City of San José Uses Creativity to Keep a Critical Link from Becoming a "Missing Link"

In the late 1970s, the City of San José converted the former Alviso Sewer Treatment Plant into a transmission pump station, known as Spreckles Pump Station, conveying approximately 1 MGD of wastewater from Alviso through 6,900 linear ft of a 10-in. AC force main to the regional wastewater facility. Since the 1970s, no significant improvements were performed to the mechanical and electrical systems at the Spreckles Pump Station. Concurrently, the 10-in. AC force main had experienced pipe ruptures due to the age and pipe material type. Due to its close proximity to an environmentally sensitive habitat, the City initiated a project to upgrade the pump station and install a supplemental force main. The paper evaluates multiple design and construction methodologies for the force main based on site-specific conditions. Also, the implementation of an alternate bid approach for trenchless technologies helped control construction costs and reduced permit requirements and project schedule by 1-2 years. A performance-based approach was utilized to help select qualified trenchless contractors during the bidding process. Other project challenges included potential presence of asbestos; pipe material, special trench details; design of access manholes; value engineering of trenchless shafts; and construction sequencing to maintain sanitary service during construction.