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/740919
PERSPECTIVE Introducing New Ideas to an Aging Bridge Inventory Implementing best practices to extend and maximize service life by Rex L. Pearce, Virginia Department of Transportation A sustainable, effective response to an aging bridge inventory is one of the greatest challenges facing departments of transportation today. Paramount are the Interstate corridors—crucial to travel, commerce, and defense—which rely on bridges that have reached design life spans. Absent the fiscal resources to support a replacement program of this magnitude, bridge maintenance, preservation, and service-life extension are critical. The Virginia Department of Transportation maintains 21,000 bridges and large culverts throughout nine regional districts. The Staunton District Bridge Section is responsible for 3500 structures: approximately 2200 bridges (45% concrete) and 1300 culverts (85% concrete). Building on a history of innovation and preservation, nearly 95% of Staunton District’s bridge inventory is not classified as structurally deficient. Know Your Bridge Inventory A current and comprehensive inventory assessment is the basis of an effective bridge maintenance program. With our good fortune of operating in a datarich era, utilizing this valuable asset to the utmost is sound logic. Trends of structure aging, conditions, materials, techniques, successes—all are there to improve program maintenance and preservation efforts as well as future implementations. Asset query software developed in Staunton District affords extensive condition and element level evaluation. A typical assessment is the recent Bridge Maintenance Study implemented for the three Interstate corridors within the Staunton District. This study produced a cost valuation of district Interstate bridges, latest condition trends by materials and components, and a prioritization of future maintenance efforts. Bridge Deck Preservation Overlays A sound bridge deck is not only paramount to the safety of the traveling public, it is essential in minimizing deterioration to superstructure and substructure components. Staunton District administers several ongoing preventive-maintenance contracts: maintenance and repair, shotcrete and self-consolidating concrete (SCC), component sealing, bridge washing, and culvert lining. In the 1980s, Interstate bridge decks began to exhibit deterioration due to chloride contamination. The district set out to overlay all Interstate corridor decks, which was accomplished by 2000. To offset the permeable concretes used in earlier eras that allowed greater chloride penetration, epoxy overlays were applied to sound decks; milling followed by latex-modified concrete rigid overlays restored the more weathered traveling surfaces. In the 1990s, silica-fume-concrete rigid overlays were added as a more cos teffective material. In the 2000s, Virginia bridge decks began to be constructed with low-permeability concretes, which are considered substantially more chloride resistant. Jointless Bridges In the 1970s, Staunton District began using continuity as the preference