Flexural behavior of tubular continuous ultra-high-performance concrete beams

In the present paper includes an experimental investigation to study the effect of steel fiber ratio (1 to 2%) on the flexural behavior of tubular continuous Ultra High-Performance Concrete beams and the effectiveness of longitudinal reinforcement bars on the flexural behavior of UHPC continuous beams. Therefore, eight continuous tubular beams consisting of two-span were tested under one-point loading for each span. In each group, two groups were constructed, four beams, three beams are tubular, and the fourth was solid to comparison. All beams had the matching overall length of 3000 mm, the clear span distance equal to 1400 mm for each span, the same height of 200 mm, and the same width of 150 mm. The results exhibit clear improvement in the first cracking load when increasing the steel fiber ratio from 1 to 1.5% and 2% at about 11.1 and 66.6% and increasing the ultimate load at about 5.2 and 18.4%. Then when compared MXB-5 (1.5% steel fiber) with reference solid (RE.S, 1.5% steel fiber), the increase in ultimate failure load was 20%, in addition to increasing compressive strength. The ultimate load was increased at about (2.6, 15.78, and 20.1%) as the positive reinforcement ratio increased from 1% to 1.12%, 1.71%, and 1% solid beam, and the optimal ratio of steel fiber was 2%.