Tension members - The Behaviour and Design of Steel Structures to EC3 - page 44

to EC3. The factor 0.9 in equation 2.20 ensures that the effective partial factor
γ M 2 / 0.9 ( ≈ 1.22 ) for the limit state of material fracture ( N u , Rd ) is suitably higher
than the value of γ M 0 ( = 1.0 ) for the limit state of yielding ( N pl , Rd ) , reflecting the
influence of greater variability in f u and the reduced ductility of members which
fail by fracture at bolt holes.

2.6.3 Eccentrically connected tension members

The EC3 method of strength design of simple angle tension members which are
connectedeccentricallyasshowninFigure2.6issimilartothemethoddiscussed
in Section 2.6.2 for concentrically loaded members, with the '0.9 A net ' used in
equation 2.20 being replaced by an effective net area A net , eff , as described in
Section 2.3.

2.6.4 Tension members with bending

2.6.4.1 Cross-section resistance

EC3 provides the conservative inequality

N t , Ed

N t , Rd + M y , Ed M y , Rd + M z , Ed M z , Rd ≤ 1

(2.21)

forthecross-sectionresistanceoftensionmemberswithdesignbendingmoments
M y , Ed and M z , Ed ,where M y , Rd and M z , Rd arethecross-sectionmomentresistances
(Sections 4.7.2 and 5.6.1.3).
Equation 2.21 is rather conservative, and so EC3 allows I-section tension
members with Class 1 or Class 2 cross-sections (see Section 4.7.2) with bending
about the major ( y ) axis to satisfy

1 − N t , Ed / N pl , Rd
1 − 0.5 a

M y , Ed ≤ M N , y , Rd = M pl , y , Rd

≤ M pl , y , Rd

(2.22)

in which M N , y , Rd is the reduced plastic design moment resistance about the
major( y )axis(reducedfromthefullplasticdesignmomentresistance M pl , y , Rd to
account for the axial force (see Section 7.2.4.1) and

a = ( A − 2 bt f )/ A ≤ 0.5, (2.23)

in which b and t f are the flange width and thickness respectively. For I-section
tension members with Class 1 or Class 2 cross-sections with bending about the