Since 2004, the City of Phoenix has initiated a Sanitary Sewer Relief Program (SSRP) to systematically address sanitary sewer mains that exceed capacity during peak wet weather flows. Dibble has participated in each phase of this program, completing 13 design projects using traditional open cut and trenchless technologies under all delivery methods. Engineering services for these projects include field survey; data research and collection; basis of design report; grade and alignment plans; preliminary, pre-final, and final construction documents; engineer's opinion of probable construction cost, technical special provisions; project management; and GMP analysis/negotiations.
Dibble performed a condition assessment and design for rehabilitating specific areas within City of Phoenix sanitary sewer system. The areas are located on 23rd, 24th, and 7th Avenues and Osborn Road with a total length of 4.5 miles. A detailed condition assessment of 57 manholes/structures and sanitary sewer pipe, ranging from 54- to 24-inch diameter, was performed utilizing closed-circuit television (CCTV) and field inspections. Information collected from the assessments was incorporated into the design and specifications that were tailored for cured-in-place pipe (CIPP) rehabilitation.
Dibble developed technical specifications and design drawings and provided quality control inspection for the rehabilitation of a potable water pipe under I-17. The existing steel pipe was leaking under I-17 causing concern for major traffic disruption and impacts if the pipe were to rupture. The design called for a structural upgrade to the aged 12-inch diameter potable water main with no disruption to commuter traffic and minimal impacts to the surrounding neighborhood. Following installation, the pipe and liner were pressure tested to 200 psi with zero leakage. The City's proactive approach to system rehabilitation potentially saved millions of dollars of taxpayer monies that would have been expended to repair a water main break under a critical transportation corridor.