Soluções para o dimensionamento de lajes nervuradas unidirecionais pré-moldadas treliçadas contínuas

Abstract

Since the precast slabs with lattice joists are widely used in Brazil, this work evaluate different ways to enable the consideration of continuous lattice slabs and rate the impact of this consideration on aspects such as slab depth, concrete consumption and steel consumption. Once that one of the main restraints while designing lattice joists slabs is the vertical displacement, this study also avaluates the influency and effectiveness of the continuity consideration on displacement reduction and on allowing lower slab heights when compared to simply supported slabs. This analysis was executed by designing a pavement composed by two equal and mirrored slab spans. Seven possibilities were designed – six of them with continuous slabs and one with simply supported slabs. Five solutions were designed by modeling the slab as independent T-shaped ribs using spreadsheets and two by grid analogy in TQS. From the obtained results, it is possible to conclude that the most effective solution in this analysis was the design that adopts the minimum effective depth possible to resist the negative moment in the middle support. This slab configuration showed a 46.6% smaller final displacement compared to the second smaller one and also the lowest steel consumption.