Horizontal shear behavior of self-compacting lightweight concrete composite beams with dry joints and unbonded reinforcements

Jin Seok Choi, Ho Jin Lee, Hyun Oh Shin, Joo Ha Lee, Young Soo Yoon

    Research output: Contribution to journalArticlepeer-review

    1 Citation (Scopus)

    Abstract

    This study aims to investigate the horizontal shear behavior of self-compacting lightweight concrete (SCLC) composite beams with dry joints and unbonded transverse reinforcement. For this, the experimental program included different concrete types, joints configurations, and the use of unbonded high-strength bars with varying levels of prestressing and transverse reinforcement ratios in composite beams. Two precast beams were fabricated using a match-cast method and integrated horizontally to form composite beams, utilizing unbonded transverse reinforcements. The composite beams incorporating lightweight aggregates (LWA) instead of normal weight aggregates (NWA) exhibited a decreased ultimate shear strength of 19.5 %; however, the addition of steel fibers into the mixtures mitigated this decrease, resulting in a 22.8 % increase in strength compared to mixture without steel fibers. The vertical prestressing level significantly influenced the horizontal shear behavior and failure mode of composite beams, with adequately prestressed composite beams exhibiting similar ductile behaviors to the monolithic beam. Composite beams with keyed joints exhibited higher horizontal shear strength, up to 65.3 % more than the beam with flat joint, attributed to the interlock provided by the shear keys. Increased slip between two precast beams activated the dowel action of unbonded reinforcements, effectively resisting horizontal shear. Predictions of the horizontal shear strength, as per current codes, were compared to the experimental results. The results indicate that the design approach in Eurocode 2 provides reasonable estimations of the strengths of composite beams with dry joints and unbonded reinforcements.

    Original languageEnglish
    Article number105687
    JournalCement and Concrete Composites
    Volume152
    DOIs
    Publication statusPublished - 2024 Sept

    Bibliographical note

    Publisher Copyright:
    © 2024 Elsevier Ltd

    Keywords

    • Composite beam
    • Dry joint
    • Horizontal shear behavior
    • Precast
    • Self-compacting lightweight concrete
    • Unbonded reinforcement

    ASJC Scopus subject areas

    • Building and Construction
    • General Materials Science

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