The Design of Modern Steel Bridges - TEDI

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Table 2.1 Properties of some commercially available steel Specification Grade Minimum yield strength (N/mm 2 ) Minimum tensile strength (N/mm 2 ) Charpy toughness Percentage elongation Maximum carbon equivalent (%) BS EN 10025: 1993[4] S235 175–235 320–510 27 J at þ20 to 20 C 21–26 0.35 to 0.40 S275 205–275 380–580 27 J at þ20 to 20 C 17–22 0.40 to 0.44 S355 275–355 450–680 27 or 40 J at þ20 to 20 C 17–22 0.45 to 0.49 BS EN 10155: 1993[5] (Weathering) BS EN 10113: 1993[6] (Heat-treated) AASHTO M270[7] or ASTM A709[8] S235 S355 215–235 315–355 340–510 490–680 27 J at 0 Cto 20 C 27 or 40 J at 0 Cto 20 C 22–26 18–22 S275 225–275 350–510 24 0.40 to 0.42 S355 S420 295–355 340–420 450–630 500–680 40 J at 20 Cto27Jat50 C 22 19 0.43 to 0.45 0.48 to 0.52 S460 400–460 550–720 17 – 36 248 400 50 345 448 AASHTO M270 contains 50W 345 483 supplementary requirements 70W 483 621 100 100W 621–689 689–758 0.44 0.52
given in this table: Types and Properties of Steel 47 (1) Western European Steel: (a) EN 10025 covers commonly used steel for welded, bolted or riveted structures for service at ambient temperature. EN 10155 covers weathering steel for similar applications. EN 10113 covers steel suitable for heavily loaded structures for service at low temperatures; it has better notch toughness values and lower carbon percentage and carbon equivalent values. (b) According to the definitions given in Section 2.1, steel grades designated S235 and S275 are weldable carbon steel; S355 weldable high strength steel, and S420 and S460 heat-treated carbon steel. (c) Each grade of steel to EN 10025 and 10155 is suffixed by quality designations JR, JO, J2 and K2 which are for successively higher qualities in Charpy toughness and weldability. Additional quality designations G1–G4 represent the deoxidation process, N represents normalised steel and C represents suitability for cold forming. (d) EN 10113 steels come with two minimum Charpy toughness values of 40 J at 20 C and 27 J at 50 C; they also come in two delivery conditions of ‘normalised’ and ‘thermo-mechanically rolled’, designated by N and M respectively; the latter steel has lower carbon percantage and carbon-equivalent values. (e) Some steel grades may not have guaranteed maximum carbonequivalent values and/or notch toughness and/or minimum percentage elongations; they should be used in welded bridge structures only after further bridge-specific testing. (f) In each grade of steel, the minimum yield strength, the minimum tensile strength and the minimum percentage elongation requirements reduce with increasing thickness of the product within the range shown in the table. Hence additional caution is needed for using very thick products. (g) E grade steel to EN 10025 may not be suitable for welded bridge structures, as it does not have guaranteed maximum carbon percentage and minimum Charpy toughness values. (2) North American Steel: (a) Steel to AASHTO designation M270 grades 36, 50, 50W and 70W are suitable for welded bridge structures; suffix W in the grade represents weathering steel. Steel to grades 100 and 100W have a rather narrow margin between yield stress and minimum strength in percentage terms, and hence structures built with such steel may not possess the post-yielding reserve of strength before collapse that can be expected from structures built with lower grade steels. (b) ASTM A709 steels are equivalent to AASHTO M270 steels of identical grades with respect to yield strength and minimum strength.
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The Design of Modern Steel Bridges
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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 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
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and stresses caused by lateral defl
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Figure 5.3 Beam cross-section. In t
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Rolled Beam and Plate Girder Design
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Table 5.2 Effective length factors
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stress is equal to p 2 E/(Le/r) 2 )
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equation (5.16) has been adopted fo
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The strain energy of the elastic re
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Figure 5.6 Buckling of plates in co
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Figure 5.8 Buckling of plate under
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techniques. It may be noted that th
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5.4.3 Effect of residual stresses R
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Aw ¼ 40 mm 2 , allowing for a smal
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Basler and Thurlimann were the firs
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Ostapenko/Chern gave the following
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where m ¼ Mp b 2 twsyw ty ¼ syw p
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the case of equal flanges, the tota
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emains flat until an elastic critic
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longitudinal compression is given b
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where Peq ¼ s1tB PE Ps Pcro Peq1
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Figure 5.27 Tension-field forces in
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5.5.6 Design of longitudinal web st
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when Le is the effective length for
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pffiffiffiffiffiffiffiffiffiffiffif
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een derived as a condition for trea
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For interaction of various stress c
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must be at least i.e. 1 IsxbB 4 2 a
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Chapter 6 Stiffened Compression Fla
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Stiffened Compression Flanges of Bo
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cross-section in which the secant s
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longitudinal compression of the lon
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webs of main girders is denoted by
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wherefrom Ms ¼ 2 3 PE P The net be
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Chapter 7 Cable-stayed Bridges 7.1
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Cable-stayed Bridges 185 cables con
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The following is a list of cable-st
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(a) Fan system (b) Harp system (c)
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7.3.2 Ropes causing lateral compres
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The spiral winding of wires around
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polyethylene or even steel tube. Or
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See Fig. 7.7. Imagine a cable-stay
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It may be noted that: Et is higher
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Reference Cable-stayed Bridges 201
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204 The Design of Modern Steel Brid
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206 The Design of Modern Steel Brid
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