Mr. Peter Mason (Member of Council) said it had been mentioned in the paper that it looked as though the Roman engineering organization for large engineering projects was very similar to that of today. There had been bills of quantities, etc. and work had been carried out by contractors. He wished to know how the engineering had been done. Had it been done by military engineers or had there been trained civilian engineers?
Mr. P. S. A. Berridge (Assistant Engineer (Bridges), Western Region, British Railways) first said how much he appreciated being allowed to join in the discussion. It was a privilege for which he was most grateful.
Dear Sir, With reference to the article, ‘The elastic analysis of simple rectangular grids by virtual work methods’ by J. B. Martin, BSc, PhD, appearing in The Structural Engineer in June 1963, I would like to point out that a numerical error has been committed in the solution for the numerical example given in the article.
A review of existing literature on epoxy concrete (in which glue is used in place of cement) and on the use of epoxy and polyester resins for joints in concrete shows that joints stronger than the concrete can be made but that poor surface preparation leads to a serious loss of strength. There is little information on the creep of joints under shear stress. R. PAUL JOHNSON
The problem of fatigue in welded crane girders is introduced and its importance as a design criterion discussed. It is attributed to the local stresses generated in the top flange and upper part of the web of the girder beneath the crane wheels. Some significant stress patterns under these conditions are enumerated and discussed. A.G. Senior
The paper describes the application of ultimate load design by yield line analysis in pavement slabs and confirms the finding of recent AASHO test results in regard to long-term serviceability of concrete pavements. Based on the following assumptions:- (1)strain is proportional to distance from the neutral axis in accordance with a straight line law, (2)elastic deformations are negligible in comparison with the plastic deformations (this means that the slab elements between the yield lines remain plane and all the deformations take place in the yield lines), (3) yield lines, which are straight, being the meeting lines of two planes, end at a boundary of the slab, (4)a yield line, or yield line extended, passes through the intersection of the axes of rotation of adjacent slab elements, (5)axes of rotation in general lie along the lines of supports of formulae has been developed for the design of concrete pavement. Dr. R. K. GHOSH