When Hurricane Wilma crashed through the Atlantic basin in October 2005, the record-breaking storm demolished docks at Cozumel, Mexico, and threatened the $5 billion tourist industry whose Caribbean cruise ships depend on those docks.
"The terminals were designed for a Category 5 hurricane, but nobody expected the 155-mph winds to remain over the island for 54 hours," says Daniel Ingram, project manager with SSA Mexico-Grupo Carrix, which owns and operates the piers.
In July 2006, SSA tackled the daunting task of reconstructing the Cozumel cruiser terminal, which consisted of a 1180-foot-long concrete pier and two dolphins (stand-alone structures used to guide and moor vessels) connected by walkways. The repairs had to be performed without interrupting cruise traffic, so most of the work was done at night when no ships were at the pier.
Approximately 6500 square feet of concrete debris needed to be cut and removed by crane, piece by piece. The kicker: most of the concrete was situated 65 to 82 feet underwater--a forbidding jobsite for the typical demolition crew.
SSA contacted Alberto Esquitin of Cobusa Co., a concrete cutting subcontractor based in Tuxpam, Mexico. The contractor organized a team of 14 experienced divers to conduct the concrete cutting, demolition, and removal. Johan Ekström and Rick Glidewell, product managers for Husqvarna Construction Products North America, trained the divers to operate the cutting equipment.
The diving team used two powerful, yet compact Husqvarna CS 2512 wire saws with a 3030 heavy-duty power pack and a WS 463 saw with a wire conversion kit. Other Husqvarna equipment used on the job included a FS 6600 flat saw with a 17 1/2- inch cutting depth and aK 650 handheld power cutter with a 6-inch cutting depth.
To provide greater power underwater, hydraulic power was used. In addition, Ekström had to modify the cutting equipment to function better underwater. He replaced the drive wheel with a wheel that would create less resistance to inhibit the wire spinning.
Two cutting methods were used, depending on the location of the concrete to be cut. In one method, the saw unit and cutting wire were underwater, mounted on a movable platform for easy setup. In other cases, it was possible to mount the saw unit on the surface and submerge the cutting wire.
The last of the underwater debris was removed in October 2007. The reconstruction cost $15 million.
"SSA has over 100 terminals all over the world, but this is the first time we had this kind of job," says Ingram. "Our engineering team proposed the sawcutting method because of the environmental regulations in Mexico. Sawcutting was the best alternative because it is nondestructive and preserves the environment."