Deformation Analysis of Prestressed Continuous Steel-Concrete Composite Beams

Deformation calculation of prestressed continuous steel-concrete composite beams accounting for the slip effect between the steel and concrete interface under service loads is analyzed. A simplified analytical model is presented. Based on this model, formulas for predicting the cracking region of concrete slab near the interior supports and the increase of the prestressing tendon force are derived. A table for calculating the midspan deflection of two-span prestressed continuous composite beams is also proposed. It is found that the internal force of the prestressing tendon under service loads can be accurately calculated using the proposed formulas. By ignoring the increase of the tendon force, the calculated deflection are overestimated, and considering the increase of the tendon force can significantly improve the accuracy of analytical predictions. As the calculated values show good agreement with the test results, the proposed formulas can be reliably applied to the deformation analysis of prestressed continuous composite beams. Finally, based on the formulas for calculating the deformation of two-span prestressed continuous composite beams, a general method for deformation analysis of prestressed continuous composite beams is proposed.