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Structural Engineering Feasibility Study Design

Replacement, Rehabilitation, and Improvements to Water Mains Crossing the Garden State Parkway

East Orange, New Jersey

The city of East Orange is bisected by the Garden State Parkway, which is constructed below street level of the city. Water is supplied to the eastern part of the city via 15 mains suspended from nine bridges crossing the Parkway. The Water Commission of East Orange owns and operates the mains. Due to the heavy traffic on the Parkway and the Turnpike Authority’s bur-densome requirements for traffic control measures, the Commission de-ferred a rigorous preventative maintenance program out of economic con-cern for its customers. Exposure to the elements has caused the mains to deteriorate. Support hangers, insulation materials, and exposed pipes are heavily corroded, creating potential hazards to motorists of falling debris and water leakage. Five mains were taken out of service to minimize these risks, however, the resulting reduced transmission capacity compromised the reliability of the system and increased its vulnerability during firefight-ing. In addition, corroded pipes degrade water quality and may expose customers to health risks. Birdsall Services Group (BSG) conducted a structural inspection and hy-draulic evaluation of all mains, and concluded that the majority of the pipe-lines present a potential hazard to traffic and jeopardize eastern East Orange’s water supply. Based on the findings, BSG has developed a reha-bilitation program for the affected mains, combining main replacements, and structural repairs to support brackets and replacement of insulation material. The budgetary estimate has been determined to be $1.96 million. About one-third of the cost is associated with traffic control measures to secure access to the mains. The Commission has adopted BSG’s recommendation to replace the mains at an incremental cost of $370,000, per year, which will provide the Com-mission with the infrastructure to safely provide water to its customers.