INTRODUCTION.

This book is the outcome of a course of six lectures delivered at the Cooper Union in the city of New York in February and March, 1902, under the auspices of Columbia University. It seemed desirable by the President of the University that the subject-matter of the lectures should be prepared for ultimate publication. The six Parts of the book, therefore, comprise the substance of the six lectures, suitably expanded for the purposes of publication.

It may be interesting to state that the half-tone illustrations have, with scarcely an exception, been prepared from photographs of the actual subjects illustrated. All such illustrations in Parts V and VI devoted to the Nicaragua and Panama Canal routes are made from photographs at the various locations by members of the force of the Isthmian Canal Commission; they are, therefore, absolutely true representations of the actual localities to which they apply.

For other illustrations the author wishes to express his indebtedness to Messrs. G. P. Putnam’s Sons, Messrs. Turneaure and Russell, John Wiley & Sons, The Morrison-Jewell Filtration Company, Mr. H. M. Sperry, Signal Engineer, The Engineering News, The Railroad Gazette, The American Society of Civil Engineers, The Standard Switch and Signal Company, The Baldwin Locomotive Works, the American Locomotive Works, Mr. Clemens Herschel, and the International Pump Company, and to others from whom the author has received courtesies which he deeply appreciates.

The classification or division of the matter of the text, and the table of contents, have been made so complete, with a view to convenience even of the desultory reader in seeking any particular subject or paragraph, that no index has been prepared, as it is believed that the table of contents, as arranged, practically supplies the information ordinarily given by a comprehensive index.

Complete and detailed treatments of the purely technical matters covered by Part II will be found in the author’s “Elasticity and Resistance of Materials” and in his “Stresses in Bridge and Roof Trusses, Arched Ribs and Suspension Bridges.”

W. H. B.

Columbia University, October 24, 1902.

CONTENTS.

PART I.

ANCIENT CIVIL-ENGINEERING WORKS.

CHAPTER I.

ART. PAGE

1. Introductory 1

2. Hydraulic Works of Chaldea and Egypt 2

3. Structural Works in Chaldea and Egypt 4

4. Ancient Maritime Commerce 7

5. The Change of the Nile Channel at Memphis 8

6. The Pyramids 8

7. Obelisks, Labyrinths, and Temples 12

8. Nile Irrigation 13

9. Prehistoric Bridge-building 14

10. Ancient Brick-making 15

11. Ancient Arches 16

CHAPTER II.

12. The Beginnings of Engineering Works of Record 19

13. The Appian Way and other Roman Roads 20

14. Natural Advantages of Rome in Structural Stones 22

15. Pozzuolana Hydraulic Cement 24

16. Roman Bricks and Masonry 25

17. Roman Building Laws 27

18. Old Roman Walls 27

19. The Servian Wall 28

20. Old Roman Sewers 29

21. Early Roman Bridges 31

22. Bridge of Alcantara 35

23. Military Bridges of the Romans 35

24. The Roman Arch 36

CHAPTER III.

25. The Roman Water-supply 37

26. The Roman Aqueducts 38

27. Anio Vetus 39

28. Tepula 40

29. Virgo 40

30. Alsietina 40

31. Claudia 41

32. Anio Novus 42

33. Lengths and Dates of Aqueducts 42

34. Intakes and Settling-basins 43

35. Delivery-tanks 44

36. Leakage and Lining of Aqueducts 44

37. Grade of Aqueduct Channels 45

38. Qualities of Roman Waters 46

39. Combined Aqueducts 46

40. Property Rights in Roman Waters 46

41. Ajutages and Unit of Measurement 47

42. The Stealing of Water 49

43. Aqueduct Alignment and Design of Siphons 49

CHAPTER IV.

44. Antiquity of Masonry Aqueducts 52

45. Pont du Gard 52

46. Aqueducts at Segovia, Metz, and other Places 53

47. Tunnels 54

48. Ostia, the Harbor of Rome 56

49. Harbors of Claudius and Trajan 58

CHAPTER V.

50. Ancient Engineering Science 60

51. Ancient Views of the Physical Properties of Materials 61

52. Roman Civil Engineers Searching for Water 62

53. Locating and Designing Conduits 63

54. Siphons 64

55. Healthful Sites for Cities 65

56. Foundations of Structures 65

57. Pozzuolana and Sand 66

58. Lime Mortar 66

59. Roman Bricks according to Vitruvius 66

60. Roman Timber 67

61. The Rules of Vitruvius for Harbors 67

62. The Thrusts of Arches and Earth;

Retaining-walls and Pavements 68

63. The Professional Spirit of Vitruvius 68

64. Mechanical Appliances of the Ancients 69

65. Unlimited Forces and Time 69

PART II.

