Unrestrained Beam Design – Ii

A cantilever beam is completely fixed at one end and free at the other. In the case of cantilevers, the support conditions in the transverse plane affect the moment pattern. For design purposes, it is convenient to use the concept of notional effective length, k, which would include both loading and support effects. The notional effective length is defined as the length of the notionally simply supported (in the lateral plane) beam of similar section, which would have an elastic critical moment under uniform moment equal to the elastic critical moment of the actual beam under the actual loading conditions. Recommended values of ‘k’ for a number of cases are given in Table 1. It can be seen from the values of ‘k’ that it is more effective to prevent twist at the cantilever edge rather than the lateral deflection.