Honorable Mention: Transportation Category
JTA Skyway Double Tee Beams Restoration
Submitted by Sika Corporation
Jacksonville Transportation Authority
Parametrix Engineering, Inc.
Structural Preservation Systems, Inc.
Jacksonville Beach, Florida
The Jacksonville Transit Authority (JTA) Skyway is a 2.5 mile elevated automated people mover system that serves downtown Jacksonville, Florida. It is a major part of the master plan for the downtown area, while alleviating a growing parking and congestion problem in the city. The Skyway was built in phases for a total cost of $184 million. Starter Line service began in 1988 with full system implementation completed in November 2000. The system is completely computerized ensuring that the trains operate smoothly on the elevated tracks.
A little more than a year after the last segment of the Skyway was completed, engineers noticed the presence of numerous hairline cracks in the precast concrete guideway beams that support the monorail track. After further analysis, it was determined that excessive debonding of the prestressing tendons caused the cracks. A cause for concern, it posed no immediate danger to the Skyway. Nevertheless, some temporary supports were installed while a determination was made on how to repair these cracks. At no time was service interrupted on the system. A total of 63 beams ends were affected, which makes up approximately thirteen percent of the 500 concrete beams in the Skyway.
After careful consideration, the engineers considered five different repair scenarios. A ranking system was established, rating the possible repair techniques by criteria such as durability, maintenance, aesthetics and cost. Ultimately, the solution chosen was a carbon fiber reinforced polymer, externally bonded onto the ends of the deficient beams, that would compensate the strength lost due to the debonded strands.