Exploration and Optimization of Combined Timber Plate and Branching Column Systems Using Evolutionary Computation

In contemporary architectural design new and experimental forms are constantly searched for and in the interaction between structural and architectural design a readable structural function adding to the architectural experience can be of interest. Cross-laminated timber plate elements show a high stiffness to weight ratio, and provide a wide range of possible structural applications. They have been analysed in structural systems for multi-storey residential buildings and in tensegric assemblies forming plane roof surfaces and single curved structures [1,2] based on a reduced number of element shapes. The application in faceted structures is possible by combining plate elements with linear edge joints or nodal joints, where the relation between wish for complexity in overall shape and desired production rationality and assembling simplicity decide the geometric character. The current work takes a plane roof structure with square elements as a point of departure for development of 3-dimensional plate structures and a study of interplay and result of combinations with branching column structures. By modifying square elements into rhombuses and combining them four together simple pyramid roof units and repetitive structures with rigid behaviour are easily obtainable. By varying the rhomboid proportions different pitches of the roof unit are obtained. By regarding physical modelling the effects of development from 2-dimensional to 3-dimensional units are studied concerning assembly stiffness and preconditions for interplay with supporting column structures. Branching column structures [3] can support the plates either at the centre of plates, which then cantilever, or at inter-plate nodes. Optimizing studies are applied on plate assembly geometry and design of supporting column structures. Using Evolutionary Computation (EC) methods [4], geometric relationships between the shells and branching columns are optimized for least weight. Parameters of shell geometry and the related branching column geometry and topology are explored. Examples of systems with good performance under load are shown and compared in terms of efficiency and stiffness.