A consideration on intermediate diaphragm spacing in steel box girder bridges with a doubly symmetric section

Influence of in-Plane Deformation in Higher Order Beam Theories

“…This approach clarifies some significant factors concerning the mechanism of distortion. Confirming BEF analogy, numerous research efforts extended classical Vlasov TTT by formulating corresponding fourthorder differential equations taking into account torsional distortion, introducing at the same time basic notions such as that of distortional warping, distortional center and distortional moment [13], [17]- [23]. The connection of the above mentioned additional distortional warping with secondary torsional shear stresses has been also highlighted [24].…”

“…Similarly, attention to distortion matters is given in other guidelines as well such as those by American Association of State Highway and Transportation Officials (AASHTO) and Hanshin Expressway Public Corporation of Japan. According to these the maximum spacing of diaphragms placed in curved girder bridges is controlled so as to minimize distortional warping normal stresses in terms of bending normal ones (less than 10% for AASHTO, less than 5% for Hanshin Expressway Public Corporation of Japan) [13].…”

Isogeometric Methods in Dynamic Analysis of Curved Beams Including Warping and Distortional Effects

“…They developed a curved box beam element which was employed in order to develop design charts for adequate spacing of the intermediate diaphragms of curved bridges. Flexural and torsional displacement functions have been based on those proposed for doubly symmetric cross section by Kang and Yoo [18] while distortional functions have been derived for a mono-symmetric cross section [19]. Yoo et al [20] applied the concept of the BEF analogy for the analysis of distortional stresses of horizontally curved box-girders.…”

Stresses due to distortion on horizontally curved tub-girders

“…The effectiveness of such charts and tables is questionable as none of the aids can be applied to the modern-day continuous curved box-girder bridges with variable cross-section properties. Park et al [5][6][7] and Kermani and Waldron [8] developed beam Nomenclature a length of the overhang; cross-frame spacing A cross-sectional area of a box section (steel) A Ã nondimensional parameter relating the cross dimensions and the distortional warping function A b area of the cross-frame member A d area of the top lateral diagonal bracing A f area of the steel flange (¼ A u1 ) A k 1 area of the truss element simulating the stiffness of the box against distortion A K 1 area of the truss element simulating the stiffness of the cross-frame/diaphragm A l area of the lower flange u =½12ð1 À u 2 Þ) I v moment of inertia of the web (¼ t 3 v =½12ð1 À u 2 Þ) I w torsional warping function I x moment of inertia with respect to the x-axis I y moment of inertia with respect to the y-axis k foundation constant k 1 distributed stiffness of the cross section against distortion K 1 concentrated stiffness of the cross-frame against distortion This can be a serious limitation. As will be shown later, distortion can be controlled by diaphragm or cross-frame spacing and its stiffness.…”