0

Oak, 52

Oakum, 51

Observance of labor laws, 1756

Obstacles,

encountering, 1860

pile driving, 1018

sinking piers, 994

Obstacles to approval of bridge plans by War Department, 1141

Obstruction of channel

by piers, 1121

freedom from, 1090

Offense to landscape, 1151

Office practice, 1370

handling of, 1387

hours for employees, 1608

laying out work in, 1371

organization, 1606

Oft-repeated stresses, 255

Ohio Avenue bridge, Kansas City, 1079

Oil, Leucol, 770

Oil, linseed, 767

Old bridges,

condemnation of, 1519

live loads for testing, 1518, 1519

removal of, 1749

repairing of, 1519

stress diagrams for, 1519

Omission (temporarily) of cantilever brackets, 1073

One-hinged arch, 624, 636

Open-bracing for cylinder piers, 1056

Open-deck construction, 348, 354

compared with ballasted deck, 347

shallow floors, 353

Open-dredging process, 967, 981-997

advantages and disadvantages of, 981

caissons, 1858

description of, 981

limiting depths for, 996

maximum depth yet used, 982

where used, 982

Open-hearth steel, acid, 46

Open-hearth steel, origin of, 17

Open-spandrel arches, 940

Open-webbed, riveted-girder spans,

details of design for, 1674

truss sections, 490-491

Openings required by War Department for movable spans, 1143

Operating machinery, 1726, 1727

drums for lift-spans, 1725

ropes for lift-spans, 1725, 1789-1791

ropes, supports for, 1726

Operation of movable bridges,

cost of, 1362

electric, 1702-1708

hand, 1702

Operator's house, 1734

Opinion, differences of, 1765

Option on project required by bankers, 1597

Order-form for blue-prints, 1402, 1403

Orders, issuing of, 1630

Oregon-Washington Railroad and Navigation Company's Bridge at Portland, Ore., 728, 730, 732, 733

chord section, 495, 502

Organization

erection, 1506, 1507

office, 1606

Origin

American cantilever bridges, 25

Bessemer Process, 17

caissons, 12

deformed bars, 28

dredging machines, 12

iron railroad bridges, 16

iron stringers, 24

long-span American bridges, 24

metal arches, 27

open-hearth steel, 17

pile out-off machines, 12

pin-connected bridges, 23

plate-girder bridges, 23

pontoon bridges, 11

reinforced concrete, 17

steel bridges, 17, 27

stress analysis, 15

structural shapes, 17

theory of stresses, 13

timber trestles, 21

truss bridges, 12

Whipple truss, 23

wooden railway trestles, 27

Ornamentation, 1152, 1154, 1162, 1176, 1177

by artistic approaches, 1178

by hand-rails, 1177

Oromocto River Lift Bridge, 743

Osborn, Frank C., 644

Osborne, Richard, 22

Other contractors' work, 1765

Outfit for borings, 1095

Outlines of bridges, 1156

Overdriving of piles, 1018

Overhang of car, 148

Overrun of angles, 430

Overtime,

payment, 1608, 1609

work, 1630

Overturning moment on shoe of column, 304

Ownership of plans, 1628