Estimating variability in point load resistance of fibre reinforced shotcrete linings

In the design of fibre reinforced shotcrete linings, the focus of attention is usually fixed on determining the maximum load capacity to satisfy ultimate limit state requirements. Less attention is focused on determining the variability in capacity, both in service and at ultimate load, but this variability is relevant to identification of a suitable partial safety factor for lining load capacity. To help address this deficit, a series of analyses have been undertaken to assess the likely magnitude of variation in the flexural and punching shear resistance of fibre reinforced shotcrete linings. The analyses have been based on an assessment of the propagation of variances using analytical and semi-empirical models of flexural and punching resistance. When compared to observed variability in full-scale tests of lining capacity, the analyses produce acceptable estimates of the measured Coefficient of Variation in lining load resistance.