Numerical assessment of the nonlinear behavior of continuous prestressed steel-concrete composite beams

•Nonlinear behavior of continuous prestressed composite beams is evaluated.•Secondary moments in continuous prestressed composite beams are significant.•External prestressing improves moment redistribution ability of composite beams. This paper evaluates the flexural performance and quantifies the secondary moments in two-span prestressed steel-concrete composite beams. A nonlinear model capable of simulating the full-range nonlinear behavior of continuous prestressed composite beams is validated against experimental results. A parametric numerical investigation is then conducted to examine the effectiveness of strengthening a continuous steel-concrete composite beam with external tendons of different cross section areas. In addition, secondary moments in continuous prestressed composite beams having different tendon layouts under symmetrical and unsymmetrical loads are investigated. The results indicate that external prestressing not only increases significantly the ultimate load-carrying capacity but also improves the moment redistribution ability of continuous steel-concrete composite beams. Moreover, the analysis shows that significant secondary moments are present in continuous prestressed composite beams throughout the loading history. It is therefore necessary to consider secondary moments in the strength design of this structural typology.