Monitoring, Repairs Stop Potential Water Main Catastrophe
Wednesday Jun 21st, 2017
Crews working for the Baltimore City Department of Public Works (DPW) were able to complete repairs to a major water transmission main in southwest Baltimore that had been showing signs of a potentially catastrophic rupture.
The repairs returned strength and stability to the affected section of pipe, and the work was completed without any customers losing water.
“I created DPW’s Office of Asset Management precisely to collect and utilize data that can help us stop problems before they happen,” said DPW Director Rudolph S. Chow, P.E. “Our team, including partners from neighboring counties and private industry, moved quickly to prevent what could have been a disastrous water main break.”
The 54-inch (4.5-feet) Southwest Transmission Main (SWTM) is the primary conduit for water to that portion of the City, Baltimore County, and portions of Howard County and Anne Arundel County. The main is a prestressed concrete cylinder pipe, installed in 1970, that uses tightly wound, prestressed wires running the circumference of the pipe to lend strength.
DPW conducted inspections of the pipe beginning in 2006, and a monitoring system was installed in August 2007 that notified engineers anytime a wire snapped. Beginning late last month, the monitoring system reported an alarming 15 wire breaks over a two-week period in one 16-foot-long segment of the pipe, raising concerns of a failure and potentially catastrophic water main break.
The affected section of the pipe is under Desoto Road, where it runs under the Interstate 95 South exit ramp towards Caton Avenue.
Engineers determined that the best option for repairing the pipe segment would be to utilize high-strength post-tensioning tendon cables. This process involved excavating around the distressed section of pipe and installing cables that are anchored directly around the pipe’s circumference.
After consulting with the City’s partners in Baltimore and Howard counties, contractors went to work on June 5 excavating the pipe and installing the post-tensioning tendon cables. They completed the installation, backfilled the excavation and the water main is expected to be put back in service on Thursday, June 22, for an estimated cost of $200,000.
“I’m heartened, as Mayor and as a resident of this great City, to see our public workers respond quickly and efficiently to preserve vital services and prevent infrastructure failures,” said Baltimore Mayor Catherine E. Pugh. “I thank everyone involved in this emergency project.”