Jp Rizzuto

Dodecahedric Mutually Supported Element Space Structure: Experimental Investigation

Circuits of mutually supported elements (MSEs) can produce novel 3-dimensional spatial structures. In the creation of a circuit, the basic concept is that the primary members rely on each other for support. These novel structural arrangements may give rise to complexity in the configuration geometry and structural behaviour due to the creation of an eccentricity between elements. An experimental programme was designed to aid understanding of the primary behaviour of structures composed of MSEs. This investigation concentrated on the structural performance, under applied static loading, of a dodecahedric MSE space structure. The main objectives of the experimental investigation were to confirm behaviour as being linear elastic within a predermined appied load range, to understand the distribution of stress and the displacements of the structural elements, later to be compared with that predicted by numerical modelling. Displacements of closed MSE circuits with different spatial orientations were considered. Differences in the recorded strains were also considered. The experiment highlighted the difficulties associated with monitoring MSE circuits, particularly support stiffness and displacements of circuits with arbitrary 3-dimensional spatial orientations. The recorded strains were complex in nature in as far as they included the effects of axial forces, bi-axial bending, shear and torsion. It was found that the maximum applied load did not cause yield of the material according to the von Mises ductile material failure criterion.

Connection systems in reciprocal frames and mutually supported elements space structure networks

Novel architectural forms can be created by connecting reciprocal frame (RF) and mutually supported elements (MSE) circuits together. These networks produce interesting architectural and engineering opportunities and challenges. The opportunities include the creation of roof and standalone structures that have distinctive architectural expression. The challenges include the determination of the often-complex configuration geometry between the elements and their connection system. A key feature of sloping RF and MSE geometry is that at the joint locations the elements centroidal axes generally do not coincide. An eccentricity at these positions has therefore to be incorporated within the connection system. This has a direct impact on element sizing, connection design, fabrication and erection sequences. RF and MSE spatial structure networks give rise to complex structural behaviour. Element-to-element connection eccentricity orientation is a controlling key feature in the determination of how the forces, moments and stresses are distributed between MSEs. The orientation of the eccentricity can be random or aligned to produce a vertical intersection distance as generally used in RF construction. The eccentricity derived from the common perpendicular to the centroidal axes is more commonly used in MSE circuit assembly. This paper considers the various methods used to connect RF and MSE networks and discusses their impact and comparative design advantages and disadvantages.