Long-term deflections of cantilever segmental bridges

The long-term defections of cast-in-place segmental bridges constructed using the cantilever method are often larger than the defections expected in the design. A detailed structural analysis and monitoring of these types of bridges have therefore become a matter of interest. The paper gives a comprehensive analysis of phenomena that frequently conspire to cause long-span pre-stressed concrete bridges to defect more than predicted. The analysis is based on a parametric study and long-term monitoring of the behavior of a motorway bridge across the Vltava River in the Czech Republic. To reveal and quantify possible reasons for excessive bridge defections, a detailed time-dependent analysis was carried out. The results of the study were compared with in-situ measurements that have been regularly carried out since the very early stage of construction. Theoretical values of the increments of defections, pre-stressing forces and concrete strains were compared with the measurements.