Experimental investigation of out-of-plane buckling of circular arches under a central radial point load

An arch under a central in-plane point load may lose its stability in an out-of-plane buckling mode when the load attends a certain value. This paper presents a theoretical study for the out-of-plane buckling of elastic circular arches under a central radial point load using an energy method and an experimental study for the out of-plane buckling load of elastic circular aluminium arches under a central radial point load. Six circular aluminium arches of doubly symmetric I-sections having different rise-to-span ratios, different load heights and different boundary conditions are tested by applying a radial point load to the crown of the arch. With specially designed supports that can simulate different in-plane boundary conditions, an ingenious loading device and high-precision real-time displacement measurement, the elastic out-of-plane buckling loads of tested arches are accurately recorded. Comparisons show that agreements of test results against theoretical solutions are very good. The influences of the slenderness ratio, in-plane boundary conditions and the load height on the out-of-plane buckling are also investigated and it is found that they influence the out-of-plane buckling load of circular arches significantly.