New type of supports and hinges

Abstract

Modem constructional tendencies are largely dependent on the increasing variety and improvement of building materials available in commercial quantities. These materials can be divided into natural and synthetic, and the distinguished engineers Leonhardt and Andrä discuss the best uses of synthetic resins and artificial rubber, as applied to new types of supports and hinges. In laboratory and full scale tests, the commercial versions of resins known as Neoprene and Teflon have been chosen as being, at least for the time being, specially suitable for the purposes envisaged by the above authors. They hope that these materials will find a growing number of uses in the field of engineering and construction. The authors have carried strict and detailed investigations on the strength and elastic properties of these resins, when subjected to high stresses. High quality materials are required to withstand the concentrated stresses close to the points of application of the loads. The fatigue effect, as a long time weakening process, must also be carefully considered. These concentrated loads, in limiting cases, may be likened in their effect to that of sharp points or edges. The new materials make it possible to reduce considerably the loadings areas. A further factor to be taken into account is the structural rigidity, which the authors have studied closely, relating it to the flexibility at the points of support and at the hinges. The various types of supports have been discussed, and graphical information on their possible uses has been provided. Specific functional requirements demand corresponding measures of flexibility at the supports, as, for instance, allowance for dilations, due to temperature changes. Furthermore, the points of support of a structure should have an optimum cross sectional area, depending on the other circumstances. Finally the authors refer to the future possibilities of these new types of supports, and they indicate a number of theoretical and technical difficulties inherent in these bearings: they also express acknowledgement to German individuals and institutions, for their contribution to this investigation.