Circular Storage Tanks and Silos

A Design Aid for Structural Engineers Circular Storage Tanks and Silos, Third Edition effectively explains and demonstrates the concepts needed in the analysis and design of circular tanks. Tanks have to sustain high-quality serviceability over a long lifespan. This text covers computing the stresses in service in several chapters. It considers thermal stresses and the time-dependent stresses produced by creep and shrinkage of concrete and relaxation of prestressed steel. It also examines the effects of cracking and the means for its control. This text is universally applicable; no specific system of units is used in most solved examples. However, it is advantageous to use actual dimensions and forces on the structure in a small number of examples. These problems are set in SI units and Imperial units; the answers and the graphs related to these examples are given in the two systems. What’s New in This Edition: Presents a new chapter on recommended practice for design and construction of concrete water tanks and liquefied natural gas tanks Includes a companion Website providing computer programs CTW and SOR Provides material on CTW (Cylindrical Tank Walls); with simple input, it performs analysis for load combinations anticipated in the design of cylindrical walls with or without prestressing Contains the finite-element computer program SOR (Shells of Revolution); it performs analysis for design of axisymmetrical shells of general shapes This guide is an authoritative resource for the analysis and design of circular storage tanks and silos.

PART I Analysis Introduction to the analysis of circular tanks Scope Basic assumptions General methods of structural analysis The displacement method The force method Flexibility and stiffness matrices Moment distribution Adjusted stiffness and flexibility coefficients General Circular walls of constant thickness Introduction Beam-on-elastic-foundation analogy General solution of the differential equation of the deflection of a wall of constant thickness Characteristic parameters Stiffness and flexibility matrices End-rotational stiffness and carry-over factor Fixed-end forces Semi-infinite beam on elastic foundation and simplified equations for long cylinders Classification of beams on elastic foundation and circular walls as long or short Examples General Circular walls of varying thickness Introduction Finite-difference equations Boundary conditions and reactions Generation of simultaneous equations Sudden change in thickness Examples Flexibility and stiffness of circular walls of variable thickness Effect of temperature General Design tables and examples of their use Introduction Description of design tables Variables Arbitrary edge conditions Examples Long cylinders Poisson’s ratio Beams on elastic foundations General Finite-element analysis Introduction Nodal displacements and nodal forces Transformation of stiffness matrix Displacement interpolations Stress resultants Stiffness matrix of individual element Analysis for effect of temperature Assemblage of stiffness matrices and load vectors Nodal forces Examples Time-dependent effects Introduction Creep and shrinkage of concrete Relaxation of prestressed steel Basic equations for stress and strain distributions in a homogeneous section Time-dependent stress and strain in a section Normal force N and bending moment M due to prestressing Time-dependent internal forces Thermal stresses Introduction Effects of temperature variation in a cylindrical wall Linear temperature variation through wall thickness Thermal internal forces in deep tanks and silos Internal forces due to shrinkage of concrete Significance of linear analysis Optimum design of prestressing Introduction Trapezoidal distribution of circumferential prestressing Design objectives Design of circumferential prestress distribution Effects of cracking of concrete Introduction Stress and strain in a cracked section Decompression forces Equilibrium equations Rectangular section analysis Tension stiffening Crack width Time-dependent strain and stress in cracked sections Influence of cracking on internal forces Control of cracking in concrete tanks and silos Introduction Causes of cracking Tensile strength of concrete Force-induced cracking Displacement-induced cracking Cracking by bending: force-induced and displacement-induced Motives for crack control Means of controlling cracking Minimum reinforcement to avoid yielding of reinforcement Amount of reinforcement to limit crack width: displacement-induced cracking Change in steel stress at cracking Part II Design tables Tables for analysis of circular walls of thickness varying linearly from top to bottom Appendices: Stiffness and fixed-end forces for circular an annular plates Computer program CTW (cylindrical tank walls) Computer program SOR (shells of revolution) Index

Amin Ghali, Ph.D., is a professor emeritus in civil engineering at the University of Calgary, Canada. His books include Ghali, Neville, and Brown, Structural Analysis, 6th ed. (CRC Press/ Spon Press, 2009) and Ghali, Favre, and Elbadry, Concrete Structures: Stresses and Deformations: Analysis and Design for Serviceability, 4th ed. (CRC Press/ Spon Press, 2011). Dr. Ghali has published more than 250 papers on analysis and design of concrete structures. He has also consulted on major projects that include three offshore platforms in the North Sea; major bridges in Canada, France, and Bahrain; and the Northumberland Strait Bridge connecting Prince Edward Island and New Brunswick.