Incremental Launching Method

Producing a cycle in the stationary production facility and launching the entire superstructure

The individual section of the superstructure 15 to 30 m long, are cast in a stationary production facility (casting yard) behind the abutment. When the concrete hardens, the new section and the existing superstructure are post-tensioned together with tendons. Then the entire superstructure is advanced across the piers by one cycle length, pushed forward by hydraulic shifting devices and moving on temporary slide bearings (Teflon-coated plates). To reduce the cantilever moments while the superstructure is being launched, a launching nose made of steel is attached to the lead section so that it is already supported by the next pier.

Highlights

reinforcing, forming, casting and advancing in the stationary production facility: process-oriented completion of the sections for high efficiency and quality
the piers are constructed in advance
work steps are separated: the trough is cast first, followed by casting of the deck slab
economical for repeat cycles and repositioning processes
bridging valleys, rivers, sea straits, nature conservation areas
nothing to obstruct traffic (road, rail, shipping) underneath the structure

Principle

Reinforcing, forming and casting in the stationary production facility
Post-tenstioning of the new cycle and the existing superstructure with tendons
Lowering of the casting yard; the superstructure is advanced by the hydraulic lifting/launching unit
Next cycle is produced