Post-Tensioning Distribution in Composite Bridges

Post-tensioning can be utilized to increase the flexural strength of beams in single-span, composite steel beam and concrete deck bridges, even when only deficient exterior beams are post-tensioned. Distribution of the axial forces and moments caused by eccentric post-tensioning of the deficient beams must be considered in the design of the strengthening system, however. Finite element models, verified with laboratory and field testing, are used with multiple linear regression to develop design equations for force and moment distribution fractions for four-beam bridges. The design equations can be used easily by practicing engineers and provide the basis for a strengthening design methodology.