Innovative geosynthetic solution saves 106-year-old Panama Canal structures FIGURE 5 Loading 99-ton (90-tonne) geotextile bag containers on barge to transfer to Gatun Locks FIGURE 6 Placing first geotextile bag container in Panama Canal barge-mounted crane lifted the sandfilled 99-ton (90-tonne) geotextile bag containers on to a transfer barge that was moved to the Gatun Locks where crews would be ready to start as soon as the 12-hour maintenance window opened (Figure 5). The first repair was performed on the approach slab to the left chamber of the Atlantic approach to the Gatun Locks. When the repair started, the scour was the entire 110-foot (33.5-m) width of the slab down to a depth of 13 feet (4 m) below the slab and 26 feet (8 m) underneath the slab. This repair would require constructing the cofferdam using 12 of the 65-cubic-yard (50-m 3) geotextile bag containers to be installed in the first scheduled 12-hour maintenance window, which was during a nighttime operation (Figure 6). During the next month's 12-hour nighttime maintenance window, more than 392 cubic yards (300 m3) of concrete was pumped behind the cofferdam and under the approach slab to fill the scour void under the slab (Figure 7). This same procedure was followed to make the scour erosion repair to both sides of the dividing wall in the approach to the Gatun Locks. This methodology has also been followed to perform similar repairs to the Miraflores and Pedro Miguel Locks over the next two years. The results There has been no scour erosion detected under any structures of the Panama Canal locks since the repairs using the geotextile bag cofferdam technology started in September 2015. In addition, the ACP has installed more than 400 geotextile bag units to construct underwater cofferdams within the Panama Canal to allow the filling of understructure voids with concrete at other detected scour erosion sites at the Gatun Locks and the other two sets of Panama Canal locks. 18 Geosynthetics | August September 2020 0820GS_p14-19.indd 18 7/23/20 12:46 AM