Micro steel fibres significantly increase the ductility of ultra-high performance concrete (UHPC) and the post cracking load-bearing behaviour under tensile loading. For an economical material use in fatigue susceptible structures, it is necessary to characterise the crack-bridging load-bearing effect of fibres under tensile loading. The following study describes experimental and numerical investigations of the load-bearing effect of micro steel fibres embedded in UHPC on the macro-level.