• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.247-255
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• 2022

In this paper, a bending test was conducted on beams with two lap splice details when the effective depth of tensile high strength headed bars overlapped is the same and different. Through bending test, the lap splice performance of the high-strength headed bars was evaluated, and the applicability of the KDS-2021 design formula was evaluated. In the LS specimens with lap splice details where the high strength bars had the same effective depth, all specimens with 1.3 times or more of the development length of the KDS-2021 equation and 1 times or more of the ACI318-19 had the flexural failure mode after the ductile behavior to ensure sufficient lap splice performance. For specimens with details of lap joints between headed bars with different effective depth, when lap splice length is calculated by the KDS-2021 formula, the flexural stress may be transmitted so that the flexural strength at the cross section with the large effective depth and the cross section with the small effective depth becomes similar.

• Molecules and Cells
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• v.27 no.6
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• pp.657-665
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• 2009

The ovomucoid pre-mRNA has been folded into mini-hairpins adaptable for the RNA recognition motif (RRM) protein binding. The number of mini-hairpins were 372 for pre-mRNA and 83-86 for mature mRNA. The spatial arrangements are, in average, 16 nucleotides per mini-hairpin which includes 7 nt in the stem, 5.6 nt in the loop and 3.7 nt in the inter-hairpin spacer. The constitutive splicing system of ovomucoid-pre-mRNA is characterized by preferred order of intron removal of 5/6 > 7/4 > 2/1 > 3. The 5' splice sites (5'SS), branch point sequences (BPS) and 3' splice sites (3'SS) were identified and free energies involved have been estimated in 7 splice sites. Thermodynamic barriers for splice sites from the least (|lowest| -Kcal) were 5, 4, 7, 6, 2, 1, and 3; i.e., -18.7 Kcal, -20.2 Kcal, -21.0 Kcal, -24.0 Kcal, - 25.4 Kcal, -26.4 Kcal and -28.2 Kcal respectively. These are parallel to the kinetic data of splicing order reported in the literature. As a result, the preferred order of intron removals can be described by a consideration of free energy changes involved in the spliceosomal assembly pathway. This finding is consistent with the validity of hnRNP formation mechanisms in previous reports.

• Steel and Composite Structures
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• v.35 no.3
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• pp.353-370
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• 2020

This paper describes a new type of replaceable fuse for moment resisting frames. Column-tree connections with beam splice connections are frequently preferred in the moment resisting frames since they eliminate field welding and provide good quality. In the column-tree connections, a part of the beam is welded to the column in the shop and the rest of the beam is bolted with the splice connection in the field. In this study, a replaceable reduced beam section (R-RBS) connection is proposed in order to eliminate welding process and facilitate assembly at the site. In the proposed R-RBS connection, one end is connected by a beam splice connection to the beam and the other end is connected by a bolted end-plate connection to the column. More importantly is that the proposed R-RBS connection allows the replacement of the damaged R-RBS easily right after an earthquake. Pursuant to this goal, experimental and numerical studies have been undertaken to investigate the performance of the R-RBS connection. An experimental study on the RBS connection was used to substantiate the numerical model using ABAQUS, a commercially available finite element software. Additionally, five different finite element models were developed to conduct a parametric study. The results of the analysis were compared in terms of the moment and energy absorption capacities, PEEQ, rupture and tri-axiality indexes. The design process as well as the optimum dimensions of the R-RBS connections are presented. It was also demonstrated that the proposed R-RBS connection satisfies AISC criteria based on the nonlinear finite element analysis results.

• Journal of Korea Multimedia Society
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• v.15 no.10
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• pp.1185-1195
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• 2012

In the general recording method of mobile broadcasting, all incoming broadcasting streams after recording time will be saved regardless of its content. In this case, as such that viewers do not want to record, commercial advertisement, are saved together. In order to solve these problems, the proposed method checks if the contents such as advertisements are exist in the target stream by analysing the splicing in incoming MPEG-2 TS streams and, if splicing happened, excludes incoming stream after the splicing in the recording process. In the proposed method, first the splice in the recording stream is verified using the related flags of adaptation field in the TS packet and, if judged to cause a splice, the time of splicing is to be estimated by evaluating the value of splice_countdown filed. In this way, the proposed algorithm provides the seamless recording method by estimating the time of splice and excluding the contents after the splicing. To evaluate the proposed seamless recording method, the simulation was carried out by modifying the software of the existing mobile broadcasting terminal.

• Journal of Korean Society of Steel Construction
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• v.28 no.6
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• pp.427-438
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• 2016

This study is experimental research for the effect of gap at the end plate on the performance of extended end-plate type splice. For this research, simple beam type specimens by using extended end-plate type splice are planned. Main variables are the initial gap between end-plates, the installation of finger shim plate before the installation of high tension bolts, the final gap between end-plates, and the installation of finger shim plate after the installation of high tension bolts. The static loading tests results show that the maximum bending strength of splice is not dependent on the gap, but the vertical displacement, initial stiffness and elastic stiffness are affected by the gap. In addition to that, the possibility of brittle fracture is increased when the torque of high tension bolt is used to control the gap. Thus, careful consideration is needed in this case.

