Arecibo to San Juan, Puerto Rico

North Coast Superaqueduct


The 72 in. dia. North Coast Superaqueduct carries water 70 km from Arecibo to San Juan. Just after construction, the aqueduct experienced failure of two pipe segments during a transient pressure event caused by sudden closure of a valve. SGH investigated the cause of failure and assessed the condition of the entire pipeline.

Highlights of our work on this project include the following:

  • Performed a condition assessment that included internal and external pipeline inspection, hydrostatic testing, wire strain test, mechanical testing of wires, tests of hydrogen content in wire, and soil corrosivity testing
  • Performed hydraulic and structural analyses
  • Conducted mechanical, metallurgical, chemical, and petrographic testing of pipe constituent components
  • Conducted chemical analysis of soil and groundwater
  • Discovered pipes with low prestress level in the wire and performed tear-down inspection of low prestress pipe
  • Determined failure to be result of the transient pressure event caused by sudden closure of a valve due to improper setting of the valve closure timing and inadequate prestress in manufactured pipe caused by breakage of wires during winding operations
  • Designed repairs that consisted of post-tensioning the low prestress pipes with strands and applying a shotcrete coating on the post-tensioned pipe

Project Summary



Completion Date
Failure Investigation
Structures | Advanced Analysis | Applied Science & Research
Infrastructure & Transportation
Dick Corporation
Specialized Capabilities
Repair & Strengthening | Buried Infrastructure | Failure Analysis | Materials Science

Key team members

Rasko Ojdrovic
Rasko Ojdrovic
Senior Principal
Mehdi Zarghamee
Mehdi Zarghamee
Senior Principal