• Title/Summary/Keyword: lap splices

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Analytical Study on Inelastic Behavior and Ductility Capacity of Reinforced Concrete Bridge Columns with Lap Splices (주철근 겹침이음을 갖는 철근콘크리트 교각의 비탄성 거동 및 연성능력에 관한 해석적 연구)

  • 김태훈;김운학;신현목;정영수
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.05a
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    • pp.931-936
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    • 2003
  • Lap splices were located in the plastic hinge region of most bridge piers that were constructed before the adoption of the seismic design provision of Korea Highway Design Specification on 1992. Lap splicing is also permitted if hoops or spiral reinforcement are provided over the lap length in the current seismic design provision. But sudden brittle failure of lap splices may occur under inelastic cyclic loading. The purpose of this study is the analytical prediction of nonlinear hysteretic behavior and ductility capacity of reinforced concrete bridge piers with lap splices under cyclic loading. For this purpose, a nonlinear analysis program, RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology) is used. Lap spliced bar element is developed to predict behaviors of lap spliced bar. Maximum bar stress and slip of lap spliced bar is considered.

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Seismic Performance Evaluation of Reinforced Concrete Bridge Piers with Lap Splices (철근의 겹침이음을 고려한 철근콘크리트 교각의 내진성능평가)

  • 김태훈;박현용;김병석;신현목
    • Journal of the Earthquake Engineering Society of Korea
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    • v.7 no.3
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    • pp.31-38
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    • 2003
  • Lap splices were located in the plastic hinge region of most bridge piers that were constructed before the adoption of the seismic design provision of Korea Highway Design Specification on 1992. But sudden brittle failure of lap splices may occur under inelastic cyclic loading. The purpose of this study is to analytically predict nonlinear hysteretic behavior and ductility capacity of reinforced concrete bridge piers with lap splices under cyclic loading. For this purpose, a nonlinear analysis program, RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology) is used. Lap spliced bar element is developed to predict behaviors of lap spliced bar. Maximum bar stress and slip of lap spliced bar is also considered, The proposed numerical method for seismic performance evaluation of reinforced concrete bridge piers with lap splices is verified by comparison with reliable experimental results.

Quasi Static Test of Lap Spliced Shear-Flexure RC Piers Using Real Scale Models (주철근 겹침이음된 휨-전단 RC교각의 실물모형 준정적 실험)

  • 곽임종;조창백;조정래;김영진;김병석
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.03a
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    • pp.203-210
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    • 2002
  • The past bridge design specifications of Korea didn't include 1imitation on the amount of lap splices in the plastic hinge zone of piers, and so do current specifications. But these specifications include just limitation on the minimal length of lap splices. Thus, a large majority of non-seismically designed bridge piers may have lap splices in plastic hinge zone. In this study, model pier was selected among existent bridge piers whose failure mode is complex shear-flexure mode. Full scaled RC pier models whose aspect ratio is about 2.67 were constructed and quasi static test according to the drift level history was implemented. From the test results, effect of the lap splices on the seismic performance of bridges piers was analyzed, and the seismic capacity of the model bridges was evaluated by capacity spectrum method.

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Comparative study of factors influencing tension lap splices in reinforced concrete beams

  • Karkarna, Yakubu M.;Bahadori-Jahromi, Ali;Jahromi, Hamid Zolghadr;Bonner, Emily;Goodchild, Charles
    • Advances in concrete construction
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    • v.10 no.4
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    • pp.279-287
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    • 2020
  • The practice of splicing reinforcing bars in reinforced concrete structures to manage insufficient bar length is a common approach, which is mainly due to transportation limitations on bar length. The splicing of reinforcing bars side by side offers a simple and economical solution to the problem of continuity. This paper examines the influence of different structural parameters such as concrete cover, lap splice length, shear links confinement and concrete strength on the lap splices based on an extensive experimental database of laps and anchorage. The current study shows that increasing the lap splices beyond 50Ø has no additional benefit for increasing its strength. The results also show that relative to the measured stress, specimens with larger concrete side covers shows higher splice stress compared to the samples with smaller concrete covers.