BRIDGES.

CHAPTER VI.

66. Introductory 70

67. First Cast-iron Arch 70

68. Early Timber Bridges in America 71

69. Town Lattice Bridge 72

70. Howe Truss 74

71. Pratt Truss 76

72. Squire Whipple’s Work 77

73. Character of Work of Early Builders 77

CHAPTER VII.

74. Modern Bridge Theory 78

75. The Stresses in Beams 79

76. Vertical and Horizontal Shearing Stresses 80

77. Law of Variation of Stresses of Tension and Compression 82

78. Fundamental Formulæ of Theory of Beams 83

79. Practical Applications 85

80. Deflection 86

81. Bending Moments and Shears with Single Load 87

82. Bending Moments and Shears with any System of Loads 89

83. Bending Moments and Shears with Uniform Loads 92

84. Greatest Shear for Uniform Moving Load 94

85. Bending Moments and Shears for Cantilever Beams 96

86. Greatest Bending Moment with any System of Loading 97

87. Applications to Rolled Beams 99

CHAPTER VIII.

88. The Truss Element or Triangle of Bracing 100

89. Simple Trusses 101

90. The Pratt Truss Type 102

91. The Howe Truss Type 105

92. The Simple Triangular Truss 106

93. Through- and Deck-Bridges 108

94. Multiple Systems of Triangulation 108

95. Influence of Mill and Shop Capacity on Length of Span 109

96. Trusses with Broken or Inclined Chords 109

97. Position of any Moving Load for Greatest Webb Stress 110

98. Application of Criterions for both Chord and Web Stresses 111

99. Influence Lines 112

100. Influence Lines for Moments both for Beams and Trusses 113

101. Influence Lines for Shears both for Beams and Trusses 115

102. Application of Influence-line Method to Trusses 118

CHAPTER IX.

103. Lateral Wind Pressure on Trusses 122

104. Upper and Lower Lateral Bracing 124

105. Bridge Plans and Shopwork 125

106. Erection of Bridges 126

107. Statically Determinate Trusses 126

108. Continuous Beams and Trusses—Theorem of Three Moments 128

109. Application to Draw- or Swing-bridges 130

110. Special Method for Deflection of Trusses 130

111. Application of Method for Deflection of Triangular Frame 133

112. Application of Method for Deflection to Truss 134

113. Method of Least Work 137

114. Application of Method of Least Work to General Problem 138

115. Application of Method of Least Work to Trussed Beam 139

116. Removal of Indetermination by Methods of

Least Work and Deflection 141

CHAPTER X.

117. The Arched Rib, of both Steel and Masonry 142

118. Arched Rib with Ends Fixed 144

119. Arched Rib with Ends Jointed 144

120. Arched Rib with Crown and Ends Jointed 145

121. Relative Stiffness of Arched Ribs 145

122. General Conditions of Analysis of Arched Ribs 146

CHAPTER XI.

123. Beams of Combined Steel and Concrete 149

CHAPTER XII.

124. The Masonry Arch 154

125. Old and New Theories of the Arch 155

126. Stress Conditions in the Arch-ring 158

127. Applications to an Actual Arch 158

128. Intensities of Pressure in the Arch-ring 162

129. Permissible Working Pressures 163

130. Largest Arch Spans 163

CHAPTER XIII.

131. Cantilever and Stiffened Suspension Bridges 166

132. Cantilever Bridges 166

133. Stiffened Suspension Bridges 168

134. The Stiffening Truss 170

135. Location and Arrangement of Stiffening Trusses 171

136. Division of Load between Cables and Stiffening Truss 173

137. Stresses in Cables and Moments and Shears in Trusses 174

138. Thermal Stresses and Moments in Stiffened

Suspension Bridges 175

139. Formation of the Cables 176

140. Economical Limits of Spans 177

PART III.

WATER-WORKS FOR CITIES AND TOWNS.

CHAPTER XIV.

