How China Builds Bridges So Fast | Gantry, Segments, and Prestressed Concrete | Launching Gantry How does China build bridges and viaducts so quickly — and why is the same technology used in Europe, Japan, Singapore, and Malaysia? Segmental bridge construction is a modern engineering method in which bridges and viaducts are assembled using launching gantries. Instead of building from the ground up, the bridge “grows” forward: the gantry moves along the already completed span, lifts concrete segm