Strip loading in steel fiber reinforced concrete: Experimental and theoretical investigation

Abstract Fiber reinforced concrete is becoming increasingly popular in engineering practice due to its high robustness, post‐cracking behavior, and crack control. For strip loading, as common, for example, in longitudinal joints of tunnel lining segments, the use of fiber reinforced concrete has the potential to reduce conventional reinforcement. However, no existing design approaches combine the effects of load dispersion, confining reinforcement, and fiber reinforcement, and experimental data is scarce. This article presents 11 tests on strip‐loaded steel fiber reinforced concrete specimens. Four of the specimens were made of purely steel fiber reinforced concrete, while the remaining seven were hybrid‐reinforced specimens containing additional confining bar reinforcement. The cracks on the specimen surfaces were measured with digital image correlation systems. Design approaches are proposed for both reinforcement cases. The results demonstrate that steel fiber reinforcement is able to enhance the load‐bearing capacity of strip‐loaded reinforced concrete and minimize crack widths. For hybrid‐reinforced specimens, steel fibers are particularly effective when combined with low conventional reinforcement ratios and are thus a viable option to reduce conventional reinforcement. The proposed modeling approach, combining load dispersion, confining reinforcement, and steel fiber reinforced concrete, is mechanically sound and shows good agreement with the experimental data, and is thus proposed for design. The purely steel fiber reinforced specimens sustained loads that exceeded those at which initial surface cracks occurred. However, their application requires further investigation, particularly regarding the consideration of the associated brittle failure mechanism.