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Mystic River, Brown balance-beam
bascule bridge, 291, 298, 308
N
National Economic League, 4
National efficiency, increasing, 2
Nature of banks and approaches, 483
Nature of bottom, 483
Navigation influences, 123
Necessity for economic studies, 7
New Orleans,
bridge project, 12
bridge studies, 151, 155
proposed bridge, 296
report, 8, 319
transbordeur, description of, 321-323
New types of ponton equipage, 472
New Westminster, B. C., bridge
over Fraser River, 131
Nichro steel, 37, 48
Nichromol steel comparison, 47
tests of, 39
Nichromol steel, 34, 37, 48
Nichro steel comparison, 47
tests of, 39
Nickel-chromium-molybdenum steel, 37
Nickel-molybdenum steel, 37
Nickel price, as affected by
Great War, 33
"Nickel Steel for Bridges," 91
Nickel steel, 26, 47
bridges, use in, 33
cables, 280, 281
floor-systems, 31
Nicmol steel comparison, 46
tests of, 41
Nicmol steel, 37, 47
Chromol steel comparison, 51
nickel steel comparison, 46
tests of, 41
Nobrac, 432
Noise of gearing, elimination of, 313
Non-continuous versus continuous
trusses, 75-82
North River crossing at New York
City, 58
highway tunnels, 56
proposed bridge for railway and
highway traffic, 60
Northwestern Elevated Railroad, 253
Number of columns per bent, best, 224
O
Objections raised to proposed
ideal method of contract-
letting, 354-356
Obstruction of waterway by pier
shafts, 170
Office work, economics of, 358-360
Old bridges,
doubling-up of, 407
pins in, 415
rule for condemnation of, 407
strengthening of, 409
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Omission of end floor beams, 203
Omissions, avoidance of, 20
One-man stones in concrete, 386
One-way versus two-way reinforcing
in slabs, 220
Open-dredging and pneumatic methods
on same job, 173
Open-dredging versus cofferdam
method, 171
Open-dredging versus pneumatic
process, 171
Open spandrel versus solid
spandrel, 228
Open timber decks, 184
Open-web girders versus
plate-girders, 255
Open-web riveted spans, economics
of, 70
Operating apparatus, ideal, 313
Operating bridges by hydraulic
pressure or compressed air, 311
Operating machinery and power,
economics of, 310-317
function of, 315
power of, 315
strength of, 315
Operation and maintenance, capitalization
of, 15
Operation costs of tunnels and bridges, 55
Opinion, expert, gratis, 7
Opposition of rival promoters, 20
Optimism, 20
Ordering quickly of materials, 385
Ordinary swing versus bob-tailed
swing, 288
Organization, field, 383
Overestimating, 20
Overloading of bridges, 13
Over-stressing counters, 423
P
Paints and Painting, 379
abrasion, 445
accessibility for, 201
application, 422
after cleaning, 446
best colors, 436
best kind, 430, 431
cement, 437
climatic influences, 421, 438, 440
colors, 428
comparative cost of application, 421
correct and economic theory of, 448
covering power, 436
deterioration, causes of, 444
economics of, 430-448
elasticity, 436
experiments at Havre de Grace, 433
factors that affect results in, 446
fire-proof, 420
for steel bridges, 421
general economic observations
concerning, 447
highway bridges, 427
importance, 421
incipient failure, 445
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