| Improvement in inspection | 283 |
| Improvements in design for Halsted Street Lift-Bridge | 113 |
| Incapacity of lacing to carry transverse load | 26 |
| Inclined end posts, bending on | 159 |
| Inclined end posts of highway bridges, bending on | 226 |
| Inclined end posts, sections of | 170 |
| Inclining truss-planes of cantilever bridges | 62 |
| Incorrect assumptions in economic investigations | 30 |
| Indexing | 345 |
| Index of tubes | 345 |
| India inks | 346 |
| Indices | 345 |
| Indirect wind load | 154 |
| Indirect wind load for draw-spans | 185 |
| Ineffective anchorages for elevated railroads | 100 |
| Ingots | 245 |
| Inherent sense of fitness | 14 |
| Injury to concrete | 293 |
| Inspecting rails | 290 |
| Inspection | 244 |
| Inspection of masonry | 294 |
| Inspection of materials and workmanship | 281 |
| Inspection of painting | 290 |
| Inspection of paints | 260 |
| Inspection of stone for masonry | 296 |
| Inspection of timber | 297 |
| Inspection, strictness of | 263 |
| Inspectors' reports | 286 |
| Instructions for checking drawings | 340 |
| Instructions to field-engineers | 288 |
| Instructions to metal-inspectors | 284 |
| Instruments for triangulation | 323 |
| Insufficiency of rivets in elevated railroads | 96 |
| Insuffiicient bases for pedestals of elevated railroads | 101 |
| Insufficient bracing between adjacent longitudinal girders in elevated railroads | 97 |
| Insufficient bracing on curves in elevated railroads | 97 |
| Intensities of working-stresses | 155 |
| Intersection of gravity axes | 20 |
| Intricacy of the science of bridge-designing | 15 |
| Intrusting designing to experts | 5 |
| Investigations concerning paints | 9 |
| Iron rods for base-line measurement | 317 |
| I struts, spacing of angles in | 177 |
| Jack-knife bridges | 107 |
| Jaw-plates | 233 |