• Journal of the Korea Concrete Institute
• /
• v.18 no.5 s.95
• /
• pp.603-610
• /
• 2006

The external unbonded strengthening offers advantages in speed and simplicity of installation over other strengthening techniques. Unlike externally bonded steel plate or carbon fiber sheet, surface preparation of the concrete for installation of high-tension bar is not required and installation is not affected by environmental conditions. Anchoring pin or anchoring plate are installed at the end of beam to connect the high-tension bar to concrete beam. The deviator are used in order that supplementary external bars would follow the curvature of the tested beam. A set often laboratory tests on reinforced concrete beam strengthened using the technique are reported. The main test parameters are the section area of strengthening bar, the depth of deviator and the number of deviators. The paper provides a general description of structural behavior of beams strengthened using the technique. The test result of strengthened beam are compared with those from a reference specimen. It is shown that the reinforcing technique can provide greater strength enhancements to unstrengthened beam and that the provision of deviator enhances efficiency. The ultimate moment of specimen with two deviators was higher than that of specimens with one deviator. It is also shown that the external bars enhance strength of beams in shear.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.26 no.1
• /
• pp.73-80
• /
• 2022

In this study, details of NRC beam-column connections were developed in which beam and columns pre-assembled in factories using steel angles were bolted on site. The developed joint details are NRC-J type and NRC-JD type. NRC-J type is a method of tensile joining with TS bolts to the side and lower surfaces of the side plate of the NRC column and the end plate of the NRC beam. NRC-JD type has a rigid joint with high-strength bolts between the NRC beam and the side of the NRC column for shear, and with lap splices of reinforcing bar penetrating the joint and the beam main reinforcement for bending. For the seismic performance evaluation of the joint, three specimens were tested: an NRC-J specimen and NRC-JD specimen with NRC beam-column joint details, and an RC-J specimen with RC beam-column joint detail. As a result of the repeated lateral load test, the final failure mode of all specimens was the bending fracture of the beam at the beam-column interface. Compared to the RC-J specimen, the maximum strength of the specimen by the positive force was 10.1% and 29.6% higher in the NRC-J specimen and the NRC-JD specimen, respectively. Both NRC joint details were evaluated to secure ductility of 0.03 rad or more, the minimum total inter-story displacement angle required for the composite intermediate moment frame according to the KDS standard (KDS 41 31 00). At the slope by relative storey displacemet of 5.7%, the NRC-J specimen and the NRC-JD specimen had about 34.8% and 61.1% greater cumulative energy dissipation capacity than the RC specimen. The experimental strength of the NRC beam-column connection was evaluated to be 30% to 53% greater than the theoretical strength according to the KDS standard formula, and the standard formula evaluated the joint performance as a safety side.

• Journal of Animal Science and Technology
• /
• v.47 no.6
• /
• pp.1041-1050
• /
• 2005

This study was conducted to investigate the quality characteristics of seasoned pork prepared by Korean traditional 4 types seasoning such as soy sauce (T1); Kimchi sauce (T2); pickled shrimps sauce (T3) and onion sauce (T4). The samples were seasoned by the proportion of meat to seasonings (1:1). The seasoned samples were aged at $1{\pm}1^{\circ}C$ for 30 days. The results obtained were as follows; pH of T3 was higher (p<0.05) than other treatments during aging periods. Saccharinity and salinity were higher in T1. Except T3, water holding capacity (WHC) have no significantly (p>0.05) different during the aging. Shear force and Volatile basic nitrogen (VBN) were increased in T1 and T4 with aging periods. TBARS have no significantly (p>0.05) different in all treatments at the 1 day of aging, however T1 was significantly higher (p<0.05) compared with other treatments after 10 days of aging. In surface meat color, a* and b* were higher in T2 and lower in T4 with aging periods. In inner meat color, L* was decreased in all treatments with aging periods, however T4 was no significantly (p>0.05) different during aging periods. a* and b* were increased with aging periods in all treatments. Total plate counts was increased at the 10 days of aging and decreased at the end of aging. Escherichia coli of T1, T2 and T3 were decreased with aging periods, however T4 was significantly (p<0.05) increased with aging periods. Lactobacilli spp. of T2 and T3 were higher than other treatments at the beginning of aging. In sensory evaluation, T4 was higher at the beginning of aging, however T1 and T3 were increased sensory evaluation value with aging periods.