Issue 16

Dr. G. H. Little (M)/Dr. A. G. Kamtekar (University of Birmingham): The problem considered in the paper, namely the effect of holes on the strength of web plates, is one of significant interest to designers of steel structures. However, we feel that the development of the theoretical method is rather brief, and we would be interested in clarifying several points that occurred to us while reading the paper.

This paper is the result of ajoint research project between the Department of the Environment (NI) Roads Service and the Department of Civil Engineering, the Queen's University of Belfast, into the economic use of M-beams for bridge decks. The results of load distribution tests on a 11.815 m span M-beam bridge deck with beams spaced at 2 m and 1.5 m and a standard 160 mm reinforced concrete slab are reported. J. Kirkpatrick, Professor A.E. Long and A. Thompson

Studies of deformation patterns and the distribution of diagonal tension strains in the webs of beams with no service holes have enabled the optimum position for such holes to be identified. B.O. Hilson and P.D. Rodd

Three standard M5 precast concrete bridge beams from a long line bed of five beams were rejected because of cracks that occurreduring manufacture. Subsequently, an extensive series of tests was carried out on the beams to investigate the effects of the early cracks on performance. It is concluded that, under certain circumstances, autogenous healing can restore the integrity of pre-tensioned beams so that service performance is not affected. A procedure for assessing the acceptability of such beams for incorporation in the permanent works is suggested. J.K. Green, P.J. Cookson and K.A.L. Johnson