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About this book

Shell structures are widely used in the fields of civil, mechanical, architectural, aeronautical, and marine engineering. Shell technology has been enhanced by the development of new materials and prefabrication schemes. Despite the mechanical advantages and aesthetic value offered by shell structures, many engineers and architects are relatively unacquinted with shell behaviour and design.
This book familiarizes the engineering and architectural student, as well as the practicing engineer and architect, with the behaviour and design aspects of shell structures. Three aspects are presented: the Physical behaviour, the structural analysis, and the design of shells in a simple, integrated, and yet concise fashion. Thus, the book contains three major aspects of shell engineering: (1) physical understanding of shell behaviour; (2) use of applied shell theories; and (3) development of design methodologies together with shell design examples.
The theoretical tools required for rational analysis of shells are kept at a modest level to give a sound grasp of the fundamentals of shell behaviour and, at the same time, an understanding of the related theory, allowing it to be applied to actual design problems. To achieve a physical understanding of complex shell behaviour, quantitative presentations are supplemented by qualitative discussions so that the reader can grasp the `physical feeling' of shell behaviour. A number of analysis and detailed design examples are also worked out in various chapters, making the book a useful reference manual.
This book can be used as a textbook and/or a reference book in undergraduate as well as graduate university courses in the fields of civil, mechanical, architectural, aeronautical, and materials engineering. It can also be used as a reference and design-analysis manual for the practicing engineers and architects. The text is supplemented by a number of appendices containing tables of shell analysis and design charts and tables.

Table of Contents

Frontmatter

Chapter 1. Introduction to Shells

Abstract
Generally speaking, shells are spatially curved surface structures which support external applied loads. Shells are found in a variety of natural structures such as eggs, plants, leaves, skeletal bones, and geological forms. Shell structures have also been built by man since the most ancient times. Many shell domes built of masonry and stone in ancient times, are still in existence in some parts of the world.
M. Farshad

Chapter 2. Preliminaries of Shell Analysis and Design

Abstract
The behavior of shell structures is, in various aspects, different from that of so-called “framed structures”. This feature originates mainly from the geometrical features of shells which make the internal force system in shells differ from those in other types of structural forms. The internal force distribution in shells is, in general, three dimensional, i.e., spatial. Moreover, shell structures carry the applied forces mostly by the so-called membrane forces, whereas other structural forms carry the applied loads by bending mechanisms. These unique features of shells are also reflected in their design as well as in their method of construction.
M. Farshad

Chapter 3. Membrane Behavior of Cylindrical Shells

Abstract
Cylindrical shell forms are used in water and gas retaining structures, circular silos, pipes, pressure vessels, and cylindrical vaulted shell roofs of various kinds. This chapter studies the membrane behavior of cylindrical shells. First, we derive the governing membrane equations. Then, we apply these equations to the analysis of various types of cylindrical shells, including vessels, pipes, and vaults. The results of the present chapter will also be used in more comprehensive analysis and design of cylindrical shells treated in future chapters. Some basic design considerations related to such shells will also be presented.
M. Farshad

Chapter 4. Bending Analysis of Circular Cylindrical Shells

Abstract
A complete analysis of various cylindrical shell forms, for silos, pressure vessels, containment shells, containers, and shell roofs, would require an appropriate bending theory. A general bending theory would embody the membrane theory of shells. It would also predict the bending action of the shell. This chapter introduces a general bending theory of circular cylindrical shells. The theoretical basis of the present chapter forms the foundation of approximate bending theories for cylindrical shells. The special theories for cylinders, such as axisymmetric cylindrical shell theory and the bending theories of cylindrical vaulted roofs, developed in future chapters, can be considered as the offspring of the general theory presented in this chapter. The theoretical developments in this chapter will lead to a set of useful relations for treating a variety of practical shell analyses and design problems.
M. Farshad

Chapter 5. Design of Concrete Cylindrical Shell Roofs

Abstract
Thin concrete cylindrical shells can cover the roofs of various buildings efficiently and aesthetically. Large roof spans of bus, railroad, and air terminals, sport stadia, and aircraft hangars have been effectively covered with reinforced concrete shells, many of which have been cylindrical. Cylindrical shell forms can be easily shored and easily reinforced. Cylindrical concrete shell roofs can also be constructed from the precast shell elements.
M. Farshad

Chapter 6. Membrane Analysis of Shells of Revolution

Abstract
In this chapter we will study the membrane behavior of shells of revolution with double curvature. The shell types analyzed in the present chapter are a subclass of shells of revolution having non-zero positive Gaussian curvature.Shells with non-zero Gaussian curvature have non-developable surfaces. Hence they are stronger, stiffer, and more stable than shells with zero Gaussian curvature.
M. Farshad

Chapter 7. Bending Analysis of Axisymmetric Shells

Abstract
By the term “axisymmetric shells”, in this chapter, we mean all doubly curved as well as conical shell forms which have an axis of symmetry and are loaded in an axisymmetric fashion. Shells of revolution such as domes, single sheet hyperbolic paraboloids (used in cooling towers), and conical shells fall in this category.
M. Farshad

Chapter 8. Design of Reinforced Concrete Domes

Abstract
Domes have synclastic shell surfaces with positive Gaussian curvature. They are strong and structurally stable. Dome roofs can be constructed from steel, various fiber reinforced composites, and reinforced concrete materials. Precast shells made of these materials have also been constructed successfully.
M. Farshad

Chapter 9. Analysis of Shells with Arbitrary Geometry

Abstract
Varieties of surfaces from which various shells may be designed and constructed are practically infinite. With the advent of such materials as reinforced concrete, prestressed concrete, ferro-cement, fiber-reinforced concrete, composites, and reinforced plastics, the varieties of shell geometries have been further increased. The choice of a particular surface geometry for the shell depends on the functional, structural, and architectural requirements.
M. Farshad

Chapter 10. Design of Hyperbolic Paraboloid Shells

Abstract
Hyperbolic paraboloid shells are doubly curved shells with negative Gaussian curvature; they are called HP or Hypar shells, and a subclass of them are called Saddle-type shells.
M. Farshad

Chapter 11. Analysis and Design of Folded Plates

Abstract
Folded plate structures are composed of a number of flat plates connected to each other. They have many uses: in roofing of large spans in an architecturally appealing appearance; as box girders in bridges and overpasses; as bunkers in silo structures; as sheet piles.
M. Farshad

Chapter 12. Design of Liquid Retaining Shells

Abstract
Liquid retaining shell structures are made of steel, concrete, reinforced plastics, and other reinforced materials; they may have circular shape or other geometrical forms; they could be located underground, over of the ground, and / or on elevated towers. Circular containers could be roofed by cones or domes; they could also have cones or flat plates as their base. In the present chapter, emphasis will be mainly placed on the design aspects of reinforced concrete circular containers.
M. Farshad

Chapter 13. Buckling of Shells

Abstract
Deformable bodies may become unstable under certain loading conditions and thus have a premature failure. The phenomenon of instability is particularly important for thin shells subjected to compressive forces. In such cases, the loadings which produce instability modes of failure are several orders of magnitudes smaller than the forces causing material collapse of the structure. A special mode of shell instability is the buckling of shells which occurs under certain static or dynamic loading conditions.
M. Farshad

Backmatter

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