Influence of geometric factors on the punching load resistance of early-age fibre reinforced shotcrete linings

Understanding the early-age properties of fibre reinforced shotcrete (FRS) is critical to the accurate estimation of the time to safe re-entry under freshly sprayed FRS linings. Previous research in the field has indicated that shear failures dominate early-age load resistance and thereby govern the performance of a lining during the first few hours after spraying. This investigation has examined the influence of several geometric variables on shear resistance in a punching mode of failure. In particular, the research has addressed the influence of the size, shape, eccentricity, and inclination of punching loads on the apparent shear strength of an early-age fibre reinforced shotcrete (FRS) lining.

► Experimental assessment of early-age shear strength in FRS.
► Examined influence of size, shape, eccentricity, and inclination of load.
► The shape and inclination of the load did not influence shear strength.
► The size and eccentricity of loading zone both influenced capacity.
► An equation was developed to predict influence of geometric factors at early ages.