Title: Prestressed Concrete Pipe Repair

Author(s): John R. Thurston and Thomas C. Fisher

Publication: Symposium Paper

Volume: 128

Issue:

Appears on pages(s): 151-160

Keywords: backfilling; concrete pipes; corrosion; finite element method; pipelines; prestressing steels; repairs; shotcrete; Construction

DOI: 10.14359/3370

Date: 11/1/1991

Abstract:
This paper describes repairs on two prestressed concrete pipelines (inverted siphons) that were found to have distressed areas. The distressed areas included disbonded mortar coating, and corroded and broken prestressing wires. The siphons were dewatered, during January and part of February 1991, for repairs and inside inspection. Repairs in areas of major corrosion and broken prestressed wires consisted of removing the earth cover, excavating a limited-length trench under a pipe unit, and completely removing the mortar coating and prestressing wire around the pipe for 360 deg. High-strength steel tendons were placed around the pipe and stressed to the initial prestressing force. Shotcrete was placed over the tendons and anchors, followed by backfilling. The two siphons were returned to service on Feb. 15, 1991. The repairs appear to be successful in restoring the concrete pipe to its initial design strength.