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Saving time and reducing costs working from a barge


The new bridge connects the two shores of the Cadiz bay opening to Puerto Real. Is the highest in Europe with an elevation of 69m, 3.157m long and 3 lanes. The marine foundations include 120 marine piles of 2.000mm diameter and depths of 45 meters. The excavation method includes a metallic casing driven 7 meters into the bottom of the river followed by soil stabilization with GEO’s synthetic fluids (PolyMud®/G3 System®). All piles were executed from a barge.

The Challenges


  • Effectively stabilize the excavation with salt water intrusion and tidal effect variation
  • Reduce the equipment and logistics in a confined space such as a barge and associated costs
  • Meet the project completion date as specified by the main contractor
  • To respect all environmental recommendations and approved legislation

The unavailability of fresh water on marine projects for logistic reasons required slurry mixing to be made with salt water on piles away from the Cadiz bay shores. The mixing using salt water was performed either directly on the pile or at the barge inner batching plant. All piles had a column of 7 meters of salt water which had to previously be mixed with the G3 System in order to speed up pile excavation.

Benefits


The works carried out in the bay, environmentally considered to be of high risk, for which thorough environmental control was carried out by government environmental agencies. The usage of the G3 System® allowed for excavation spoils to be directly discharged into the river. As previously confirmed by testing, there was no negative environmental impact for marine live.

It was possible to meet completion deadlines, saving time and reducing costs by increasing the production rates.

With the usage of the stabilization fluids G3 System® it was achieved:

  • Environmental preservation in a very sensitive area
  • Light support marine logistics
  • Reduction of equipment and personnel
  • Use of barge for slurry storage
  • Easiness and low cost fluid disposal
  • Time and cost savings comparing the G3 system to full casing
  • High Production rates
  • Usage of salt water for slurry mixing

An example of quality with the G3 System®