The summary provided by the authors of various recommendations and 13 'rule of thumb' equations, supported by a most impracticable example, is of doubtful value to the designer. The proposed method for the solution of the problem is given in a complicated form. S.K. Liszka
A method of designing reinforced concrete sections subjected to membrane stresses has been presented. The method proposes separate design for horizontal, vertical and shear stresses which are in excess of the concretess carrying capability. The method is simple and is suitable for use in the everyday design work of such structural elements. N.K. Subedi
Mr. K. M. Brook: It is a pleasure to read a paper in which the authors have presented their results and observations so very clearly. This clarity should not, however, cause us to overlook the considerable amount of painstaking effort involved in their work.
Guidelines arising from the use of grillage analysis in the design of cellular bridge decks are discussed. Differences between the physical behaviour of cellular decks and a grillage of beams are identified, leading to conclusions on the evaluation of stiffness parameters for an idealized grillage. E.C. Hambly and E. Pennells
Conversion Measurements of the degree of conversion of the concrete in existing buildings indicate that most concrete has reached a high level of conversion in a few years. The results of crushing tests on highly converted concrete specimens cut from beams also indicate that strength is very variable and that some concrete suffers substantial losses of strength with respect to the strength at one day on which the design was usually based. In the appraisal of buildings therefore it is advisable to assume that all concrete has reached or will reach, during its expected life, a high level of conversion, nevertheless, in the majority of constructions the loss of strength is not sufficient to endanger the structure.
A braced core may be defined as a particular form of bracing a steel skeleton in which the members, designed specifically for carrying the forces and moments due to lateral loads, are confined to within the core area of the building. A study is made in this paper of the behaviour of such a braced core subjected to torsional loads. B.S. Taranath
Our thanks to Mr. A. H. Jenkins (F) who has enlightened us about Paxton's source of inspiration (May 75) : : The water lily was at Chatsworth, not Kew. George F. Chadwick in Works of Sir Joseph Paxton gives the reference as Royal Society of Arts, Transactions, Vol. LVII, 1850-51. The idea had been developed before in connection with the Chatsworth Lily House detailing. Verulam