were produced and tested. Test results were compared with those of conventional concrete structural members. Increased limestone powder contents of ECC provides higher ductility of the composites while generally resulting in a lower strength property. ECC structural members exhibited higher flexural ductility, higher flexural load-carrying capacity and tighter crack width compared to conventional structural members.

• Steel and Composite Structures
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• v.6 no.3
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• pp.257-284
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• 2006

The behaviour of hollow structural steel (HSS) stub columns and beams filled with normal concrete and recycled aggregate concrete (RAC) under instantaneous loading was investigated experimentally. A total of 40 specimens, including 30 stub columns and 10 beams, were tested. The main parameters varied in the tests were: (1) recycled coarse aggregate (RCA) replacement ratio, from 0 to 50%, (2) sectional type, circular and square. The main objectives of these tests were threefold: first, to describe a series of tests on new composite columns; second, to analyze the influence of RCA replacement ratio on the compressive and flexural behaviour of recycled aggregate concrete filled steel tubes (RACFST), and finally, to compare the accuracy of the predicted ultimate strength, bending moment capacity and flexural stiffness of the composite specimens by using the recommendations of ACI318-99 (1999), AIJ (1997), AISC-LRFD (1999), BS5400 (1979), DBJ13-51-2003 (2003) and EC4 (1994).

• Journal of Korean Association for Spatial Structures
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• v.23 no.1
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• pp.53-60
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• 2023

A bending experiment was conducted to verify the structural performance of the U-flange truss hybrid bean using rebars or steel pipes to reinforce the upper compression zone. As a result of evaluating the bending strength of the truss hybrid beam according to the Structural Design Standard (KDS 14 2020: 2022) by introducing the lattice member as a tensile resistance element, the following conclusions were obtained. Considering the lattice element as a tensile resistance element, the nominal bending strength was increased by 38.57 to 47.90 kN.m. As a result of reviewing the experiment as to whether the flexural member has proper ductility, it was found that it is desirable to place appropriate rebars, steel quality plans, and lateral restraints on the upper and lower parts of the hybrid beam to have sufficient ductility ratio.

• Structural Engineering and Mechanics
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• v.84 no.2
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• pp.225-238
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• 2022

In order to improve the cracking resistance of reinforced concrete and give full play to the advantages of prefabricated assembly structure in construction, prestressed reinforced concrete composite beam (PRCC) is proposed. Through the bending static test of seven I-shaped beam specimens, the bending failure modes and bearing capacity of PRCC and reinforced concrete composite beam are compared and analyzed, and the effects of prestress size, prestressed reinforcement layout and prestress application sequence on the flexural behavior of PRCC beams are studied. The results show that the cracking load and ultimate load of PRCC beams significantly increased after prestressing, and prestressed tendons can effectively control the crack development. With the increase of prestressing degree, the deformation resistance and bending stiffness of PRCC beams are increased. The application sequence of prestress has little influence on the mechanical properties of PRCC beams. The crack width, stiffness and normal section bearing capacity of PRCC beam are analyzed, and the calculated results are in good agreement with the experimental results.