Applied Loads and Stability of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 190

0 : 9 A net f u

g M2

N u , Rd ¼ ð 3 : 87 Þ

where A net is the net area of a cross section (its gross area A less appropriate
deductions for all holes and other openings) and f y and f u are the yield and
ultimate stresses of steel, respectively. Where capacity design is requested,
the design plastic resistance N pl,Rd should be less than the design ultimate
resistance of the net section at fasteners holes N u,Rd . In category C connec-
tions, detailed in EC3 (BS EN 1993-1-8) [2.13], the design tension resis-
tance N t,Rd of the net section at holes for fasteners should be taken as
N net,Rd , where

A net f y
g M0

N net , Rd ¼ ð 3 : 88 Þ

3.9.3 Design of Compression Members
Similar to tension members, the design of compression members is also cov-
ered by EC3 [1.27,2.11]. The code recommends that the design strength of
the compression force N Ed at each cross section shall satisfy
N Ed

N c , Rd 1

: 0 ð 3 : 89 Þ

The design resistance of the cross section for uniform compression N c,Rd
should be determined as follows:

Af y
g M0

N c , Rd ¼ for class 1, 2, or 3 cross sections ð 3 : 90 Þ

A eff f y
g M0

N c , Rd ¼ for class 4 cross sections ð 3 : 91 Þ

According to EC3 [2.11], a compression member should be verified
against buckling as follows:

N Ed
N b , Rd 1

: 0 ð 3 : 92 Þ

where N Ed is the design value of the compression force and N b,Rd is the
design buckling resistance of the compression member. The design buckling
resistance of a compression member should be taken as

wAf y
g M1

N b , Rd ¼ for class 1, 2, and 3 cross sections ð 3 : 93 Þ