Effect of steel fibers on the compression behavior of isolated reinforced concrete panel: An experimental investigation and analytical model

This paper presents experimental results for 43 steel fiber-reinforced concrete (SFRC) panel specimens tested to failure. When a load is applied to a relatively small area of the thin concrete panel, it is expected that an isolated bottle-shaped strut will form. To further understand the behavior of these isolated struts, panels with two different aspect ratios were built. The factors that differed were the layout of the reinforcing bars, reinforcement ratio, reinforcement yield strength, and fiber volume fraction. The specified concrete compressive strength was 70 MPa, with the inclusion of a single type of fiber, i.e. hooked-end steel fiber. The test results indicate that concrete elements showed increased resistance to spalling and cracking, with the layout of the reinforcement and the reinforcement ratio influencing the strength of the bottle-shaped strut. An analytical model is presented for calculating the ultimate strength (peak loading stage) of the bottle-shaped strut. Based on the pragmatic constitutive laws of concrete, the applicability of the existing softened strut-and-tie (SST) model is extended to include the effect of fiber addition. The predictions of the analytical model are compared with the experimental results, allowing for a comparison that captures the ultimate strength with reasonable accuracy.