A fatigue behavioral simulation for steel fiber reinforced concrete (SFRC) subjected to high cycle repetition of loads is presented. The fatigue constitutive models for normal strength concrete developed in the past decades are extended to those for SFRC with regard to tension, compression and shear transfer along dispersed cracking. The hysteretic path-dependency of SFRC is extensively focused on as well as post-cracking tension softening, because it greatly affects the stress-strain amplitudes of SFRC inside structures. The interaction of multi-directional cracks is taken into account based upon the fixed crack approach for enabling the damage evolution under the principal stress rotation. The rate effect on the stress and strain relation is also formulated to take into account the nonlinearity related to both loading rates and numbers of cycles. These proposed models for SFRC are experimentally verified in view of S-N diagrams of flexural tension for practical use.

There exist in-service RC bridge slabs suffering greatly from the fatigue loads of moving vehicles and serious cracking may often be observed. For quantitative assessment of residual fatigue life of bridge slabs under expected future loads, the past traffic loads' record is not available in most cases. Then, this paper aims to present pseudo-cracking approach to remaining fatigue life assessment of existing RC bridge slabs based on site crack inspection data alone. First, inspected crack width and its spacing are converted to the space-average strain field, on which finite element analysis can be carried out to predict the residual fatigue life of the cracked slabs. To prove the applicability of this simulation system proposed, parametric analysis is conducted to compute the S-N diagram of the damaged slabs and comparison is made with simplified deterioration grades specified in the manual of maintenance based upon experiences of bridge management. Furthermore, two bridge slabs in service with real crack inspection data were examined as a case study of application.