141. Introductory 179

142. First Steam-pumps 180

143. Water-supply of Paris and London 181

144. Early Water-pipes 181

145. Earliest Water-supplies in the United States 182

146. Quality and Uses of Public Water-supply 182

147. Amount of Public Water-supply 183

148. Increase of Daily Consumption and the Division

of that Consumption 183

149. Waste of Public Water 186

150. Analysis of Reasonable Daily Supply per Head of Population 188

151. Actual Daily Consumption in Cities of the United States 189

152. Actual Daily Consumption in Foreign Cities 191

153. Variations in Rate of Daily Consumption 192

154. Supply of Fire-streams 193

CHAPTER XV.

155. Waste of Water, Particularly in the City of New York 196

156. Division of Daily Consumption in the City of New York 197

157. Daily Domestic Consumption 198

158. Incurable and Curable Wastes 199

159. Needless and Incurable Waste in City of New York 200

160. Increase in Population 200

161. Sources of Public Water-supplies 202

162. Rain-gauges and their Records 204

163. Elements of Annual and Monthly Rainfall 204

164. Hourly or Less Rates of Rainfall 207

165. Extent of Heavy Rain-storms 207

166. Provision for Low Rainfall Years 208

167. Available Portion of Rainfall or Run-off of Watersheds 209

168. Run-off of Sudbury Watershed 211

169. Run-off of Croton Watershed 211

170. Evaporation from Reservoirs 213

171. Evaporation from the Earth’s Surface 215

CHAPTER XVI.

172. Application of Fitzgerald’s Results to the Croton Watershed 216

173. The Capacity of the Croton Watershed 217

174. Necessary Storage for New York Supply to Compensate

for Deficiency 218

175. No Exact Rule for Storage Capacity 220

176. The Color of Water 221

177. Stripping Reservoir Sites 222

178. Average Depth of Reservoirs should be as

Great as Practicable 224

179. Overturn of Contents of Reservoirs Due to

Seasonal Changes of Temperature 224

180. The Construction of Reservoirs 225

181. Gate-houses, and Pipe-lines in Embankments 229

182. High Masonry Dams 230

CHAPTER XVII.

183. Gravity Supplies 234

184. Masonry Conduits 234

185. Metal Conduits 236

186. General Formula for Discharge of Conduits—Chezy’s Formula 237

187. Kutter’s Formula 239

188. Hydraulic Gradient 241

189. Flow of Water in Large Masonry Conduits 244

190. Flow of Water through Large Closed Pipes 245

191. Change of Hydraulic Gradient by Changing Diameter of Pip 250

192. Control of Flow by Gates at Upper End of Pipe-line 251

193. Flow in Old and New Cast-iron Pipes—Tubercles 251

194. Timber-stave Pipes 253

CHAPTER XVIII.

195. Pumping and Pumps 254

196. Resistances of Pumps and Main—Dynamic Head 258

197. Duty of Pumping-engines 260

198. Data to be Observed in Pumping-engine Tests 261

199. Basis of Computations for Duty 262

200. Heat-units and Ash in 100 Pounds of Coal, and

Amount of Work Equivalent to a Heat-unit 262

201. Three Methods of Estimating Duty 265

202. Trial Test and Duty of Allis Pumping-engine 265

203. Conditions Affecting Duty of Pumping-engines 266

204. Speeds and Duties of Modern Pumping-engines 266

CHAPTER XIX.

205. Distributing-reservoirs and their Capacities 267

206. System of Distributing Mains and Pipes 268

207. Diameters of and Velocities in Distributing Mains and Pipes 269

208. Required Pressures in Mains and Pipes 270

209. Fire-hydrants 270

210. Elements of Distributing Systems 270

CHAPTER XX.

