A unifying methodology to design un-notched plain and short-fibre/particle reinforced concretes against fatigue

• A design curve to estimate fatigue damage in plain and short-fibre/particle is proposed.
• The proposed fatigue design curve takes into account the mean stress effect.
• This design fatigue curve can safely be used in situations of practical interest.

This paper summarises an attempt of proposing a unifying design curve suitable for estimating fatigue damage in un-notched plain and short-fibre/particle reinforced concretes subjected to in-service uniaxial cyclic loading. The above reference fatigue curve was determined by post-processing about 1500 experimental results taken from the literature and generated by testing both plain and short-fibre/particle reinforced concretes cyclically loaded either in tension, in tension/compression, in compression, or in bending. Further, the effect on the fatigue behaviour of concretes of both lateral static loading and stress concentrator was investigated. The most relevant peculiarity of the proposed design methodology is that the mean stress effect is directly taken into account by using the maximum stress in the cycle under either tension/compression or bending, and the absolute value of the minimum stress under compression (the above design stresses being normalised through the corresponding static strength). This strategy resulted in a great simplification of the problem, allowing all the considered experimental results to fall within a narrow scatter band. The high level of accuracy which can be reached through the proposed unifying fatigue assessment methodology strongly supports the idea that this approach can successfully be used in situations of practical interest to design concretes against fatigue by remarkably reducing the time and costs associated with the design process.