An investigation into the behaviour of sand in a model silo

Dr. D. V. Reddy (Associate-Member) writes that Mr. Rawlings needs to be commended for the generalization of the moment distribution procedure for space frames. The use of direction cosines and matrix formulation of carry-over terms makes the analysis very elegant.

The behaviour of rigidly-jointed redundant trusses when loaded to collapse is investigated both theoretically and experimentally. Trusses which apart from the effect of joint rigidity are singly redundant are considered, and it is shown that their behaviour can be predicted by a method due to Ziegler if the relationships between axial load and axial deformation are known. For a particular set of model light alloy trusses the behaviour under steadily increasing load is predicted using axial load-axial deformation relations for the compression members obtained in a previous series of tests. Satisfactory agreement between predicted and observed collapse loads is demonstrated and the ability of the trusses to carry additional load after buckling of the compression members is also shown. B. G. NEAL and D. M. GRlFFITHS If the relationship between

Mr. J. R. Lowe (Member) said there was a great deal of useful information in the two papers and that he intended to confine his remarks mainly to the engineering applications, rather than to the research work described. He showed illustrations of the Hobart Bridge, which had been the initial cause of the paper by Dr. Rydzewski and Mr. Whitbread (who at the commencement of the work had been in the employment of Mr. Lowe’s firm, E. W. H. Gifford and Partners).