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Zarrimpour pdf See discussions stats and author profiles for this publication at https www researchgate net publication Shear Strength Enhancement Mechanisms of Steel Fiber-Reinforced Concrete Slender Beams Article in Aci Structural Journal May DOI CITATI

See discussions stats and author profiles for this publication at https www researchgate net publication Shear Strength Enhancement Mechanisms of Steel Fiber-Reinforced Concrete Slender Beams Article in Aci Structural Journal May DOI CITATIONS authors including Shih-Ho Chao University of Texas at Arlington PUBLICATIONS CITATIONS SEE PROFILE READS Some of the authors of this publication are also working on these related projects Bond Stress-Slip of Reinforcing Bars and Prestressing Strands in HPFRC Composites View project Full-Scale RC and HPFRC Frame Subassemblages Subjected to Collapse-Consistent Loading Protocols for Enhanced Collapse Simulation and Internal Damage Characterization View project All content following this page was uploaded by Shih-Ho Chao on September The user has requested enhancement of the downloaded file ACI STRUCTURAL JOURNAL n TECHNICAL PAPER Title No -S Shear Strength Enhancement Mechanisms of Steel FiberReinforced Concrete Slender Beams by Mohammad Reza Zarrinpour and Shih-Ho Chao An experimental study was conducted to identify the shear-enhancement and failure mechanisms behind the ultimate shear strength of steel fiber-reinforced concrete SFRC slender beams by using the full field-deformation-measuring capability of digital image correlation DIC technology A total of large-scale simply supported SFRC and RC beams with an overall height from to in to mm were tested under monotonic point load up to failure The greater shear strength in SFRC beams originates from the ability of the fiber bridging effect that delays the propagation of the cracks into the compression zone whose shear strength is enhanced by the compressive stresses induced by the higher load The slow progression of the cracks keeps the compression zone depth large thereby enabling it to contribute to a higher shear resistance In contrast with the traditional assumption for either plain concrete or SFRC beams where the shear contribution resulting from dowel action is completely neglected this research clearly shows that the dowel action has an appreciable effect on the ultimate shear strength Its contribution varies from to when the beam depth increases from to in to mm On the other hand the compression zone ? s contribution decreases from to with the increase in beam depth In addition the shear contribution from the fiber bridging effect along the critical shear crack stays approximately unchanged at irrespective of the beam depth In this study the minimum shear strength obtained was in the range of ? fc psi ? fc MPa for the beams with the greatest depth This indicates that the maximum allowed shear stress limit of ? fc psi ? fc MPa specified in ACI - is on the very conservative side Keywords dowel action hooked-end steel fiber shear strength steel fiber-reinforced concrete INTRODUCTION While there is a rather universal acknowledgement of diagonal shear failure in plain concrete PC beams without transverse reinforcement different models with distinct perspectives have been proposed to explain the shear resistance mechanism of PC beams One explanation is found in the Modified Compression Field Theory Vecchio and Collins where the aggregate interlock based on aggregate sizes crack width spacing and straining effect due to longitudinal reinforcement are