The Design of Modern Steel Bridges - TEDI

Recommendations

Info

154 The Design of Modern Steel Bridges Yielding check – Hencky–Mises equivalent stress at top edge: se ¼f150 2 þ 3 60 2 g 0:5 ¼ 182:5N=mm 2 Reference [2] allows for some plastic redistribution of the bending component of the longitudinal stress by taking only 0.77 times the bending stress. The top panel is subjected to 107 N/mm 2 direct compression and 43 N/ mm 2 bending stress. Hence se ¼fð107 þ 0:77 43Þ 2 þ 3 60 2 g 0:5 ¼ 176:4N=mm 2 Bottom edge: se ¼f280 2 þ 3 60 2 g 0:5 ¼ 298:7N=mm 2 With plastic redistribution of bending stress in bottom panel se ¼fð176:8 þ 0:77 103:2Þ 2 þ 3 60 2 g 0:5 ¼ 276:5N=mm 2 Limiting value of se ¼ 355=ð1:1 1:05Þ ¼307:4N=mm 2 Hence the design is satisfactory for yielding. Buckling check (1) Top panel: to check if the panel can be deemed restrained for compressive and shear stresses. To take compression first BT 2 f b2 500 252 ¼ t 5002 ¼ 0:125 10 which is greater than the minimum required as calculated below sf ¼ 152:15 1:1 1:05 ¼ 175:7N=mm 2 S ¼ b t rffiffiffiffiffi rffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi sy 355 ¼ 50 ¼ 2:08 E 205 000 0:024ðS 1Þfs 2 yf =ðs2yf s2f Þg ¼ 0:024 1:08 1:325 ¼ 0:0343 For shear, also, the slenderness ratio is such that the plate can be taken as restrained. The panel is subjected to 107 N/mm 2 compressive, 43 N/mm 2 bending and 60 N/mm 2 shear stresses. Buckling stress coefficients are obtained from Reference [2] for rffiffiffiffiffiffiffi b sy ¼ 50 and f ¼ 3 t 355 as follows: K1 ¼ coefficient for axial compression ¼ 0.675 Kb ¼ coefficient for pure bending ¼ 1.205 (a value higher than 1.0 recognises plastic redistribution of bending stress at ultimate state) Kq ¼ coefficient for shear ¼ 0.966.
For interaction of various stress components the following ratios are calculated: mc ¼ s1g mg f3 syK1 mb ¼ sbg mg f3 syKb mq ¼ tg mg f3 syKq 2 ¼ 2 ¼ ¼ 107 1:05 1:1 355 0:675 43 1:05 1:1 355 1:205 60 1:05 1:1 355 0:966 mc þ mb þ 3mq ¼ 0:652 < 1:00 ¼ 0:516 2 ¼ 0:013 2 ¼ 0:041 Hence the panel is safe for buckling. (2) Middle panel: this panel is subjected to 4.8 N/mm 2 tensile, 68.8 N/mm 2 bending and 60 N/mm 2 shear stresses. Being an internal panel, it is deemed to be restrained. Buckling stress coefficients are obtained from Reference [2] for rffiffiffiffiffiffiffi b sy ¼ 80, and f ¼ t 355 150 ¼ 1:875 80 as follows: K1 ¼ 48 Kb ¼ 1:15; interpolating between f ¼ 1 and 2 Kq ¼ 0:939 4:8 1:1 1:05 mc ¼ 355 0:48 2 68:8 1:1 1:05 mb ¼ 355 1:15 mq ¼ 60 1:1 1:05 355 0:939 mc þ mb þ 3mq
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 16 and 17:
Page 18 and 19:
Page 20 and 21:
Page 22 and 23:
10 The Design of Modern Steel Bridg
Page 24 and 25:
Page 26 and 27:
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Page 34 and 35:
Page 36 and 37:
Page 38 and 39:
Page 40 and 41:
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Table 2.1 Properties of some commer
Page 60 and 61:
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: Rolled Beam and Plate Girder Design
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 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 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: een derived as a condition for trea
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 183 and 184: wherefrom Ms ¼ 2 3 PE P The net be
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

Create successful ePaper yourself

Delete template?

Save as template?