• Land and Housing Review
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• v.6 no.3
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• pp.129-138
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• 2015

The building structure in Korea is planned to maximize the use of space in recent. The hybrid OCB(Optimized Composite Beam) beam is developed to take advantage of using the space. The OCB beam is composed of the steel H-beam section reinforced by open strands in negative moment zone and the pretensioned PSC concrete section in positive zone. Flexural behavior of typical architectural hybrid OCB beam section was investigated by F.E.M. The 15m, 20m, 30m OCB models were tested on nonlinear material and geometry under static loading system. Following results are obtained from the analysis; 1)The OCB beam develop initial flexural cracking over full service loading. 2)Overall deflections of OCB beam under the service loads are less than those of the allowable limits in KCI Code(2012). 3)The ultimate load capacity get over the nominal strength of the OCB main section. The OCB beam is verified of structural reliability from the finite element analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.275-285
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• 2015

This experimental study presents the fatigue evaluation of a precast deck connected using Ultra-High Performance, Fiber Reinforced Concrete (UHPFRC). Four types of two identical large-scale specimens were fabricated with simplified splice rebar details which had a short splice length of ten times rebar diameter. The flexural behavior of each type of specimens until failure was investigated and fatigue behavior of the same type of specimens was then evaluated using two-million cyclic loading. In the flexural tests, tensile rebars exhibited the deformation exceeding yielding strain but failure mode related to the splice details was not observed in spite of such a short splice length. In the fatigue tests, damage was not appreciably accumulated by the cyclic loading except initial flexural cracks and the stress variations in tensile rebars was less than the allowable stress range. These experimental results demonstrate that all types of specimens exhibited acceptable fatigue performance and indicate that enhanced mechanical properties of ultra-high performance material permits to use a simplified splice details along with short joint width.

• Journal of the Korea Concrete Institute
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• v.13 no.1
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• pp.46-53
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• 2001

Two full scale precast pretensioned dapped ended rectangular beams designed by PCI design handbook for a major domestic live load of market and parking building - 500kgf/㎡ and 1,200kgf/㎡ were investigated experimentally. The bottom length of beams was 60cm which was same to the length of rectangular column in the base of five-story market or parking buildings. The height of dap was web hight plus half of the flange height within the allowable limit of PCI method. Shear tests were performed on four beam ends. Followings were obtained from the experimental study. All of the specimens were fully complied with the PCI design handbook. Two of four specimens which were designed for live load of 1,200kgf/㎡ showed crackings at the re-entrant corner of dap before the full service loadings, and failed by direct shear at the load level much less than their calculated nominal strength. The specimens designed for live load of 1,200kgf/㎡ failed at 772 tonf and 78.36tonf by direct shear crackings. This strength was less than PCI limit of 81.9 tonf and higher than ACI limit of 65.62tonf. Thus, the limit suggested by ACI seems more reasonable in regard of safety in view of this test results. According to load-strain curves, the strain of hanger reinforcement reached almost yield strain. It is recommended to use more inclined hanger reinforcement of improve the strength and serviceability.