Incremental launching is an economical construction technology used for building concrete bridge structures. The method is particularly suitable for constructing continuous prestressed multi-span bridges. It involves building the superstructure in sections of 15-30 meters in a stationary formwork behind the abutment and pushing the completed portion of the bridge forward using hydraulic jacks and tendons or a dedicated lift-and-push launching equipment. The segments are constructed as cast-in-situ and then prestressed. The structure moves on temporary sliding bearings. To maintain a low bending moment in the superstructure during construction, a launching nose is attached to the front of the structure.
The key advantages of using this construction methodology over other traditional methods are:
- Minimal disruptions in environmentally sensitive areas. Requires a smaller construction site area.
- Enhanced safety during construction, primarily conducted at ground level.
- Rapid construction pace.
- Savings in transportation and overall reduction in construction elements.
- Higher quality finishing and efficiency resulting from easier working conditions and task repeatability.
- Easy access to limited or restricted locations, such as over rivers, deep valleys, road or railway lines, poor soil conditions, or environmentally protected areas.