Effects of Lap Splice Details on Seismic Performance of RC Columns (RC기둥의 내진성능에 미치는 겹침 이음상세의 영향)

  • Kim, Chul-Goo;Park, Hong-Gun;Kim, Tae-Wan;Eom, Tae-Sung
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.6
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    • pp.351-360
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    • 2016
  • In regions of low-to-moderate seismicity, various types of lap splices are used for longitudinal reinforcement of columns at the plastic hinge zones. The seismic performance of such lap spliced columns, such as strength, deformation capacity, and energy dissipation, is affected by material strengths, longitudinal re-bar size, confinement of hoops, lap splice location, and lap splice length. In the present study, cyclic loading tests were performed for columns using three types of lap splices (bottom offset bar splice, top offset bar splice, and splice without offset bend). Lap splice length($40d_b$ and $50d_b$) was also considered as test parameters. Ties with 90-degree end hooks were provided in the lap splice length. The test results showed that strength, deformation capacity, and energy dissipation of columns significantly differed depending on the details and the length of lap splices. The bottom offset bar splice showed high ductility and energy dissipation but low strength; on the other hand, the top offset bar splice and the splice without offset bend showed high strength but moderate ductility and energy dissipation.

Reinforced concrete beam-column joints with lap splices under cyclic loading

  • Karabinis, Athanasios I.
    • Structural Engineering and Mechanics
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    • v.14 no.6
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    • pp.649-660
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    • 2002
  • Experimental results are presented from tests conducted on reinforced concrete beam-column joints with lap splices under reversed cyclic loading simulating earthquake action. Response curves are compared for twenty-four specimens designed according to Eurocode 2. The main parameters of the investigation are, the geometry of the reinforcing bar extension, the applied axial load (normalized), the available cover over lap splice region extended as length required from Eurocode 2, as well as the shape and the volumetric percentage of the stirrups confining the lap splice zone. The results are evaluated with regards to the load intensity, the energy absorption capacity and the characteristics of the load deflection curve.

Improvement of the cyclic response of RC columns with inadequate lap splices-Experimental and analytical investigation

  • Kalogeropoulos, George I.;Tsonos, Alexander-Dimitrios G.
    • Earthquakes and Structures
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    • v.16 no.3
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    • pp.279-293
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    • 2019
  • The overall seismic performance of existing pre 1960-70s reinforced concrete (RC) structures is significantly affected by the inadequate length of columns' lap-spliced reinforcement. Due to this crucial structural deficiency, the cyclic response is dominated by premature bond - slip failure, strength and stiffness degradation, poor energy dissipation capacity and low ductility. Recent earthquakes worldwide highlighted the importance of improving the load transfer mechanism between lap-spliced bars, while it was clearly demonstrated that the failure of lap splices may result in a devastating effect on structural integrity. Extensive experimental and analytical research was carried out herein, to evaluate the effectiveness and reliability of strengthening techniques applied to RC columns with lap-spliced reinforcement and also accurately predict the columns' response during an earthquake. Ten large scale cantilever column subassemblages, representative of columns found in existing pre 1970s RC structures, were constructed and strengthened by steel or RC jacketing. The enhanced specimens were imposed to earthquake-type loading and their lateral response was evaluated with respect to the hysteresis of two original and two control subassemblages. The main variables examined were the lap splice length, the steel jacket width and the amount of additional confinement offered by the jackets. Moreover, an analytical formulation proposed by Tsonos (2007a, 2019) was modified appropriately and applied to the lap splice region, to calculate shear stress developed in the concrete and predict if yielding of reinforcement is achieved. The accuracy of the analytical method was checked against experimental results from both the literature and the experimental work included herein.

