• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.319-322
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• 2005

Experimental results on splice strength of concrete and hybrid fiber reinforced cementitious composite are reported. Two series of tests, with six specimens each, were carried out. The research parameters were: bar diameter(D16, D22), lap splice length(50, 75, 100$\%$). The current experimental results demonstrated clearly that the use of hybrid fibers in cementitious matrixes increases significantly the splice strength of reinforcing bars in tension. Also, the presence of fibers increased the number of cracks formed around the spliced bars, delayed the growth of the splitting cracks, and consequently, improved the ductility of bond failure.

• Journal of the Korea Concrete Institute
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• v.24 no.2
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• pp.129-136
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• 2012

Compression splices are required for all compression members in almost all of the floors in high-rise buildings. Therefore, a clear understanding of the behavior of compression splices can provide a rational design of compression splices. Tests of compression splices with bearing only and bond only cases were conducted to investigate the component resistance characteristics of compression splices. Test results showed that the circumferential tensile stresses induced by bearing and bond overlapped at the end of the splice length deterred bond and bearing splices from developing target splicing strength when both normal bond and bearing splices were used. In particular, the bearing strength was more significantly reduced than the bond strength since the bearing relied on the limited area near the end of the splice length. However, the strength of the normal splice was always higher than the strength of the bond only or the bearing only case. Consequently, the study results showed that splice strength in compression cannot be improved by means of removing bond or bearing. In addition, the bond strength in bond only splices was nearly same as the bond strength in tension splices and the strength increase of compression splice is attributed to end bearing only characteristic.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.1
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• pp.19-27
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• 2020

Reinforced concrete (RC) buildings built in the 1980s are vulnerable to seismic behavior because they were designed without any consideration of seismic loads. These buildings have widely spaced transverse reinforcements and a short lap splice length of longitudinal reinforcements, which makes them vulnerable to severe damage or even collapse during earthquakes. The purpose of this study is to investigate the impact of bidirectional lateral loads on RC columns with deficient reinforcement details. An experimental test was conducted for two full-scale RC column specimens. The test results of deficient RC columns revealed that bidirectional loading deteriorates the seismic capacity when compared with a column tested unidirectionally. Modeling parameters were extracted from the tested load-displacement response and compared with those proposed in performance-based design standards. The modeling parameters proposed in the standards underestimated the deformation capacity of tested specimens by nearly 50% and overestimated the strength capacity by 15 to 20%.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.319-326
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• 2000

The purpose of this study is to evaluate seismic performance of reinforced concrete pier columns in Seohae Ground Bridge. Since the bridge was designed before preparing the seismic design specification the bridge columns of hollow hexagonal section were designed and constructed with insufficient seismic reinforcement details such as longitudinal and transverse reinforcement lap-splices. In order to take the necessary measures to improve its seismic performance experimental study was performed by small-scale test for the bridge columns, From the quasi-static test for small-scale column specimens the lap-splices were not critical for overall behavior of the column if sufficient lap-splice-length was provided. The test results of failure mode effective stiffness ductility and equivalent viscous damping ratio are presented.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.571-576
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• 2001

The objective of this study is to assess seismic damage potential and evaluate structural performance of columns in concrete moment frames. For this purpose the results of 3 former studies are compared. Experimental variables considered in these studies are lap-splice of longitudinal reinforcement, axial load level, longitudinal reinforcement ratio, etc. The columns in 1st story of the building are considered in these studies since the columns in 1st story shall resist largest axial force during an earthquake. Based on test results strength, ductility capacities as well as plastic hinge length are compared and discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.737-742
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• 1997

In this paper the effect of tie wire in lap spliced bars is investigated by experiment. The variables considered in the beam behaviors are beam dimension, lapped splice length and numbers of tie wire. 3 test pieces having the same variables consist one series and a total of 6 series ar tested. The test results show the beam behavior is not affected by numbers of tie wire but by the manner of tie. It was revealed hat the load bearing capacity of the beam is increased when the tie wire is extended to top bar.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.33-34
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• 2010

A compression lap splice becomes an important issue due to development of ultra-high strength concrete. Based on the basic form of design equations for development lengths of deformed bars and hooks in tension, simplifed design equation of deformed bars in compression was proposed using regression analyses.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.6
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• pp.119-128
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• 2008

In this study, new moment-resisting precast concrete beam-column joint is proposed for moderate seismic regions. It has the connection reinforcing bars, penetrated the joint and lap-spliced with the bottom bars of precast U-shaped PC beam. To evaluate the performance for noncontact lapped splice, experimental and analytical works were conducted. Major variables for tests are the length of lap, the diameter of connection reinforcing bars, and the distance between lapped bars. Analytic research was performed nonlinear finite element method. Analytic research focused on crack pattern, load-deflection curve, comparison of internal force, evaluation of ductility strains of reinforcement bar. Results of experimental and analytical works show that the these variables has much influence on flexural strength and ductility, and joint behavior.

• Structural Engineering and Mechanics
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• v.19 no.3
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• pp.337-346
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• 2005

The paper reports on a study of bond strength between reduced-water-content concrete and tensile reinforcement in spliced mode. Three different diameters (12, 16 and 22 mm) of tensile steel were spliced in the constant moment zone, where there were two bars of same size in tension. For each diameter of reinforcement, a total of nine beams ($1900{\times}270{\times}180mm$) were tested, of which three beams were with no axial force (positive bending) and the other six beams were with axial force (combined bending). The splice length was selected so that bars would fail in bond, splitting the concrete cover in the splice region, before reaching the yield point. It was found that there was a considerable size effect in the experimental results, i.e., as the diameter of the reinforcement reduced the bond strength and the deflection recorded at the midspan increased significantly, whilst the stiffness of the beams reduced. It was also found for all reinforcement sizes that higher bond strength and stiffness were obtained for beams tested in combined bending than that of the beams tested in positive bending only.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.196-205
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• 2017

In precast deck system, structural performance and serviceability are mostly determined by the connection methods between the precast decks. This study proposes precast deck system with asymmetric ribbed connection details using High Strength Fiber Reinforced Concrete(HSFRC) with filler. To verify the proposed method, the flexural performance experiment was carried out with variation of joint cross section type and splice rebar details. From the test results, regardless of joint details, spliced tensile rebars of specimens were deformed to yielding strain level. Also, all types of specimens resulted in sufficient flexural performance. These test results show that the minimum lap splice length specified in current Korea Highway Bridge Design Code is conservative for precast deck joint using HSFRC. Therefore, splice details can be simplified and joint width can be reduced by using HSFRC with filler between the precast decks, and the proposed precast deck systems can be applied to the connection part of precast decks effectively.