T.Y. Lin International (TYLI), a globally recognized full-service infrastructure consulting firm, announces that the Skyway, the longest portion of the San Francisco-Oakland Bay Bridge New East Span (East Span), has won the 2015 Project of the Year Award from the Post-Tensioning Institute (PTI). This highly-prized award is given every two years to a single project that demonstrates excellence in post-tensioning applications and stands out above all other entries in every category. TYLI, in a joint venture with Moffatt & Nichol, was the Engineer of Record for the Skyway project. The 2015 Project of the Year Award was presented to TYLI and its project partners at the PTI Project Awards Dinner on Monday, April 27th in Houston, Texas.
The seismically-resilient, 1.2-mile-long Skyway, with its sweeping twin viaducts, carries a total of 10 lanes of traffic in both directions, as well as a new bicycle/pedestrian path. The 452 concrete segments that comprise the Skyway decks are the largest of their kind ever cast, each weighing as much as 750 tons. Fabricated at a specialized casting yard in Stockton, California, the segments were transported by barge 70 miles to the project site, where Self-Launching Erection Devices were used to lift and post-tension the segments in place on the cantilevers.
PTI judging criteria included creativity, innovation, ingenuity, cost-effectiveness, functionality, constructability, and aesthetics. Judges’ comments included calling the Skyway “…a perfect 10 – truly an engineering feat when you take into account how heavy each segment is.” The structure was also described as exemplifying innovation in design and constructability, and “using construction materials and post-tensioning to their fullest in a (high) seismic zone.”
The Skyway was the first portion of the new East Span to be built. High-performance, low-permeability 8000 psi concrete was used throughout the superstructure, which is post-tensioned longitudinally, transversely, and vertically to minimize concrete cracking. TYLI’s design for the parallel viaducts also includes 60-foot-long hinge pipe beams and specially-designed expansion joints that absorb seismic energy and ensure that the bridge can open to emergency traffic shortly after the largest anticipated earthquake.
“T.Y. Lin International’s design of the Skyway features tremendous innovations in post-tensioning technology, seismic design, and segmental bridge engineering,” said Sajid Abbas, Ph.D., P.E., TYLI Vice President and Lead Design Engineer for the Skyway Project. “It is an honor to have our work recognized with the prestigious 2015 Post-Tensioning Institute Project of the Year Award.”