Strukturmekanik & arkitektur Om strukturmekanisk förståelse i gestaltningsprocessen

Doktorsavhandling, 2005

Organizing material to produce space and a load-carrying structure are central tasks in the architectural design process. In trying out and examining design ideas, use of language and tools appropriate to the purpose is fundamental.The thesis begins with reflections on the different processes that utilize knowledge of structural mechanics, how that subject is commonly presented, and how the presentation of it is affected by various tacit aims. There are two main tasks of the structural engineer: description and analysis of structural behaviour through mathematical modelling, and evaluation of safety and reliability as expressed in design codes. These tasks are compared with those of the architect in developing load-carrying structures that interact in a logical and meaningful way with spatial functions and with the needs and aims of architectural expression.The thesis, which takes as its point of departure Structural Mechanical traditions, considers concepts and approaches that help provide a better qualitative understanding of compound and complex structural behaviour. Alongside the concept of equilibrium, that of stiffness is examined as a means of achieving structural mechanical understanding.A new design conception, that of ‘canonical stiffness’, is proposed as a means of gaining insight into the static behaviour of structures, allowing patterns (modes) of deformation for which a structure is weak to be determined on the basis of the stiffness of its various parts. From these patterns, the static load cases that produce the largest deformations of the structure can also be determined. Computational tools are proposed that can support a dialog between the architect and the engineer at early stages of the design process. Three computer codes – ForcePAD, pointSketch and CALFEM – are presented and discussed as examples of proposals initiated and/or developed within the spirit of the thesis.