211. Sanitary Improvement of Public Water-supplies 276

212. Improvement by Sedimentation 277

213. Sedimentation Aided by Chemicals 279

214. Amount of Solid Matter Removed by Sedimentation 279

215. Two Methods of Operating Sedimentation-basins 279

216. Sizes and Construction of Settling-basins 280

217. Two Methods of Filtration 281

218. Conditions Necessary for Reduction of Organic Matter 282

219. Slow Filtration through Sand—Intermittent Filtration 283

220. Removal of Bacteria in the Filter 286

221. Preliminary Treatment—Sizes of Sand Grains 286

222. Most Effective Sizes of Sand Grains 288

223. Air and Water Capacities 288

224. Bacterial Efficiency and Purification—Hygienic Efficiency 290

225. Bacterial Activity near Top of Filter 290

226. Rate of Filtration 291

227. Effective Head on Filter 291

228. Constant Rate of Filtration Necessary 292

229. Scraping of Filters 293

230. Introduction of Water to Intermittent Filters 294

231. Effect of Low Temperature 294

232. Choice of Intermittent or Continuous Filtration 294

233. Size and Arrangement of Slow Sand Filters 295

234. Design of Filter-beds 296

235. Covered Filters 299

236. Clear-water Drain-pipes of Filters 299

237. Arrangement of the Sand at Lawrence and Albany 300

238. Velocity of Flow through Sand 302

239. Frequency of Scraping and Amount Filtered between Scrapings 303

240. Cleaning the Clogged Sand 303

241. Controlling or Regulating Apparatus 305

242. Cost of Slow Sand Filters 307

243. Cost of Operation of Albany Filter 308

244. Operation and Cost of Operation of Lawrence Filter 309

245. Sanitary Results of Operation of Lawrence

and Albany Filters 310

246. Rapid Filtration with Coagulants 311

247. Operation of Coagulants 312

248. Principal Parts of Mechanical Filter-plant—

Coagulation and Subsidence 313

249. Amount of Coagulant—Advantageous Effect

of Alum on Organic Matter 314

250. High Heads and Rates for Rapid Filtration 315

251. Types and General Arrangement of Mechanical Filters 316

252. Cost of Mechanical Filters 318

253. Relative Features of Slow and Rapid Filtration 318

PART IV.

SOME FEATURES OF RAILROAD ENGINEERING.

CHAPTER XXI.

254. Introductory 320

255. Train Resistances 322

256. Grades 322

257. Curves 324

258. Resistance of Curves and Compensation in Grades 324

259. Transition Curves 325

260. Road-bed, including Ties 327

261. Mountain Locations of Railroad Lines 328

262. The Georgetown Loop 331

263. Tunnel-loop Location, Rhætian Railways, Switzerland 331

CHAPTER XXII.

264. Railroad Signalling 335

265. The Pilot Guard 335

266. The Train-Staff 335

267. First Basis of Railroad Signalling 336

268. Code of American Railway Association 337

268a. The Block 338

269. Three Classes of Railroad Signals 338

270. The Banner Signal 338

271. The Semaphore 340

272. Colors for Signalling 340

273. Indications of the Semaphore 341

274. General Character of Block System 342

275. Block Systems in Use 343

276. Locations of Signals 344

277. Home, Distant, and Advance Signals 344

278. Typical Working of Auto-controlled Manual System 345

279. General Results 348

280. Distant Signals 349

281. Function of Advance Signals 349

282. Signalling at a Single-track Crossing 350

283. Signalling at a Double-track Crossing 352

284. Signalling for Double-track Junction and Cross-over 352

285. General Observations 353

286. Interlocking-machines 354

287. Methods of Applying Power in Systems of Signalling 357

288. Train-staff Signalling 358

CHAPTER XXIII.

289. Evolution of the Locomotive 363

290. Increase of Locomotive Weight and Rate

of Combustion of Fuel 365

291. Principal Parts of a Modern Locomotive 366

292. The Wootten Fire-box and Boiler 367

293. Locomotives with Wootten Boilers 370

294. Recent Improvements in Locomotive Design 372

295. Compound Locomotives with Tandem Cylinders 373

296. Evaporative Efficiency of Different Rates of Combustion 375

296a. Tractive Force of a Locomotive 376

297. Central Atlantic Type of Locomotive 378

298. Consolidation Engine, N. Y. C. & H. R. R. R. 379

299. P., B. & L. E. Consolidation Engine 380

300. L. S. & M. S. Fast Passenger Engine 381

301. Northern Pacific Tandem Compound Locomotive 382

302. Union Pacific Vauclain Compound Locomotive 384

303. Southern Pacific Mogul with Vanderbilt Boiler 384

304. The “Soo” Decapod Locomotive 385

305. The A., T. & S. F. Decapod, the Heaviest Locomotive

yet Built 386

306. Comparison of Some of the Heaviest Locomotives in Use 389

PART V.

THE NICARAGUA ROUTE FOR A SHIP-CANAL.

