Structures: Or Why Things Don't Fall Down

Citation

Gordon, J. E. (2003). Structures: Or Why Things Don't Fall Down. Da Capo Press. (First published 1978.)

Chapter Summary

The book has sixteen chapters: an opening chapter and then four parts. Like Gordon's earlier The New Science of Strong Materials, each chapter title pairs a plain subject with a playful subtitle. The page ranges below are from the 1978 edition, whose chapters run to page 373; the publisher lists the Da Capo paperback at 424 pages. Philip Ball, in his introduction to the earlier book, describes Structures as its popular sequel and notes that both draw heavily on naval history.

Chapter 1: The structures in our lives – or how to communicate with engineers

An introductory chapter of about fourteen pages on why structures matter in everyday life and how a non-specialist can talk with engineers about them.

Chapters 2–5: Why structures carry loads – or the springiness of solids; The invention of stress and strain – or Baron Cauchy and the decipherment of Young's modulus; Designing for safety – or can you really trust strength calculations?; Strain energy and modern fracture mechanics – with a digression on bows, catapults and kangaroos

Part One, "The difficult birth of the science of elasticity", explains how solids carry load by deforming elastically, how the concepts of stress, strain and Young's modulus came to be defined, and how far strength calculations can be trusted. Chapter 5, at nearly forty pages the longest in the book, introduces strain energy and fracture mechanics, with stored energy in bows, catapults and kangaroos as examples.

Chapters 6–8: Tension structures and pressure vessels – with some remarks on boilers, bats and Chinese junks; Joints, fastenings and people – also about creep and chariot wheels; Soft materials and living structures – or how to design a worm

Part Two, "Tension structures", covers structures that work in tension: pressure vessels, joints and fastenings (with creep), and soft biological materials. The last chapter is one the publisher singles out by its subtitle. Ball's introduction recalls that the book's discussion of natural structures, such as the shock resistance of bird feathers, bat wings and the arrangement of muscles and tendons, inspired early work in biomimetics.

Chapters 9–13: Walls, arches and dams – or cloud-capp'd towers and the stability of masonry; Something about bridges – or Saint Bénezèt and Saint Isambard; The advantage of being a beam – with observations on roofs, trusses and masts; The mysteries of shear and torsion – or Polaris and the bias-cut nightie; The various ways of failing in compression – or sandwiches, skulls and Dr Euler

Part Three, "Compression and bending structures", is the longest part, about 130 pages. It moves from masonry walls, arches and dams through bridges, beams (with roofs, trusses and masts), shear and torsion, to buckling and other compression failures, including Euler's column theory and sandwich construction.

Chapters 14–16: The philosophy of design – or the shape, the weight and the cost; A chapter of accidents – a study in sin, error and metal fatigue; Efficiency and aesthetics – or the world we have to live in

Part Four, "And the consequence was...", widens out to design itself: how shape, weight and cost are traded against each other, how structures fail through error and metal fatigue, and how efficiency relates to appearance.

Key Concepts

Chapters 1–5: Introduction and Part One

• Elasticity: the way solids deform under load and recover, which allows them to carry it.
• Stress, strain and Young's modulus: the quantities that describe load intensity, deformation and stiffness.
• Designing for safety: providing a margin between calculated strength and expected load, and knowing the limits of strength calculations.
• Strain energy and fracture mechanics: energy stored in a loaded structure and its role in the spread of cracks.

Chapters 6–8: Part Two

• Pressure vessels: containers whose walls carry internal pressure in tension.
• Joints and creep: how connections transfer load, and slow deformation under sustained load.
• Soft and living structures: how biological materials and organisms carry loads.

Chapters 9–13: Part Three

• Stability of masonry: walls, arches and dams that stand by their shape and weight in compression.
• Beams and trusses: members and frameworks that carry load in bending.
• Shear and torsion: sliding and twisting deformations.
• Buckling: failure of compression members by instability, described by Euler's theory.

Chapters 14–16: Part Four

• Design trade-offs: the balance of shape, weight and cost.
• Metal fatigue: failure under repeated loading, one of the causes of accidents discussed.
• Structural efficiency and aesthetics: the relationship between good structure and good appearance.

Critical Analysis

Strengths

• Concepts explained without jargon. The publisher presents the book as an informal explanation of the forces in everyday things, from buildings and bodies to aircraft and eggshells, and highlights its explanations of stress, shear, torsion, fracture and compression. Scientific American called it "rich and readable".
• Remarkable range of examples. The chapter titles alone point to boilers, bats and Chinese junks, chariot wheels, worms, towers, dams, bridges, masts, nightdresses, skulls and kangaroos. Engineering and natural structures are treated side by side, an approach that Ball links to the founding of biomimetics.
• History alongside science. Part One tells how elasticity, stress and strain came to be understood, and Part Four looks at design, accidents and appearance, so students see the subject as something people developed and still argue about.
• Engineering judgement. Chapters on whether strength calculations can be trusted and on accidents caused by error and fatigue address how and why structures fail, as well as how they work.

Limitations

• Not a calculation text. The book is a popular account; it develops no systematic method of structural analysis and is no substitute for a textbook.
• Age of the text. First published in 1978, it reflects engineering as it stood then; its examples are largely historical, and later developments in materials, analysis and structural form are not covered.
• Selective coverage. The chapters follow Gordon's interests, so some topics get long treatment (fracture, compression failure) while others central to civil engineering courses, such as indeterminate structures, are not chapter topics at all.

Where It Fits in the Course

In the civil and structural engineering course, Gordon is the book to read first, or alongside the first weeks of a technical course. Ji, Bell and Ellis's Understanding and Using Structural Concepts is the closest companion: it too aims at intuition, but sets out each concept with definitions, a short theory and simple physical demonstrations, so it bridges Gordon's narrative and the technical texts. Hibbeler's Structural Analysis and Megson's Structural and Stress Analysis provide the methods for determinate and indeterminate structures that Gordon describes only in words.

The more advanced books come much later: McGuire, Gallagher and Ziemian's Matrix Structural Analysis develops computer-based stiffness methods, and Chopra's Dynamics of Structures treats vibration and earthquake engineering. Gordon's chapters on buckling, fatigue and accidents are good background for both. His The New Science of Strong Materials, in the mechanics-of-materials course, covers the materials side of the same story.

How to Use This Book

The book suits first-year civil, structural, mechanical and aeronautical engineering students, architecture students and general readers. No technical background is needed beyond school arithmetic and curiosity.

A practical plan:

• Read Chapter 1 and Part One (Chapters 2–5) first. They set up stress, strain, stiffness, safety and fracture, which the rest of the book uses.
• Core for structural engineers: Part Three (Chapters 9–13) on arches, bridges, beams, shear, torsion and buckling, which maps directly onto a first structures course.
• Choose by interest: Part Two for pressure vessels, joints and biological structures; Part Four for design philosophy, failures and aesthetics. Chapter 15 on accidents is good reading before any course on fatigue or failure analysis.

Read it alongside a technical course: after each Gordon chapter, find the matching chapter in a structural analysis or mechanics-of-materials text and work a few problems on the same idea. Note the historical figures he mentions, such as Cauchy, Young and Euler, and look up how their results are stated in the textbook.