The Water Stop Machine
The second piece of equipment GOMACO built for the All-American Canal paving train is the water stop machine. It follows directly behind the canal paver inserting the transverse water stop material every 15 feet (4.6 m). The production rate on the project is all dependent on this one machine, and that created an extra challenge in the design process.
The water stop machine is made of eight foot (2.4 m) square frame sections. It features a fixed and hydraulically-adjustable end car and Powered Wedge similar to the paver to match the canal profile. The inserter is powered by an 80 horsepower (59.7 kw) engine and runs on Series Six tracks that are 16 feet (4.9 m) long with 20 inch (508 mm) polyurethane track pads.
The rubber water stop material is inserted into the wet concrete by a specially-designed inserter mechanism that rides on a rail-mounted carriage. A platform positioned horizontally above the framework on the top side has reels that hold two spools of material.
The material is attached to the carriage, and as it moves down the canal wall, it pulls the water stop material off the spool and down the slope. At the bottom of the canal, a worker anchors the material to the canal floor. The carriage, with the inserter mechanism, then moves up the canal wall while vibrating and inserting the water stop material to a job specific depth and orientation.
The top of the rubber water stop material is placed one-eighth of an inch (3 mm) below the surface to allow for controlled cracking in the canal. The inserter is designed to capture the twisted material and place it untwisted and in the vertical, upright position in the concrete. When the carriage reaches the top, a worker cuts the material to complete the joint. He then pulls from the spool above and clamps the material to the carriage to be pulled down the slope again. The process is repeated every 15 feet (4.6 m) along the length of the canal. The entire process has be to completed in under three minutes to allow the machine to keep up with the paver.
The water stop machine has to be able to keep up with the paver so the concrete doesn’t cure and become too hard to insert the material. That’s one challenge. Another challenge is project specifications.
“This machine has to be able to insert a joint every three minutes to be able to pave five feet (1.5 m) per minute,” Steve Johnson, GOMACO R&D senior engineer, said. “If they can keep concrete in front of the paver for that kind of production, this machine is certainly capable of keeping up.”
Extensive research and testing took place to create the insertion device. Not only does it have to place the material on-the-go in the paving process, but place it at the required depth, standing in the upright position, and with the concrete consolidated around the material.
“The concept itself is relatively easy,” Homan explained. “But in the environment the inserter has to work in, the complications of going through a radius, and other aspects, make this an interesting challenge, and thus a very important machine in the canal paving process.”
The Canal’s Work Bridge/Cure Machine
Like all the machines for this project, the work bridge is a unique design with several different aspects to it. It mirrors the paver and water stop inserter in several features to match the changing dimensions of the canal, including a fixed and hydraulically-adjustable end car and Powered Wedge. The continuation of the same components on the different canal machines helps out in the field with operation and maintenance.
The framework itself is four feet (1.2 m) wide by seven feet (2.1 m) tall, with the console located at the bottom of the machine. It runs on Series Two tracks equipped with 19.7 inch (500 mm) polyurethane track pads. During the second paving pass, the machines run on the concrete from the first pass. The extra large track pads keep the work bridge from cracking or marring the surface of the new canal.
The work bridge is the third piece of equipment in Coffman Specialties’ canal paving train. It gives finishers a platform to work from and is used to cure the finished canal. A curing mechanism is mounted to the back of the work bridge to apply the white curing compound.