The concept of transferring forces in a reciprocal way has always been related to the use of elongated timber elements. However, planar components can also be considered - circular tiles, squares, triangles and more articulated or irregular geometries are all valid alternatives. This paper proposes an initial study on reciprocal systems based on planar elements in order to guide further morphological research activities. It also presents some prototypes developed by the students of the École des Ponts in Paris during two workshops run in March 2012 and 2013.

This paper discusses the application of a Multi-Objective Search method to the design of shell structures. Contrasting objectives of lightweight and high stiffness are considered for two case studies with different geometry and constraints. The Multi-Objective search is performed in the frame of the Pareto theory of non-domination, implemented in the NSGA-II algorithm. The research focuses on the way a designer can interact with the search computational procedure, driving it towards the desired solution. Diversely from pure optimization techniques, search strategies as Multi-Objective search produce sets of feasible solutions, which the designer can evaluate and use it their work, accordingly with other architectural requirements and purposes.

This paper deals with a multi-objective design/optimization grid-shell problem. Structural behavior and light absorption/shading have been selected as fitness functions. Such performance criteria can separately lead to different and divergent optimal solutions but, if they are considered as a whole, they are expected to result in several equivalent or similar sub-optimal shapes. This multi-objective optimization problem has been performed here with the aid of a Genetic Algorithm (GA). GAs explore and search widely for suitable solutions and, in this way, they become design tools rather than solution ones. Three benchmarks were established and then a more complex application was made to an existing case study, i.e. the Esplanade in Singapore, designed by DP Architects (DPA) and Michael Wilford & Partners (MWP).

This paper deals with the design of reciprocal spatial configurations, based on the use of planar elements, which are investigated and classified according to their morphological characteristics and design potential. Reciprocal structures were first originated as assemblies of elongated elements. In Europe, the concept of spanning longer distances than the length of the available timber beams was the key reason for the use of such structures, which were therefore called ‘short-beams’. In the East and especially in China, the use of interwoven strips of bamboo for the construction of baskets is an old tradition that was transferred to larger scale objects, and which has also led to the development of reciprocal configurations based on linear elements. In this framework, a study of reciprocal systems, based on the use of 2D planar panels, is proposed. A first morphological classification of reciprocal systems based on planar elements, which have been divided according to the shape of the elements and growth possibilities of their assembly, is provided. Moreover, some research issues for future investigations are highlighted. The presented systems and prototypes were developed by students at the École des Ponts in Paris during their Master’s degree and a workshop run by the authors in March 2012.