A Conception of the Creep of Unreinforced Concrete, and an Estimation of the Limiting Values

DURING the last few years the term "Stadia" has frequently been used in describing sports enclosures. It is derived from the old Greek word " Stadium," which originally applied to the foot race course at Olympia. This structure was erected in the 3rd century, B.C., and was 630 feet in length, with two parallel tiers of stone seats along each side, joined at one end by a semicircular curve. It is interesting to note that the distance between the two end pylons measured 606.75 feet, and that this was afterwards adopted by the Romans as a measure of distance, eight "Stadia" being equal to one Roman Mile. James Reed

WHEN the fist oil well was sunk by Col. Edwin L. Drake in 1859, the chief aim of the oil refiners from then until the late nineties, when the automobile made its appearance, was the production of paraffin or lamp oil, and all the by-products were surreptitiously emptied into any near-by creek or river, as being the easiest way of disposing of this residue, which was of no apparent use. George Noble

It is no exaggeration to say that the success of reinforced concrete as a structural material has depended very largely on the ability of concrete to adjust itself to stress conditions by means of creep. Scattered through the literature of reinforced concrete we find reference to this power of self -adjustment from the very early days of reinforced concrete construction, but it is only comparatively recently that the mechanism by which it operates has been investigated sufficiently to enable us to predict the progressive stress changes with some semblance of accuracy. It may well be suggested that this investigation, involving as it does all the factors producing progressive volume and length changes in concrete, has done more to extend our knowledge of the behaviour of reinforced concrete than anything else during the last decade. As a consequence, those who have studied these changes have learned to regard the assumptions we have to make in order to produce designs within a reasonable period from a new angle, and to realise that, although they serve reasonably well as a means to an end, they result in computed stresses that are, in general, very different from the actual stresses. W.H. Glanville