Final - transformed section properties:

The largest stress to strength ratio will be the larger of the permanent action/£mod.perm and the combined permanent and variable action/kmod.short. Let the ratio of one to the other be r:


i.e. the variable loading will produce the higher stress/strength ratio, so the factor f2 will be associated with variable loading.

The psi factor for this loading condition is f 2a = 0

Consequently, for this condition the instantaneous and final properties will be the same. We only need to analyse for the instantaneous condition.

7. Bending stress check in the flange

Stress in flange due to bending: Bending stress in the top flange,

Bending stress in the bottom flange,

Md i, hbf\ E1p.c.0.mean 2 Of.t.max.d.c = — ' I h - J - I ' - Of.t.max.d.c = 2.62 N/mm2

Axial strength of the top flange,

Axial strength of the bottom flange,

Stresses in the top and bottom flanges are OK

8. Bending and shear stress check in the web

Bending stress in the web:

Maximum distance from the NA to the extreme fibre, y1

Bending strength of the web, fw.d ' ksys ' kh ' fm.k ^ _ . . ,T, 2

Bending stress in the web is OK

Shear strength of the web:

First moment of area of the section above the NA about the NA, 5t f NA

( htf \ (yt - htf)2 5 3 St.f.NA = bef.c.tfd ■ htf ■ I yt - — I + bw.ef.f--2--St.f.NA = 8-92 x 105 mm3

Shear stress at the NA position, rv.d = ——Tv.d = 0.26 N/mm2

Shear strength of the web fv.d =-:---- fv.d = 1.54 N/mm2

material, fv.d Km

Design shear strength is greater than shear stress; therefore OK

Shear strength of the glued joint between the web and the flanges:

First moment of area of the top St.f = bef c tfd ■ htf ■ I yt —— flange about the NA, St.f ^

First moment of area of the bottom Sb f = bef t tfd ■ hbf ■ I h - yt--

Shear width at beam/flange inter- beffw = 3 ■ bw + br face, beffw

Mean shear stress in the top flange ttmean.d =---- —--

above the glue line, ttmean.d Ief' f w E0 mean

Mean shear stress in the bottom tbmean.d =

If. hpff Fc flange below the glue line, tbmean.d Ief ff w E0 mean

Rolling shear strength of the top flange /v.2.90.d ' ksys ' / 2p.r.k

Rolling shear strength of the bottom flange, /v190 d

Rolling shear criteria /v.90.d (equation (7.56) (EC5, 9.1.2(6))

0 0

Post a comment