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 NRS AS: Friday, November 21, 2008 Advanced Concept 

The UNDERSLUNG MSS concept:


A typical construction cycle with the underslung MSS:

  1. After concreting, curing and tensioning of cables, the Main Girders are lowered by the main jacks at the rear Suspension Gallow and on the front Pier Bracket.
  2. The joints in the middle of the Transverse Beam system are released and the Main Girders are moved transversely into a position where the Transverse Beams can pass the piers.
  3. The MSS is ready for launching. The launching operation to the next concreting position is to be carried out. The two Main Girders are moved independently to the next span.
  4. During the launching operation, the Suspension Gallow is moved to its next position.
  5. The two girders are moved transversely and joined in the middle of the Transverse Beam system.
  6. The Main Girders are raised to the concreting position by the Main Jacks.
  7. Adjusting the formwork by means of the screw jacks and the adjustable supports.
  8. For box girder bridges: After placing the reinforcement and tendons of the bottom slab and webs, the Internal Formwork is moved to its next position.
  9. When placing of reinforcement and tendons is finished, the MSS is ready for concreting of the next span of the superstructure.
  10. During the concreting period, the rear pair of Pier Brackets are dismounted, moved to the next front pier and re-installed.


Special features:

Launching of MSS with hydraulically folded bottom slab formwork ( limited space for transverse movement) Transport of one span's (up to 50m) reinforcement and prestressing ducts by the Rebar Cage. (Cycle time: 4,5 days / span) Remote controlled Internal Formwork Rolling Wagon (folded position). Hydraulic cylinders fold the formwork, launching by hydr. motors.

For more information: See Our Projectgallery