Title: Condition Evaluation and Monitoring for Management of Post-tensioned Segmental Concrete Bridges

Author(s): Michael Brown

Publication: Web Session

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Date: 10/25/2020

Abstract:
The Varina-Enon Bridge, southeast of Richmond, VA, opened to traffic in July 1990 and carries Route I-295 over the James River between Chesterfield and Henrico Counties. The 4,686 feet long bridge consists of two parallel approach structures and a single 7-span cable-stayed structure supported by pylons at Piers 16 and 17. The 1,530-feet long main span unit, comprised of a 630-feet center span flanked on each side by three 150-feet spans, provides a navigation channel of 145 feet vertical clearance and 300 feet horizontal clearance. The single main span structural unit comprises two single-cell precast post-tensioned box girders connected with a median precast delta frame to which a single plane of grouted stay cables is anchored, which pass through the pylons for support. The post-tensioned box girder approach superstructures rest on post-tensioned segmental piers on concrete footings and prestressed concrete piles. WSP USA recently completed a series of tasks to investigation condition, develop repair plans, and preserve the structure. Focus areas ranged from concrete footings to longitudinal, transverse and vertical post-tensioning systems, pylon strengthening, cable stay maintenance, load rating and structural monitoring. Existing information was compiled to develop a management plan to achieve a target 100-year service life.