The secondary prestressing method of the steel box girder by down-up method

 

 After the deck concrete has been poured and cured in the state of that additional compressed stress is introduced  into the low flange by adopting hinged ends as fixed ends and by the movable support downed on the simple beam system, the method that introduce the compressing stress which is against negative moment stress into deck concrete from fixed ends by upping the downed support.

 

Steps of constructing

The diagram and state of each steps used by Down-up method

 

 

 

 

Detailed drawing

Connect the steel box girder and pier at the fixed end