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Steel Design to Eurocode 3

Tension Members As the tensile force increases on a member it willstraighten out as the load is increased. For a

member that is purely in tension, we do not needto worry about the section classification since it willnot buckle locally.

A tension member fails when it reached theultimate stress and the failure load is independentof the length of the member. Tension membersare generally designed using rolled section, barsor flats.

Tensile Resistance

EN 1993-1-1 Clause 6.2.3(1) Equation 6.5 statesthat the design tensile force (N t,Ed ) must be lessthan the design tensile resistance moment (N t,Rd )

The tensile resistance is limited by the lesser of:

Design Plastic Resistance N pl,Rd

Design Ultimate Resistance N u,Rd

Design Plastic Resistance, N pl,Rd

Npl,Rd is the plastic design resistance, and isconcerned with the yielding of the gross cross-section .

Equation 6.6 gives the expression used tocalculate N pl,Rd :

Design Ultimate Resistance, N u,Rd

Nu,Rd is the design ultimate resistance of the netcross-section, and is concerns with the ultimatefracture of the net cross-section, which willnormally occur at fastener holes.

Equation 6.7 gives the expression used tocalculate N u,Rd :

Partial Factors M

M UK N.A. ValueM0 Resistance of cross-sections 1.0

M2 Resistance of cross-sectionsin tension to fracture 1.25

Characteristic Strengths f y and f u

The UK National Annex says you should get thevalues of f y and f u from the product standards. For hot-rolled sections you can use the table below.

Steelgrade

f y (N/mm2) f u (N/mm

2)

t

1 6

1 6

< t

4

0

4 0

< t

6

3

6 3

< t

8

0

t