Geometrical data for lattice spatial structures : regularity, historical background and education.
Creators: name: Behnejad, S. Alireza
Publisher: name: University of Surrey
Year: 2020

description: Dealing with geometrical information has been an important aspect of the knowledge required for construction of a structure. In particular, data generation techniques appropriate for complex geometries are crucial for the design and construction of spatial structures. This may be referred to as ‘Configuration Processing’ and has been the centre of attention for some researchers in the past few decades. A main focus of this thesis is the ‘regularity’ in structural forms and the present research shows that the ‘metric properties’ of structural forms, suggested by the Author, are fundamental for the study of regularity. Metric properties refer to the geometrical information necessary for design, and in particular, construction of lattice spatial structures. To elaborate, the research addresses the following questions: • What are the metric properties for a lattice structure and how can these be evaluated? • What is the definition of regularity for lattice structures and how can this be quantified? • How could the regularity of a lattice structure be improved? The Author is an architect and structural engineer who has been involved in the design and construction of lattice spatial structures for 20 years. The experience of the actual construction over the years has shown that there are advantages in keeping the number of different types of structural components small. In another front, the study of regularity of forms for lattice structures may involve the ‘visual aspects’, ‘arrangements of elements’ or ‘structural components’. The first two aspects are subjective matters and the latter one, that is the focus of the present work, is an objective matter. The present research shows that the metric properties of structural forms are fundamental for the study of component regularity. There are considerable benefits in terms of the construction of structures which have a high degree of regular components. The benefits include savings in time and cost of construction, as well as a reduction in probability of having a wrong arrangement during assembly. In this sense, the present work could be considered as a research of fundamental importance which provides a basis for the knowledge in this field. Most of the examples in the Thesis are single layer lattice structures with straight elements and further research on other types of lattice structures is recommended. This thesis consists of six chapters, the first of which entitled ‘Introduction’ provides background information about the research and discusses the research aims. Chapter 2 on the ‘Literature Review’ concerns the few available publications relevant to the research. The third chapter entitled ‘Metric Properties’ defines a number of geometrical parameters which are being used to generate the geometrical information. Also, the mathematics involved for the necessary calculations are discussed. This chapter is a major contribution of the thesis and to the available knowledge in terms of introduction a set of well defined geometrical parameters for design and construction of lattice spatial structures. Chapter 4 is dedicated to discussion of different aspects of ‘Regularity’ of lattice structures. To begin with, the idea of regularity is elaborated upon and then the concept of ‘regularity indicators’ are discussed. These indicators help to quantify regularity of components. Here again, this chapter presents a novel idea in the field of lattice spatial structures. Another major contribution of this thesis to the general knowledge is Chapter 5 entitled ‘Sphere Packing’. This is a particular technique for configuration processing developed by the Author to improve the member length regularity of lattice structures. An example of the application of the technique for configuration processing of spherical domes is also discussed in details. Moreover, a comparison on the variation of the member lengths of different dome configurations is discussed which shows that around 50% of the members of a dome created by sphere packing technique are with the same length. This proportion of equal length members is considerably higher than that of the other dome configurations (10%-33%). Finally, Chapter 6 provides the conclusions and some important suggestions for the continuation of the research. In addition to the main body of this thesis, copy of the relevant publications by the Author are provided as Annexes in the following three categories: i. Geometrical data generation for lattice spatial structures is the core of the Annexes A to E, then, ii. Annexes F and G are focusing on the education of spatial structures, and finally, iii. Historical background of spatial structures is discussed in the Annexes H and I.