Crews continue battling the weather as they work to repair a collapsed 72-inch storm drain off the street but adjacent to the corner of South Windermere Street and West Oxford Avenue.

“The pipe failure created a sink hole in the grassy area right by the Martin Plastic building,” Tom Brennan, utilities engineer, said July 28. “Crews have dug up the area where the pipe collapsed and we are trying to determine the extent of the needed repairs.”

On July 30 he said the collapsed pipe had been removed, the area was stabilized and handled the July 29 storm water well.

Plans are to replace the collapsed section of metal pipe with concrete pipe. Brennan said the accomplished one big task by finding a source for the section of concrete pipe 78 inches in diameter and the new pipe is scheduled to be delivered Aug. 3.

“The new pipe will extend from the pipe junction adjacent to Martin Plastics to where it will connect with the concrete pipe just east of the rail tracks,” the utility engineer said. “Our plans are later this year to do a thorough inspection of the 170 feet of remaining metal pipe east of where we are working with the eventual goal of replacing all of that metal pipe with concrete pipe.”

The collapse was discovered July 18 and the city hired American Civil Constructors to work on project. Brennan said the contractor was hired to do the work because they had the necessary equipment to do the work on a job that was beyond the scope of utilities department equipment to handle.

Brennan said the current rains aren’t make the job any easier. The collapsed metal pipe is part of the huge storm drain that runs under and parallel to Oxford from Clarkson Street to where it empties into the South Platte River. He said the recent series of storms have been dropping one to two inches of rain on the area in a couple hours. Rains that heavy tax the storm drains and frequently completely fill the 78 -inch pipe. That type of flow puts strain on the pipe, he said.

On July 28, the crew was on scene. They had already uncovered the corrugated pipe and removed the collapsed section. Despite the break, the pipe system must continue to operate by collecting thousands of gallons of water from the recent rain storm and empty it into the South Platte River. So the construction crews put in a section of metal trench reinforcement that channels the water through the area where the collapsed pipe was removed and into the storm drain pipe that continues west to the river.

The massive hole about 40 feet long and 17 feet deep was dug by a piece of construction equipment called a tracked excavator. The diesel-powered machine scooped up dirt in its large bucket as the operator enlarged the hole to make working on the project safer because it is necessary to do a visual inspection of the pipe to determine how much of the storm drain must be replaced.

Brennan said, while the work is being done, the city is checking on the type of pipe used on this storm drain. . He said the pipe was replaced by the Colorado Department of Transportation in 1992 during the project to widen Santa Fe Drive and create the underpass on Oxford. The plans show the pipe was concrete but, when the area was uncovered, the pipe was corrugated metal.

“We are working with CDOT to determine just what type of pipe was authorized in this area,” the utilities engineer said. “Normally, you would expect it to be a concrete pipe because it is running about 15 to 20 feet underground. Traditionally, corrugated metal pipe isn’t used when it is to be buried that deep unless there is a concrete bed built under it and there is no concrete bed under this pipe.”

The utilities department had problems with a pipe collapse on the same line but in the area where the pipe empties into the river. Repairs made it necessary to close West Oxford Avenue at the South Platte River bridge for a few days. Those repairs were about completed when the latest pipe collapse was discovered.