par Vilquin, Thomas 
Editeur scientifique Cruz, Paulo
Référence Structures and Architecture(1: juillet 2010: Guimaraes, Portugal), Structures and Architecture, CRC Press, Leiden
Publication Publié, 2010-07
Editeur scientifique Cruz, Paulo
Référence Structures and Architecture(1: juillet 2010: Guimaraes, Portugal), Structures and Architecture, CRC Press, Leiden
Publication Publié, 2010-07
Publication dans des actes
| Résumé : | In a world where thriving for a limited consumption of the resources (materials, energy, cleanness of environment and disposal space) is decisive for our future quality of life, architects and engineers must, like everyone, act responsibly towards the use of these resources that is associated with their activity – especially as construction is one of the sector that consumes the most. To this purpose, specific tools need to be developed. Here we extend from the path initiated in the first half of the 2000 decade by Belgian engineers Philippe Samyn and Pierre Latteur, with the indicators method, an analytical tool of structural optimisation. It allows studying the influence, on the material volume and/or weight of a morphology, of various parameters (like overall proportions, material choice, etc.) in a general way. This knowledge leads to design guidelines about these parameters, aiming at a lighter structure, valid whatever the other conditions are, and which can be applied since an early stage of design. Here we propose to study the simple column, made of homogenous material. Handling the simplified but acceptable model of Rankine for taking account of buckling, an expression of the material volume of a column is developed, which exhibits the 4 parameters at work, independently from each other: with the material volume of the column, its cross-section and its weight; the "0" index refers to the hypothetical situation where no buckling would appear. This formulation thus represents the measure in which buckling intervenes in the dimensioning of the column. As buckling induces a "waste" of material, this ensemble should be kept as low as possible, in order to produce a column where the material works at the maximum possible rate. The various parameters are: the material, through the factor , with the resistance and the Young modulus of the constituting material; the cross-section geometry, through a non-dimensional factor , where is its moment of inertia; the bearing conditions, via the factor, deriving from the definition of the buckling length , with the column length; the scale of the problem, through the structural index , with the vertical load applied on the column. The above-mentioned formula enables the separate study of the influence of each of these parameters on the column's volume – while at the same time keeping an eye on its bulkiness, which is of architectural interest, through a similar formulation of the width of the cross-section. Of particular interest is the study of the influence of cross-section geometry. A quantified comparison between different forms and proportions can be done, which is valid whatever the other parameters are. Practitioners can then directly have a relative idea, when choosing one cross-section form/proportions upon another, of its consequences on the use of material in their project, while fulfilling the same program. |
