Behaviour of round steel fibre reinforced concrete panels under point loads

The objective of this investigation was to examine methods of testing round Steel Fibre Reinforced Concrete (SFRC) panels to obtain empirical estimates of post-crack load capacity under point loads. The performance of steel fibre reinforced concrete panels under point loads is of interest because such tests are commonly used to determine the suitability of a concrete mix for use in sprayed tunnel lining construction. This investigation has focussed on experimental obstacles to the reliable determination of post-crack load capacity. To examine possible differences in behaviour between continuous in situ tunnel linings and specimen panels representing portions of a lining, four modes of edge support were used to restrain round specimens that varied in both thickness and diameter. Determinate and simple support conditions were examined as possible modes of panel support for routine laboratory testing. Fully clamped and quasi-continuous edge restrained panels were used as approximations of an in situ lining. Performance was measured in terms of peak load capacity and energy absorption.