Design model for the fatigue behaviour of normal-strength, high-strength and ultra-high-strength concrete

Fatigue design according to CEB-FIP Model Code 90 is limited to concrete grades up to C80. In addition, the design rules include a strength-dependent reduction in the fatigue reference strength, which leads to uneconomical design of high-strength concrete. Considering comprehensive knowledge now available concerning the fatigue behaviour of normal-strength and high-strength concretes, the amount of this reduction can no longer be justified. A new design model for compressive fatigue loading and its derivation is presented in this article. A comparison between the new design model and the current standard ones reveals that the new design model ensures safe and economical design of normal-strength, high-strength and ultra-high-strength concrete. This new design model is included in the new fib Model Code 2010.