ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.
Issue link: http://www.aspiremagazinebyengineers.com/i/306864
Creating effective noise and visual barriers to light-rail train (LRT) traffic, while providing pleasing aesthetics that don't disrupt the community's ambience, pose significant challenges for urban planners. The recent precast concrete structure over South Watt Avenue in Sacramento, Calif., provides an example of how these challenges can be met with an innovative "trough" cross section. The five-span, 540-ft-long project resulted from the South Watt Area Tr a n s p o r t a t i o n S t u d y ( S W AT S ) , w h i c h e v a l u a t e d t h e e n t i re Wa t t Avenue corridor. The SWATS study produced a list of short- and long- term upgrades necessary to improve safety and efficiency for the corridor's transportation system. Among these changes were modifications to create a grade separation between two light- rail tracks and highway vehicles at the South Watt/Folsom Blvd. intersection. It is located just to the south of, and parallel to, Folsom Boulevard, with a parking area for the Manlove Light Rail Station in the intersection's southeast corner. In addition, a freight railroad line runs parallel with the LRT tracks and Folsom Boulevard. To accommodate the long-term plan for the Watt Avenue Corridor, the structure also had to accommodate a future grade separation between South Watt Avenue and Folsom Boulevard. As a result, the substructure was designed to allow South Watt Avenue to be lowered by up to 20 ft. The grade-separation structure features a "trough" cross section, consisting of three precast, prestressed concrete girders spanning in the longitudinal direction, and precast, prestressed concrete slabs spanning between adjacent girders in the transverse direction. After erection, the deck-slab panels were joined through longitudinal post-tensioning. Their integration into the superstructure was completed by post-tensioning with transverse profile SOUTH WATT AVENUE LIGHT-RAIL BRIDGE / SACRAMENTO, CALIFORNIA E NgINEEr: AECOM, Sacramento, Calif. PrIME CoNTrACTor: Viking Construction, Rancho Cordova, Calif. BrIDgE DESCrIPTIoN: A five-span, 540-ft-long light-rail bridge that features a "trough" cross section consisting of three precast, prestressed concrete girders spanning in the longitudinal direction, and precast, prestressed concrete slabs spanning between adjacent girders in the transverse direction. by Thomas R. Barnard and Ahmad M. Abdel-Karim, AECOM Precast 'Super-Girders' Aid Light Rail Three-girder 'trough' cross section spans longitudinally while concrete slabs span transversely between girders The five-span, 540-ft-long light-rail train project over South Watt Avenue in Sacrament, Calif., features an innovative "trough" cross section of through-girders that reduced construction time, improved aesthetics, and limited road closures. All Photos and Drawing: AECOM. 32 | ASPIRE , Summer 2010 ASP10-1625.indb 32 6/21/10 12:20 PM