Solid softwood

member where the contact

Member support condition

timber member

length t > 400 mm

Continuous support (Figure C1a)

kc,90 = 1-25

kc,90 = 1-5

Discrete support (Figure C1b)

kc,90 = 1-5

kc,90 = 1-75

6.1.7 Shear

In the proposed amendment, a section will be added to take account of the influence of cracks on the shear strength of members subjected to bending. In the proposal the width of the member will be reduced by multiplying its width, b, by a modification factor, kcr, the value of which will be dependent on the member material being used. The effective width of the member, bef, will be:

bef = kcrb where b is the actual width of the member and the value of kcr for different materials will be as given in Table C2.

The derivation of the shear stress will remain as described in 4.5.2, but the effective width, bef, rather than the actual member width, b, shall be used where the influence of cracks in the member has to be taken into account. The derivation of the shear strength is not altered.

8.3.1 Laterally loaded nails

The proposed change requires pre-drilling to be used in timber when the diameter, d, of a laterally loaded nail exceeds 6 mm. This corrects the wrong value of 8 mm given in EC5,, and the error has been referred to in the book.

(a) Member on a continuous support (b) Member on a discrete support

Fig. C.1. Members with continuous or discrete support.


a is the centre of gravity of the threaded part of the length of the screw in the member.

Fig. C.2. Spacings, edge and end distances for screws.

Table C2 The value for kcr for flexural members formed from solid timber, glued laminated timber or other wood-based products

Member material

Value for kcr

Solid timber member

0 0

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