THE PRESIDENT proposing a vote of thanks to the Author, congratulated Mr. Underwood on his up to date paper and said the subject of off-street parking was very much in our minds and would be of considerably more importance in the future than it had been in the past.
THE PRESIDENT introduced the Author, who then gave a precis of his paper, illustrating it with a series of diagrams and photographs on the screen.
The Author develops a method of design of slab type stairways, based on deductions made from full scale and scale model tests, which incorporates the extcnsional stiffness produced by the interaction of the stair flights and landings and which has been succcssfully applied in practice. A. C. Liebenberg
The article gives an approximate analysis, using the energy method, for the elastic stability out of their plane of trusses with outstanding compression chords, the tension chord being held in position. Previous discussions of this problem have usually considered it in terms of the stability of the compression chord as a member subjected to various elastic restraints. In the present treatment, the truss is considered as a whole, account being taken of the flexural and torsional rigidities of all the members, and of partial restraint of the tension chord against twisting. The analysis is interpreted in relation to a number of common arrangements of vertical and diagonal web members. The analysis is derived for a truss in which the compression chord is of uniform section, carrying a uniform thrust, but the use of some of the results as approximate criteria of stability for non-uniform conditions is also discussed. M. R. Horne