A Convergence Technique for Determining the Elastic Critical Load of Rigidly Jointed Trusses Written

THE PRESIDENT said the meeting would agree that they had listened to a very able introduction of a most informative paper. A good deal of work in connection with this subject had passed and was passing through Mr. Waters' hands and it was being dealt with in the efficient and quiet way which was symbolised by the efficient and quiet way in which he had introduced the paper.

The different types of shear failure of reinforced concrete rectangular and T-beams are described in order to show that the shear strength depends on factors additional to those recognized by the design formulae. Results of experiments on the influence on shear strength of the size of the compression zone of the beam and of hooks on plain and deformed bars are presented. Tests on rectangular beams with varying amounts of compression reinforcement suggest that this does not affect the shear capacity of the beam. A. M. Neville and and E. Lord

The problems connected with the design of pile groups are often the subject of lengthy and complicated analyses. This applies particularly to pile groups which have to withstand relatively large horizontal thrusts, where the use of raking piles would be advantageous. Because of the indeterminate nature of piled foundation structures, an exact analysis of structural members has not yet been possible; and this presents a difficulty which is quite apart from the problems of soil mechanics involved. Investigations into the action of earth mass around piles and attempts to utilize the shear strength or the modulus of elasticity of soil for defining the ground resistance to horizontal thrust, do not appear to have yielded conclusive results of great practical value; and easily applied design methods have certainly not yet been derived from them. A. Kroie