This paper presents an optimization procedure for the solution of the planarity problem, a requirement of grid shells with four or more sides faces that need of having four adjacent nodes laying on a plane in order to use plane glass slabs as cladding elements. It can be satisfied by applying specific geometric rules in the grid generation phase but, when the architectural shape is already defined at the conceptual stage, an optimization procedure can yield to suitable configurations. A Relaxation method based on nodal planarity errors and an evolutionary population-based Genetic Algorithm have been applied to set of benchmarks, in order to tune parameters and to obtain general information about the solution. the problem and their efficiency compared. The Relaxation method in general shows better efficiency in reaching optimal solutions, as an effect of the regularity of the target function. The Genetic Algorithm, on the other hand, performs a wider exploration of feasible solutions, generating unexpected sub-optimal configurations.

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This paper presents a critical study about the church of Longuelo (Italy), designed in 1966 by Giuseppe “Pino” Pizzigoni (1901–1967), an Italian architect who lived and worked in Bergamo. He began his studies on shell structures in the 1950s and many of his buildings show outstanding skills in conceiving and handling complex structures. The church is probably his masterpiece, taken on with a combination of limited analytic knowledge about structures, perseverance and partial unconsciousness, typical at time. The cultural background of the architect and the whole conception of the project, as well as the peculiar building characters, its construction history and impact on the architectonic culture will be investigated in this paper.

The optimization problem related to the tessellation of free-form grid shells is presented in this paper. This kind of structure is generally composed of a supporting grid that defines the geometry of a large number of cladding elements that are always different from each other. From the construction point of view this means that every single piece needs to be designed and produced “ad hoc”, then marked and positioned with the aid of an assembling table. In order to reduce the heterogeneity of grid shell elements, several optimization strategies, referring both to evolutionary and gradient-based techniques, have been tested and compared. All the free-form geometries are defined and handled with a commercial NURBS based software, while the development of all the optimization procedures has been made thanks to the VB based programming language implemented inside the NURBS based software. Due to the smoothness of the solution domain of this specific problem, gradient-based procedures seem to be the most efficient for the rapid convergence to the optimal solution. Finally, a multiobjective procedure that involves static analysis combined with the discussed geometrical optimization is proposed in view of future developments.

International Photo Contest - Third Prize.

Photo and short image description published in "Structural Engineering International", November 2009.

Footbridges designed by Calatrava are famous landmarks all over the world: perspective views and lights are an integral part of his structural design, emphasized in this picture with a night shot that allows a better reading of all structural lines, outlined by the lights and reflected into the water. Palm fronds in the foreground, in relationship with the footbridge, accentuate also the interesting tension between a natural contest and its wonderful artificial addiction.

In occasione della conferenza tenuta al Politecnico di Torino il 6 novembre abbiamo incontrato Mutsuro Sasaki, strutturista giapponese noto per le collaborazioni con architetti «eccellenti» nelle quali ha contribuito alla definizione della forma architettonica fin dal primo momento, enfatizzando il carattere intrinsecamente multdisciplinare del progetto architettonico, e allo stesso tempo denotando con una curiosa somiglianza le forme prodotte da studi anche molto diversi tra loro come quelli di Arata Isozaki, Toyo Ito o SANAA.

This paper was awarded the IASS Hangai Prize on 6 December 2007 (IASS 2007, Venice, Italy)

The paper presents a method to generate and structurally optimize the shape of free form shells by means of a genetic algorithm. The shape of the shell is described with the aid of a NURBS representation and the algorithm modifies and improves it on the basis of the structural behaviour. A FEM analysis is performed for each individual and at each generation of the evolutionary process, in order to evaluate the structural behaviour in terms of maximum vertical displacement under a distributed load condition. The method is applied to a recent example of free-form architecture and the results are discussed referring in particular to the role of the architect as 'decision maker' in the evolutionary process. From this point of view the necessity to fit different requirements (structural, functional, aesthetic) involving the work of many professionals, can then be interpreted as a problem of multiobjective optimization.