Design Challenges and Sustainability Provisions for the Paradise Whitney Interceptor

The Paradise Whitney interceptor project for the Clark County Water Reclamation District will relieve capacity deficiencies for the existing sewer interceptors and provide capacity for the future. The whole PWI project was divided into three packages. The subject of this paper will discuss design challenges and sustainability provisions for Project 669 (Package 2) portion of the project, the first package out to bid. Project No. 669 includes construction of approximately 27,138 linear feet of new sanitary sewer interceptor utilizing trenchless methods for eight reaches totaling 13,964 linear feet and open cut methods for 13,174 linear feet. The gravity sewer ranges in inside diameter from 66- to 84-in., some with 76-in. steel casing. The project presented numerous design challenges including community and business impacts, complicated geology, close proximity to existing underground utilities, limited surface access, and other factors forcing trenchless drive lengths up to 1,500 ft. The tunnels were constructed utilizing trenchless methods that included earth pressure balance machines and micro-tunnel machines; ground improvement was required on many of the drives. Construction of this project began in late 2014 and is expected to be complete in 2016 with a total construction budget of $62.3 M. Sustainability provisions included fiberglass reinforced pipe (FRP) and polymer concrete manholes.