Tucson Boulevard Diversion Structure FRP Replacement


The Pima County Regional Wastewater Reclamation Department (RWRD) owns and operates a sanitary sewer diversion structure located at the intersection of the Roger Road alignment and Tucson Boulevard. The existing diversion structure produced excessive amounts of hydrogen sulfide (H2S) gas due to highly turbulent flow within a confined space. This gas was corrosive to materials within and near the structure, including concrete, steel, and cast iron. In addition, RWRD wanted the ability to divert flows as needed.

Diversion structure prior to FRP rehabilitation

Dibble designed a diversion structure and new pipeline segments to mitigate slope issues and to connect to the new diversion structure and 10 new manholes. The design included fiber reinforced polymer (FRP) specified at the connection points between the existing sewer pipeline and new sewer pipeline connections.

Diversion structure during FRP rehabilitation

The FRP used at the connection point strengthens and protects the system and provides a good seal at the pipe joints. FRP’s corrosion-resistant properties will provide a long-lasting connection in the sewer system. The internal application of the FRP at the connection points does not reduce the inner pipe diameter and therefore does not change the flow volume of the pipe.

Dibble provided construction administration and special inspection services during the FRP installation.

Diversion structure after FRP rehabilitation


Pima County RWRD

Tucson, AZ

$247K (design and CA&I)

Construction Cost

Project Lifecycle