• Journal of the Korea Concrete Institute
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• v.21 no.1
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• pp.65-74
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• 2009

Glass fiber reinforced polymer (GFRP) bars are sometimes used when corrosion of conventional reinforcing steel bar is of concern. In this study, a total of 36 beams and one-way slabs reinforced using GFRP bars were tested in flexure. Four different GFRP bars of 13 mm diameter were used in the test program. In most test specimens, the GFRP bars were lap spliced at center. All beams and slabs were tested under 4-point loads so that the spliced region be subject to constant moment. Test variables were splice lengths, cover thicknesses, and bar spacings. No stirrups were used in the spliced region so that the tests result in conservative bond strengths. Average bond stresses that develop between GFRP bars and concrete were determined through nonlinear analysis of the cross-sections. An average bond stress prediction equation was derived utilizing two-variable linear regression. A splice length equation based on 5% fractile concept was then developed. As a result of this study, a rational equation with which design splice lengths of the GFRP bars can be determined, was proposed.

• Composites Research
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• v.16 no.2
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• pp.26-32
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• 2003

Optical fibers, for splice, are stripped of their plastic coatings with a plastic stripper and cut off at the end. Therefore, stripped fibers often receive accidental damages and sustain small flaws or cracks. As a result, the breaking strength of a fiber splice made under normal conditions is reduced to about 0.4∼1 ㎏ on the average, nearly one-tenth of the fiber's strength. This makes it necessary to reinforce the splice. One of the most practical and reliable methods for optical fiber splicing is fusion splicing, comprising the steps of tripping the plastic coatings from the two fiber ends to be splice, placing the two bare fiber ends in an end-to-end position, and of fusion splicing, such as are fusion. Generally, steel bar (SB) sleeve is used to reinforce this fusion-splicing region. However, this type of sleeve has a critical defect to keep optical lose after bent by a sudden load. New type of composite spring (CS) sleeve is developed to make up for the weak points in the SB sleeve. This sleeve has an effect on restoration to the original state after eliminating the bending load. The optical spectrum analyzes results show the availability of reinforcement for the fusion splicing optical fiber using small diameter composite springs under the various loading conditions.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.2
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• pp.175-182
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• 2020

The application of epoxy coated reinforcements is increased as a means to prevent a corrosion of reinforcements embedded in reinforced concrete structures, However, epoxy coating may reduce the bond capacity between concrete and reinforcement, which results a longer development length and lap splice length. This paper aims to the possibility of modification in lap splice length from reduction of basic development length which was confirmed using a direct pull out test. Total 36 beam specimens were tested to compare the lap splice properties of normal and epoxy coated reinforcements with beam-end test for various lap lengths and diameters of reinforcements. According to the results on failure modes, deformations, and crack widths of this experiments, the modification factor of 1.2 should be used, though the direct bond capacity is assured through direct pull out test.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.131-142
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• 2021

For old piers constructed when seismic design code had not been developed, lap splices usually exist in plastic hinge region. Corrosion of rebars causes decreasement in cross-sectional area of rebar and deterioration of lap-splice behaviour, thereby reducing the seismic performance of the old piers. In this research, according to these characteristics of old piers, test specimens are designed and manufactured considering rebar corrosion, lap splice, seismic design details, and seismic reinforcement. These effects are investigated through experiments. As a result of these experiment, rebar corrosion as well as lap splice reduces displacement ductility. When seismic design details or steel-plate reinforcement are applied, sufficient displacement ductility is expressed. For non-seismically designed specimens, loosening of the lap splice of transverse rebars caused buckling of longitudinal rebars and crushing of core concrete in plastic hinge region . For seismically designed specimen, area-reducing and untying of transverse rebars due to corrosion of rebars caused buckling of longitudinal rebars and crushing of core concrete.

• Journal of the Earthquake Engineering Society of Korea
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• v.27 no.1
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• pp.37-47
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• 2023

A new clamped mechanical splice system was proposed to develop structural performance and constructability for precast concrete connections. The proposed mechanical splice resists external loading immediately after the engagement. The mechanical splices applicable for both large-scale rebars for plants and small-scale rebars for buildings were developed with the same design concept. Quasi-static lateral cyclic loading tests were conducted with reinforced and precast concrete members to verify the seismic performance. Also, shaking table tests with three types of seismic wave excitation, 1) random wave with white noise, 2) the 2016 Gyeongju earthquake, and 3) the 1999 Chi-Chi earthquake, were conducted to confirm the dynamic performance. All tests were performed with real-scale concrete specimens. Sensors measured the lateral load, acceleration, displacement, crack pattern, and secant system stiffness, and energy dissipation was determined by lateral load-displacement relation. As a result, the precast specimen provided the emulative performance with RC. In the shaking table tests, PC frames' maximum acceleration and displacement response were amplified 1.57 - 2.85 and 2.20 - 2.92 times compared to the ground motions. The precast specimens utilizing clamped mechanical splice showed ductile behavior with energy dissipation capacity against strong motion earthquakes.