The Design of Modern Steel Bridges - TEDI

Recommendations

Info

20 The Design of Modern Steel Bridges Substantial movements in wind were previously found in the 2300 ft (701 m) span Bronx Whitestone Bridge, which had a 74 ft (23 m) wide deck, and also in the Golden Gate Bridge, and diagonal stays between the cable and the deck and additional lateral bracing in the deck structure had to be provided. A chain pier at Brighton, England, had collapsed in a storm several years earlier. The positive outcome of the Tacoma disaster was the extensive wind tunnel testing of scaled models and aerodynamic analysis of various deck shapes in all wind speeds. This practice re-established long-span construction on a firmer basis, leading not only to the reconstruction of the Tacoma Bridge in 1950 with a wider 60 ft (18.3 m) deck with 33 ft (10 m) deep stiffening trusses, but several more such bridges were built, e.g. Mackinac Bridge in Michigan in 1957 with 3800 ft (1159 m) span, designed by David Steinmann, and finally in 1965 the 4260 ft span (1298 m) Verrazano Narrows Bridge across the New York harbour entrance, designed by Ammann, which just exceeded the then longest span length of the Golden Gate Bridge. Steinmann introduced the concept of leaving slots in the deck, so that wind vortices escape upwards from underneath, thus setting up turbulence and thereby reducing the rhythmic up and down forces on the deck. In Europe, Tancarville Bridge over the Seine at Le Havre with a main span of 610 m (2000 ft) was completed in 1959. The non-American features of Tancarville Bridge were the concrete towers and the continuity of the stiffening girder between the main and the side spans. This was followed in 1964 by the huge bridge over the Tagus at Lisbon with a central span of 1013 m (3323 ft) and almost at the same time the Forth Road Bridge near Edinburgh Figure 1.19 Forth Road Bridge, Scotland (1964).
Figure 1.20 Salazar Bridge over the Tagus, Portugal (1964). Figure 1.21 Severn Road Bridge, England (1966). Types and History of Steel Bridges 21 with a suspended central span of 1006 m (3300 ft). Then came the revolutionary 988 m (3240 ft) central span Severn Bridge in 1966, with its all-welded aerofoil-shaped box girder suspended structure in which the functions of a stiffening girder and a road deck were integrated, resulting in a very substantial reduction in the weight of deck steelwork and cable sizes. The hangers by which the deck is supported from the main cables were made inclined rather than vertical, thus constituting a triangulated lattice pattern; this was expected
Page 1: The Design of Modern Steel Bridges
Page 5 and 6: The Design of Modern Steel Bridges
Page 7 and 8: Contents Preface vii Acknowledgemen
Page 9 and 10: Preface Bridges are great symbols o
Page 11: Acknowledgements The figures in Cha
Page 14 and 15: 2 The Design of Modern Steel Bridge
Page 22 and 23: 10 The Design of Modern Steel Bridg
Page 58 and 59: Table 2.1 Properties of some commer
Page 63 and 64: Chapter 3 Loads on Bridges 3.1 Dead
Page 65 and 66: 3.3 Design live loads in different
Page 67 and 68: interstate highways are designed fo
Page 69 and 70: a coefficient that depends on the n
Page 71 and 72: Loads on Bridges 59 In Germany, a n
Page 73 and 74: Table 3.6 Typical values of U and P
Page 75 and 76: 3.5 Longitudinal forces on bridges
Page 77 and 78: wind loading on the traffic. An upl
Page 79 and 80: where r is the air density ¼ 1.226
Page 81 and 82: Loads on Bridges 69 minimum and max
Page 83 and 84:
3.8 Other loads on bridges There ar
Page 85 and 86:
References Loads on Bridges 73 wher
Page 87 and 88:
Chapter 4 Aims of Design 4.1 Limit
Page 89 and 90:
critical components of the structur
Page 91 and 92:
But this is an attempt to achieve u
Page 93 and 94:
If the basic variables R and S are
Page 95 and 96:
educed variables defined by oi ¼ x
Page 97 and 98:
will have a probability of failure
Page 99 and 100:
Aims of Design 87 g m ¼ g m1 g m2
Page 101 and 102:
Table 4.2 Failure probabilities of
Page 103 and 104:
Chapter 5 Rolled Beam and Plate Gir
Page 105 and 106:
as possible. But deep and thin webs
Page 107 and 108:
eam, with an effective area equal t
Page 109 and 110:
and stresses caused by lateral defl
Page 111 and 112:
Figure 5.3 Beam cross-section. In t
Page 113 and 114:
Rolled Beam and Plate Girder Design
Page 115 and 116:
Table 5.2 Effective length factors
Page 117 and 118:
stress is equal to p 2 E/(Le/r) 2 )
Page 119 and 120:
equation (5.16) has been adopted fo
Page 121 and 122:
The strain energy of the elastic re
Page 123 and 124:
Figure 5.6 Buckling of plates in co
Page 125 and 126:
Figure 5.8 Buckling of plate under
Page 127 and 128:
techniques. It may be noted that th
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
5.4.3 Effect of residual stresses R
Page 135 and 136:
Aw ¼ 40 mm 2 , allowing for a smal
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Basler and Thurlimann were the firs
Page 143 and 144:
Ostapenko/Chern gave the following
Page 145 and 146:
where m ¼ Mp b 2 twsyw ty ¼ syw p
Page 147 and 148:
the case of equal flanges, the tota
Page 149 and 150:
emains flat until an elastic critic
Page 151 and 152:
Page 153 and 154:
longitudinal compression is given b
Page 155 and 156:
where Peq ¼ s1tB PE Ps Pcro Peq1
Page 157 and 158:
Figure 5.27 Tension-field forces in
Page 159 and 160:
5.5.6 Design of longitudinal web st
Page 161 and 162:
when Le is the effective length for
Page 163 and 164:
pffiffiffiffiffiffiffiffiffiffiffif
Page 165 and 166:
een derived as a condition for trea
Page 167 and 168:
For interaction of various stress c
Page 169 and 170:
must be at least i.e. 1 IsxbB 4 2 a
Page 171 and 172:
Chapter 6 Stiffened Compression Fla
Page 173 and 174:
Stiffened Compression Flanges of Bo
Page 175 and 176:
cross-section in which the secant s
Page 177 and 178:
longitudinal compression of the lon
Page 179 and 180:
webs of main girders is denoted by
Page 181 and 182:
Page 183 and 184:
wherefrom Ms ¼ 2 3 PE P The net be
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Chapter 7 Cable-stayed Bridges 7.1
Page 197 and 198:
Cable-stayed Bridges 185 cables con
Page 199 and 200:
The following is a list of cable-st
Page 201 and 202:
(a) Fan system (b) Harp system (c)
Page 203 and 204:
7.3.2 Ropes causing lateral compres
Page 205 and 206:
The spiral winding of wires around
Page 207 and 208:
polyethylene or even steel tube. Or
Page 209 and 210:
See Fig. 7.7. Imagine a cable-stay
Page 211 and 212:
It may be noted that: Et is higher
Page 213:
Reference Cable-stayed Bridges 201
Page 216 and 217:
204 The Design of Modern Steel Brid
Page 218 and 219:
206 The Design of Modern Steel Brid
show all

The Design of Modern Steel Bridges - TEDI

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?