Numerical modeling of externally prestressed steel–concrete composite beams

• A FE model for externally prestressed steel–concrete composite beams is developed.
• Time-dependent effects are considered.
• Geometric and material nonlinearities are considered.
• Short and long-term behavior of composite beams is analyzed.

A finite element model to analyze externally prestressed steel–concrete composite beams under short and long-term loads is developed. The nonlinear geometric effect is considered by introducing flexural and axial interaction in the finite element formulation and by updating the eccentricities of external tendons in the numerical procedure. A layered technique is employed to describe varied material properties across the composite section. The time-dependent effects are also introduced in the model. External prestressing is considered to contribute to equivalent nodal loads. The analysis is able to simulate the short-term behavior of externally prestressed composite beams at all ranges of loading up to failure and also to model the long-term behavior of these beams at service loads. The proposed model is validated by comparisons with available experimental data as well as other analysis results. Typical short and long-term responses of steel–concrete composite beams with and without external prestressing are evaluated.