Single Angle Struts:
The slenderness ratio (λ) should not exceed 180. Here leff is taken as the centre to centre of intersections at each end, if connected through a single bolt/rivet. If connected by two or more such rivets/bolts in line of the member or with welds a coefficient of 0.85 may be used.
The procedure of design (or finding the member size when the load is given) is a trial and error process involving the following steps:
(a) Supposing an arbitrary value of λ, the value of σac for the particular σy may be taken from Table 2.
(b) An approximate sectional area, A = P/σac is calculated and an angle section of this area.
The actual effective length (leff) and the minimum radius of gyration (rmin) of the angle chosen is then taken from the Handbook and actual λ is calculated. The corresponding σac is compared with the σac assumed in Step (a) above. Modifications are made if σac (actual) is less than σac (assumed) or is much greater than it (difference more than 5%), and a retrial is made with a different section.