Seismic performance and damage assessment of reinforced concrete bridge piers with lap-spliced longitudinal steels

  • Chung, Young S.;Park, Chang K.;Lee, Eun H.
    • Structural Engineering and Mechanics
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    • v.17 no.1
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    • pp.99-112
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    • 2004
  • It is known that lap splices in the longitudinal reinforcement of reinforced concrete (RC) bridge columns are not desirable for seismic performance, but it is sometimes unavoidable. Lap splices were practically located in the potential plastic hinge region of most bridge columns that were constructed before the 1992 seismic design provisions of the Korea Bridge Design Specification. The objective of this research is to evaluate the seismic performance of reinforced concrete (RC) bridge piers with lap splicing of longitudinal reinforcement in the plastic hinge region, to develop an enhancement scheme for their seismic capacity by retrofitting with glassfiber sheets, and to assess a damage of bridge columns subjected to seismic loadings for the development of rational seismic design provisions in low or moderate seismicity region. Nine (9) test specimens with an aspect ratio of 4 were made with three confinement ratios and three types of lap splice. Quasi-static tests were conducted in a displacement-controlled way under three different axial loads. A significant reduction of displacement ductility was observed for test columns with lap splices of longitudinal reinforcements, whose displacement ductility could be greatly improved by externally wrapping with glassfiber sheets in the plastic hinge region. A damage of the limited ductile specimen was assessed to be relatively small.

Seismic Performance Evaluation of Shear-Flexure RC Piers through Comparative test of Real Scale and Reduced Scale Model (실물 및 축소모형 비교실험을 통한 휨-전단 RC교각의 내진성능평가)

  • 곽임종;조창백;조정래;김영진;김병석
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.849-854
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    • 2002
  • From the analysis results of some as-built drawings in national roadway bridges in Korea, many bridge piers are expected to show complex shear-flexural behaviour under earthquakes. But the previous research works about the seismic evaluation of bridges considered flexural behaviour RC piers only. In addition, the past bridge design specifications in Korea didn't include limitation on the amount of longitudinal lap splices in the plastic hinge zone of piers. Thus a large majority of non-seismically designed bridge piers in Korea may have lap splices in plastic hinge zone. In this study, prototype pier was selected among existent bridge piers whose failure mode is expected to be complex shear-flexural mode. And then, full scale and 1/2 reduced scale model RC piers with various longitudinal lap splice details were constructed. From the quasi static test results on these model RC piers, the effect of longitudinal lap splices on the seismic performance of bridges piers was analyzed. And the seismic capacity of the non-seismically designed shear-flexural RC piers was evaluated.

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Displacement Ductility Ratio of Reinforced Concrete Bridge Piers with Lap-splices (주철근 겹침이음 비율에 따른 RC교각의 연성능력 평가)

  • Park, Kwang-Soon;Ju, Hyeong-Seok;Shin, Hyun-Mock;Kim, Moon-Kyum
    • Journal of the Earthquake Engineering Society of Korea
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    • v.12 no.6
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    • pp.1-12
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    • 2008
  • As internal and external seismic experiment results, the seismic performance of RC bridge piers is largely dependent on the ratio of lap-spliced bars to all longitudinal reinforcing bars in plastic hinge regions, and confining effects of transverse reinforcements. Capacity and displacement ductility of non-seismically designed existing RC piers are reduced by lap splices in plastic hinge regions. The provision for the lap splice of longitudinal reinforcing bars was not specified in KBDS (Korean Bridge Design Specifications) before the implementation of 1992 seismic design code, but the ratio of lap-spliced bars to all longitudinal reinforcing bars in plastic hinge regions is restricted to 50% in the 2005 version of KBDS. This paper presents a seismic assessment of RC piers at lap-splicing ratios of 0%, 50%, and 100%. Through a comparison of experimental and analytic results of RC piers, we introduce an appropriate ultimate strain of confined concrete in plastic hinge regions with lap-splices, and propose a method for estimating displacement ductility ratios of non-seismically designed existing RC piers using fiber element analysis.