Building Better Bridges: Concrete Vs. Steel

The authors debate the merits of concrete segmental and steel bridge design and construction based on five criteria: initial and life-cycle costs; structural advantages; durability; construction advantages; and aesthetic and environmental issues. With a 20-year track record now in place, concrete segmental bridges may be on the way to shedding the label of new technology. According to data from National Bridge Inventory (compield by the Federal Highway Administration), prestressed concrete became the most widely used U.S. bridge material in the mid-1970s. FHWA statistics for 1990 indicate that $532 million was authorized for 414 new prestressed concrete bridges, compared with $397 million for 309 new steel bridges. After 100 years of construction, steel continues to be a tried-and-true material for bridges. Produced under tightly controlled mill conditions, steel is homogeneous and predictable in behavior. And in the coming years, steel bridges should be even more cost-effective through the use of weathering steel, high-performance paint systems and improved design.