VIDEO: Portland engineers use dish soap to move century-old bridge
EQW Staff | July 10, 2013


Engineers in Portland, Oregon, had to get creative when they needed to replace the Sellwood Bridge.

Cracks had begun to appear in the support beams of the 100-year-old bridge, and, as our sister site, Equipment World, reported, the structure’s unique design forced the engineers to move the bridge in one whole 1,100-foot piece.

The engineers built tracks, covered them with Teflon pads and poured liquid soap on them. Forty 150-ton hydraulic jacks lifted the 3,400-ton bridge and placed it on the soapy tracks to slide it into place.

Here’s a rundown of the process:

  • 3,400 tons: Weight of the entire bridge
  • 1,100 feet: Length of the entire bridge, including the overhang
  • 1,091 feet and 2-1/4 inches: Actual length on the continuous steel truss between end bearing points
  • Five: Number of concrete piers supporting the bridge (three in the river and one on each shoreline)
  • Two: Number of steel bearings supporting the truss at each of the five piers
  • Four: Number of spans between support piers
  • 245 feet, 300 feet, 300 feet and 246 feet: Lengths of each of the four spans
  • 10: Number of bearing points
  • 66 feet: Distance west end of the bridge was moved
  • 33 feet: Distance east end of the bridge was moved
  • 40: Number of hydraulic jacks used to lift the bridge
  • 19 hours: Amount of time it took to move the bridge
  • 1924: Year the individual parts of the steel truss were fabricated
  • 30,500: Number of vehicles that would have been rerouted miles away if the bridge was destroyed

Check out the video below to watch the 19-hour process take place in a 38-second time-lapse.

[vimeo 57807120 nolink]

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