TECHNOLOGY AND ASSESSMENT QUESTIONS ON REINFORCED CONCRETE BEAMS BUILT AT THE BEGINNING OF THE 20TH CENTURY

摘要

In European cities there are many R.C. buildings and constructions belonging to the early 20th century and, in most cases, these pieces of work so rich in historical, architectural and cultural significance urgently require maintenance and rehabilitation. It appears particularly important to study in detail the historical examples, and to recognize those characters and technical details of the solutions in order to keep the trace of the history and preserve the memory of the architectural and structural 20th century buildings.Reinforced concrete works, from the origins until the release of the first national technical standards, were built by applying patented systems (i.e. the Monnier's or the Hennebique's system) that were often the result of individual intuitions more than the product of coherent and established scientific and technical knowledge. This is one of the reasons why many of structures built in those years, and still surviving, could not be considered reliable with regard to the structural safety, as it is presently intended.In this scenario, the evaluation of R.C. beam shear capacity becomes crucial. In this paper, starting from the tests carried out in Stuttgart in the early 20th century, an analysis of shear capacity evaluation is presented. The aim is to show that the relations given for 'new beams' in the present codes cannot be used, without any modification, for the verification of 'historical beams'.