It is an effective launching system and will only be economically viable for a relatively long stretch (> 1.5km) of viaduct construction due to the rather high capital investment of the launching girder. Generally, the radius of curvature of the viaduct alignment must also not be too small (>200m).
Girders to be launched are delivered to the launching girder either from the rear or from beneath the erected spans. They are then lifted up and placed in the final positions using hydraulic jacks or winches.
Considerations must be made for the availability of a huge space to assemble and erect the launching girder, and to dismantle it upon project completion, which could be a problem if carried out in urbanised areas and heavily congested roads.