• 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 Korean Society of Steel Construction
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• v.23 no.3
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• pp.295-304
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• 2011

Bracket-type connection is often used for the weak-axis steel connection. In general, a beam-to-column connection for the bracket type is fabricated at the shop and abeam splice is additionally attached to the bracket in the site. Therefore, steel construction would not be competitive due to the increase of beam splice fabrication cost and overall construction period. This paper now proposes the new weak-axis connection types without a scallop, which has more definite strength flow, simple connection details, and better workability. From the series of experiments, the proposed connections showed better strength and ductility in comparison with standard details with scallop because the thickness of the welding plate for wide-flanged, beam-to-column connection can be easily adjusted.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.519-525
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• 2010

Data from beam-based bond tests for FRP bars in the literature were collected and regression analyses were conducted for the data of splitting failure. Average bond strengths obtained from splice tests were found to be lower and more affected by C/$d_b$ values than average bond strengths from anchorage tests, indicating needs of new design equation for the splice length of FRP bars based on the data of splice tests only. In addition, the variation of bond strengths was greater than that of tensile strengths of FRP bars and, therefore, a new safety factor should be involved for the design equation. Five percent fractile coefficients were used to develop the design equations based on the assumption that load and resistance factors for FRP reinforced concrete structures are same to the factors for steel reinforced concrete structures. The proposed design equations give economical and reliable lengths for development and splice of FRP bars. The proposed equation for splice provides shorter lengths than the ACI 440 equation in case of C/$d_b$ of 3.0 or greater. Because FRP bars are expected to be used in slabs and walls exposed to weather with thick cover and large spacing between bars, the proposed equation gives optimal splice lengths.

• Journal of the Earthquake Engineering Society of Korea
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• v.27 no.5
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• pp.203-211
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• 2023

For fast-built and safe precast concrete (PC) construction, the dry mechanical splicing method is a critical technique that enables a self-sustaining system (SSS) during construction with no temporary support and minimizes onsite jobs. However, due to limited experimental evidence, traditional wet splicing methods are still dominantly adopted in the domestic precast industry. For PC beam-column connections, the current design code requires achieving emulative connection performances and corresponding structural integrity to be comparable with typical reinforced concrete (RC) systems with monolithic connections. To this end, this study conducted the standard material tests on mechanical splices to check their satisfactory performance as the Type 2 mechanical splice specified in the ACI 318 code. Two PC beam-column connection specimens with dry mechanical splices and an RC control specimen as the special moment frame were subsequently fabricated and tested under lateral reversed cyclic loadings. Test results showed that the seismic performances of all the PC specimens were fully comparable to the RC specimen in terms of strength, stiffness, energy dissipation, drift capacity, and failure mode, and their hysteresis responses showed a mitigated pinching effect compared to the control RC specimen. The seismic performances of the PC and RC specimens were evaluated quantitatively based on the ACI 374 report, and it appeared that all the test specimens fully satisfied the seismic performance criteria as a code-compliant special moment frame system.

• International Journal of Concrete Structures and Materials
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• v.18 no.1E
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• pp.49-54
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• 2006

Confinement is major contribution to bond strength between reinforcement steel bars and concrete. Cover thickness, bar spacing and transverse reinforcement are the key confinement factors of current provisions for the development and splices of reinforcement. However, current provisions are still too complicated to determine the values of the confinement, which need to be well delineated in the process of design. In this study, an experimental work using beam-end and splice specimens was performed to examine the effect of concrete cover on bond strength. The results of this experiment and previously available data are analyzed to identify the effects of confinement on bond strength. From this reevaluation, new provisions for the development and splices of reinforcement are proposed. The provisions suggest some limitations in the confinement index. The new provisions will allow the engineers to use a simple and yet satisfactory and appropriate method or a precise approach for design to determine the values of confinement on the calculation of development and splice lengths.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.207-210
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• 2003

