November 09, 2015
T.Y. Lin International Wins Three 2015 Bridge Awards of Excellence from American Segmental Bridge Institute
T.Y. Lin International (TYLI), a globally recognized full-service infrastructure consulting firm, announces that three of the firm’s projects have won a 2015 Bridge Award of Excellence from the American Segmental Bridge Institute (ASBI). The award-winning projects include Tilikum Crossing, Bridge of the People, in Portland, Oregon, for Long Span and Cable Stayed Bridges (spans of 400’ or greater), the Caijia Rail Transit Bridge in Chongqing, China, for Mass Transit/Rail Bridges, and the San Francisco-Oakland Bay Bridge New East Span Skyway for Long Span and Cable Stayed Bridges (spans of 400’ or greater).
The biennial ASBI Bridge Awards of Excellence serve to recognize the Owners of bridges that exemplify concrete segmental bridge design and construction excellence. TYLI accepted the awards with its project partners at the ASBI 27th Annual Convention in Dallas, Texas, on November 2, 2015.
About Tilikum Crossing, Bridge of the People
TYLI served as the Engineer of Record for the 1,720-foot-long Tilikum Crossing, Bridge of the People (Tilikum Crossing) in Portland, Oregon. Tilikum Crossing is the largest transit-only bridge in the United States, built to carry only light rail, buses, cyclists, pedestrians, and eventually streetcars, but no private vehicles. Designed to accommodate the multimodal transportation needs of the Tri-County Metropolitan Transportation District of Oregon, the new bridge is a vital component of the Portland-Milwaukie Light Rail Transit Project.
Tilikum Crossing is a hybrid between a traditional cable-stayed layout and an extradosed bridge, with two distinctive, 180-foot-tall stay-cable towers and two landside piers. The bridge deck consists of 78 segments and was built using classical cantilever form travelers, one on each side of the tower, in alternating sections to balance the structure. An innovative temporary stay cable system, anchored at the pylon top to a temporary match cast precast stressing frame, provided leading-edge support of every other superstructure segment. Cantilevers at both pylons were built concurrently to meet the accelerated schedule.
TYLI engineers also introduced numerous value engineering concepts, including optimizing the foundation system by reducing the number and size of drilled shafts and providing a cost-effective, alternative structural solution that removed the need to stabilize contaminated soil on the west approach. The design-build project had an aggressive schedule that called for work to begin in the river only five months after notice-to-proceed. Tilikum Crossing is the first cable-stayed bridge built in Portland and opened on September 12, 2015.
ASBI Jury Comments included: “Great example of the competitiveness of segmental bridges in a design-build environment. Showcases how a segmental solution can provide both strength and slenderness for long-span cable supported bridges. This bridge is outstanding in so many ways. The design-build team finessed every detail in producing a great technical achievement with iconic aesthetics.”
About the Caijia Rail Transit Bridge
Designed by TYLI, the Caijia Rail Transit Bridge (Caijia Bridge) carries two mass transit rail tracks across the Jialing River in Chongqing, China. The 4,034-foot-long crossing is considered the highest metro line bridge in the world at about 328 feet above water level. Because the bridge is located in a district that is one of Chongqing’s most scenic, design aesthetics were of significant importance.
TYLI’s cable-stayed design for the Caijia Bridge meets stringent Chinese rail specifications and offers the advantages of both a visually-appealing profile, with two diamond-shaped towers that stand 610 feet from the top of the pile cap, and the appropriate deflection control. The bridge design also had to match the 820-foot main span length of two nearby bridges and accommodate substantial variances in river height and width, as water levels at this location can rise nearly 100 feet during flood seasons.
The box girder in the cable-stayed portion of the bridge was constructed segmentally using form travelers, with four form travelers utilized to expedite construction and segment length matching the approximately 26-foot cable spacing. After each segment was completed, a cable pair was installed, one cable on each side of the deck. The box girder was prestressed longitudinally and transversely, and the slab atop the girder was prestressed transversely. The side and approach spans were constructed using a self-advancing underslung truss. To facilitate the advance of the truss, the middle portion of each pier top was hollowed out, and the box girder was then cast on top of the truss.
Built for the Chongqing Rail Transit Group, the Caijia Bridge opened to rail traffic on December 30, 2013 and is contributing significantly to the development of northwestern Chongqing.
ASBI Jury Comments included: “Challenging design requirements for limited live load deflections were met by combining segmental with cable-stayed technology, demonstrating how a segmental bridge solution addressed the unique demands for a heavy rail bridge structure. In addition to outstanding aesthetics, the engineering team should be commended for the rigor required to analyze and design this cable stayed bridge built using cast-in-place balanced cantilever construction.”
About the San Francisco-Oakland Bay Bridge New East Span Skyway
TYLI, in a joint venture with Moffatt & Nichol, led the design of the new 2.2-mile-long San Francisco-Oakland Bay Bridge New East Span (East Span) in San Francisco, California. The signature bridge includes the iconic, single-tower Self-Anchored Suspension Span (SAS) and the sweeping parallel decks of the 1.2-mile-long Skyway, which comprises the longest portion of the East Span and ascends from the Oakland shoreline to connect with the SAS.
The twin viaducts of the Skyway carry 10 traffic lanes (five eastbound, five westbound) and a bicycle-pedestrian path, and are precast segmental bridges, erected in balanced cantilever, with a typical span of 525 feet. The 452 concrete segments used to construct 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 (SLEDs) were used to lift and post-tension the segments in place on the cantilevers.
The East Span project, which was led by the California Department of Transportation, working in conjunction with the Metropolitan Transportation Commission and the California Transportation Commission, represents the largest public works project in State of California history.
ASBI Jury Comments included: “Truly a landmark structure that is sleek, yet robust, and establishes a new gold standard in seismic performance for lifeline structures. Massive precast segments, long spans, and durable post-tensioned concrete all within the most severe of seismic environments-absolutely impressive.”