Flexural behaviour of continuous steel beam prestressed via externally unbonded tendons: numerical modelling, parametric study and statistical analysis

Abstract

Prestressed steel beam has the advantages of lightweight sections; this makes them economical and feasible solution in various practical situations. Prestressing the steel beams using externally unbonded tendons improves their load-carrying capacity and serviceability performance. This paper reports the flexural behaviour of continuous steel beams strengthened by prestressed tendons under concentrated load using finite element software, ANSYS. Mid-span deflection of the beam is essential to decide its functionality requirement. The effect of tendon eccentricity and prestressing force on the mid-span deflection has been analysed in detail through parametric studies. Furthermore, a simplified model derived from multivariable regression analysis is proposed for predicting the deflection of the prestressed continuous steel beam. The proposed model is based on applied load, the eccentricity of tendons and prestressing force with a high coefficient of determination (R2 > 0.99). Numerical results show 15–27% improvement in flexural capacity in terms of reduction in mid-span deflection.