Chapter 4: The Construction Process of Segmental Bridges
Launching Girder, Placement Phase
Placement of Segments
Lauching Girder, Advancement Phase
Direction of Advancing
Figure 4-6: Working Scheme of Long Launching Girder
4.2.3 Incremental Launching
Incremental launching was developed by the German engineers Fritz Leonhardt and Willi Baur for the Rio Caroní Bridge in Venezuela (Podolny and Muller 1982), which was built from 1962 to 1964. The incremental launching technique, as opposed to other methods presented in this chapter, consists of casting a continuous chain of segments at one particular location on site and then pushing the growing superstructure out over site to be bridged. A casting bed with adjustable formwork for the superstructure segments is set up. This casting bed can also be enclosed in a heated tent so that controlled casting and curing conditions are achieved. The normal cycle time, regardless of segment length is one week. Segment lengths according to Liebenberg (1992) typically range between 15 and 30 m.