A statically indeterminate existing viaduct of two spans consists of 5 parallel post-tensioned box girders. They are joined with concrete diaphragms and an in situ concrete deck. At the skewed middle support, five post-tensioned concrete diaphragms are present. The existing viaduct occupies the location of a planned road project. A temporary bypass will be built on the east side of the eastern viaduct to handle the traffic during the demolition of the existing western viaduct. To make space for building the temporary bypass, one box girder from the eastern viaduct must be removed. Prior to this, the post tensioning in all the diaphragms must be eliminated and the resulting forces recovered by active jacks on scaffolding underneath the viaduct. In this paper the new situation (4 box girders, eliminated transverse prestressing and active jacking) is compared to the existing situation (5 box girders).
Boer et al. (Wed,) studied this question.