Innovative Numerical Approaches for Strain Limited Design of Composite Beams

For composite cross‐section in steel and concrete plastic bending resistance is often used. However, also for cross‐section of class 1 and 2 rotation capacity may be reduced, then strain‐limited or elastic resistance becomes important. The strain‐limited resistance refers to the design of concrete sections according to EN 1992‐1‐1, considering the material nonlinearity. For the numerical approaches, the conventional “finite fibre method” demands high programming and calculation efforts due to the vast amount of fibres to be computed. In this article, three alternative numerical approaches: the finite cell method, the integral strain method and the direct analytical method are introduced. These approaches reduce the number of elements compared to the fibre method. They take different levels of simplification, varies in application ranges, accuracy and calculation speed. For conventional composite beam and slim‐floor beam cross‐sections, an efficient alternative to the fibre method is presented by the alternates.