In this process, the falsework is moved to a new concreting position along with the formwork. Contrary to the cantilever launching method (compare page 24 ff), the concreted component remains in its position. Depending on the shape of the structure, an upper or a lower mobile support is used.
The advantages of the upper system are high capacity on curves and free selection of the bridge cross-section. Moreover, the railway loading gauge under the new structure is not affected normally.
The variant with the lower mobile support is advantageous due to lower cost implications. Furthermore, pre-assembled reinforcing elements can be brought in with the crane (time advantage) and suspensions through the structure are not required.
As a rule, bridge structures that are constructed with the help of mobile falseworks are designed as box girder cross-sections. In exceptional cases, even T-beam cross-sections are used.
In the case of mobile falseworks, the formwork is constructed from standard components of the girder wall formwork. Steel beams with special connections and joints are mainly used for mobile support.
While planning, it must be ensured that the formwork and scaffolding systems are well coordinated since there is a close interaction between both systems.