Incremental launching - Applications
The advantages and disadvantages of incremental launching are given below.
●There is no need for false work to support the deck during casting in the spanned area.
●The deck is cast at one location, hence improving concrete quality control and saving on formwork.
●Nearly all the sections of the deck would experience both sagging and hogging moments during launching that are higher than the moments in an instantaneously built deck.
●Deck has to be straight or of constant curvature.
●Special bearings are required at the supports.
●A jacking system is required to push the segments forward.
●Launching is carried out by specialist contractors that could result in increased price.
Caption: Jules Verne Viaduct incremental lauching method
See also Concrete Society Current Practice Sheet 151, Incrementally launched concrete bridges, by Simon Bourne (Benaim), CONCRETE, July 2007, pp. 7–8. [Note that copies of Current Practice Sheets can be downloaded form the Members´ Area of the Concrete Society web site.]