SEMI-INTEGRAL BRIDGES: MOVEMENTS AND FORCES

For six decades the state of Ohio has been building continuous concrete slab bridges with flexible integral abutments. For three decades it has been building continuous steel beam and girder bridges with flexible integral abutments. Although this type of construction is now routine in Ohio for most bridges, there were a number of exceptions for such applications. For example, bridges skewed greater than 30 degrees, continuous bridges longer than 300 ft (91.4 m), and bridges with abutments on rigid foundations were routinely provided with movable deck joints at abutments. More recently, however, Ohio has conceived and is developing a semi-integral abutment concept that has enabled it to extend the application range of bridges with jointless decks to most bridges--even to those applications with exceptional characteristics. This semi-integral abutment concept is also now being used to retrofit existing end-jointed continuous bridges. Ohio's concept for semi-integral bridges is described, and a number of the peculiarities that should be recognized and provided for are discussed. Properly designed and constructed, this semi-integral bridge concept should extend the application range of bridges with jointless decks to most applications--even to those not normally associated with integral types of construction.