The strength of laterally restrained, rein forced concrete slabs is significantly enhanced by the effect of ‘arching’ or ‘compressive membrane action ’. In this paper, details and results of seven tests carried out on uniformly loaded, laterally restrained rectangular slabs are presented. These results are compared with the results of similar tests on unrestrained slabs. The basic formulations of a simple, rationally based method for predicting the enhanced load capacity of rigidly restrained slabs are then given. The method is shown to give good correlation with a wide range of test results from various sources. G.I.B. Rankin, A.S. Skates and Professor A.E. Long
Mr J. A. Waller (F) (Oscar Faber Consulting Engineers) Mr Marsh has presented a very important message - unfortunately, it is a message which has not yet reached many purchasers of buildings.
Preservation of structural timbers Mr P. A. Campbell, of Vermont South in the State of Victoria, Australia, has written voicing concern at the statement appearing on p10 of BS 5589 to the effect that ‘the heartwood of radiata pine is treatable’. He believes that this information may be misleading and, if not modified, could lead to the premature failure of ‘significant engineering structures’: Among other uses, treated radiata pine is being used for crib retaining walls in the UK and the untreatable heartwood should fail within a few years. Do any of our members have any experience of this? Verulam