Civil Engineering Reference
In-Depth Information
span. The entire cycle of launching the deck and then moving the gantry forwards to
the next span took no longer than 4.5 hours. This exceptional site demonstrated the
possibilities of this form of construction where long viaducts need to be built quickly,
Figure 15.45 and Figure 15.46.
It may be considered that the launcher was too sophisticated for its task, as it spent
most of its time idle, waiting for the next span. It would have been better suited to a
site equipped with multiple moulds, capable of producing several deck units per day.
The deck was designed to be continuous, the continuity being created by casting a
narrow concrete stitch over the piers and stressing capping cables. However, as decks
were delivered along the completed viaduct every two or three days there was no
time to cast and cure the joint, and to install, stress and grout the capping tendons.
Figure 15.45
Poggio Iberna Viaduct, Italy: launching gantry (Photo: David Benaim)
Figure 15.46
Poggio Iberna Viaduct, Italy: deck unit on its transporter (Photo: David Benaim)
