An approach to patents of prestressed concrete in 20th Century's arquitecture

Abstract

Around 1906, there was a discussion in the various publications on reinforced concrete about the problem of how to avoid the cracks on it, due to tension that occurred inside. First attempts to avert it failed since the tension applied to the steel was lost with the passage of time, as much for the hydraulic retraction of the concrete as for the use of not very high strength steels, and also because of the stress imposed were insufficient for targeted outcomes. In 1928, E. Freyssinet registered the first patent of prestressed concrete, and this originated a new constructive technology, which subsequently consolidated due to the rehabilitation of the foundations of the harbor of Le Havre (1933-1935). When making a previous prestressed of the oncrete reinforcement, forces created on-demand in the construction are placed compensating the effect of its own weight and of the permanents loads acting on the structure. With this consideration, the deformation that the system takes may become non-existing, reducing their stress state to a single longitudinal compression. The material with this technology becomes a tough mechanism with a system according to the structural features appropriate to concrete as material. Prestressed concrete is considered the major structural invention of the twentieth century and for several authors it proves to be a new material different than concrete, due to is own conception. According to José Antonio Fernández Ordoñez, "only the appearance of the arch is comparable in importance to the invention of Freyssinet". (Fernandez Ordoñez 1978). Using a technique of control of the force lines, the prestressed, they will develop a construction technology able to control the geometry of the shape (Anaya 2011). The present text attempts to establish whether individual prestressed concrete systems give rise to new types of construction, or whether they are systematically used in the same building typologies. Moreover, attempts to evaluate how, a control of the shape geometry has been achieved by utilizing this prestressed technique, which offers a project liberty ampler than previously maintained without the introduction of these stress.