Ultimate Analysis of Monolithic and Segmental Externally Prestressed Concrete Bridges

Abstract

A numerical model for the ultimate analysis of externally prestressed concrete bridges has been developed. The proposed model can analyze simply supported or continuous, monolithic or segmental bridges, with external unbonded prestressing and/or internal bonded prestressing. The model evaluates the behavior up to failure of this type of structures, calculating displacements, rotations, joint opening for segmental bridges, internal forces, and prestressing steel stresses at each load increment. Some codes recommend values or approximate formulas for the increase of stress of the prestressing steel at ultimate. These values are sometimes too conservative or unreasonably high. The proposed model includes reinforced concrete, prestressing tendons, and joint finite elements. These elements are described in this paper. A comparison between the numerical model and available test results is also provided, showing excellent correlation.