Two feats of engineering: the bridge that the machine is building and the machine itself. This is the 580 ton, 91.8 meter (301 foot) long, 7.4 meter (24 foot) wide SLJ900/32 Bridge Girder Erection Machine by the Beijing Wowjoint Machinery Company. From Digital Trends:
This bridge-building process may appear complicated, but it is in fact brilliantly simple. It begins when the machine picks up a new beam from the casting yard. The machine drives to the site of the bridge, where the pillars have already been erected. It lowers a pneumatic support structure, which stabilizes the machine as it extends out to the first pillar some distance away. A second support structure is lowered onto the pillar, at which point the first one is slid along the machine’s length to the join the second at the pillar. With both support structures in place, the machine has a solid foundation for laying down the new beam.
The machine now drives further forward, carrying the beam with it. The beam is lowered into place between the bridge’s starting point and the first column. With the beam secured, the machine drives backwards, taking the two portable support structures with it. When it returns with another beam, it drives along the first installed segment, and the process is repeated to place the next beam between the first and second columns.
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