CONTENTS Preface page ix 1 Introduction 1 1.1 Structural criteria 3 1.2 Modern analysis 5 1.3 The elastic solution 8 1.4 Plastic theory 10 2 Structural Theory of Masonry 12 2.1 The voussoir arch 15 2.2 The geometrical factor of safety 20 2.3 The master 'safe' theorem 22 2.4 Settlement and cracking 23 2.5 Time scale for settlement 24 2.6 Models 25 3 Domes 27 3.1 The dome as a membrane 28 3.2 Stresses in shells 30 3.3 The uniform hemispherical dome 31 3.4 Cracking of domes 35 3.5 The minimum thickness of a hemispherical dome 39 3.6 Incomplete hemispheres 41 3.7 Segmental domes 46 4 The Masonry Vault 48 4.1 The barrel vault 48 4.2 The cross-vault 51 4.3 Vault thrusts 55 4.4 Ungewitter's tables 62 4.5 The pathology of the quadripartite vault 66 4.6 Superimposed loads on vaulting 71 4.7 The sexpartite vault 73 4.8 The fan vault 75 5 Some Structural Elements 83 5.1 The wall 83 5.2 The pier 86 5.3 The pinnacle 88 5.4 The flying buttress 91 5.5 The tas de charge 106 6 Towers and Bells 109 6.1 The Campanile in Venice 109 6.2 Collapses at Beauvais, 1284 and 1573 111 6.3 The crossing tower 118 6.4 The effects of bell-ringing 121 6.5 Wind loads 125 7 Spires 127 7.1 The spire tip 129 7.2 The spire as a conical shell 131 7.3 The octagonal spire 133 7.4 Leaning spires 136 7.5 Timber spires 137 8 Some Historical Notes 139 8.1 Villard de Honnecourt(l) 139 8.2 Before Villard 141 8.3 Villard(2) 143 8.4 The expertises at Milan 143 8.5 The Renaissance 150 Bibliography 155 Index 159