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As the result is less than 1 the section is satisfactory as a latticed column in strength class C22 timber a m,z

Forces in the bracing members and their connections

Shear force across the flanges, Vd (equation (8.35); EC5, equation (C.5)) vd =

60 kc if Xef < 30 if 30 < Xef < 60 if 60 < Xef

Member and connection forces - noting bracing is on both faces:

Design force in each horizontal bracing Td = - ■ Vd Td = 1.29 x 103 N

member, Td

Design force in each diagonal bracing Tb =-^-

member, Tb

The design forces in the end connections will be Td/2 and Tb/2.

Example 8.8.4 The built-up box section, shown in Figure E8.8.1, is to be assembled using nailed joints rather than glue and will be as shown in Figure E8.8.4. It is made from 200 mm by 44 mm solid sections of strength class C16 timber to BS EN 338:2003, functioning under service class 2 conditions. The column is 4.50 m high, is pinned and held laterally in position at each end, and is in a Category C area in accordance with BS EN 1991-1-1:2002. The nails are smooth round, 3.00 mm diameter at 75 mm c/c, the stiffness per nail at the SLS is 928 N/mm, and the lateral design strength of each nail is 421 N.

Check if this section complies with the strength requirements of EC5 at the ULS, when subjected to the loading applied to the column in Example 8.8.1, taking creep effects into account.

The axial compression loading is along the centroidal axis and:

The characteristic permanent action is 40 kN; The characteristic variable action (medium term) is 80 kN.

200 mm

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