Static analysis of structural grillages made of steel reciprocal beams

The article concerns structural grillages made of short reciprocally supported beams. The history of reciprocal structures, as well as origin of the renewed interest in them have been characterised in the introductory part of the article. The main part presents the methodology of forming the grillages from short beams and the results of a static analysis. It has aimed at comparing the values of maximum bending moments and deflections of the grillages, due to the load acting perpendicular to the plane of the grillage. The first series of tests has included the grillages differing in the beams configuration, which supported the identical square slab. The second series has included the grillages of analogous configuration, but supporting the square slabs of different sizes. The results prove that the configuration of the beams does not have a significant impact on the values of bending moments and deflections, which are mainly determined by the overall dimensions of the grillage. The conclusion is that configuration of grillage based on reciprocity of beams let to replace rigid joints with articulated ones, which does not affect the load-bearing capacity and facilitates construction of the grillage.