Influência da distribuição de cordoalhas engraxadas e plastificadas em projetos de lajes lisas protendidas

Abstract

The prestressed concrete is increasingly present in building structures due to the need to overcome large free spans with elements of reduced height. It is possible to met this need with the development of slabs without the use of beams. Civil engineers must seek an optimized structural system, where there is safety, good performance, and reduced cost. Thus, in a project using prestressed flat slabs, the tendon layout becomes a very important analysis item. This paper presents a study that analyzes the influence of tendon arrangement in the sizing of prestressed flat slabs, using the TQS software. Five prestressed flat slabs of the same geometry were dimensioned, but with different tendon layouts. Were studied two models of layouts with tendons concentrated in one direction and distributed in the opposite direction, a layout concentrated in two directions, another layout concentrated and distributed in two directions, and finally a layout distributed in two directions.The mixed tendon layout in the two directions presented lower displacements, evidencing the greater efficiency of this methodology. The layout of concentrated tendons in both directions also presented satisfactory efficiency. In parallel, the layout of distributed tendons in the two directions presented less efficiency, due to the accentuated displacements observed. Finally, was concluded that the layouts that present concentrated tendons in one direction and distributed in the other one showed similar results, with slight benefit when concentrating tendons in the direction of the largest span.