Impact of geometric slab parameters on the technical and economic efficiency of bubbledeck-type lightweight slabs

This article presents the results of a numerical study on the performance of various configurations of lightweight monolithic slabs of the BubbleDeck system, which use hollow plastic ball inserts to eliminate inefficient concrete from the slab's neutral zone. This approach makes it possible to significantly reduce the weight of the structure without compromising its load-bearing capacity. The study aimed to investigate the influence of geometric parameters of the slab—namely, the diameter of the plastic balls, slab height, and span—on the stress-strain behavior and techno-economic indicators of BubbleDeck-type slabs. To achieve this goal, nine design variants of lightweight slabs were modeled using plastic balls with diameters of 180 mm, 315 mm, and 500 mm, embedded in slabs sized 6×6 m, 7×7 m, and 8×8 m, respectively. The slab height varied depending on the ball diameter, ranging from 230 mm to 600 mm. All variants were modeled in the LIRA structural analysis software. The models accounted for actual loading conditions, including self-weight, service load, and snow load. The analysis showed that the use of plastic inserts can reduce the weight of the slab by up to 36% compared to conventional solid slabs. At the same time, deflections in all variants remained within the permissible limits. The best overall techno-economic performance was observed in the variant with 315 mm diameter balls and a 7×7 m span. In this case, the volume of concrete was reduced by 28%, and reinforcement consumption by 10–12%. The article also provides deformation diagrams and comparative tables of characteristics for all slab variants. Conclusions are drawn regarding the feasibility of using the BubbleDeck system in civil building design, especially in conditions with limited foundation load capacity or when material and logistics costs need to be minimized.