The Challenge

The project had to improve the drainage facilities that remove storm runoff from the nearby cross streets of Greenway, Thunderbird, Cactus, and Peoria, assisting in reducing the potential for flooding at Interstate 17. In place was a 1960s pump station that did not provide adequate drainage for cross streets. Before starting, the team, which included the Arizona Department of Transportation, local consulting engineers, subcontractors, and Rinker Materials, evaluated conditions on the project by assessing soil conditions, engineering analysis, stabilization measures, casing design, jack and bore options with reinforced concrete pipe, bury depth considerations, quality control, regulatory concerns, and contingency plans.

The Solution

The team reviewed and addressed the I-17 challenges of collecting stormwater from surrounding cross streets and discharging the stormwater into the Arizona Canal Diversion Channel (ACDC) using Rinker Material’s rubber gasketed reinforced concrete pipe. The new system greatly simplified the old mechanical drainage system into an easily maintainable gravity fed conveyance system.

The two locations required a trenchless installation of reinforced concrete pipe (RCP) through steel casing crossing under Interstate 17. Sizes ranged from 15″ to 90″.  Once the steel casing was jacked into place and the hand tunneling excavation method was used to combat the unstable silty sand soil conditions and deep bury depths of 30ft. The boring contractor pulled each piece of RCP from a receiving pit using a winch and a plate to help distribute pulling force across the entire face of the pipe. The RCP joints were placed on a guide rail secured on the inside of the steel casing rather than pushing through the steel casing. By using the trenchless method contractors were able to install the new drainage upgrades without rerouting or shutting down I-17 traffic.

The newly installed I-17 frontage road drainage system now safely carries away stormwater from major routes, providing safe passage for motorists. By choosing RCP, owners can know that the new system will be resilient and durable, lasting for decades to come with a proven service life of 100+ years.