WEB POST STRENGTH IN CASTELLATED STEEL BEAMS

An experimental study is reported in which 16 castellated beam specimens of the standard British module have been subjected to locally applied compressive loading over a web post. Experimental failure loads were found to be relatively insensitive both to cross-section geometry and to the exact way in which the load was introduced into the web post. The results have been used as the basis for a critical evaluation of a number of possible design approaches, which has shown that modified versions of accepted methods for determining the local web strength of solid web sections are not generally suitable for castellated beams. On the basis of the mode of failure observed in the tests an equivalent strut method has been proposed as a suitable basis for design. The geometrical similarity of standard British castellated sections suggests that a simple version of this method, in which an average compressive strength is used, would be suitable for preliminary strength estimates.