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/395356
PROJECT U.S. ROUTE 460 PHASE I CONNECTOR Over Grassy Creek & Route 610 Durable and cost-effective cast-in-place segmental design-build project in Virginia by Leo Spaans, Janssen & Spaans Engineering Inc. Located in western Virginia near the state line with Kentucky, the U.S. Route 460 Phase I Connector over Grassy Creek and Route 610 in Buchanan County spans a deep valley. Due to the need for such tall, flexible columns, geometry control for the superstructure became quite challenging. This article describes the project and further explains how critical geometry control for both the substructure and superstructure was maintained. DESCRIPTION OF PROJECT The project consists of twin, castin-place, segmental concrete superstructures with one prestressed concrete I-beam approach span at each end. The total length of the structure is 1725 ft. Span lengths for spans 1 through 6 are 110, 268.5, 489, 489, 268.5, and 103 ft. The pier heights measured from the bottom of the footing to the top of the superstructure for piers 1 through 5 are 109.5, 227, 261.5, 158.75, and 72.5 ft. Piers 1 and 5, which support the prestressed concrete I-beam spans and the end spans of the cast-inplace segmental structure, are a more common pier type. This type consists of a concrete footing supported by either micro-pile or directly founded on rocks (spread footing). The column consists of two circular columns that are 6 ft in diameter with a 42-ft-wide cap. Piers 2 through 4 have a spread footing founded on rock, with an H-shaped column integrally connected to the castin-place concrete superstructure. COST-EFFECTIVE SOLUTION Since the project used a design-build contract, it provided the designer with unique opportunities; it allowed the designer to evaluate the different options, such as the best solution for the project based on the capabilities of the specific contractor with which the designer is working. With contractor’s team input, the design options/ alternatives were directly evaluated for cost effectiveness as well as utilizing the contractor’s experience and capabilities. PROFILE U.S. ROUTE 460 PHASE I CONNECTOR OVER GRASSY CREEK AND ROUTE 610 Buchanan County, VA COMMONWEALTH OF VIRGINIA DEPARTMENT OF TRANSPORTATION, OWNER BRIDGE DESIGN AND CONSTRUCTION ENGINEER: Janssen & Spaans Engineering Inc., Indianapolis, Ind. INDEPENDENT QUALITY CONTROL: Entran PLC, Lexington, Ky. PRIME CONTRACTOR: Bizzack, Lexington, Ky./CJ Mahan, Columbus, Ohio PRECASTER: Prestress Services Industries Inc., Melbourne, Ky.—a PCI-certified producer POST-TENSIONING CONTRACTOR & FORM TRAVELER: VSL, Dallas, Tex. EXPANSION JOINT & BEARING SUPPLIER: D.S. Brown, North Baltimore, Ohio OTHER SUPPLIERS: MMFX, Irvine, Calif. BRIDGE DESCRIPTION: Twin, 1725-ft-long, post-tensioned, cast-in-place, segmental box girder bridge STRUCTURAL COMPONENTS: Each bridge consists of five cast-in-place concrete pier columns supporting four spans of cast-in-place single-cell box girder and two spans of precast, prestressed concrete I-beams BRIDGE CONSTRUCTION COST: $47 million ($314/ft²) AWARDS: Roads & Bridges magazine Top Ten Bridges, Number 1