By Charlie Ingram
Field adaptability convinced utility managers to install ductile iron pipe in the St. Just project in Puerto Rico to work around obstacles in an urban congested area.
Urban congestion in San Juan, Puerto Rico prompted the island's water utility, Metropolitan Region for Compania de Aguas de Puerto Rico to try an innovative pipeline installation project. Construction crews recently completed the installation of a 25,000-foot pipeline under a narrow highway used daily by 30,000 motorists in a suburb of San Juan.
The utility decided to install the four-mile water line under the road so that its route did not run into schools, businesses, or industries. The line was laid under State Road 848 in a crowded area east of San Juan by a local contractor, Longo P.R.
Most of the pipeline was laid at night to minimise traffic disruption. Construction crews backfilled the trench after finishing their work and prepared it for the next morning's traffic. The task was made immeasurably more difficult by an extensive network of utilities - telephone, electric and cable lines - encountered along the pipeline route.
The utility selected ductile iron pipe manufactured by American Cast Iron Pipe Company (ACIPCO), based in Birmingham, Alabama, USA, for the St. Just project largely because of its field adaptability. ACIPCO ductile iron pipe is precision cut in the field, which enables crews to work around underground utilities and unexpected obstacles. Thirty- and 42-inch-diameter pipes were installed.
"We prayed every night that we didn't hit a utility," said Eric Flores, general manager/Metropolitan Region for Compania de Aguas de Puerto Rico, which is in charge of administration and water service for the island. "There were lots of existing utilities underground, and you can do more work with ACIPCO ductile iron pipe with less damage to utilities. It's more manageable in the field and provides more flexibility during installation. If you run into a utility you don't think is there, you can go back and cut the ductile iron pipe to the size that you need and work around the utility. The joints on ACIPCO pipe provided thrust restraint without the use of concrete thrust blocks."
Jose Ocasio Rivera, P.E., president of Jose A. Ocasio & Associates in Rio Piedras explained that "A thrust block is a lot of work and you've got to follow certain regulations. This line was being installed in a state road, so thrust blocks couldn't be used anyway."
The St. Just pipeline will distribute water from San Juan to four municipalities east of the city: Trujillo Alto, Carolina, Loiza, and Canovanas. Each of the four municipalities now has two sources of water instead of just one. The water supply includes water sent 54 miles to San Juan via the Super Aqueduct, located on the island's northern coast. The Super Aqueduct draws water from the Arecibo River, which flowed unused into the Atlantic Ocean until the aqueduct was put into operation.
Some 150,000 people - 35,000 households and businesses - will use the water provided by the St. Just project, one of 68 different housing and commercial development projects.
Charlie Ingram is the senior public relations supervisor for Luckie & Company, located in Birmingham, Alabama, USA.