307. Feasibility of Nicaragua Route 390

308. Discovery of Lake Nicaragua 390

309. Early Maritime Commerce with Lake Nicaragua 391

310. Early Examination of Nicaragua Route 392

311. English Invasion of Nicaragua 392

312. Atlantic and Pacific Ship-canal Company 392

313. Survey and Project of Col. O. W. Childs 393

314. The Project of the Maritime Canal Company 393

315. The Work of the Ludlow and Nicaragua Canal Commissions 394

316. The Route of the Isthmian Canal Commission 395

317. Standard Dimensions of Canal Prism 396

318. The San Juan Delta 397

319. The San Carlos and Serapiqui Rivers 398

320. The Rapids and Castillo Viejo 399

321. The Upper San Juan 399

322. The Rainfall from Greytown to the Lake 399

323. Lake-surface Elevation and Slope of the River 400

324. Discharges of the San Juan, San Carlos, Serapiqui 401

325. Navigation on the San Juan 401

326. The Canal Line through the Lake and Across the West Side 402

327. Character of the Country West of the Lake 403

328. Granada to Managua, thence to Corinto 404

329. General Features of the Route 404

330. Artificial Harbor at Greytown 405

331. Artificial Harbor at Brito 407

332. From Greytown Harbor to Lock No. 2 408

333. From Lock No. 2 to the Lake 409

334. Fort San Carlos to Brito 410

335. Examinations by Borings 411

336. Classification and Estimate of Quantities 412

337. Classification and Unit Prices 413

338. Curvature of the Route 413

339. The Conchuda Dam and Wasteway 414

340. Regulation of the Lake Level 417

341. Evaporation and Lockage 418

342. The Required Slope of the Canalized River Surface 419

343. All Surplus Water to be Discharged over the Conchuda Dam 419

344. Control of the Surface Elevation of the Lake 420

345. Greatest Velocities in Canalized River 425

346. Wasteways or Overflows 427

347. Temporary Harbors and Service Railroad 427

348. Itemized Statement of Length and Cost 427

PART VI.

THE PANAMA ROUTE FOR A SHIP-CANAL.

349. The First Panama Transit Line 429

350. Harbor of Porto Bello Established in 1597 429

351. First Traffic along the Chagres River, and

the Importance of the Isthmian Commerce 431

352. First Survey for Isthmian Canal Ordered in 1520 431

353. Old Panama Sacked by Morgan and the Present City Founded 431

354. The Beginnings of the French Enterprise 432

355. The Wyse Concession and the International Congress of 1870 432

356. The Plan without Locks of the Old Panama Canal Company 433

357. The Control of the Floods in the Chagres 434

358. Estimate of Time and Cost—Appointment of Liquidators 435

359. The “Commission d’Etude” 435

360. Extensions of Time for Completion 436

361. Organization of the New Panama Canal Company, 1894 437

362. Priority of the Panama Railroad Concession 437

363. Resumption of Work by the New Company—The Engineering

Commission and the Comité Technique 438

364. Plan of the New Company 439

365. Alternative Plan of the New Panama Canal Company 440

366. The Isthmian Canal Commission and its Work 441

367. The Route of the Isthmian Canal Commission that of

the New Panama Canal Company 441

368. Plan for a Sea-level Canal 443

369. Colon Harbor and Canal Entrance 443

370. Panama Harbor and Entrance to Canal 444

371. The Route from Colon to Bohio 445

372. The Bohio Dam 446

373. Variation in Surface Elevation of Lake 448

374. The Extent of Lake Bohio and the Canal Line in It 448

375. The Floods of the Chagres 449

376. The Gigante Spillway or Waste-weir 450

377. Storage in Lake Bohio for Driest Dry Season 451

378. Lake Bohio as a Flood Controller 452

379. Effect of Highest Floods on Current in Channel in Lake Bohio 453

380. Alhajuela Reservoir not Needed at Opening of Canal 453

381. Locks on Panama Route 454

382. The Bohio Locks 454

383. The Pedro Miguel and Miraflores Locks 454

384. Guard-gates near Obispo 455

385. Character and Stability of the Culebra Cut 455

386. Length and Curvature 456

387. Small Diversion-channels 457

388. Principal Items of Work to be Performed 457

389. Lengths of Sections and Elements of Total Cost 458

390. The Twenty Per Cent Allowances for Exigencies 459

391. Value of Plant, Property, and Rights on the Isthmus 460

392. Offer of New Panama Coal Company to Sell for $40,000,000 461

393. Annual Costs of Operation and Maintenance 462

394. Volcanoes and Earthquakes 463

395. Hygienic Conditions on the Two Routes 464

396. Time of Passage Through the Canal 465

397. Time for Completion on the Two Routes 466

398. Industrial and Commercial Value of the Canal 469

399. Comparison of Routes 471