Relief Sewer Project Wins Award

February 2010 Vol. 65 No. 2

Project Engineering Consultants (PEC), Phoenix, AZ, won an Engineering Excellence Award for the city of Phoenix Water Services Department 2005 Relief Sewer Project, constructed at 35th Avenue and Peoria Avenue.

The firm was recognized for its use of trenchless technology to install upsized relief sewers at the 29th Annual Engineering Excellence Awards Gala held by the American Council of Engineering Companies (ACEC) of Arizona, Oct. 24, 2009.

PEC chose static pipe bursting to install No-Dig vitrified clay pipe (VCP), an inert product with a life expectancy of more than 100 years. The pipe bursting benefits included a shortened construction schedule, reduced social-economic impact, less disruption to traffic and reduced carbon emissions. The static pipe bursting installation was the first in the United States to accomplish a maximum drive of 448 feet using VCP and the first to perform a double upsize pipe burst with VCP. Kiewitt Construction was the contractor for this project and the Grundoburst 2500G manufactured by TT Technologies, was used on site.

The final plans and specification using static pipe bursting resulted in a GMP of $5.3 million and decreased the construction schedule from 12 months to nine months. The initial cost saving to the city was more than $2 million over traditional open-cut construction.

Population growth that taxed Phoenix’s collection system prompted the city to develop the Sanitary Sewer Relief and Replacement Program to tackle these issues. Full pipe replacement and upsizing, diversions and other techniques were considered as solutions to this potential capacity deficiency. The use of trenchless technologies was determined to be a suitable alternative approach to minimize the impact created by all of these construction projects. Pipe bursting was chosen to fulfill the need for upsizing these capacity deficient pipes without open trenching their streets.

Project details

The total project consisted of upsizing of nearly 6,400 linear feet of 12- and 15-inch pipe with a 10- to 20-foot depth within major streets with the usual multitude of utilities. Trenchless equipment manufacturer TT Technologies, Aurora, IL, provided the Grundoburst static pipe bursting equipment and technical instruction during the design and construction phases. Mission Clay Products, Corona, CA, supplied the 15- and 18-inch No-Dig VCP, which the city preferred.