The flexural behavior of horizontally curved steel I-girder bridge systems and single-girders

• The flexural behavior of curved I-girders in multi-girder bridges is evaluated.
• Behavioral response of multi-girder models is compared against single girders.
• Single girder models cannot predict the elastic vertical and lateral deflections.
• Flexural strength, plasticity and failure mode of single and multi-girders match.

The structural system of a horizontally curved steel I-girder bridge consists of a number of curved girders that are laterally braced by interconnected cross-frames. The modeling and nonlinear analysis procedures of large and complex systems of curved bridges are time consuming and demand a high computational cost. In order to facilitate the preliminary design procedures, it is suggested that the complicated bridge system might be replaced by simple single curved I-girders. In this paper, the applicability of single-girder models in determining the flexural response, elastic stiffness and the ultimate strength of curved bridge girders is examined. In addition, a series of finite element parametric studies is conducted to consider the effect of curvature on the accuracy of single-girder models. It is observed that the spread of plasticity, flexural strength and failure mechanism of bridge girders can be well predicted by the use of equivalent single-girder models. Yet, single-girder models cannot accurately predict the elastic stiffness and vertical and lateral and deflections of horizontally curved steel bridge girders.