Finite element analysis of prestressed concrete box girder bridge

Abstract

Curved concrete bridge girders have very complex internal forces, stress and strain distribution. As a consequence of their shape, not only the usual bending moments and shear forces are generated, but also important torsion moments are created. These moments rotate the axes of principal tensional stresses and increasing the risk of cracking. A study of torsional moment is found limited in the literature. Post-tensioning can prevent the cracks, but the additional of compression forces in different directions increase the complexity of stress and strain fields sometimes tendons lead to break away the web. Therefore, the curved post-tensioned concrete girders must be particularly designed and carefully constructed. The complete Senai Bridge has been modeled and used for a case study. Trapezoidal section has been chosen in the present investigation. The linear analysis of the box girder has been carry out by using LUSAS software. Three dimensional line modeling have been employed for discretization of domain and to analyze the complex behavior of straight and curved box-girders. Dead Load and Live Load according to British Standard code of practice, for zero torsion as well as maximum torsion are considered. Box section produces higher torsion in curved span compared to straight span with considering the same load. From the analysis result shows that higher thickness of the base and walls leads to increasing the torsional moment.