As reviewing of current trend on PC connection details, owing to effective stress transfer in the connection, it grow to increase that use of mechanical splices, reinforcements or welded splices, and prestressing. However such devices as reinforcement, mechanical splices entail not only more cost resulted from materials but also extra construction process so as to cause PC used method to lower competition against conventional method. Therefore more enhanced connection details which help working process simplified and construction cost reduced. In this research, as replace 9.3mm 7strand for reinforcement, it is attempt to devise connection detail which makes workability improve and confirm effective stress transfer in the region of connection. The experimental research is proceeded by partial tension test of specimen. The splice lengths of 7strand is decided to be variations. The flexural capability is verified to depend on spice length. An an appropriate splice length could be also determined as a precedent research on improving PC connection detail.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.865-871
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• 2003

This paper presents the test results of 24 beam-end specimens to investigate the effect of concrete strength and cover thickness on the development resistance capacity in tensile lap splice length regions. The results showed that as higher strength concrete was employed, nor only development resistance capacity was influenced by cover thickness, but also more sufficient safety factor reserved shorter than the lap splice length provision in current design code. From experimental research results, high-strength concrete development length was not inverse ratio of ($\sqrt{f_{ck}}$) but directly inverse of $f_{ck}$, and it is also said that there is a certain limit length of the embedded steel over which the assumption of uniform bond stress distribution is valid specially for high-strength concrete not having a same embed length such as normal-strength concrete in current design criteria hypothesis.

• Structural Engineering and Mechanics
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• v.27 no.1
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• pp.63-75
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• 2007

The code provisions on lap splices are critically assessed in the light of 203 beams without transverse reinforcement and 278 beams with transverse reinforcement. For comparison, the provisions given in the ACI 318, Eurocode 2, and TS 500 Codes are considered. The ACI Committee 408 recommended provision and a new proposal are also taken into account throughout the assessment. The comparison with real beam tests where the splice region was subjected to constant moment indicates that current provisions in the Codes do not agree acceptably with test results. The steel stress prediction graphs calculated by means of the Code provisions show high scatter and remain unsafe especially for test data without transverse reinforcement. Both the recent recommended provision by ACI Committee 408 and a new design expression proposed by the author have much less scatter with fewer unsafe predictions. The simplified design provision proposed by ACI Committee 408 does not yield similar results to that of the advanced design provision proposed by the same committee and therefore it could conveniently be replaced with the simpler equation proposed by the author.

• Structural Engineering and Mechanics
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• v.90 no.3
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• pp.301-311
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• 2024

Different methods have been proposed in the literature for splicing the reinforcing bars in the construction of concrete structures, which are alternatively used depending on design requirements. The most common approach is the lap splicing which is known as a cost-effective method although, its main disadvantages including congestion of bars at the lap zone and consequently, material wastage has motivated utilization of the other techniques such as mechanical splices (couplers). To better evaluate the performance of the couplers, 6 reinforced concrete (RC) beams whose difference is only the type and location of splices have been experimentally studied in this paper. Based on the results, the mechanical connection of the bars did not markedly affect the load-carrying capacity of the specimens. Moreover, it was observed that after applying the loads and failure of the specimens, none of the bars ruptured at the splice location and all couplers remained undamaged.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.149-156
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• 2021

FRP has been proposed to replace the steel as a reinforcement in the concrete structures for addressing the corrosion issue. However, FRP-Rebar does not behave in the same manner as steel because the properties of FRP are different. For example, FRP-Rebar has a high tensile strength, low stiffness, and linear elastic behavior which results in a difference bonding mechanism to transfer the load between the reinforcement and the surrounding concrete. Therefore, bonding behavior between FRP-Rebar and concrete has to be investigated using the bonding test. So, Pull-out test has been used to estimate bond behavior because it is simple. However, the results of pull-out test have a difference with flexural-boding behavior of FRP-Rebar concrete member. So, it is needed to evaluate the real fleuxral-bonding behavior. In this study, the evaluation method to flexural-bonding behavior of FRP-Rebar concrete member was reviewed and compared. It was found that the most accurate evaluation method for the fleuxral-bonding behavior of FRP-Rebar concrete member was splice beam test, however, the size and length of specimen have to increase than other test method and the design and analysis of splice beam is complex. Meanwhile, characteristics of concrete could be reflected by using arched beam test, unlike hinged beam test which is based on the ignored change of moment arm length in equilibrium equation. However, the possibility of shear failure exists before the flexural-bonding failure occur.