Abstract
Non-rectangular steel panels are increasingly used in the design of new bridges due to architectural and/or structural demands. At large spans, in order to save material and consequently to decrease the impact on the environment, the girders are curved in the longitudinal direction with a maximum depth at intermediate support and minimum depth at midspan. Steel bridges built up of slender plates, which tend to buckle, may be designed based on EN 1993-1-5, which offers several methods such as “Effective Width Method” (EWM), “Reduced Stress Method” (RSM) or “Verification based on Finite Element Methods of analysis”. Among the mentioned methods, the Effective Width Method is based on the reduction of the cross-section area considering the local buckling of the sub-panels between the stiffeners and the global buckling of the stiffened panel. As a consequence, of the optimised shape of bridges non-rectangular plates occur, most commonly as web panels of girders with a lower flange curved in the longitudinal direction. However, for an application of the Effective Width Method according to EN 1993-1-5:2006 only rectangular panels with parallel flanges are assumed. According to the existing rules, the Effective Width Method may only be applied for angle up to 10.
In frame of a European research project OUTBURST the buckling behaviour of non-rectangular panels experimental and numerical are investigated. The tests were conducted on six welded plate girders within the field of bending-shear interaction. The tests explicitly focused on the angle of panels under the interaction of bending moment and shear. The results show that with decreasing angle the maximum load increases. For further numerical investigations, the tests have been recalculated for the verification of the FE-model. The numerical models were simplified. The results of the numerical simulations were validated against the results of the experimental tests. The numerical simulations show a good agreement with test results. Then, a numerical parametric study on stiffened and unstiffened panels has been performed to cover different configurations. Based on experimental and numerical results a design approach is proposed. The numerical data in comparison to the proposal are statistically evaluated. It is observed for a tapered panel with inclined compression flange that the effect of flange inclination can be taken in to account. The obtained results with consideration of the flange force show more economic results.
The application of the proposal leads to safe results. The proposal is now implemented in the second generation of the Eurocode prEN 1993-1-5 and may be applied to non-rectangular fields with an angle greater than 10° and less than or equal to 17.5°.
Project Team
University of Stuttgart, Vahid Pourostad, University of Ljubljana, Primož Može; GRID international consulting engineers sa, José Oliveira Pedro; MCE GmbH, Johannes Eitelberger; ABES wagner & partner zt- GmbH, Martin Pircher; ATKINS, Chris Hendy; University of Coimbra, Luís Simões da Silva.
Project Funding
RFCS – Spendengeber: MCE
Project Duration
01.07.2016 - 30.06.2019