Structure Movement Systems Approach to Effective Bridge Design

To achieve more effective designs for small- and medium-size highway bridges, bridge designers are urged to view such bridges holistically as structure movement systems instead of elementalistically as a collection of relatively independent structural elements to be shaped and sized to meet only stress, strength, and durability requirements. A number of design examples in which such holistic views were not in evidence and in which movement system components were not recognized as such are presented. Consequently, for these and similar examples, component designs were ineffective and damage- and maintenance-prone structures were the result. It is explicitly recognized that small- and medium-size highway bridges, especially integral and semi-integral bridges, achieve their primary vertical support and longitudinal and lateral stability by being constructed compositely with and functioning in concert with in situ foundation materials, embankments, backfill, pavements, and so forth. Because of the critical importance of such construction, transportation engineers are also urged to recognize that bridges are major components of larger composite structures requiring a multidisciplinary effort to achieve satisfactory designs. Consequently, bridge engineers should cooperate with other transportation engineering specialists to devise and provide more fully effective movement system components, and thus more functional movement systems and more economical and durable structures.