Three million pounds in motion along Utah's I-80

The system consists of four transports that are connected through a computer system. Each transport houses 72 wheels that can collectively bear the weight of the bridges. The transport system can move in any direction and even make minor adjustments between its transports to accommodate uneven surfaces.

As the bridge reaches the gap it will eventually fill, four skid shoes are welded to support beams below the bridge. Like a roller skate, the skid shoes will slide the bridge across tracked beams lubricated with dish soap that span the gap. The bridge will be slowly pushed and pulled across the gap by a hydraulic ram until it is in position above hydraulic jacks resting on the street below. The jacks are encased by numerous blocks of ironwood, an extremely dense wood that sinks in water.

Once the bridge is resting on the hydraulic jacks, it becomes a sort of controlled Jenga game to lower the structure the remaining 15 feet, Montoya said. The jacks lift the bridge off the ironwood supports, it is locked in place with steel pins, a layer of wooden blocks is removed, and the jack is lowered again. Each time a layer of ironwood blocks is removed, the bridge is lowered four inches.

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