EFFECTIVE BRACING FOR STEEL I-GIRDER AND TUB GIRDER SYSTEMS
Todd A. Helwig 1
1 The University of Texas at Austin, Austin, Texas, USA
Steel I-girder and tub girders are commonly used in both straight and horizontally curved geometries There are a number of unique geometrical configurations that complicate the behavior of the girders and the bracing systems both during construction and in-service. While bracing exists in many different forms, frequently used systems include cross frames, diaphragms, and top lateral trusses. The role of the bracing includes providing stability as well as increasing the torsional or flexural stiffness of the girder system. The effectiveness and economy of these bracing systems are heavily affected by the details and geometry of the braces and girder systems that are used. This paper focuses on a several past studies on the bracing behavior in a number of different applications. Both existing and newly-proposed details are outlined. The work includes laboratory testing, field monitoring, and parametric finite element analyses. The work includes the development of new bracing details, design methodologies, as well as software tools for predicting the behavior.
I-girders; Tub girders; Bracing; Stability