Intricacies and Unique Detailing of External Pipe Repairs Using GFRP

In 2020, a water treatment plant, which supplies drinking water to two municipalities in the Dallas metropolitan area, experienced issues with a degrading 48-in. (1.2 m) diameter centrifugally spun reinforced concrete pipe. The pipeline location, at the bottom of a 13-ft-deep (3.96 m) pipe trench in the plant’s high service pump station and beneath two other large diameter pipes in this trench, made it nearly impossible to perform a “remove-and-replace” repair. Thus, an external repair using a unidirectional glass fiber reinforced polymer (GFRP) became the most economical solution. This allowed for continued use of this 70-year-old asset by providing structural reinforcement around several lateral connections (to high service pumps) and a 48-in. (1.2 m) diameter tee. The project was completed within two weeks, leading to high savings for the client. However, the external repairs presented their own unique set of challenges. Elements such as steel saddles, flanges, and crotch plates created obstructions. As a result, special detailing was required to address these existing conditions while maintaining the structural integrity of the GFRP repairs.