Continuous simply supported prestressed concrete box beam - has stressing cables forming tie between beam sections and additional reinforcement at cable entry points

摘要

The prestressing cables (3, 3A) are placed in a continuous beam (A) in zones of tensile stress i. e. in the top slab of the beam (1) over the supports (P1, P2) and in the bottom slab of the beam (2) between supports. The cables are sheathed while they are in the slabs but are free between slabs. The zone of the slab at cable entry e.g. at point (c) is strongly reinforced to withstand tangential forces due to change in tensioned cable direction. risers (8) can be provided to brace the top and bottom beam members against the pull of the free portion of the cables.