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This volume provides: a) an overview of bracing utilized for I-girders, b) a discussion of the bracing systems for tub girders, and c) design requirements for the members and connections of bracing systems.
Torsional brace strength requirements for steel I-girders. Yangqing Liu1, Matthew C. Reichenbach2, Todd A. Helwig3. Abstract. Torsional bracing is often used to stabilize beams in building and bridge applications. The bracing improves the stability by restraining twist of the cross section.
It contains span tables covering various primary and secondary beam spans with common design floor loadings. It is intended that these tables will be used by engineers to assist in the preliminary design of a composite steel and concrete floor system. The solutions provided may be conservative but can be refined during the final design process.
Torsional bracing is aimed to prevent twisting of the cross-section and improve lateral-torsional buckling (LTB) strength of steel I-girders (Fig. 1). Bridge girders with torsional bracing are usually designed assuming that buckling length is equal by the distance between the brace points.
This design example illustrates the design calculations for a curved steel I-girder bridge, considering the Strength, Service, Fatigue and Constructability limit states in accordance with the AASHTO LRFD
13 lis 2019 · This paper presents a parametric study on the strength requirements of beam torsional bracing. An overview of the many factors affecting bracing behavior is provided. The paper demonstrates that the latest expression results in brace strength predictions that can be significantly nonconservative.
Recent research has demonstrated the propensity of I-girder systems with a relatively large length/width ratio (ie. narrow girder systems) to fail by a system mode of buckling that is not sensitive to the spacing between traditional torsional bracing systems.
