A large number of our nation's bridges have reached the age where serious deterioration requires replacement of the roadway deck. Where first cost is the determining factor, replacement in kind—usually reinforced concrete—is the normally accepted method. However, where life cycle costs are considered, or where availability of traffic capacity during commuting hours is important, orthotropic steel deck construction offers a practical solution. Orthotropic deck construction consists of a steel plate stiffened by single web (open) or double web (closed) ribs and paved—usually prior to installation—with a layer of asphalt. In a typical application, a section of the old deck is cut and removed during low-density traffic hours and immediately replaced by a modular section of new orthotropic deck. As soon as this section is connected to the supporting framework, it can be opened to traffic without restrictions. Several such decks have been installed recently on major bridge structures, similar in principle but quite different in details and execution.