90. Materials. 91. Vitrified Clay Pipe. 92. Cement and Concrete Pipe. 93. Proportioning of Concrete. 94. Waterproofing of Concrete. 95. Mixing and Placing Concrete. 96. Sewer Brick. 97. Vitrified Clay Sewer Block. 98. Cast Iron, Steel, and Wood. 164–193 CHAPTER IX DESIGN OF THE SEWER RING 99. Stresses in Buried Pipe. 100. Design of Steel Pipe. 101. Design of Wood Stave Pipe. 102. External Loads on Buried Pipe. 103. Stresses in Circular Ring. 104. Analysis of Sewer Arches. 105. Reinforced Concrete Sewer Design. 194–210 CHAPTER X CONTRACTS AND SPECIFICATIONS 106. Importance of the Subject. 107. Scope of the Subject. 108. Types of Contracts. 109. The Agreement. 110. The Advertisement. 111. Information and Instructions for Bidders. 112. Proposal. 113. General Specifications. 114. Technical Specifications. 115. Special Specifications. 116. The Contract. 117. The Bond. 211–232 CHAPTER XI CONSTRUCTION 118. Elements. WORK OF THE ENGINEER. 119. Duties. 120. Inspection. 121. Interpretation of Contract. 122. Unexpected Situations. 123. Cost Data and Estimates. 124. Progress Reports. 125. Records. EXCAVATION. 126. Specifications. 127. Hand Excavation. 128. Machine Excavation. 129. Types of Machines. 130. Continuous Bucket Excavators. 131. Cableway and Trestle Excavators. 132. Tower Cableways. 133. Steam Shovels. 134. Drag Line and Bucket Excavators. 135. Excavation in Quicksand. 136. Pumping and Drainage. 137. Trench Pump. 138. Diaphragm Pump. 139. Jet Pump. 140. Steam Vacuum Pumps. 141. Centrifugal and Reciprocating Pumps. 142. Well Points. 143. Rock Excavation. 144. Power Drilling. 145. Steam or Air for Power. 146. Depth of Drill Hole. 147. Diameter of Drill Hole. 148. Spacing of Drill Holes. SHEETING AND BRACING. 149. Purposes and Types. 150. Stay Bracing. 151. Skeleton Sheeting. 152. Poling Boards. 153. Box Sheeting. 154. Vertical Sheeting. 155. Pulling Wood Sheeting. 156. Earth Pressures. 157. Design of Sheeting and Bracing. 158. Steel Sheet Piling. LINE AND GRADE. 159. Locating the Trench. 160. Final Line and Grade. 161. Transferring Grade and Line to the Pipe. 162. Line and Grade in Tunnel. TUNNELLING. 163. Depth. 164. Shafts. 165. Timbering. 166. Shields. 167. Tunnel Machines. 168. Rock Tunnels. 169. Ventilation. 170. Compressed Air. EXPLOSIVES AND BLASTING. 171. Requirements. 172. Types of Explosives. 173. Permissible Explosives. 174. Strength. 175. Fuses and Detonators. 176. Care in Handling. 177. Priming, Loading, and Firing. 178. Quantity of Explosive. PIPE SEWERS. 179. The Trench Bottom. 180. Laying Pipe. 181. Joints. 182.