A maintenance crew at a large California marina was reinforcing the concrete seawall between the boardwalk and parking lot when they became aware of a 2-inch pressurized waterline leak. Excavating to locate the source, they exposed an 18-inch fabricated steel stormwater pipe buried 4 feet deep.
The flattened pipe had no visible outlet in the seawall, yet apparently was connected to a catch basin in the middle of the three-quarter-acre parking lot. The marina’s building superintendent researched solutions on the Internet, then called John Rafferty of TRIC Tools Inc. and asked if sliplining would work.
“A 10-inch fused polyethylene pipe would handle twice as much water as that old line,” says Rafferty. “The mess, inconvenience to boaters, and expense of ripping up the parking lot and boardwalk to replace it would be huge.”
The superintendent agreed to the project if Rafferty could complete it by Friday night. Although the pull was only 175 feet, the pipe had to traverse open water, snake across docks, surmount an increasing elevation as the Pacific Ocean tide went out, and navigate through a 45-degree bend. Despite an unexpected delay, Rafferty met his deadline, enabling weekend boaters to arrive unaware that anything had happened.
Making the pipe
The maintenance crew excavated 3.5-foot-deep pits at the 45-degree bend and behind the 3-foot-square catch basin, then bored through the basin wall opposite the stormwater pipe. Rafferty and civil engineer Ian Hom televised the line using a Mini-SeeSnake camera from RIDGID taped to a fiberglass duct rodder.
The pipe, partially collapsed at points, was full of sediment and appeared to have no tie-ins except the 8-inch line at the 45-degree bend. The invert was paper thin, but the top of the pipe was 1/4-inch thick steel.
Although the distance from the catch basin to the seawall was 160 feet, a 15-foot planned extension under the boardwalk would enable the marina crew to align the pipe while reinforcing the seawall and pouring concrete. The crew’s main challenges were where to fuse the pipe and how to set it up.
Using a McElroy 314 fusing machine, Rafferty and Hom worked with the entire marina crew to fuse five sections of 40-foot pipe in the parking lot on Thursday. The marina’s forklift assisted with fusion, and a backhoe was used to tug the pipe along and ease it down the gangway. Setting up and fusing a joint took 30 minutes; cooling it in the jig took another half hour. “Done correctly, the joints can be flattened by a tank and won’t separate,” says Rafferty.
Because moving the 1,500-pound fused length of pipe could damage the marina buildings, wood boardwalk and docks, the men put 2-foot lengths of 2-inch galvanized pipe under it at 20- to 30-foot intervals.
To prevent the semi-flexible pipe from slapping or scraping against the boats, the marina crew attached ropes and guided it from the parking lot, across the 50-foot-wide boardwalk, down the gangway, and along the 6-foot-wide dock beside the boat berths. Once the pipe was on the dock, they lifted the head end of it onto a hand cart. “Moving the pipe was the most manually intensive portion of the job, since we couldn’t have any heavy equipment on the dock,” says Rafferty.
Long, black snake
On Friday morning, everyone returned to position the pipe for the pull. “From the dock, our line of sight to the entry pit was straight across the slips to the seawall under the boardwalk,” says Rafferty. “The excavation was at the seawall where the asphalt met the boardwalk.”
The marina crew moved two boats from their slips to create a path for the pipe. They detached a section of dock from the first and second berths and used them as rafts.
Rafferty strung the cable from the exit pit so he could pull the bursting head most of the way through the back wall of the catch basin, leaving a foot of pipe inside the catch basin for inlet reconstruction. The cable was ferried on a raft from the seawall across 60 feet of water to the dock.
After the puller was set up in the parking lot, and as the tide subsided, TRIC mechanical engineer Robert Ding made hurried modifications to the 8-inch Unified Force bursting head so that it could pull the 10-inch expander statically without its pneumatic core. Ninety minutes later, the cable, head, and skirt were attached. As the pull began, the marina crew manned the ropes and the lengths of galvanized pipe, shepherding the new pipe on its journey to the seawall.
The job required only a few tons of pull, but Rafferty selected a 1-inch compact swaged cable rated at 74 tons, the TRIC WC40 ram rated at 100 tons, and a two-stage pump with a flow of 20 gpm at 0 to 2,000 psi, and 10 gpm from 2,000 to 4,000 psi. “I didn’t know how collapsed the line was and wanted additional horsepower to expand the earth if we hit an obstruction,” he says.
The ram dragged the head off the dock and over the water in a 45-degree arch toward the boardwalk. The rafts, positioned at the halfway point, supported the pipe and kept it in line with the 14-inch entry hole in the plywood form for the seawall repair. The uneventful pull took half an hour, and all signs of it were gone by Friday night.
The marina then hired TRIC to slipline the 60-foot, disintegrating 8-inch tie-in. The job involved core-drilling of the new stormwater line at the 45-degree bend, pulling in 6-inch polyethylene pipe, and connecting the two with a mechanical saddle.
