Pipe and site constraints work against plan A

摘要

Concern about the inferior Class Ⅳ wires that were used in the City of Baltimore's prestressed concrete cylinder pipeline in the Southwest Diversion led the engineering staff to call f°r support. A combination of risk-assessment and closed-circuit television studies confirmed that 2.7 km (1.7 mi) of the gravity sections were at risk for failure due to interior corrosion.