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Steel Designers' Manual - 6th Edition (2003)
718 Plate and stiffener elements in connections
SI
Fig. 25.6 Deduction factors
direction
of stress
Deduction for holes equals greatest of:
(1) Area of hole B
(2) Area of holes B+C—
(3) Area of holes A+B+C— s12t —
(4) Area of holes A+C—
(Si— s2)2t
4(g1÷ 92)
25.6), 1 where s is the bolt pitch in the direction of stress, t is the thickness of the
material and g is the bolt gauge transverse to the pitch.
Where plates are loaded in shear, the beneficial effects of strain hardening permit
the presence of bolt holes to be ignored provided that A v.net ≥ 0.85 A v / K e, where
A v.net is the net area of the plate and K e is the effective net area coefficient, taken as
1.2 for S275 steel and 1.0 for S355 steel. If A v.net is less than 0.85A v√K e then the shear
capacity is given by 0.7p yK eA v.net.
Where holes are present in a compression flange no allowance need be made for
them. The presence of holes in a tension flange may be ignored if the net area of
the tension element (after deducting the holes), anet, is greater than the area of the
tension element divided by K e, the effective net area coefficient. Where this is not
the case, the effective net area may be taken as K ea net.
25.4.2 Gusset plates
The design of gusset plates can be carried out by developing separate rules for each
of the possible modes of failure (e.g. in Fig. 25.7, failure on line A–F or failure by
tearing out of the section G–C–D–H, etc.).A simpler procedure is normally adopted
in which dispersion of the load is assumed and only transverse sections are checked
in tension or compression (with the addition of bending where appropriate). It is
considered that 30° is a satisfactory maximum angle of dispersion.
4g2