To prevent undue vibration of tension members, AISC specifications for ASD and LRFD suggest that the slenderness ratio L/ r be limited to 300. This limit does not apply to rods.
Tension members have three strength-limit states, yielding in the gross section, fracture in the net section, and block shear (see Table 6.17 and Art 6.15.3).
For fracture in the net section, as defined by the AISC specifications, the critical net section is the critical cross section over which failure is likely to occur through a chain of holes. The critical section may be normal to the tensile force, on a diagonal, or along a zigzag line, depending on which is associated with the smallest area.
A net section is determined by the net width and the thickness of the joined part. Net width is defined as the gross width less the sum of the diameters of all holes in the chain plus s2/4g for each gage space in the chain, where s is the spacing center-to-center in the direction of the tensile force (pitch) of consecutive holes and g is the transverse spacing center-to-center (gage) of the same consecutive holes. The critical net section is defined by the chain of holes with the smallest net width.
For angles, the gross width is the sum of the width of the legs less the thickness. In determining the net section, the gage should be taken as the sum of the gages, measured from the backs of the angles, less the thickness of leg.
In the computation of net section for any tension member, the width of the bolt hole should be taken as 1â„16 in greater than the nominal dimension of the hole normal to the direction of the applied stress. Nominal hole dimensions are summarized in Table 6.30. For design of splice and gusset plates in bolted connections, the net area should be evaluated, as indicated above, except that the actual net area may not exceed 85% of the gross area.
