Projeto e análise de escadas autoportantes em concreto armado

Abstract

The present paper is about a survey of structural analysis methods of self-supporting stairs and about dimensioning self-supporting stairs in reinforced concrete. In the development of the research, topics related to the main subject were covered, historical aspects of stairs, meaning of stairs, belonging parts, usual measures, use of reinforced concrete, loading calculus, reinforcement dimensioning and the self-supporting stairs, its technical features and particularities that make it a special case of stairs. Researches of authors that developed dimensioning manual calculus were discussed. Papers of Brazão Farinha, Knijinik and Tavares about the method of Cusens and Kuang, and Guerrin and Lavaur were studied. When analyzing the three methods, it was pointed out that the Brazão Farinha method shows a second degree of hyperstability system, having two bending moments as unknowns, such as the Cusens and Kuang method, that has as hyperstatic unknowns the bending moment and the horizontal load at the middle of the stairs. Both analyzes consider the stairs as a fixed ended. In the Guerrin and Lavaur analysis, the calculus is very simple, different from the others, because it considers the stairs hinged on the supports and at the union with the stairs landing, which is rigid enough to allow the disconsideration the horizontal deformation. Owing to the distinct considerations, the stairs dimensioning was developed just by the Brazão Farinha and Cusens and Kuang methods. The chosen location for the stairs design was the block C of the Federal Technological University of Paraná – Campus Toledo. The project was carried out respecting the dimensions established by the Toledo Construction Code (Código de Obras de Toledo) and also the standard limits of Brazilian Association of Technical Standards (Associação Brasileira de Normas Técnicas). The results obtained by both methods were alike, although they showed some differences. Using the method of Brazão Farinha, the stairs obtained has more and thicker stirrups, but smaller bending reinforcement in the landing. Using the Cusens and Kuang method, the stairs obtained has more reinforcement in its landing, but with the torsion calculus leading to smaller stirrups. Finally, the details were exposed in plant and in section for both methods.