Behavior of Non-Shear-Strengthened UHPC Beams under Flexural Loading: Influence of Reinforcement Depth

This study was carried out in order to the flexural behavior of fiber-reinforced ultra-high-performance concrete (UHPC) containing hybrid microsteel straight fibers and natural fine aggregates under four-point loading. The experimental results revealed that fiber pullout mechanism had a progressive (collapse) mode. A highly crack developed when pulling explicitly triggered, leading failure most beams. maximum load beams reinforced by 1.2, 1.6, 2.0% exceeded without longitudinal reinforcement 56, 73, 94%, respectively. Further, bar reinforcements at 125, 115, 95, 85, 75 mm depths led increases 55, 96, 94% beam capacity, In addition, reduced beams’ ductility 40, 23, 35, 39% compared those with 125 depth. All studied UHPC an uncracked phase extended curvature about 7.5 × 10−6 rad, which occurred 10 kNm. use design experiments exploited this investigation develop prediction model for ultimate moment capacity took into account sectional material properties To carry analysis, database 25 beams, other investigators, as well present authors, utilized. With mean prediction-to-test ratio 0.92, reasonable performance capacity. turn, used generate isoresponsive surface contours could be design.