Projects

US07 Washington

14.12.07

In 1986, the US Congress established the United States Institute of Peace (USIP) and has provided 68 million Euros for the construction of a permanent headquarters facility in Washington D.C. The “USIP Sewer Rehabilitation Project” will ensure structural integrity to the existing brick sewer that is located under the proposed building site.

A sewer that was reportedly built in 1896 has been serving the area. Planners decided that it needed permanent preservation to support future construction. They also decided that slipline rehabilitation was necessary to ensure the sewer would not interfere with the future USIP facility. HOBAS CC-GRP SewerLine® Systems was the only product that met all of the project requirements. The pipe to be installed had to be structurally sound, grouted in place and capable of handling the final loads.

The existing brick sewer was sliplined with 110 m of 1750 diameter HOBAS CC-GRP Pipe. The actual inside diameter of the original brick sewer varied between 1850 and 1900 mm. The engineering firm of Metcalf & Eddy thoroughly evaluated the host pipe conditions in order to maximize the diameter of the sliplining pipe. The radial clearance calculated between the HOBAS Pipe OD and the brick host pipe ID ranged between 6 and 32 mm.

CC-GRP Pipes have an efficient cross-section providing high strength with a thin wall. HOBAS also offers many pipe diameter choices for this type of application and not only standard diameters. The very tight fit, possible with the flush bell spigot pipe connectors, contributed to maximum flow recovery as well.
“The sliplining went very well,” said K. Michael Hall (Hall Contracting, installation subcontractor for the sliplining operation), “and after the pipe insertion, we grouted the annular space ourselves with a lightweight grout. Three ports were installed at the 12 o’clock position spaced evenly along the 100 m run. We removed the valves and replaced the tapped holes with 38 mm PVC plugs.” The plugs were provided by HOBAS. The new CC-GRP SewerLine® is structurally sound, leak free and provides adequate capacity. Hall had utilized HOBAS on more than 10 past projects dating back to 1997. K. Michael Hall, CEO, noted “Hall tackles tough large diameter slipline projects and has used HOBAS Pipe almost exclusively due to its toughness and ease of installation. This job was no exception.”

With sewer work complete, the engineer and installer both said they were pleased with the performance of the pipe and the level of service provided by HOBAS.