Analytical investigation of flexural torsional buckling resistance design of steel circular arches with elastic end bending restraints

The distinguishing characteristics of an arch are the presence of horizontal reactions at the ends and the considerable rise of the axis at the centre span which differ arch from beams. In case of beams supporting uniformly distributed load the bending moment increases with the square of span and hence they become uneconomical for long span structures. Long span structure arches have an advantage as they would develop horizontal reactions which reduce the design bending moment. An arch has tendency to buckle in its plane of the arch loading due to axial compression. Due to curved profile arches have high-efficient in-plane load carrying capacity but steel arches are prone to out-of-plane buckling that controls its design strength rather than in-plane flexural buckling. For pinned arches, in practical use arch ends can be treated as in-plane free to rotate but with respect to out-of-plane bending they are actually semi-rigidly restrained rather than fully restrained. That is why in practical engineering design; much attention needs to be paid to the case of arch with elastic end bending restrained. In practice arches having uniformly distributed vertical loading slightly bending forces and mainly compressive forces are induced on the arch structure. That is why in practical engineering design much attention needs to be paid in the case of arches having uniformly distributed vertical loading, and design method needs to be proposed for this case. The aim of the study is to predict the flexural torsional buckling resistance design of steel circular arch loaded in-plane uniformly distributed vertical loads that buckles out-of-plane in flexural torsional mode before in-plane failure. From this study we can predict the design method for arches with uniformly distributed vertical loads and elastic end bending restraining conditions.