Bridge construction using pre-cast segments erected with a Launching Gantry (LG) is widely used for both highway and railway bridges, and often referred to as PSM (Precast Segment Method).
PSM Launching Gantry of SDI exceeds conventional design limits in modern bridge construction!We supply kinds of PSM launching Gantries tailored in accordance with project conditions and requirements, generally divided into Overhead Type and Underslung Type.
Both the overhead and underslung LG consist of two independent self – supporting main structures combined with advanced lifting equipment, creating an exceptionally flexible system for both the balanced cantilever and the span-by-span method.
Overhead LG Innovations of Strukturas/SDI:
- Our glue-as-you-go procedure is a special erection method for glued span-by-span bridges. A stiff main girder allows limited pre-loading of the LG, avoiding time consuming double handling.
- A symmetrical system allows turnaround of the LG without dismantling and re-erection. A special gantry crane, able to travel over hinges, combined with a 360 degree horizontal bearing on the bottom block, allows very flexible and smooth segment installation.
- Tower elements placed below the support beams allow substantial changes in the longitudinal slope. This facilitates compensation or elevation differences between neighboring bridges and repositioning of the LG in a vertical direction by vertical climbing of the LG.
Easy extension of the support beam for overhead Launching Gantries makes sideways movement of the whole system to the neighboring bridge or over existing superstructures possible.
Underslung LG innovations of Strukturas/SDI:
- Independent main structures, only connected by the gantry crane, allowing transverse adjustment from single to double and even to triple track.
- Implementation of hinges on our underslung LG has made it possible to erect spans with a horizontal radius down to 75m.
- The underslung hydraulic adjustment system permits the whole span to be adjusted in all directions to correct possible misalignments during erection.
- Both the overhead and underslung LG consist of two independent self-supporting main structures combined with advanced lifting equipment, creating an exceptionally flexible system for both the balanced cantilever and the span-by-span method.