• Journal of the Korea Concrete Institute
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• v.25 no.3
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• pp.283-294
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• 2013

The high strength materials have been more widely used in reinforced concrete structures, specially, the reinforcing steel is permitted to used in RC structures up to yielding strength of 600 MPa. The strength of materials in RC beam section effects on the behavior and ductility of the RC members. In this study, the numerical analysis has been conducted to obtain the complete moment-curvature relation and the curvature ductility factor for the rectangular RC beams sections under the various reinforcement conditions and the effects of concrete strength, yield strength of reinforcement steel on the behavior and the curvature ductility factor of RC beam sections have been evaluated. The compressive strength of concrete and yield strength of steel have effected in various manner on the behavior and the curvature ductility factor of RC beam sections under reinforcement conditions. In the case of beam sections with equal resisting moment. the curvature ductility factor of RC beam section decreased with an increase in the yield strength of steel and increased with an increase in the concrete strength. When the yield strength of steel increased from 400 MPa to 600 MPa, the curvature ductility factor reduced about 30% and as the concrete strength increased from 30 MPa to 70 MPa, the curvature ductility factor of RC beam section increased about 3 times.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.401-409
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• 2007

The objective of this research is to provide better knowledge on the behavior of strong axis SRC column-RC beam joint, supported by experimental results, that can be broadly applicable to many structures. For this purpose, firstly literature reviews and field survey were made to classify the most commonly used for these types of joints. Then, experimental program was designed and performed including 6 SRC column-RC beam joint specimens designed with various joint details. Using the experimental results obtained from the quasi-static cyclic tests, structural performances of the joints such as hysteretic curves, maximum strength capacities, strength degradation beyond the maximum strength, ductilities, and energy dissipation capacities were investigated. Test results showed that specimens with wide beam shape (RCW-P, RCW-W, RCW-F) and T beam shape (RCT-W) showed better structural performances than the bracket type specimens (HBR-L, HBR-S). These specimens also revealed to have higher strength capacities than the nominal design strength. However, H beam bracket type specimens (HBR-L, HBR-S) need further study both analytically and experimentally to verify the reason for unexpected structural performances.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.1
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• pp.46-53
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• 2023

In this paper, we evaluated the flexural performance of three types of reinforced concrete beams (SHCC-RB, SHCC-SB, SHCC-FRP) strengthened with ordinary steel rebar, very high strength (super strength) rebar, and FRP bars together with strain-hardening cement composite (SHCC). For this purpose, a series of beam specimens were manufactured and four-point load bending experiments were performed. As a result of the experiment, all specimens strengthened with SHCC exhibited tightly controlled flexural microcrakcs with the crack width of less than 100 ㎛. This is mostly due to the material properties of SHCC showing tensile strain hardening properties with multiple microcracks under uniaxial tension. The specimen SHCC-FRP showed lower initial cracking moment and yield flexural strength than SHCC-RB, whereas the maximum flexural strength of SHCC-FRP was superior to that of SHCC-RC. This is because the tensile strength of FRP bars is higher than that of ordinary steel reabr. The initial cracking moment of the beam specimen SHCC-SB was similar to that of SHCC-RB, but the yield flexural strength and maximum flexural strength of SHCC-SB were evaluated to be the highest.