Moment Redistribution in Segmental Cantilever Bridges: Simplified Approach

Abstract

Moment redistribution due to creep of concrete in cast-in-place segmental cantilever bridges can be accounted for with sophisticated software. Although this approach to design frequently is preferred, experienced engineers often do a final check based on hand calculations that have stood the test of time. This paper deals with the latter approach. Principles governing moment redistribution due to creep were revised, and results from this investigation were used to develop a novel graphical aid suitable for hand calculations in an attempt to estimate the magnitude of tensile stresses due to moment redistribution because of creep. It was found that tension stresses due to creep are not likely to exceed 2 MPa (290 psi) because the post-tensioning provided by top cables balance approximately 70%–85% of the bending moments due to concrete weight. An example for routine designs was provided.