Effects of Fabrication Process on Prestressed Composite Arches

Abstract

Previous studies suggest that intentional buckling of wide shallow members as a fabrication method for arches and domes could result in buckling loads much lower than the conventional rigid (i.e., nonprestressed) structures of the same shape and weight. A modified prestressing technique is discussed in which single-layer struts are separately but simultaneously buckled into arch shape, and then attached to each other and to the supports to form a sandwich composite section. A nonlinear finite-element model is developed to study the effects of this technique on the stability behavior of prestressed sandwich arches. Equivalent rigid arches of elastica shape are studied by initializing the residual stresses prior to loading. A prestressed homogeneous arch that is twice as thick as each face layer of the sandwich section is used for comparison. Prestressing forces that were known to reduce the buckling loads of homogeneous arches by as much as 25%, are shown to have negligible effect on the stability of sandwich arches. Those negative effects almost completely vanish as the thickness of the core layer is increased relative to the overall thickness of the sandwich section.