A visco-elastic GBT-based finite element for steel-concrete composite beams

This paper reports the latest developments concerning the use of Generalised Beam Theory (GBT) in the field of steel-concrete composite beams. In particular, a GBT-based finite element is presented that uses a linear viscoelastic material law to capture, accurately and efficiently (with a very low computational cost), the effects of concrete creep, as well as cross-section distortion and shear lag in complex cross-sections (combining closed cells and open branches). It is shown that the versatility of the GBT approach makes it possible to obtain accurate solutions with a fairly small number of cross-section deformation modes (cross-section DOFs), leading to significant computational savings with respect to standard shell finite element models. Several numerical examples are presented, to illustrate the capabilities and potential of the proposed GBT-based finite element.