Thousand Oaks Installs Piping

Under it all is an infrastructure that is maintained in a way that could be an example for many other municipalities.

When a sewer line carrying two-thirds of the city's flow needed repair, Hobas pipe was chosen as part of the solution because of its projected long operational life. The

The new Unit "W" Trunk Sewer replacement, Phase II, utilized abrasion resistant pipe. The new line traversed some rugged country. It was installed under a creek bed in the middle of a steep canyon that dropped more than 140 vertical feet from end to end of the 5,000-foot-long pipeline.

Never-Ending Mission

The city of Thousand Oaks maintains more than 500 miles of wastewater pipeline. Their collection system has an excellent operational and environmental record. Construction is ongoing to improve the collection system along with treatment plant capacity and reliability in order to minimize the possibility of system overflows, decrease liability exposure and simultaneously improve effluent quality and protect the environment.

Meeting new and more stringent environmental standards and regulations is a never-ending challenge and ongoing mission of the Thousand Oaks professional wastewater system staff.

Pipe Choice

Several pipe alternatives were specified on the project including PVC lined reinforced concrete pipe, polyurethane lined ductile iron, solid wall polyethylene, and Hobas. The 30-inch, 36-inch and 48-inch diameter, 46-psi pipe stiffness pipe was specified for the wastewater line to add increased competition on the project.

Some of the design considerations for this challenging installation were the long-term corrosion resistance and the durability of the product.

"We are confident the installation resulted in a good 50-year pipe," said John Turner, P.E .of Boyle Engineering Corporation of Ventura, Calif., design engineer for the pipeline.

Tough Canyon Installation

Although the contractor, ASI Civil of Carlsbad, Calif., had many options to choose from, they utilized Hobas because of the handling and workability advantages that would make it easier to install in the constraints of the canyon. It did not require add-on linings and coatings, which could be damaged. The pipe was easily joined with push together joints eliminating the need for on-site heat fusion that would be necessary for the solid wall polyethylene pipe.

Custom Fittings/Testing

The complex installation included many factory-made mitered elbows and several bends that the contractor accomplished in the field by offsetting joints. Hobas provided custom elbows to meet the specific project criteria. Short pipe segments were also utilized to maneuver radius curves. As the project progressed, each reach was pressure tested by surcharging the line and no problems were found. The project was completed and is in service.